Chapter 20 The Perception of Space.

The Feeling of Crude Extensity.

IN the sensations of hearing, touch, sight, and pain we are accustomed to distinguish from among the other elements the element of voluminousness. We call the reverberations of a thunderstorm more voluminous than the squeaking² of a slate-pencil; the entrance into a warm bath gives our skin a more massive feeling than the prick³ of a pin; a little neuralgic pain, fine as a cobweb, in the face, seems less extensive than the heavy soreness of a boil or the vast discomfort⁶ of a colic or a lumbago; and a solitary⁷ star looks smaller than the noonday sky. In the sensation of dizziness or subjective⁸ motion, which recent investigation⁹ has proved to be connected with stimulation¹⁰ of the semi-circular canals of the ear, the spatial¹¹ character is very prominent. Whether the 'muscular sense' directly yields us knowledge of space is still a matter of litigation among psychologists. Whilst some go so far as to ascribe our entire cognition of extension to its exclusive aid, others deny to it all extensive quality whatever. Under these circumstances we shall do better to adjourn¹² its consideration; admitting, however, that it seems at first sight as if we felt something decidedly more voluminous when we contract our thigh¹⁵-muscles than when we twitch¹⁶ an eyelid¹⁷ or some small muscle in the face. It seems, moreover, as if this difference lay in the feeling of the thigh-muscles themselves.

In the sensations of smell and taste this element of varying vastness seems less prominent but not altogether absent. Some tastes and smells appear less extensive than complex flavors, like that of roast meat or plum pudding, on the one hand, or heavy odors like musk¹⁸ or tuberose, on the other. The epithet¹⁹ sharp given to the acid class would seem to show that to the popular mind there is something narrow and, as it were, streaky, in the impression they make, other flavors and odors being bigger and rounder. The sensations derived²¹ from the inward organs are also distinctly more or less voluminous. Repletion²⁴ and emptiness, suffocation²⁵, palpitation, headache, are examples of this, and certainly not less spatial is the consciousness we have of our general bodily condition in nausea²⁶, fever, heavy drowsiness²⁷, and fatigue²⁸. Our entire cubic content seems then sensibly manifest to us as such, and feels much larger than any local pulsation²⁹, pressure, or discomfort. Skin and retina are, however, the organs in which the space-element plays the most active part. Not only does the maximal vastness yielded by the retina surpass that yielded by any other organ, but the intricacy with which our attention can subdivide³¹ this vastness and perceive it to be composed of lesser³² portions simultaneously³³ coexisting along-side of each other is without a parallel elsewhere. 2 The ear gives a greater vastness than the skin, but is considerably³⁴ less able to subdivide it. 3

Now my first thesis is that this element, discernible in each and every sensation, though more developed in some than in others, is the original sensation of space, out of which all the exact knowledge about space that we afterwards come to have is woven by processes of discrimination, association, and selection. 'Extensity,' as Mr. James Ward²³ calls it 4 on this view, becomes an element in each sensation just as intensity³⁶ is. The latter every one will admit to be a distinguishable though not separable ingredient of the sensible quality. In like manner extensity, being an entirely³⁷ peculiar³⁸ kind of feeling indescribable except in terms of itself, and inseparable in actual experience from some sensational³⁹ quality which it must accompany, can itself receive no other name than that of sensational element.

It must now be noted⁴⁰ that the vastness hitherto spoken of is as great in one direction as in another. Its dimensions are so vague that in it there is no question as yet of surface as opposed to depth; 'volume' being the best short name for the sensation in question. Sensations of different orders are roughly comparable, inter⁴¹ se, with respect to their volumes. This shows that the spatial quality in each is identical wherever found, for different qualitative⁴² elements, e.g. warmth and odor, are incommensurate. Persons born blind are reported surprised at the largeness with which objects appear to them when their sight is restored. Franz says of his patient cured of cataract⁴³: "He saw everything much larger than he had supposed from the idea obtained by his sense of touch. Moving, and especially living, objects appeared very large." 5 Loud sounds have a certain enormousness of feeling. It is impossible to conceive of the explosion of a cannon⁴⁵ as fining a small space. In general, sounds seem to occupy all the room between us and their source; and in the case of certain ones, the cricket's song, the whistling of the wind, the roaring of the surf, or a distant railway train, to have no definite starting point.

In the sphere of vision we have facts of the same order. 'Glowing' bodies, as Hering says, give us a perception "which seems roomy (raumhaft) in comparison with that of strictly⁴⁷ surface color. A glowing iron looks luminous¹ through and through, and so does a flame." 6 A luminous fog, a band of sunshine, affect us in the same way. As Hering urges:

" We must distinguish roomy from superficial, as well as distinctly from indistinctly bounded, sensations. The dark which with closed eyes one sees before one is, for example, a roomy sensation. We do not see a black surface like a wall in front of us, but a space fined with darkness, and even when we succeed in seeing this darkness as terminated by a black wall there still remains⁴⁸ in front of this wall the dark space. The same thing happens when we find ourselves with open eyes in an absolutely dark room. This sensation of darkness is also vaguely⁴⁹ bounded. An example of a distinctly bounded roomy sensation is that of a clear and colored fluid seen in a glass; the yellow of the wine is seen not, only on the bounding surface of the glass; the yellow sensation fins⁵⁰ the whole interior of the glass. By day the so-called empty space between us and objects seen appears very different from what it is by night. The increasing darkness settles not only upon the things but also between us and the things. so as at last to cover them completely and fin⁵ the space alone. If I look into a dark box I find it fined with darkness, and this is seen not merely as the dark-colored sides or walls of the box. A shady corner in an otherwise well-lighted room is full of a darkness which is not only on the walls and floor but between them in the space they include. Every sensation is there where I experience it, and if I have it at once at every point of a certain roomy space, it is then a voluminous sensation. A cube of transparent⁵² green glass gives us a spatial sensation; an opaque⁵³ cube painted green, on the contrary, only sensations of surface." 7

There are certain quasi-motor sensations in the head when we change the direction of the attention, which equally seem to involve three dimensions. If with closed eyes we think of the top of the house and then of the cellar, of the distance in front of us and then of that behind us, of space far to the right and then far to the left, we have something far stronger than an idea, -- an actual feeling, namely, as if something in the head moved into another direction. Fechner was, I believe, the first to publish any remarks on these feelings. He writes as follows:

"When we transfer the attention from objects of one sense to those of another we have an indescribable feeling (though at the same time one perfectly⁵⁴ determinate and reproducible at pleasure) of altered direction, or differently localized tension (Spannung). We feel a strain forward in the eyes, one directed sideways in the ears, increasing with the degree of our attention, and changing according as we look at an object carefully, or listen to something attentively⁵⁶; wherefore we speak of straining the attention. The difference is most plainly felt when the attention vibrates rapidly between eye and ear. This feeling localizes itself with most decided¹³ difference in regard to the various sense-organs according as we wish to discriminate⁵⁸ a thing delicately by touch, taste, or smell.

"But now I have, when I try to vividly⁵⁹ recall a picture of memory or fancy, a feeling perfectly analogous⁶⁰ to that which I experience when I seek to grasp a thing keenly by eye or ear; and this analogous feeling is very differently localized. While in sharpest possible attention to real objects (as well as to after-images) the strain is plainly forwards, and, when the attention changes from one sense to another, only alters its direction between the sense-organs, leaving the rest of the head free from strain, the case is different in memory or fancy; for here the feeling withdraws entirely from the external sense-organs, and seems rather to take refuge in that part of the head which the brain fins. If I wish, for example, to recall a place or person, it will arise before me with vividness, not according as I strain my attention forwards, but rather in proportion as I, so to speak, retract⁶¹ it backwards⁶²." 8

It appears probable that the feelings which Fechner describes are in part constituted by imaginary semi-circular canal sensations. 9 These undoubtedly⁶⁴ convey the most delicate perception of change in direction; and when, as here, the changes are not perceived as taking place in the external world, they occupy a vague internal space located within the head. 10

In the skin itself there is a vague form of projection⁶⁵ into the third dimension to which Hering has called attention.

" Heat is not felt only against the cutaneous surface, but when communicated through the air may appear extending more or less out from the surface into the third dimension of surrounding space . . . We can determine in the dark the place of a radiant body by moving the hand to and fro, and attending to the fluctuation⁶⁶ of our feeling of warmth. The feeling itself, however; is not projected fully⁵⁵ into the spot at which we localize the hot body, but always remains in the neighborhood of the hand."

The interior of one's mouth-cavity feels larger when explored by the tongue than when looked at. The crater⁶⁷ of a, newly-extracted tooth, and the movements of a loose tooth in its socket⁶⁸, feel quite monstrous⁶⁹. A midge buzzing against the drum of the ear will often seem as big as a butterfly. The spatial sensibility of the tympanic membrane⁷⁰ has hitherto been very little studied, though the subject will well repay much trouble. If we approach it by introducing into the outer ear some small object like the tip of a rolled-up tissue-paper lamplighter, we are surprised at the large radiating sensation which its presence gives us, end at the sense of clearness and openness which comes when it is removed. It is immaterial to inquire whether the far-reaching sensation here be due to actual irradiation upon distant nerves or not. We are considering now, not the objective causes of the spatial feeling, but its subjective varieties, and the experiment shows that the same object gives more of it to the inner than to the outer cuticle⁷¹ of the ear. The pressure of the air in the tympanic cavity upon the membrane gives an astonishingly large sensation. We increase the pressure by holding our nostrils⁷² and closing our mouth and forcing air through our Eustachian tubes by an expiratory effort; and we can diminish it by either inspiring or swallowing under the same conditions of closed mouth and nose. In either case me get a large round tridimensional sensation inside of the head, which seems as if it must come from the affection of an organ much larger than the tympanic membrane, whose surface hardly exceeds that of one's little-finger-nail.

The tympanic membrane is furthermore able to render sensible differences in the pressure of the external atmosphere, too slight to be, felt either as noise or in this more violent way. If the reader will sit with closed eyes and let a friend approximate some solid object, like a large book, noiselessly to his face, he min immediately become aware of the object's presence and position -- likewise of its departure. A friend of the writer, making the experiment for the first time, discriminated⁷⁴ unhesitatingly between the three degrees of solidity of a board, a lattice-frame, and a sieve⁷⁵, held close to his ear. Now as this sensation is never used by ordinary persons as a means of perception, we may fairly assume that its felt quality, in those whose attention is called to it for the first time, belongs to it quâ sensation, and owes nothing to educational suggestions. But this felt quality is most distinctly and unmistakably one of vague spatial vastness in three dimensions -- quite as much so as is the felt quality of the retinal sensation when we lie on our back and fin the entire held of vision with the empty blue sky. When an object is brought near the ear we immediately feel shut in, contracted; when the object is removed, we suddenly feel as if a transparency, clearness, openness, had been made outside of us. And the feeling will, by any one who will take the pains to observe it, be acknowledged to involve the third dimension in a vague, unmeasured state.

The reader will have noticed, in this enumeration⁷⁶ of facts, that voluminousness of the feeling seems to bear very little relation to the size of the organ that yields it. The ear and eye are comparatively minute organs, yet they give us feelings of great volume. The same lack of exact proportion between size of feeling and size of organ affected⁷⁷ obtains within the limits of particular sensory⁷⁸ organs. An object appears smaller on the lateral⁷⁹ portions of the retina than it does on the fovea, as may be easily verified by holding the two forefingers⁸¹ parallel and a couple of inches apart, and transferring the gaze of one eye from one to the other. Then the finger not directly looked at will appear to shrink, and this whatever be the direction of the fingers. On the tongue a crumb⁸², or the calibre of a small tube, appears larger than between the fingers. If two points kept equidistant (blunted compass- or scissors-points, for example) be drawn⁸³ across the skin so as really to describe a pair of parallel lines, the lines will appear farther apart in some spots than in others. If, for example, me draw them horizontally across the face, so that the mouth falls between them, the person experimented upon will feel as if they began to diverge⁸⁴ near the mouth and to include it in a well- marked ellipse. In like manner, if we keep the compass-points one or two centimetres apart, and draw them down the forearm over the wrist and palm, finally drawing one along one finger, the other along its neighbor, the appearance will be that of a single line, soon. breaking into two, which become more widely separated below the wrist, to contract again in the palm, and finally diverge rapidly again towards the finger-tips. The dotted lines in Figs⁸⁶. 51 and 52 represent the true path of the compass-points; the full lines their apparent path. The same length of skin, moreover, will convey a more extensive sensation according to the manlier⁸⁷ of stimulation. If the edge of a card be pressed against the skis, the distance between its extremities⁸⁸ will seem shorter than that between two compass-tips touching⁸⁹ the same terminal points. 12

In the eye, intensity of nerve-stimulation seems to increase

the volume of the feeling as well as its brilliancy. If we raise and lower the gas alternately, the whole room and all the objects in it seem alternately to enlarge and contract. If we cover half a page of small print with a gray glass, the print seen through the glass appears decidedly smaller than that seen outside of it, and the darker the glass the greater the difference. When a circumscribed⁹⁰ opacity⁹¹ in front of the retina, keeps off part of the light from the portion which it covers, objects projected on that portion may seem but half as large as when their image falls outside of it.  The inverse⁹² effect seems produced by certain drugs and anæsthetics. Morphine, atropine, daturine, and cold blunt the sensibility of the skin, so that distances upon it seem less. Haschish produces strange perversions⁹³ of the general sensibility. Under its influence one's body may seem either enormously enlarged or strangely contracted. Sometimes a single member will alter its proportion to the rest; or one's back, for instance, will appear entirely absent, as if one mere⁵¹ hollow behind. Objects comparatively near will recede⁹⁴ to a vast distance, a short street assume to the eye an immeasurable perspective. Ether and chloroform occasionally produce not wholly dissimilar results. Panum, the German physiologist⁹⁵, relates that when, as a, boy, he was etherized for neuralgia, the objects in the room grew extremely small and distant, before his held of vision dark-hued over and the roaring in his ears began. He also mentions that a friend of his in church, struggling in vain to keep awake, saw the preacher grow smaller and smaller and more and more distant. I myself on one occasion observed the same recession of objects during the beginning of chloroformization. In various cerebral⁹⁶ diseases we find analogous disturbances⁹⁸.
Can we assign the physiological⁹⁹ conditions which make the elementary sensible largeness of one sensation vary so much from that of another? Only imperfectly. One factor in the result undoubtedly is the number of nerve-terminations simultaneously excited by the outward agent that awakens¹⁰² the sensation. When many skin-nerves are warmed, or much retinal surface illuminated¹⁰³, our feeling is larger than when a lesser nervous surface is excited. The single sensation yielded by two compass-points, although it seems simple, is yet felt to be much bigger and blunter than that yielded by one. The touch of a single point may always be recognized by its quality of sharpness. This page looks much smaller to the reader if he closes one eye than if both eyes are open. So does the moon, which latter fact shows that the phenomenon has nothing to do with parallax. The celebrated¹⁰⁴ boy couched for the cataract by Cheselden thought, after his first eye was operated, "all things he saw extremely large," but being couched of his second eye, said "that objects at first appeared large to this eye, but not so large as they did at first to the other; and looking upon the same object with both eyes, he thought it looked about twice as large as with the first couched eye only, but not double, that we can anyways discover."

The greater extensiveness that the feeling of certain parts of the same surface has over other parts, and that one order of surface has over another (retina over skin, for example), may also to a certain extent be explained by the operation of the same factor. It is an anatomical fact that the most spatially¹⁰⁵ sensitive surfaces (retina, tongue, fingertips, etc.) are supplied by nerve-trunks of unusual thickness, which must supply to every unit of surface-area an unusually large number of terminal fibres. But the variations of felt extension obey probably only a very rough law of numerical proportion to the number of fibres, A sound is not twice as voluminous to two ears as to one; and the above-cited variations of feeling, when the same surface is excited under different conditions, show that the feeling is a resultant of several factors of which the anatomical one is only the principal. Many ingenious hypotheses have been brought forward to assign the co-operating factors where different conditions give conflicting amounts of felt space, Later we shall analyze¹⁰⁶ some of these cases in detail, but it must be confessed here in advance that many of them resist analysis altogether. 14
The Perception of Spatial Order.

So far, all we have established or sought to establish is the existence of the vague form or quale of spatiality¹⁰⁷ as an inseparable element bound up with the other peculiarities¹⁰⁸ of each and every one of our sensations. The numerous examples we have adduced of the variations of this extensive element have only been meant to make clear its strictly sensational character. In very few of them will the reader have been able to explain the variation by an added intellectual element, such as the suggestion of a recollected¹⁰⁹ experience. In almost all it has seemed to be the immediate⁷³ psychic¹¹⁰ effect of a peculiar sort of nerve-process excited; and all the nerve-processes in question agree in yielding what space they do yield, to the mind, in the shape of a simple total vastness, in which, primitively¹¹¹ at least, no order of parts or of subdivisions reigns¹¹³.

Let no one be surprised at this notion of a space without order. There may be a space without order just as there may be an order without space. 15 And the primitive¹¹² perceptions of space are certainly of an unordered kind. The order which the spaces first perceived potentially include must, before being distinctly apprehended¹¹⁵ by the mind, be woven into those spaces by a rather complicated set of intellectual acts. The primordial¹¹⁷ largenesses which the sensations yield must be measured and subdivided¹¹⁸ by consciousness, and added together, before they can form by their synthesis what we know as the real Space of the objective world. In these operations, imagination, association, attention, and selection play a decisive part; and although they nowhere add any new material to the space-data of sense, they so shuffle¹¹⁹ and manipulate these data and hide present ones behind imagined ones that it is no wonder if some authors have gone so far as to think that the sense-data have no spatial worth at all, and that the intellect, since it makes the subdivisions, also gives the spatial quality to them out of resources of its own.

As for ourselves, having found that all our sensations (however as yet unconnected and undiscriminated) are of extensive objects, our next problem is: How do we ARRANGE these at first chaotically¹²¹ given spaces into the one regular and orderly world of space which we now know?

To begin with, there is no reason to suppose that the several sense-spaces of which a sentient¹²² creature may become conscious, each fined with its own peculiar content, should tend, simply because they are many, to enter into any definite spatial intercourse¹²³ with each other, or lie in any particular order of positions. Even in ourselves we can recognize this. Different feelings may coexist in us without assuming any particular spatial order. The sound of the brook¹²⁴ near which I write, the odor of the cedars¹²⁵, the comfort with which my breakfast has fined me, and my interest in this paragraph, all lie distinct in my consciousness, but in no sense outside or alongside of each other. Their spaces are interfused and at most fin the same vaguely objective world. Even where the qualities are far less disparate, we may have something similar. If me take our subjective and corporeal¹²⁶ sensations alone, there are moments when, as we lie or sit motionless, we find it very difficult to feel distinctly the length of our back or the direction of our feet from our shoulders. By a strong effort we can succeed in dispersing¹²⁷ our attention impartially¹²⁸ over our whole person, and then we feel the real shape of our body in a sort of unitary way. But in general a few parts are strongly emphasized to consciousness and the rest sink out of notice; and it is then remarkable¹³⁰ how vague and ambiguous our perception of their relative order of location is. Obviously, the orderly arrangement of a multitude of sense-spaces in consciousness, something more than their mere separate existence is required. What is this further condition?

If a number of sensible extents are to be perceived alongside of each other and in definite order they must appear as parts in a vaster sensible extent which can enter the mind simply and at once. I think it will be seen that the difficulty of estimating correctly the form of one's body by pure feeling arises from the fact that it is very hard to feel its totality as a unit at all. The trouble is similar to that of thinking forwards and backwards simultaneously. When conscious of our head we tend to grow unconscious of our feet, and there enters thus an element of time-succession into our perception of ourselves which transforms the latter from an act of intuition to one of construction. This element of constructiveness¹³¹ is present in a still higher degree, and carries with it the same consequences, when we deal with objective spaces too great to be grasped by a single look. The relative positions of the shops in a town, separated by many tortuous¹³² streets, have to be thus constructed from data apprehended in succession, and the result is a greater or less degree of vagueness.

That a sensation be discriminated as part from out of a, larger enveloping¹³⁴ space is then the condition sine quâ non of its being apprehended in a definite spatial order. The problem of ordering our feelings in space is then, in the first instance, a problem of discrimination, but not of discrimination pure and simple; for then not only coexistent sights but consistent sounds would necessarily assume web order, which they notoriously do not. Whatever is discriminated will appear as a small space within a larger space, it is true, but this is but the very rudiment¹³⁵ of order. For the location of it within that space to become precise, other conditions still must supervene; and the best way to study what they are will be to pause for a little and analyze what the expression 'spatial order' means.

Spatial order is an abstract term. The concrete perceptions which it covers are figures, directions, positions, magnitudes, and distances. To single out any one of these things from a total vastness is partially¹²⁹ to introduce order into the vastness. To subdivide the vastness into a multitude of these things is to apprehend¹¹⁶ it in a completely orderly way. Now what are these things severally? To begin with, no one can for an instant hesitate to say that some of them are qualities of sensation, just as the total vastness is in which they lie. Take figure: a square, a circle, and a triangle appear in the best instance to the eye simply as three different kinds elf impressions, each so peculiar that we should recognize it if it were to return. When Nunnery's patient had his cataracts¹³⁶ removed, and a cube and a sphere were presented to his notice, he could at once perceive a difference in their shapes; and though he could not say which was the cube and which the sphere, he saw they were not of the same figure. So of lines: if we can notice lines at all in our field of vision, it is inconceivable that a vertical¹³⁷ one should not affect us differently from an horizontal one, and should not be recognized as affecting us similarly when presented again, although we might not yet know the name 'vertical,' or any of its connotations, beyond this peculiar affection of our sensibility. So of angles: an obtuse¹³⁸ one affects our feeling immediately in a different way from an acute one. Distance-apart, too, is a simple sensation -- the sensation of a line joining the two distant points: lengthen¹³⁹ the line, you alter the feeling and with it the distance felt.
Space-relations.

But with distance and direction we pass to the category of space-relations, and are immediately confronted by an opinion which makes of all relations something tote coelo different from all facts of feeling or imagination whatsoever¹⁴⁰. A relation, for the Platonizing school in psychology¹⁴¹, is an energy of pure thought, and, as such, is quite incommensurable with the data of sensibility between which it may be perceived to obtain. We may consequently imagine a disciple¹⁴² of this school to say to us at this point: "Suppose you have made a, separate specific sensation of each line and each angle, what boots it? You have still the order of directions and of distances to account for; you have still the relative magnitudes of all these felt figures to state; you have their respective positions to define before you can be said to have brought order into your space. And not one of these determinations can be effected except through an act of relating thought, so that your attempt to give an account of space in terms of pure sensibility breaks down almost at the very outset. Position, for example, can never be a sensation, for it has nothing intrinsic about it; it can only obtain between a spot, line, or other figure and extraneous¹⁴³ coordinates¹⁴⁴, and can never be an element of the sensible datum¹⁴⁵, the line or the spot, in itself. Let us then confess that Thought alone can unlock the riddle¹⁴⁶ of space, and that Thought is an adorable but unfathomable mystery. Such a method of dealing¹⁴⁷ with the problem has the merit of shortness. Let us, however, be in no such hurry, but see whether we cannot get a little deeper by patiently considering what these space-relations are.

'Relation' is a very slippery word. It has so many different concrete meanings that the use of it as an abstract universal may easily introduce bewilderment into our thought. We must therefore be careful to avoid ambiguity¹⁴⁸ by making sure, wherever we have to employ it, what its precise meaning is in that particular sphere of application. At present we have to do with space-relations, and no others. Most 'relations' are feelings of an entirely different order from the terms they relate. The relation of similarity, e.g., may equally obtain between jasmine and tuberose, or between Mr. Browning's verses and Mr. Story's; it is itself neither odorous nor poetical¹⁴⁹, and those may well be pardoned who have denied to it all sensational content whatever. But just as, in the field of quantity, the relation between two numbers is another number, so in the field of space the relations are facts of the same order with the facts they relate. If these latter be catches in the circle of vision, the former are certain other patches between them. When we speak of the relation of direction of two points toward each other, we mean simply the sensation of the line that joins the two points together. The line is the relation; feel it and you feel the relation, see it and you see the relation; nor call you in any conceivable way think the latter except by imagining the former (however vaguely), or describe or indicate the one except by pointing to the other. And the moment you have imagined the line, the relation stands before you in all its completeness, with nothing further to be done. Just so the relation of direction between two lines is identical with the peculiar sensation of shape of the space enclosed between them. This is commonly called an angular relation.

If these relations are sensations, no less so are the relations of position. The relation of position between the top and bottom points of a vertical line is that line, and nothing else. The relations of position between a point and a horizontal line below it are potentially numerous. There is one more important than the rest, called its distance. This is the sensation, ideal or actual, of a perpendicular¹⁵⁰ drawn from the point to the line. 16 Two lines, one from each extremity¹⁵¹ of the horizontal to the point, give us a peculiar sensation of triangularity¹⁵³. This feeling may be said to constitute the locus¹⁵⁴ of all the relations of position of the elements in question. Rightness and leftness, upness and downness, are again pure sensations differing specifically from each other, and generically¹⁵⁵ from everything else. Like all sensations, they can only be indicated, not described. If we take a cube and label one side top, another bottom, a third front, and a fourth back; there remains no form of words by which we can describe to another person which of the remaining sides is right and which left. We can only point and say here is right and there is left, just as we should say this is red and that blue. Of two points seen beside each other at all, one is always affected by one of these feelings, and the other by the opposite; the same is true of the extremities of any line. 17

Thus it appears indubitable that all space-relations except those of magnitude are nothing more or less than pure sensational objects. But magnitude appears to outstep this narrow sphere. We hare relations of muchness and littleness between times, numbers, intensities¹⁵⁷, and qualities, as well as spaces. It is impossible, then, that such relations should form a particular kind of simply spatial feeling. This we must admit: the relation of quantity is generic¹⁵⁶ and occurs in many categories of consciousness, whilst the other relations we have considered are specific and occur in space alone. When our attention passes from a shorter line to a longer, from a smaller spot to a larger, from a, feebler light to a stronger, from a paler blue to a richer, from a march tune¹⁵⁸ to a galop, the transition is accompanied in the synthetic¹⁶⁰ field of consciousness by a peculiar feeling of difference which is what we call the sensation of more, -- more length, more expense, more light, more blue, more motion. This transitional sensation of more must Be identical with itself under all these different accompaniments, or me should not give it the same name in every case. We get it when we pass from a short vertical line to a long horizontal one, from a small square to a large circle, as well as when we pass between those figures whose shapes are congruous. But when the shapes are congruous our consciousness of the relation is a good deal more distinct, and it is most distinct of all when, in the exercise of our analytic¹⁶¹ attention, we notice, first, a part, and then the whole, of a single line or shape. Then the more of the whole actually sticks out, as a separate piece of space, and is so envisaged¹⁶². The same exact sensation of it is given when we are able to superpose one line or figure on another. This indispensable condition of exact measurement of the more has led some to think that the feeling itself arose in every case from original experiences of superposition. This is probably not an absolutely true opinion, but for our present purpose that is immaterial. So far as the subdivisions of a, sense-space are to be measured exactly against each other, objective forms occupying one subdivision must directly or indirectly¹⁶³ be superposed upon the other, and the mind must get the immediate feeling of an outstanding plus. And even where we only feel one subdivision to be vaguely larger or less, the mind must pass rapidly between it and the other subdivision, and receive the immediate sensible shock of the more.

We seem thus to have accounted for all space-relations, and made them clear to our understanding. They are nothing but sensations of particular lines, particular angles, particular forms of transition, or (in the case of a distinct more) of particular outstanding portions of space after two figures have been superposed. These relation-sensations may actually be produced as such, as when a geometer draws new lines across a figure with his pencil to demonstrate the relations of its parts, or they may be ideal representations of lines, not really drawn. But in either case their entrance into the mind is equivalent to a more detailed¹⁶⁵ subdivision, cognizance, and measurement of the space considered. The bringing of sub-divisions to consciousness constitutes, then, the entire process by which we pass from our first vague feeling of a total vastness to a cognition of the vastness in detail. The more numerous the subdivisions are, the more elaborate and perfect the cognition becomes. But inasmuch as all the sub-divisions are themselves sensations, and even the feeling of 'more' or 'less' is, where not itself a figure, at least a sensation of transition between two sensations of figure, it follows, for aught we can as yet see to the contrary, that all spatial knowledge is sensational at bottom, and that, as the sensations lie together in the unity¹⁶⁶ of consciousness, no new material element whatever comes to them from a supra-sensible source. 18

The bringing of subdivisions to consciousness! This, then, is our next topic. They may be brought to consciousness under three aspects in respect of their locality, in respect of their size, in respect of their shape.
The Meaning of Localization.

Confining ourselves to the problem of locality for the present, let us begin with the simple case of a sensitive surface, only two points of which receive stimulation from without. How, first, are these two points felt as alongside of each other with an interval¹⁶⁷ of space between them? We must be conscious of two things for this: of the duality of the excited points, and of the extensiveness of the unexcited interval. The duality alone, although a necessary, is not a sufficient condition of the spatial separation. We may, for instance, discern two sounds in the same place, sweet and sour in the same lemonade, warm and cold, round and pointed¹⁶⁸ contact in the same place on the skin, etc. 19 In all discrimination the recognition of the duality of two feelings by the mind is the easier the more strongly the feelings are contrasted in quality. If our two excited points awaken¹⁰¹ identical qualities of sensation, they must, perforce, appear to the mind as one; and, not distinguished¹⁶⁹ at all, they are, a fortiori, not localized apart. Spots four centimetres distant on the back have no qualitative contrast at all, and fuse into a single sensation. Points less than three thousandths of a millimetre apart awaken on the retina sensations so contrasted that we apprehend them immediately as two. Now these unlikenesses which arise so slowly when we pass from one point to another in the back, so much faster on the tongue and finger-tips, but with such inconceivable rapidity on the retina, what are they? Can we discover anything about their intrinsic nature?

The most natural and immediate answer to make is that they are unlikeness of place pure and simple. In the words of the German physiologist 20 to who psychophysics owes much:

" The sensations are from the outset (von vornherein) localized. . . . Every sensation as such is from the very beginning affected with the spatial quality, so that this quality is nothing like an external attribute coming to the sensation from a higher faculty¹⁷¹, but must be regarded as something immanently residing in the sensation itself."

And yet the moment we reflect on this answer an insuperable logical difficulty seems to present itself. No single quail¹⁷² of sensation can, by itself, amount to a consciousness of position. Suppose no feeling but that of a single point ever to be awakened¹⁷³. Could that possibly be the feeling of any special whereness or thereness? Certainly not. Only when a second point is felt to arise can the first one acquire a determination of up, down, right or left, and these determinations are all relative to that second point. Each point, so far as it is placed, is then only by virtue¹⁷⁴ of what it is not, namely, by virtue of another point. This is as much as to say that position has nothing intrinsic about it; and that, although a feeling of absolute bigness may, a feeling of place cannot, possibly form an immanent element in any single isolated¹⁷⁵ sensation. The very writer we have quoted has given heed¹⁷⁶ to this objection, for he continues (p. 335) by saying that the sensations thus originally localized "are only so in themselves, but not in the representation of consciousness, which is not yet present . . . . They are, in the first instance, devoid¹⁷⁷ of all mutual¹⁷⁸ relations with each other." But such a localization of the sensation 'in itself' would seem to mean nothing more than the susceptibility or potentiality of being distinctly localized when the time came and other conditions became fulfilled. Can we now discover anything about such susceptibility in itself before it has borne its ulterior fruits in the developed consciousness?
'Local Signs.'

To begin with, every sensation of the skin and every visceral sensation seems to derive²² from its topographic seat a peculiar shade of feeling, which it would not have in another place. And this feeling per se seems quite another thing from the perception of the place. Says Wundt: 21

"If with the finger we touch first the cheek and then the palm, exerting each time precisely¹⁷⁹ the same pressure, the sensation shows notwithstanding a distinctly marked difference in the two cases. Similarly, when we compare the palm with the back of the hand, the nape of the neck with its anterior¹⁸⁰ surface, the breast with the back; in short, any two distant parts of the skin with each other. and moreover, we easily remark, by attentively observing, that spots even tolerably close together differ in respect of the quality of their feeling. If we pass from one point of our cutaneous surface to another, we find a perfectly gradual and continuous alteration¹⁸¹ in our feeling, notwithstanding the objective nature of the contact has remained the same. Even the sensations of corresponding points on opposite sides of the body, though similar, are not identical. If, for instance, we touch first the back of one hand and then of the other, we remark a qualitative unlikeness of sensation. It must not be thought that such differences are mere matters of imagination, and that we take the sensations to be different because we represent each of them to ourselves as occupying a different place. With sufficient sharpening of the attention, we may, confining ourselves to the quality of the feelings alone, entirely abstract from their locality, and yet notice the differences quite as markedly."

Whether these local contrasts shade into each other with absolutely continuous gradations, we cannot say. But we know (continues Wundt) that

"they change, when we pass from one point of the skin to its neighbor, with very different degrees of rapidity. On delicately-feeling parts, used principally for touching, such as the finger-tips, the difference of sensation between two closely approximate points is already strongly pronounced; whilst in parts of lesser delicacy¹⁸², as the arm, the back, the legs, the disparities of sensation are observable only between distant spots."

The internal organs, too, have their specific qualia of sensation. An inflammation of the kidney is different from one of the liver; pains in joints¹⁸⁴ and muscular insertions are distinguished. Pain in the dental nerves is wholly unlike the pain of a burn. But very important and curious similarities prevail throughout these differences. Internal pains, whose seat we cannot see, and have no means of knowing unless the character of the pain itself reveal it, are felt where they belong. Diseases of the stomach, kidney, liver, rectum, prostate, etc., of the bones, of the brain and its membranes¹⁸⁵, are referred to their proper position. Nerve-pains describe the length of the nerve. Such localizations as those of vertical, frontal, or occipital headache of intracranial origin force us to conclude that parts which are neighbors, whether inner or outer, may possess by mere virtue of that fact a common peculiarity¹⁸⁷ of feeling, a respect in which their sensations agree, and which serves as a token of their proximity¹⁸⁸. These local colorings are, moreover, so strong that we cognize them as the same, throughout all contrasts of sensible quality in the accompanying perception. Cold and heat are wide as the poles asunder¹⁸⁹; yet if both fall on the cheek, there mixes with them something that makes them in that respect identical; just as, contrariwise, despite the identity of cold with itself wherever found, when we get it first on the palm and then on the cheek, some difference comes, which keeps the two experiences for ever asunder." 22

And now let us revert¹⁹² to the query¹⁹³ propounded¹⁹⁴ a, moment since: Can these differences of mere quality in feeling, varying according to locality yet having each sensibly and intrinsically and by itself nothing to do with position, constitute the 'susceptibilities' we mentioned, the conditions of being perceived in position, of the localities to which they belong? The numbers on a row of houses, the initial letters of a set of words, have no intrinsic kinship with points of space, and yet they are the conditions of our knowledge of where any house is in the row, or any word in the dictionary. Can the modifications¹⁹⁵ of feeling in question be tags or labels of this kind which in no wise originally reveal the position of the spot to which they are attached, but guide us to it by what Berkeley would call a 'customary tie'? Many authors have unhesitatingly replied in the affirmative; Lotze, who in his Medzinische Psychologie 23 first described the sensations in this way, designating them, thus conceived, as local-signs. This term has obtained wide currency in Germany, and in speaking of the 'LOCAL-SIGN THEORY' hereafter, I shall always mean the theory which denies that there can be in a sensation any element of actual locality, of inherent spatial order, any tone as it were which cries to us immediately and without further ado, 'I am here,' or 'I am there.' If, as may well be the case, we by this time and ourselves tempted¹⁹⁷ to accept the Local-sign theory in a general way, we have to clear up several farther matters. If a sign is to lead us to the thing it means, we must have some other source of knowledge of that thing. Either the thing has been given in a previous experience of which the sign also formed part-they are associated; or it is what Reid calls a 'natural' sign, that is, a feeling which, the first time it enters the mind, evokes¹⁹⁹ from the native powers thereof a cognition of the thing that hitherto had lain dormant²⁰⁰. In both cases, however, the sign is one thing, and the thing another. In the instance that now concerns us, the sign is a quality of feeling and the thing is a position. Now we have seen that the position of a point is not only revealed, but created, by the existence of other points to which it stands in determinate relations. If the sign can by any machinery²⁰¹ which it sets in motion evoke¹⁹⁸ consciousness either of the other points, or of the relations, or of both, it would seem to fulfil its function, and reveal to us the position we seek.

But such a machinery is already familiar to us. It is neither more nor less than the law of habit in the nervous system. When any point of the sensitive surface has been frequently excited simultaneously with, or immediately before or after, other points, and afterwards comes to be excited alone, there will be A tendency for its perceptive²⁰² nerve-centre to irradiate into the nerve-centres of the other points. Subjectively²⁰³ considered, this is the same as if we said that the peculiar feeling of the first point SUGGESTS the feeling of the entire region with whose stimulation its own excitement has been habitually²⁰⁴ ASSOCIATED.

Take the case of the stomach. When the epigastrium is heavily pressed, when certain muscles contract, etc., the stomach is squeezed, and its peculiar local sign awakes in consciousness simultaneously with the local signs of the other squeezed parts. There is also a sensation of total vastness aroused by the combined irritation²⁰⁶, and somewhere in this the stomach-feeling seems to lie. Suppose that later a pain arises in the stomach from some non-mechanical cause. It will be tinged²⁰⁷ by the gastric²⁰⁸ local sign, and the nerve-centre supporting this latter feeling will excite the centre supporting the dermal²⁰⁹ and muscular feelings habitually associated with it when the excitement was mechanical. From the combination the same peculiar vastness will again arise. In a word, 'something' in the stomach-sensation 'reminds' us of a total space, of which the diaphragmatic and epigastric sensations also form a part, or, to express it more briefly²¹⁰ still, suggests the neighborhood of these latter organs. 24

Revert to the case of two excited points on a surface with an unexcited space between them. The general result of previous experience has been that when either point was impressed by an outward object, the same object also touched the immediately neighboring parts. Each point, together with its local sign, is thus associated with a circle of surrounding points, the association fading in strength as the circle grows larger. Each will revive its own circle; but when both are excited together, the strongest revival²¹¹ will be that due to the combined irradiation. Now the tract¹⁴ joining the two excited points is the only part common to the two circles. And the feelings of this whole tract will therefore awaken with considerable vividness in the imagination when its extremities are touched by an outward irritant. The mind receives with the impression of the two distinct points the vague idea of a line. The twoness of the points comes from the contrast of their local signs: the line comes from the associations into which experience has wrought²¹² these latter. If no ideal line arises me have duality without sense of interval; if the line be excited actually rather than ideally, we have the interval given with its ends, in the form of a single extended object felt. E. H. Weber, in the famous article in which he laid the foundations of all our accurate knowledge of these subjects, laid it down as the logical requisite²¹³ for the perception of two separated points, that the mind should, along with its consciousness of them, become aware of an unexcited interval as such I have only tried to show how the known laws of experience may cause this requisite to be fulfilled. Of course, if the local signs of the entire region offer but little qualitative contrast inter se, the line suggested will be but dimly defined or discriminated in length or direction from other possible lines in its neighborhood. This is what happens in the back, where consciousness can sunder¹⁹⁰ two spots, whilst only vaguely apprehending²¹⁴ their distance and direction apart.

The relation of position of the two points is the suggested interval or line. Turn now to the simplest case, that of a single excited spot. How can it suggest its position? Not by recalling any particular line unless experience have constantly been in the habit of marking or tracing some one line from it towards some one neighboring point. Now on the back, belly²¹⁵, viscera, etc., no such tracing habitually occurs. The consequence is that the only suggestion is that of the whole neighboring circle; i.e., the spot simply recalls the general region in which it happens to lie. By a process of successive construction, it is quite true that we can also get the feeling of distance between the spot and some other particular spot. Attention, by reinforcing the local sign of one part of the circle, can awaken a new circle round this part, and so de proche en proche we may slide our feeling down from our cheek, say, to our foot. But when we first touched our cheek we had no consciousness of the foot at all. 25 In the extremities, the lips, the tongue and other mobile parts, the case is different. We there have an instinctive²¹⁶ tendency, when a, part of lesser discriminative²¹⁷ sensibility is touched, to move the member so that the touching object glides²¹⁸ along it to the place where sensibility is greatest. If a body touches our hand we move the hand over it tin the finger-tips are able to explore it. If the sole of our foot touches anything we bring it towards the toes, and so forth²¹⁹. There thus arise lines of habitual²⁰⁵ passage from all points of a member to its sensitive tip. These are the lines most readily recalled when any point is touched, and their recall is identical with the consciousness of the distance of the touched point from the 'tip.' I think anyone must be aware when he touches a point of his hand or wrist that it is the relation to the finger-tips of which he is usually most conscious. Points on the fore-arm suggest either the finger-tips or the elbow (the latter being a spot of greater sensibility 26 ). In the foot it is the toes, and so on. A point can only be cognized in its relations to the entire body at once by awakening²²⁰ a visual image of the whole body. Such awakening is even more obviously than the previously²²¹ considered cases a matter of pure association.

This leads us to the eye. On the retina the fovea and the yellow spot about it form a focus of exquisite²²² sensibility, towards which every impression falling on an outlying portion of the field is moved by an instinctive action of the muscles of the eyeball. Few persons, until their attention is called to the fact, are aware how almost impossible it is to keep a conspicuous²²³ visible abject²²⁴ in the margin²²⁵ of the field of view. The moment volition²²⁶ is relaxed we find that without our knowing it our eyes have turned so as to bring it to the centre. This is why most persons are unable to keep the eyes steadily²²⁷ converged²²⁹ upon a point in space with nothing in it. The objects against the walls of the room invincibly²³⁰ attract the foveæ to themselves. If we contemplate²³¹ a blank wall or sheet of paper, we always observe in a moment that we are directly looking at some speck²³² upon it which, unnoticed at first, ended by 'catching²³³ our eye.' Thus whenever an image falling on the point P of the retina excites attention, it more habitually moves from that point towards the fovea than in any one other direction. The line traced thus by the image is not always a straight line. When the direction of the point from the fovea is neither vertical nor horizontal but oblique²³⁴, the line traced is often a curve, with its concavity directed upwards²³⁵ if the direction is upwards, downwards²³⁶ if the direction is downwards. This may be verified by anyone who will take the trouble to make a simple experiment with a luminous body like a candle-flame in a dark enclosure, or a star. Gazing first at some point remote from the source of light, let the eye be suddenly turned full upon the latter. The luminous image will necessarily fall in succession upon a continuous series of points, reaching from the one first affected to the fovea. But by virtue of the slowness with which retinal excitements die away, the entire series of points will for an instant be visible as an after-image, displaying the above peculiarity of form according to its situation. 27 These radiating lines are neither regular nor invariable in the same person, nor, probably, equally curved in different individuals. We are incessantly²³⁸ drawing them between the fovea and every point of the held of view. Objects remain in their peripheral²³⁹ indistinctness only so long as they are unnoticed. The moment we attend to them they grow distinct through one of these motions -- which leads to the idea prevalent among uninstructed persons that we see distinctly all parts of the field of view at once. The result of this incessant²³⁷ tracing of radii²⁴⁰ is that whenever a local sign P is awakened by a spot of light falling upon it, it recalls forthwith, even though the eyeball be unmoved, the local signs of all the other points which lie between P and the fovea. It recalls them in imaginary form, just as the normal reflex movement would recall them in vivid form; and with their recall is given a consciousness more or less faint of the whole line on which they lie. In other words, no ray of light can fall on any retinal spot without the local sign of that spot revealing to us, by recalling the line of its most habitual associates, its direction and distance from the centre of the held. The fovea acts thus as the origin of a system of polar co-ordinates, in relation to which each and every retinal point has through an incessantly-repeated process of association its distance and direction determined²⁴¹. Were P alone illumined and all the rest of the field dark we should still, even with motionless eyes, know whether P lay high or low, right or left, through the ideal streak²⁰, different from all other streaks²⁴², which P alone has the power of awakening." 28

And with this we can close the first great division of our subject. We have shown that, within the range of every sense, experience takes ab initio the spatial form. We have also shown that in the cases of the retina and skin every sensible total may be subdivided by discriminative attention into sensible parts, which are also spaces, and into relations between the parts, these being sensible spaces too. Furthermore, we have seen (in a foot-note) that different parts, once discriminated, necessarily fall into a determinate order, both by reason of definite gradations in their quality, and by reason of the fixed²⁴³ order of time-succession in which movements arouse them. But in all this nothing has been said of the comparative measurement of one sensible space-total against another, or of the way in which, by summing our divers²⁴⁴ simple sensible space-experiences together, we end by constructing what we regard as the unitary, continuous, and infinite objective space of the real world. To this more difficult inquiry²⁴⁵ we next pass.
The Construction of 'Real' Space.

The problem breaks into two subordinate problems.

(1) How is the subdivision and measurement of the several sensorial spaces completely effected? and

(2) How do their mutual addition and fusion²⁴⁶ and reduction to the same scale, in a word, how does their synthesis, occur?

I think that, as in the investigation just finished, we found ourselves able to get along without invoking²⁴⁷ any data but those that pure sensibility on the one hand, and the ordinary intellectual powers of discrimination and recollection on the other, were able to yield; so here we shall emerge from our more complicated quest with the conviction that all the facts can be accounted for on the supposition that no other mental forces have been at work save those we find everywhere else in psychology: sensibility, namely, for the data; and discrimination, association, memory, and choice for the rearrangements and combinations which they undergo.
1. The Subdivision of the Original Sense-spaces.

How are spatial subdivisions brought to consciousness? in other words, How does spatial discrimination occur? The general subject of discrimination has been treated in a previous chapter. Here we need only inquire what are the conditions that make spatial discrimination so much finer in sight than in touch, and in touch than in hearing, smell, or taste.

The first great condition is, that different points of the surface shall differ in the quality of their immanent sensibility, that is, that each shall carry its special local-sign. If the skin felt everywhere exactly alike, a foot-bath could be distinguished from a total immersion²⁴⁸, as being smaller, but never distinguished from a wet face. The local-signs are indispensable; two points which have the same local-sign will always be felt as the same point. We do not judge them two unless we have discerned their sensations to be different. 29 Granted none but homogeneous irritants, that organ would then distinguish the greatest multiplicity of irritants -- would count most stars or compass-points, or best compare the size of two wet surfaces -- whose local sensibility was the least even. A skin whose sensibility shaded rapidly off from a focus, like the apex²⁴⁹ of a boil, would be better than a homogeneous integument²⁵⁰ for spatial perception. The retina, with its exquisitely²⁵¹ sensitive fovea, has this peculiarity, and undoubtedly owes to it a great part of the minuteness with which we are able to subdivide the total bigness of the sensation it yields. On its periphery²⁵² the local differences do not shade off very rapidly, and we can count there fewer subdivisions.

But these local differences of feeling, so long as the surface is unexcited from without, are almost null. I cannot feel them by a pure mental act of attention unless they belong to quite distinct parts of the body, as the nose and the lip, the finger-tip and the ear; their contrast needs the reinforcement of outward excitement to be felt. In the spatial muchness of a colic -- or, to call it by the more spacious-sounding vernacular²⁵³, of a 'bellyache' -- one can with difficulty distinguish the north-east from the south-west corner, but can do so much more easily if, by pressing one's finger against the former region, one is able to make the pain there more intense.

The local differences require then, an adventitious²⁵⁴ sensation, superinduced upon them, to awaken the attention. After the attention has once been awakened in this way, it may continue to be conscious of the unaided difference; lust²⁵⁵ as a sail on the horizon may be too faint for us to notice until someone's finger, placed against the spot, has pointed it out to us, but may then remain visible after the finger has been withdrawn²⁵⁶. But all this is true only on condition that separate points of the surface may be exclusively stimulated²⁵⁷. If the whole surface at once be excited from without, and homogeneously, as, for example, by immersing the body in salt water, local discrimination is not furthered. The local signs, it is true, all awaken at once; but in such multitude that no one of them, with its specific quality, stands out in contrast with the rest. If, however, a single extremity be immersed, the contrast between the wet and dry parts is strong, and, at the surface of the water especially, the local-signs attract the attention, giving the feeling of a ring surrounding the member. Similarly, two or three wet spots separated by dry spots, or two or three hard points against the skin, will help to break up our consciousness of the latter's bigness. In eases of this sort, where points receiving an identical kind of excitement are, nevertheless, felt to be locally distinct, and the objective irritants are also judged multiple, -- e.g., compass-points on skin or stars on retina, -- the ordinary explanation is no doubt just, and we judge the outward causes to be multiple because we have discerned the local feelings of their sensations to be different.

Capacity for partial stimulation is thus the second condition favoring discrimination. A sensitive surface which has to be excited in all its parts at once can yield nothing but a sense of undivided largeness. This appears to be the case with the olfactory²⁵⁸, and to all intents and purposes with the gustatory, surfaces. Of many tastes and flavors, even simultaneously presented, each affects the totality of its respective organ, each appears with the whole vastness given by that organ, and appears interpenetrated by the rest. 30

I should have been wining some years ago to name with- out hesitation²⁶⁰ a third condition of discrimination-saying it would be most developed in that organ which is susceptible²⁶¹ of the most various qualities of feeling. The retina is un- questionably²⁶² such an organ. The colors and shades it perceives are infinitely²⁶³ more numerous than the diversities of skin-sensation. And it can feel at once white and black, whilst the ear can in nowise so feel sound and silence. But the late researches of Donaldson, Blix, and Goldscheider, 31 on specific points for heat, cold, pressure, and pain in the skin; the older ones of Czermak (repeated later by Klug in Ludwig's laboratory), showing that a hot and a cold compass-point are no more easily discriminated as two than two of equal temperature; and some unpublished experiments of my own -- all disincline me to make much of this condition now. 32 There is, however, one quality of sensation which is particularly exciting, and that is the feeling of motion over any of our surfaces. The erection of this into a separate elementary quality of sensibility is one of the most recent of psychological achievements, and is worthy²⁶⁵ of detaining us a while at this point.
The Sensation of Motion over Surfaces.

The feeling of motion has generally been assumed by physiologists²⁶⁶ to be impossible until the positions of terminus ad quem and terminus ad quem are severally cognized, and the successive occupancies of these positions by the moving body are perceived to be separated by a distinct interval of time. 33 As a matter of fact, however, we cognize only the very slowest motions in this way. Seeing the hand of a clock at XII and afterwards at VI, we judge that it has moved through the interval. Seeing the sun now in the east and again in the west, I infer it to have passed over my head. But we can only infer that which we already generically know in some more direct fashion, and it is experimentally certain that we have the feeling of motion given us as a direct and simple sensation. Czermak long ago pointed out the difference between seeing the motion of the second-hand²⁶⁷ of a watch, when we look directly at it, and noticing the fact of its having altered its position when we fix our gaze upon some other point of the dial-plate. In the first case we have a specific quality of sensation which is absent in the second. If the reader will find a portion of his skin -- the arm, for example -- where a pair of compass-points an inch apart are felt as one impression, and if he will then trace lines a tenth of an inch long on that spot with a pencil-point, he will be distinctly aware of the point's motion and vaguely aware of the direction of the motion. The perception of the motion here is certainly not derived from a pre-existing knowledge that its starting and ending points are separate positions in space, because positions in space ten times wider apart fail to be discriminated as such when excited by the dividers. It is the same with the retina. One's fingers when cast upon its peripheral portions cannot be counted -- that is to say, the five retinal tracts²⁶⁸ which they occupy are not distinctly apprehended by the mind as five separate positions in space -- and yet the slightest movement of the fingers is most vividly perceived as movement and nothing else. It is thus certain that our sense of movement, being so much more delicate than our sense of position, cannot possibly be derived from it. A curious observation by Exner 34 completes the proof that movement in a primitive form of sensibility, by showing it to be much more delicate than our sense of succession in time. This very able physiologist caused two electric sparks to appear in rapid succession, one beside the other. The observer had to state whether the right-hand one or the left-hand one appeared first. When the interval was reduced to as short a time as 0.044" the discrimination of temporal order in the sparks became impossible. But Exner found that if the sparks were brought so close together in space that their irradiation-circles overlapped²⁷⁰, the eye then felt their flashing as if it were the motion of a single spark from the point occupied by the first to the point occupied by the second, and the time-interval might then be made as small as 0.015" before the mind began to be in doubt as to whether the apparent motion started from the right or from the left. On the skin similar experiments gave similar results.

Vierordt, at almost the same time, 35 called attention to certain persistent²⁷¹ illusions, amongst which are these: If another person gently trace a line across our wrist or finger, the latter being stationary²⁷², it will feel to us as if the member were moving in the opposite direction to the tracing point. If, on the contrary, we move our limb across a fixed point, it will be seen as if the point were moving as well. If the reader will touch his forehead with his forefinger⁸⁰ kept motionless, and then rotate the head so that the skin of the forehead passes beneath the finger's tip, he will have an irresistible²⁷³ sensation of the latter being itself in motion in the opposite direction to the head. So in abducting²⁷⁴ the fingers from each other; some may move and the rest be still still, but the still ones will feel as if they were actively²⁷⁵ separating from the rest. These illusions, according to Vierordt, are survivals of a primitive form of perception, when motion was felt as such, but ascribed to the whole content of consciousness, and not yet distinguished as belonging exclusively to one of its parts. When our perception is fully developed we go beyond the mere relative motion of thing and Bound, and can ascribe absolute motion to one of these components²⁷⁶ of our total object, and absolute rest to another. When, in vision for example, the whole background moves together, we think that it is ourselves or our eyes which are moving; and any object in the foregound which may move relatively²⁷⁷ to the background is judged by us to be still. But primitively this discrimination cannot be perfectly made. The sensation of the motion spreads over all that we see and infects it. Any relative motion of object and retina both makes the object seem to move, and makes us feel ourselves in motion. Even now when our whole object moves we still get giddy; and we still see an apparent motion of the entire held of view, whenever we suddenly jerk our head and eyes or shake them quickly to and fro. Pushing our eyeballs gives the same illusion. We know in all these cases what really happens, but the conditions are unusual, so our primitive sensation persists unchecked. So it does when clouds float by the moon. We know the moon is still; but we see it move even faster than the clouds. Even when we slowly move our eyes the primitive sensation persists under the victorious²⁷⁸ conception. If we notice closely the experience, we find that any object towards which we look appears moving to meet our eye. But the most valuable contribution to the subject is the paper of G. H. Schneider, 36 who takes up the matter zoologically, and shows by examples from every branch of the animal kingdom that movement is the quality by which animals most easily attract each other's attention. The instinct of shamming²⁷⁹ death 'is no shamming of death at all, but rather a paralysis²⁸⁰ through fear, which saves the insect, crustacean²⁸¹, or other creature from being noticed at all by his enemy. It is paralleled in the human race by the breath-holding stillness of the boy playing 'I spy,' to whom the seeker is near; and its obverse side is shown in our involuntary waving of arms, jumping up and down, and so forth, when we wish to attract someone's attention at a distance. Creatures 'stalking' their prey²⁸² and creatures hiding from their pursuers alike show how immobility diminishes conspicuity²⁸⁴. In the woods, if we are quiet, the squirrels and birds will actually touch us. Flies will light on stuffed birds and stationary frogs. 37 On the other hand, the tremendous shock of feeling the thing we are sitting on begin to move, the exaggerated start it gives us to have an insect unexpectedly pass over our skin, or a cat noiselessly come and snuffle about our hand, the excessive reflex effects of tickling²⁸⁵, etc., show how exciting the sensation of motion is per se. A kitten cannot help pursuing a moving ball. Impressions too faint to be cognized at all are immediately felt if they move. A fly sitting is unnoticed, -- we feel it the moment it crawls. A shadow may be too faint to be perceived. As soon as it moves, however, we see it. Schneider found that a shadow, with distinct outline, and directly fixated, could still be perceived when moving, although its objective strength might be but half as great as that of a stationary shadow so faint as just to disappear. With a blurred²⁸⁶ shadow in indirect vision the difference in favor of motion was much greater -- namely, 13.3:40.7. If me hold a finger between our closed eyelid and the sunshine we shall not notice its presence. The moment we move it to and fro, however, we discern it. Such visual perception as this reproduces the conditions of sight among the radiates. 38

Enough has now been said to show that in the education of spatial discrimination the motions of impressions across sensory surfaces must have been the principal agent in breaking up our consciousness of the surfaces into a consciousness of their parts. Even to-day the main function of the peripheral regions of our retina is that of sentinels, which, when beams of light move over them, cry 'Who goes there?' and call the fovea to the spot. Most parts of the skin do but perform the same of office for the finger-tips. Of course finger-tips and fovea leave some power of direct perception to marginal retina and skin respectively. But it is worthy of note that such perception is best developed on the skin of the most movable parts (the labors²⁸⁷ of Vierordt and his pupils have well shown this); and that in the blind, whose skin is exceptionally discriminative, it seems to have become so through the inveterate²⁸⁸ habit which most of them possess of twitching²⁸⁹ and moving it under whatever object may touch them, so as to become better acquainted with the con- formation of the same. Czermak was the first to notice this. It may be easily verified. Of course movement of surface under object is (for purposes of stimulation) equivalent to movement of object over surface. In exploring the shapes and sizes of things by either eye or skin the movements of these organs are incessant and unrestrainable. Every such movement draws the points and lines of the object across the surface, imprints²⁹⁰ them a hundred times more sharply, and drives them home to the attention. The immense part thus played by movements in our perceptive activity is held by many psychologists 39 to prove that the muscles are themselves the space-perceiving organ. Not surface-sensibility, but 'the muscular sense,' is for these writers the original and only revealer of objective extension. But they have all failed to notice with what peculiar intensity muscular contractions²⁹¹ call surface-sensibilities into play, and that the mere discrimination of impressions (quite apart from any question of measuring the space between them) largely depends on the mobility²⁸³ of the surface upon which they fall. 40
2. The Measurement of the sense-spaces against each other.

What precedes is all we can say in answer to the problem of discrimination. Turn now to that of measurement of the several spaces against each other, that being the first step in our constructing out of our diverse space-experiences the one space we believe in as that of the real world.

The first thing that seems evident is that we have no immediate power of comparing together with any accuracy the extents revealed by different sensations. Our mouth-cavity feels indeed to itself smaller, and to the tongue larger, than it feels to the finger or eye, our tympanic membrane feels larger than our finger-tip, our lips feel larger then a surface equal to them on our thigh. So much comparison is immediate; but it is vague; and for anything exact; we must resort to other help.

The great agent in comparing the extent felt by one sensory surface with that felt by another, is superposition-superposition of one surface upon another, and superposition of one outer thing upon many surfaces. Thus are exact equivalencies and common measures introduced, and the way prepared for numerical results.

Could we not superpose one part of our skin upon another, or one object on both parts, we should hardly succeed in coming to that knowledge of our own form which we possess. The original differences of bigness of our different parts would remain vaguely operative, and we should have no certainty as to how much lip was equivalent to so much forehead, how much finger to so much back.

But with the power of exploring one part of the surface by another we get a direct perception of cutaneous equivalencies. The primitive differences of bigness are over-powered when we feel by an immediate sensation that a certain length of thigh-surface is in contact with the entire palm and fingers. And when a motion of the opposite finger-tips draws a line first along this same length of thigh and then along the whole of the hand in question, we get a new manner of measurement, less direct but confirming the equivalencies established by the first. In these ways, by superpositions of parts and by tracing lines on different parts by identical movements, a person deprived of sight can soon learn to reduce all the dimensions of his body to a homogeneous scale. By applying the same methods to objects of his own size or smaller, he can with equal ease make himself acquainted with their extension stated in terms derived from his own bulk, palms, feet, cubits, spans, paces, fathoms²⁹⁴ (armspreads), etc. In these reductions it is to be noticed that when the resident sensations of largeness of two opposed surfaces conflict, one of the sensations is chosen as the true standard and the other treated as illusory. Thus an empty tooth-socket is believed to be really smaller than the finger-tip which it will not admit, although it may feel larger; and in general it may be said that the hand, as the almost exclusive organ of palpation, gives its own magnitude to the other parts, instead of having its size determined by them. In general, it is, as Fechner says, the extent felt by the more sensitive part to which the other extents are reduced. 41

But even though exploration of one surface by another were impossible, we could always measure our various surfaces against each other by applying the same extended object first to one and then to another. We should of course have the alternative of supposing that the object itself waxed and waned²⁹⁵ as it glided²⁹⁶ from one place to another (cf. above, p. 141); but the principle of simplifying as much as possible our world would soon drive us out of that assumption into the easier one that objects as a rule keep their sizes, and that most of our sensations are affected by errors for which a constant allowance must be made.

In the retina there is no reason to suppose that the bignesses of two impressions (lines or blotches) falling on different regions are primitively felt to stand in any exact mutual ratio. It is only when the impressions come from the same object that we judge their sizes to be the same. And this, too, only when the relation of the object to the eye is believed to be on the whole unchanged. When the object by moving changes its relations to the eye the sensation excited by its image even on the same retinal region becomes so fluctuating that we end by ascribing no absolute import whatever to the retinal space-feeling which at any moment we may receive. So complete does this overlooking of retinal magnitude become that it is next to impossible to compare the visual magnitudes of objects at different distances without making the experiment of superposition. We cannot say beforehand how much of a distant house or tree our finger will cover. The various answers to the familiar question, How large is the moon? -- answers which vary from a cartwheel to a wafer -- illustrate²⁹⁷ this most strikingly. The hardest part of the training of a young draughtsman is his learning to feel directly the retinal (i.e. primitively sensible) magnitudes which the different objects in the held of view subtend. To do this he must recover what Ruskin calls the 'innocence²⁹⁸ of the eye' -- that is, a sort of childish perception of stains of color merely as such, without consciousness of what they mean. With the rest of us this innocence is lost. Out of all the visual magnitudes of each known object we have selected one as the REAL one to think of, and degraded all the others to serve as its signs. This 'real' magnitude is determined by aesthetic²⁹⁹ and practical interests. It is that which we get when the object is at the distance most propitious³⁰⁰ for exact visual discrimination of its details. This is the distance at which we hold anything we are examining. Farther than this we see it too smell, nearer too large. And the larger and the smaller feeling vanish in the act of suggesting this one, their more important meaning. As I look along the dining-table I overlook the fact that the farther plates and glasses feel so much smaller than my own, for I know that they are all equal in size; and the feeling of them, which is a present sensation, is eclipsed in the share of the knowledge, which is a, merely imagined one.

If the inconsistencies of sight-spaces inter se can thus be reduced, of course there can be no difficulty in equating³⁰¹ sight-spaces with spaces given to touch. In this equation it is probably the touch-feeling which prevails as real and the sight which serves as sign -- a reduction made necessary not only by the far greater constancy of felt over seen magnitudes, but by the greater practical interest which the sense of touch possesses for our lives. As a rule, things only benefit or harm us by coming into direct contact with our skin: sight is only a sort of anticipatory³⁰² touch; the letter is, in Mr.Spencer's phrase, the 'mother-tongue of thought,' and the handmaid's idiom must be translated into the language of the mistress before it can speak clearly to the mind. 42

Later on we shall see that the feelings excited in the joints when a limb moves are used as signs of the path traversed by the extremity. But of this more anon. As for the equating of sound-, smell-, and taste-volumes with those yielded by the more discriminative senses, they are too vague to need any remark. It may be observed of pain, however, that its size has to be reduced to that of the normal tactile³⁰⁴ size of the organ which is its seat. A finger with a felon³⁰⁵ on it, and the pulses of the arteries³⁰⁶ therein, both 'feel' larger than we believe they really 'are.'

It will have been noticed in the account given that when two sensorial sense-impressions, believed to come from the same object, differ, then THE ONE MOST INTERESTING, practically or æsthetically, Is JUDGED TO BE THE TRUE ONE. This law of interest holds throughout -- though a permanent interest, like that of touch, may resist a strong but fleeting³⁰⁷ one like that of pain, as in the case just given of the felon.
3. The Summation³⁰⁸ of the Sense-spaces.

Now for the next step in our construction of real space: How are the various sense-spaces added together into a consolidated³⁰⁹ and unitary continuum? For they are, in man at all events, incoherent at the start.

Here again the first fact that appears is that primitively our space-experiences form a chaos³¹⁰, out of which we have no immediate faculty for extricating³¹¹ them. Objects of different sense-organs, experienced together, do not in the first instance appear either inside or alongside or far outside of each other, neither spatially continuous nor discontinuous, in any definite sense of these words. The same thing is almost as true of objects felt by different parts of the same organ before discrimination has done its finished work. The most we can say is that all our space-experiences together form an objective total and that this objective total is vast.

Even now the space inside our mouth, which is so intimately known and accurately³¹² measured by its inhabitant the tongue, can hardly be said to have its internal directions and dimensions known in any exact relation to those of the larger world outside. It forms almost a little world by itself. Again, when the dentist excavates³¹³ a small cavity in one of our teeth, we feel the hard point of his instrument scraping, in distinctly differing directions, a surface which seems to our sensibility vaguely larger than the subsequent use of the mirror tells us it 'really' is. And though the directions of the scraping differ so completely inter se, not one of them can be identified with the particular direction in the outer world to which it corresponds. The space of the tooth-sensibility is thus really a little world by itself, which can only become congruent with the outer space-world by farther experiences which shall alter its bulk, identify its directions, fuse its margins³¹⁴, and finally embed³¹⁵ it as a definite part within a definite whole. And even though every joint¹⁸³'s rotations³¹⁷ should be felt to vary inter se as so many differences of direction in a common room; even though the same were true of diverse tracings on the skin, and of diverse tracings on the retina respectively, it would still not follow that feelings of direction, on these different surfaces, are intuitively comparable among each other, or with the other directions yielded by the feelings of the semi-circular canals. It would not follow that we should immediately judge the relations of them all to each other in one space-world.

If with the arms in an unnatural³¹⁸ attitude we 'feel' things, we are perplexed³¹⁹ about their shape, size, and position. Let the reader lie on his back with his arms stretched above his head, and it will astonish him to find how in able he is to recognize the geometrical relations of objects placed within reach of his hands. But the geometrical relations here spoken of are nothing but identities recognized between the directions and sizes perceived in this way and those perceived in the more usual ways. The two ways do not fit each other intuitively.

How lax the connection between the system of visual and the system of tactile directions is in man, appears from the facility with which microscopists learn to reverse the movements of their hand in manipulating things on the stage of the instrument. To move the slide to the seen left they must draw it to the felt right. But in a very few days the habit becomes a second nature. So in tying our cravat³²⁰, shaving before a mirror, etc., the right and left sides are inverted³²¹, and the directions of our hand movements are the opposite of what they seen. Yet this never annoys us. Only when by accident we try to tie the cravat of another person do we learn that there are two ways of combining sight and touch perceptions. Let any one try for the first time to write or draw while looking at the image of his hand and paper in a mirror, and he will be utterly³²² bewildered. But a very short training will teach him to undo⁶³ in this respect the associations of his previous lifetime.

Prisms show this in an even more striking way. If the eyes be armed with spectacles containing slightly prismatic glasses with their bases turned, for example, towards the right, every object looked at will be apparently³²³ translocated to the left; and the hand put forth to grasp ally which object will make the mistake of passing beyond it on the left side. But less than an hour of practice in wearing such spectacles rectifies³²⁴ the judgment³²⁵ so that no more mistakes are made. In fact the new-formed associations are already so strong, that when the prisms are first laid aside again the opposite error is committed, the habits of a lifetime violated, and the hand now passed to the right of every object which it seeks to touch.

The primitive chaos thus subsists³²⁶ to a great degree through life so far as our immediate sensibility goes. We feel our various objects and their bignesses, together or in succession; but so soon as it is a question of the order and relations of many of them at once our intuitive apprehension³²⁷ remains to the very end most vague and incomplete. Whilst we are attending to one, or at most to two or three objects, all the others lapse³²⁸, and the most we feel of them is that they still linger on the outskirts³²⁹ and can be caught again by turning in a certain way. Nevertheless throughout all this confusion we conceive of a world spread out in a perfectly fixed and orderly fashion, and we believe in its existence. The question is: How do this conception and this belief arise? How is the chaos smoothed and straightened out?

Mainly by two operations: Some of the experiences are apprehended to exist out- and alongside of each other, and others are apprehended to interpenetrate each other, and to occupy the same room. In this way what was incoherent and irrelative ends by being coherent and definitely related; nor is it hard to trace the principles, by which the mind is guided in this arrangement of its perceptions, in detail.

In the first place, following the great intellectual law of economy, we simplify, unify³³⁰, and identify as much as we possibly can. Whatever sensible data can be attended to together we locate together. Their several extents seem one extent. The place at which each appears is held to be the same with the place at which the others appear. They become, in short, so many properties of ONE AND THE SAME REAL THING. This is the first and great commandment, the fundamental 'act' by which our world gets spatially arranged.

In this coalescence³³² in a 'thing,' one of the coalescing³³³ sensations is held to be the thing, the other sensations are taken for its more or less accidental properties, or modes of appearance. 43 The sensation chosen to be the thing essentially³³⁴ is the most constant and practically important of the lot; most often it is hardness or weight. But the hardness or weight is never without tactile bulk; and as we can always see something in our hand when me feel something there, we can always see something there when we essence of the 'thing.' Frequently a shape so figures, sometimes a, temperature, a taste, etc.; but for the most part temperature, smell, sound, color, or whatever other phenomena³³⁵ may vividly impress us simultaneously with the bulk felt or seen, figure among the accidents. Smell and sound impress us, it is true, when we neither see nor touch the thing; but they are strongest when we see or touch, so we locate the source of these properties within the touched or seen space, whilst their properties themselves we regard as overflowing³³⁶ in a weakened form into the spaces fined by other-things. In all this, it will be observed, the sense-data whose spaces coalesce³³¹ into one are yield by different sense-organs. Such data have no tendency to displace each other from consciousness, but can be attended to together all at once. Often indeed they vary concomitantly and reach a maximum together. We may be sure, therefore, that the general rule of our mind is to locate IN each other all sensations which are associated in simultaneous experience, and do not interfere³³⁷ with each other's perception. 44

Different impressions on the same sense-organ do interfere with each other's perception, and cannot well be attended to at once. Hence we do not locate them in each other's spaces, but arrange them in a serial³³⁸ order of exteriority³³⁹, each alongside of the rest, in a space larger than that which any one sensation brings. This larger space, however, is an object of conception rather than of direct intuition, and bears all the marks of being constructed piecemeal³⁴⁰ by the mind. The blind man forms it out of tactile, locomotor, and auditory experiences, the seeing men out of visual ones almost exclusively. As the visual construction is the easiest to understand, let us consider that first.

Every single visual sensation or 'field of view' is limited. To get a new field of view for our object the old one must disappear. But the disappearance³⁴¹ may be only partial. Let the first field of view be A B C. If we carry our attention to the limit C, it ceases to be the limit, and becomes the centre of the field, and beyond it appear fresh parts where there were none before: 45 A B C changes, in short, to C D E. But although the parts A B are lost to sight, yet their image abides³⁴² in the memory; and if we think of our first object A B C as having existed or as still existing at all, we must think of it as it was originally presented, namely, as spread out from C in one direction just as C D E is spread out in another. A B and D E can never coalesce in one place (as they could were they objects of different senses) because they call never be perceived at once: we must lose one to see the other. So (the letters standing¹⁶⁴ now for 'things') we get to conceive of the successive fields of things after the analogy of the several things which we perceive in a single field. They must be out- and along-side of each other, and we conceive that their juxtaposed spaces must make a larger space. A B C + C D E must, in short, be imagined to exist in the form of A B C D E or not imagined at all.

We can usually recover anything lost from sight by moving our attention and our eyes back in its direction; and through these constant changes every field of seen things comes at last to be thought of as always having a fringe of other things possible to be seen spreading in all directions round about it. Meanwhile the movements concomitantly with which the various fields alternate are also felt and remembered; and gradually (through association) this and that movement come in our thought to suggest this or that extent of fresh objects introduced. Gradually, too, since the objects vary indefinitely in kind, we abstract from their several natures and think separately of their mere extents, of which extents the various movements remain as the only constant introducers and associates. More and more, therefore, do we think of movement and seen extent as mutually involving? each other, until at last (with Bain and J. S. Mill) we may get to regard them as synonymous, and say, "What is the meaning of the word extent, unless it be possible movement?" 46 We forget in this conclusion that (whatever intrinsic extensiveness the movements may appear endowed with), that seen spreadoutness which is the pattern of the abstract extensiveness which we imagine came to us originally from the retinal sensation.

The muscular sensations of the eyeball signify this sort of visible spreadoutness, just as this visible spreadoutness may come in later experience to signify the 'real' bulks, distances, lengths and breadths known to touch and locomotion³⁴³. 47 To the very end, however in us seeing men, the quality, the nature, the sort of thing we mean by extensiveness, would seem to be the sort of feeling which our retinal stimulations bring.

In one deprived of sight the principles by which the notion of real space is constructed are the same. Skin-feelings take in him the place of retinal feelings in giving the quality of lateral spreadoutness, as our attention passes from one extent of them to another, awakened by an object sliding along. Usually the moving object is our hand; and feelings of movement in our joints invariably accompany the feelings in the skin. But the feeling of the skin is what the blind man means by his skin; so the size of the skin-feelings stands as the absolute or real size, and the size of the joint-feelings becomes a sign of these. Suppose, for example, a blind baby with (to make the description shorter) a blister³⁴⁴ on his toe, exploring his leg with his finger-tip and feeling a pain shoot up sharply the instant the blister is touched. The experiment gives him four different kinds of sensation -- two of them protracted³⁴⁵, two sudden. The first pair are the movement-feeling in the joints of the upper limb, and the movement-feeling on the skin of the leg and foot. These, attended to together, have their extents identified as one objective space -- the hand moves through the same space in which the leg lies. The second pair of objects are the pain in the blister, and the peculiar feeling the blister gives to the finger. Their spaces also fuse; and as each marks the end of a peculiar movement-series (arm moved, leg stroked), the movement-spaces are emphatically identified with each other at that end. Were there other small blisters³⁴⁷ distributed down the leg, there would be a number of these emphatic³⁴⁶ points; the movement-spaces would be identified, not only as totals, but point for point. 48

Just so with space beyond the body's limits. Continuing the joint-feeling beyond the toe, the baby hits another object which he can still think of when he brings his back to its blister again. That object at the end of that joint feeling means a new place for him, and the more such objects multiply in his experience the wider does the space of his conception grow. If, wandering through the woods to-day by a new path, I find myself suddenly in a glad which affects my senses exactly as did another I reached last week at the end of different walk, I believe the two identical affection to present the same persisting glade³⁴⁸, and infer that I have attained³⁴⁹ it by two differing roads. The case in whit²⁶⁴ differs when shorter movements are concerned. If, moving first one arm and then another, the blind child gets the same kind of sensation upon the hand, and gets it again as often as he repeats either process, he judges that he has touched the same object by both motions, and concludes that the motions terminate in a common place. From place to place marked in this way he moves, and adding the places moved through, one to another, he builds up his notion of the extent of the outer world. The seeing man's process is identical; only his units, which may be successive bird's-eye view, are much larger than in the case of the blind.
Feelings in Joints and Feelings in Muscles
1. Feelings of Movement in Joints

I have been led to speak of feelings which arise in joints. As these feeling have too much neglecting Psychology hitherto, in entering now somewhat minutely in the interest of the reader, which under the rather dry abstractions of the previous pages may presumably have flagged.

When by simply flexing³⁵¹ my right forefinger on its metacarpal joint, I trace with its tip an inch on the palm of my left hand, is my feeling of the size of the inch purely³⁵² and simply a feeling in the skin of the palm, or have the muscular contractions of the right hand and forearm anything to do with it? In the preceding pages I have constantly assumed spatial sensibility to be an affair of surfaces. At first starting, the consideration of the 'muscular sense' as a space-measurer was postponed³⁵⁴ to a later stage. Many writers, of whom the foremost was Thomas Brown, in his Lectures on the Philosophy of the Human Mind, and of whom the latest is no less a Psychologist than Prof. Delboeuf, 49 hold that the consciousness of active muscular motion, aware of its own amount, is the fons et origo of all spatial measurement. It would seem to follow, if this theory were true, that two skin-feelings, one of a large patch, one of small one, possess their difference of spatiality, not as an immediate element, but solely³⁵⁵ by virtue of the fact that the large, to get its points successively excited, demands more muscular contraction²⁹² than the small one does. Fixed associations with the several amounts of muscular contractions required in this particular experience would thus explain the apparent sizes of the skin-patches, which sizes would consequently not be primitive data but derivative³⁵⁶ results.

It seems to me that no evidence of the muscular measurements in question exists; but that all the facts may be explained by surface-sensibility, provided we take that of the joint-surfaces also into account. The most striking argument, and the most obvious one, which an upholder of the muscular theory is likely to produce is undoubtedly this fact: if, with closed eyes, we trace figures in the air with the extended forefinger (the motions may occur from the metacarpal-, the wrist-, the elbow-, or the shoulder-joint indifferently), what we are conscious of in each case, and indeed most acutely conscious of, is the geometric path described by the finger-tip. Its angles, its subdivisions, are all as distinctly felt as if seen by the eye; and yet the surface of the finger-tip receives no impression at all. 50 But with each variation of the figure, the muscular contractions vary, and so do the feelings which these yield. Are not these latter the sensible data that make us aware of the lengths and directions we discern in the traced line?

Should we be tempted to object to this supposition of the advocate of perception by muscular feelings, that we have learned the spatial significance of the feelings by reiterated³⁵⁷ experiences of seeing what figure is drawn when each special muscular grouping is felt, so that in the last resort the muscular space feelings would be derived from retinal-surface feelings, our opponent might immediately hush³⁵⁸ us by pointing to the fact that in persons born blind the phenomenon in question is even more perfect than in ourselves. If we suggest that the blind may have originally traced the figures on the cutaneous surface of cheek, thigh, or palm, and may now remember the specific figure which each present movement formerly³⁵⁹ caused the skin-surface to perceive, he may reply that the delicacy of the motor perception far exceeds that of most of the cutaneous surfaces; that, in fact, we can feel a figure traced only in its differentials, so to speak, -- a figure which we merely start to trace by our finger-tip, a figure which, traced in the same way on our finger-tip by the hand of another, is almost if not wholly unrecognizable.

The champion of the muscular sense seems likely to be triumphant³⁶⁰ until we invoke³⁶¹ the articular cartilages, as internal surfaces whose sensibility is called in play by every movement we make, however delicate the latter may be.

To establish the part they play in our geometrizing, it is necessary to review a, few facts. It has long been known by medical practitioners³⁶² that, in patients with cutaneous anæsthesia of a limb, whose muscles also are insensible to the thrill of the faradic current, a very accurate sense of the way in which the limb may be flexed³⁶³ or extended by the hand of another may be preserved. 51 On the other hand, we may have this sense of movement impaired³⁶⁴ when the tactile sensibility is well preserved. That the pretended feeling of outgoing innervation can play in these cases no part, is obvious from the fact that the movements by which the limb changes its position are passive ones, imprinted³⁶⁵ on it by the experimenting physician. The writers who have sought a rationale of the matter have consequently been driven by way of exclusion³⁶⁶ to assume the articular surfaces to be the seat of the perception in question. 52

That the joint-surfaces are sensitive appears evident from the fact that in inflammation they become the seat of excruciating pains, and from the perception by everyone who lifts weights or presses against resistance, that every increase of the force opposing him betrays itself to his consciousness principally by the starting-out of new feelings or the increase of old ones, in or about the joints. If the structure and mode of mutual application of two articular surfaces be taken into account, it will appear that, granting the surfaces to be sensitive, no more favorable mechanical conditions could be possible for the delicate calling of the sensibility into play than are realized in the minutely graduated rotations and firmly resisted variations of pressure involved in every act of extension or flexion. Nevertheless it is a greet pity that we have as yet no direct testimony³⁶⁷, no expressions from patients with healthy joints accidentally laid open, of the impressions they experience when the cartilage is pressed or rubbed.

The first approach to direct evidence, so far as I know is contained in the paper of Lewinski, 53 published in 1879. This observer had a patient the inner half of whose leg was anæsthetic. When this patient stood up, he had a curious illusion about the position of his limb, which disappeared the moment he lay down again: he thought himself knock-kneed. If, as Lewinski says, we assume the inner half of the joint to share the insensibility of the corresponding part of the skin, then he ought to feel, when the joint-surfaces pressed against each other in the act of standing, the outer half of the joint most strongly. But this is the feeling he would also get whenever it was by any chance sought to force his leg into a knock-kneed attitude. Lewinski was led by this case to examine the feet of certain ataxic patients with imperfect sense of position. He found in every instance that when the toes were flexed and drawn upon at the same time (the joint-surfaces drawn asunder) all sense of the amount of flexion disappeared. On the contrary, when he pressed a toe whilst flexing it, the patient's appreciation³⁶⁸ of the amount of flexion was much improved, evidently because the artificial increase of articular pressure made up for the pathological insensibility of the parts.

Since Lewinski's paper an important experimental research by A. Goldscheider 54 has appeared, which completely establishes our point. This patient observer caused his fingers, arms, and legs to be passively rotated upon their various joints in a mechanical apparatus³⁶⁹ which registered both the velocity³⁷⁰ of movement impressed and the amount of angular rotation³¹⁶. No active muscular contraction took place. The minimal³⁷¹ felt amounts of rotation were in all cases surprisingly small, being much less than a single angular degree in all the joints except those of the fingers. Such displacements³⁷³ as these, the author says (p. 490), can hardly be detected by the eye. The point of application of the force which rotated the limb made no difference in the result. Rotations round the hip-joint, for example, were as delicately felt when the leg was hung by the heel as when it was hung by the thigh whilst the movements were performed. Anæsthesia of the skin produced by induction³⁷⁴-currents also had no disturbing effect on the perception, nor did the various degrees of pressure of the moving force upon the skin affect it. It became, in fact, all the more distinct in proportion as the concomitant pressure-feelings were eliminated by artificial anæsthesia. When the joints themselves, however, were made artificially anæsthetic the perception of the movement grew obtuse and the angular rotations had to be much increased before they were perceptible. All these facts prove according to Herr Goldscheider, that the joint surfaces and these alone are the starting point of the impressions by which the movements of our members are immediately perceived.

Applying this result, which seems invulnerable, to the case of the tracing finger-tip, we see that our perception of the latter gives no countenance³⁷⁵ to the theory of the muscular sense. We indubitably localize the finger-tip at the successive points of its path by means of the sensations which we receive from our joints. But if this is so, it may be asked, why do we feel the figure to be traced, not within the joint itself, but in such an altogether different place? And why do we feel it so much larger than it really is?

I will answer these questions by asking another: Why do we move our joists at all? Surely to gain something more valuable than the insipid³⁷⁶ joint-feelings themselves. And these more interesting feelings are in the main produced upon the skin of the moving part, or of some other part over which it passes, or upon the eye. With movements of the fingers we explore the configuration³⁷⁷ of all real objects with which we have to deal, our own body as well as foreign things. Nothing that interests us is located in the joint; everything that interests us either is some part of our skin, or is something that we see as we handle it. The cutaneously felt and the seen extents come thus to figure as the important things for us to concern ourselves with. Every time the joint moves, even though we neither see, nor feel cutaneously, the reminiscence of skin-events and sights which formerly coincided with that extent of movement, ideally awaken as the movement's import, and the mind drops the present sign to attend to the import alone. The joint-sensation itself, as such, does not disappear in the process. A little attention easily detects it, with all its fine peculiarities, hidden beneath its vaster suggestions; so that really the mind has two space-perceptions before it, congruent in form but different in scale and place, either of which exclusively it may notice, or both at once, -- the joint-space which it feels and the real space which it means.

The joint-spaces serve so admirably as signs because of their capacity for parallel variation to all the peculiarities of external motion. There is not a direction in the real world nor a ratio of distance which cannot be matched by some direction or extent of joint-rotation. Joint-feelings, like all feelings, are roomy. Specific ones are contrasted inter se as different directions are contrasted within the same extent. If I extend my arm straight out at the shoulder, the rotation of the shoulder-joint will give me one feeling of movement; if then I sweep the arm forward, the same joint will give me another feeling of movement. Both these movements are felt to happen in space and differ in specific quality. Why shall not the specificness of the quality just consist in the feeling of a peculiar direction? 55 Why may not the several joint-feelings be so many perceptions of movement in so many different directions? That we cannot explain why they should is no presumption³⁷⁸ that they do not, for we never can explain why any sense-organ should awaken the sensation it does.

But if the joint-feelings are directions and extents, standing in relation to each other, the task of association in interpreting their import in eye- or skin-terms is a good deal simplified. Let the movement bc, of a certain joint, derive its absolute space-value from the cutaneous feeling it is always capable of engendering³⁷⁹; then the longer movement abcd of the same joint will be judged to have a greater space-value, even though it may never have wholly merged³⁸⁰ with a skin-experience. So of differences of direction: so much joint-difference = so much skin-difference; therefore, more joint-difference = more skin-difference. In fact, the joint-feeling can frequently serve as a map on a reduced scale, of a reality which the imagination can identify at its pleasure with this or that sensible extension simultaneously known in some other way.

When the joint-feeling in itself acquires an emotional interest, -- which happens whenever the joint is inflamed³⁸¹ and painful, -- the secondary suggestions fail to arise, and the movement is felt where it is, and in its intrinsic scale of magnitude. 56

The localization of the joint-feeling in a space simultaneously known otherwise (i.e. to eye or skin), is what is commonly called the extradition³⁸² or eccentric projection of the feeling. In the preceding chapter I said a good deal on this subject; but we must now see a little more closely just what happens in this instance of it. The content of the joint-feeling, to begin with, is an object, and is in itself a place. For it to be placed, say in the elbow, the elbow as seen or handled must already have become another object for the mind, and with its place as thus known, the place which the joint- feeling fins must coalesce. That the latter should be felt 'in the elbow' is therefore a 'projection' of it into the place of another object as much as its being felt in the finger-tip or at the end of a cane³⁸³ can be. But when we say 'projection' we generally have in our mind the notion of a there as contrasted with a here. What is the here when we say that the joint-feeling is there? The 'here' seems to be the spot which the mind has chosen for its own post of observation, usually some place within the head, but sometimes within the throat or breast -- not rigorously fixed spot, but a region from any portion of which it may send forth its various acts of attention. Extradition from either of these regions is the common law under which we perceive the whereabouts of the north star, of our own voice, of the contact of our teeth with each other, of the tip of our finger, of the point of our cane on the ground, or of a movement in our elbow-joint.

But for the distance between the 'here' and the 'there' to be felt, the entire intervening space must be itself an object of perception. The consciousness of this intervening space is tile sine guâ non of the joint-feeling's projection to the farther end of it. When it is fined by our own bodily tissues (as where the projection Only goes as far as the elbow or finger-tip) we are sensible of its extent alike by our eye, by our exploring movements, and by the resident sensations which fin its length. When it reaches beyond the limits of our body, the resident sensations are lacking, but limbs and hand and eye suffice to make it known. Let me, for example, locate a feeling of motion coming from my elbow-joint in the point of my cane a yard beyond my hand. Either I see this yard as I flourish the cane, and the seen end of it then absorbs my sensation just as my seen elbow might absorb it, or I am blind and imagine the cane as an object continuing my arm, either because I have explored both arm and cane with the other hand, or because I have pressed them both along my body and leg. If I project my joint-feeling farther still, it is by a conception rather than a distinct imagination of the space. I think: 'farther,' 'thrice as far,' etc.; and thus get a symbolic³⁸⁴ image of a distant path at which I point. 57 But the 'absorption' of the joint- feeling by the distant spot, in whatever terms the latter may be apprehended, is never anything but that coalescence into one 'thing' already spoken of on page 184, of whatever different sensible objects interest our attention at once.
2. Feelings of Muscular Contraction.

Readers versed³⁰³ in psychological literature will have missed, in our account thus far, the usual invocation of 'the muscular sense.' This word is used with extreme vagueness to cover all resident sensations, whether of motion or position, in our members, and even to designate the supposed feeling of efferent discharge from the brain. We shall later see good reason to deny the existence of the latter feeling. We have accounted. for the better part at least of the resident feelings of motion in limbs by the sensibility of the articular surfaces. The skin and ligaments also must have feelings awakened as they are stretched or squeezed in flexion or extension. And I am inclined to think that the sensations of our contracting muscles themselves probably play as small a part in building up our exact knowledge of space as any class of sensations which we possess. The muscles, indeed, play an all-important part, but it is through the remote effect of their contractions on other sensitive parts, not through their own resident sensations being aroused. In other words, muscular contraction is only indirectly instrumental, in giving us space-perceptions, by its effects on surfaces. In skin and retina it produces a motion of the stimulus³⁸⁵ upon the surface; in joints it produces a motion of the surfaces upon each other -- such motion being by far the most delicate manner of exciting the surfaces in question. One is tempted to doubt whether the muscular sensibility as such plays even a subordinate part as sign of these more immediately geometrical perceptions which are so uniformly associated with it as effects of the contraction objectively viewed.

For this opinion many reasons can be assigned. First, it seems a priori improbable that such organs as muscles should give us feelings whose variations bear any exact proportion to the spaces traversed when they contract. As G. E. Müller says, 58 their sensory nerves must be excited either chemically or by mechanical compression whilst the contractions last, and in neither case can the excitement be proportionate to the position into which the limb is thrown. The chemical state of the muscle depends on the previous work more than on the actually present contraction; and the internal pressure of it depends on the resistance offered more than on the shortening attained. The intrinsic muscular sensation are likely therefore to be merely those of massive strain or fatigue, and to carry no accurate discrimination with them of lengths of path moved through.

Empirically we find this probability confirmed by many facts. The judicious³⁸⁶ A. W. Volkman observes 59 that:

"Muscular feeling gives tolerably fine evidence as to the existence of movement, but hardly any direct information about its extent or direction. We are not aware that the contractions of a supinator longus have a wider range than those of a supinator brevis; and that the fibres of a bipenniform muscle contract in opposite directions is a fact of which the muscular feeling itself gives not the slightest intimation. Muscle-feeling belong to that class of general sensations which tell us of our inner states, but not of outer relations; it does not belong among the sense-perceiving senses."

E. H. Weber in his article Tastsinn called attention to the fact that muscular movements as large and strong as those of the diaphragm go on continually without our perceiving them as motion.

G. H. Lewes makes the same remark. When we think of our muscular sensations as movements in space, it is because we have ingrained with them in our imagination a movement on a surface simultaneously felt.

"Thus whenever we breathe there is a contraction of the muscles of the ribs³⁸⁷ and the diaphragm. Since we see the chest expanding, we know it as a movement and can only think of it as such. But the diaphragm itself is not seen, and consequently by no one who is not physiologically³⁸⁸ enlightened on the point is this diaphragm thought of in movement. Nay³⁸⁹, even when told by a physiologist that the diaphragm moves at each breathing, every one who has not seen it moving down- ward pictures it as an upward movement, because the chest moves upward." 60

A personal experience of my own seems strongly to corroborate³⁹⁰ this view. For years I have been familiar, during the act of gaping³⁹¹, with a large, round, smooth sensation in tile region of the throat, a sensation characteristic of gaping and nothing else, but which, although I had often wondered about it, never suggested to my mind the motion of anything. The reader probably knows from his own experience exactly what feeling I mean. It was not till one of my students told me, that I learned its objective cause. If we look into the mirror while gaping, we see that at the moment we have this feeling the hanging palate rises by the contraction of its intrinsic muscles. The contraction of these muscles and the compression of the palatine mucous³⁹² membrane are what occasion the feeling; and I was at first astonished that, coming from so small an organ, it could appear so voluminous. Now the curious point is this -- that no sooner had I learned by the eye its objective space-significance, than I found myself enabled mentally to feel it as a movement upwards of a body in the situation of the uvula. When I now have it, my fancy injects it, so to speak, with the image of the rising uvula; and it absorbs the image easily and naturally. In a word, a, muscular contraction gave me a sensation whereof I was unable during forty years to interpret a motor meaning, of which two glances of the eye made me permanently³⁹³ the master. To my mind no further proof is needed of the fact that muscular contraction, merely as such, need not be perceived directly as so much motion through space.

Take again the contractions of the muscles which make the eyeball rotate. The feeling of these is supposed by many writers to play the chief part in our perceptions of extent. The space seen between two things means, according to these authors, nothing but the amount of contraction which is needed to carry the fovea from the first thing to the second. But close the eyes and note the contractions in themselves (even when coupled as they still are with the delicate surface sensations Of the eyeball rolling under the lids), and we are surprised standing how vague their space- import appears. Shut the eyes and roll them, and you call with no approach to accuracy tell the outer object which shall first be seen when you open them again. 61 Moreover, if our eye-muscle-contractions had much to do with giving us our sense of seen extent, we ought to have a natural illusion of which we and no trace. Since the feeling in the muscles grows disproportionately intense as the eyeball is rolled into an extreme eccentric position, all places on the extreme margin of the field of view ought to appear farther from the centre than they really are, for the fovea cannot get to them without an amount of this feeling altogether in excess of the amount of actual rotation. 62 When we turn to the muscles of the body at large we find the same vagueness. Goldscheider found that the minimal perceived rotation of size depend on a comparison of a limb about a joint was no less when the movement was 'active' or produced by muscular contraction than when it was 'passively' impressed. 63 The consciousness of active movement became so blunt when the joint (alone!) was made anæsthetic by faradization, that it became evident that the feeling of contraction could never be used for fine discrimination of extents. And that it was not used for coarse discriminations appeared clear to Goldscheider from certain other results which are too circumstantial for me to quote in detail. 64 His general conclusion is that we feel our movements exclusively in our articular surfaces, and that our muscular contractions in all probability hardly occasion this sort of perception at all. 65

My conclusion is that the 'muscular sense' must fall back to the humble³⁹⁴ position from which Charles Bell raised it, and no longer figure in Psychology as the leading organ in space perception which it has been so long 'cracked up' to be.

Before making a minuter study of Space as apprehended by the eye, we must turn to see what we can discover of space as known to the blind. But as we do so, let us cast a glance upon the results of the last pages, and ask ourselves once more whether the building up of orderly space-perceptions out of primitive incoherency requires any mental powers beyond those displayed in ordinary intellectual operations. I think it is obvious -- granting the spacial qualia to exist in the primitive sensations -- that discrimination, association, addition, multiplication³⁹⁵, and division, blending into generic images, substitution of similars, selective emphasis, and abstraction from uninteresting details, are quite capable of giving us all the space-perceptions we have so far studied, without the aid of any mysterious 'mental chemistry' or power of 'synthesis' to create elements absent from the original data of feeling. It cannot be too strongly urged in the face of mystical attempts, however learned, that there is not a landmark³⁹⁶, not a length, not a point of the compass in real space which is not some one of our feelings, either experienced directly as a presentation or ideally suggested by another feeling which has come to serve as its sign. In degrading some sensations to the rank of signs and exalting³⁹⁷ others to that of realities signified, we smooth out the wrinkles of our first chaotic¹²⁰ impressions and make a continuous order of what was a rather incoherent multiplicity. But the content of the order remains identical with that of the multiplicity -- sensational both, through and through.
How the Blind Perceive Space.

The blind man's construction of real space differs from that of the seeing man most obviously in the larger part which synthesis plays in it, and the relative subordination of analysis. The seeing baby's eyes take in the whole room at once, and discriminative attention must arise in him before single objects are visually discerned. The blind child, on the contrary, must form his mental image of the room by the addition, piece to piece, of parts which he learns to know successively. With our eyes we may apprehend instantly, in an enormous bird's-eye view, a landscape which the blind man is condemned³⁹⁸ to build up bit by bit after weeks perhaps of exploration. We are exactly in his predicament, however, for spaces which exceed our visual range. We think the ocean as a whole by multiplying mentally the impression we get at any moment when at sea. The distance between New York and San Francisco is computed³⁹⁹ in days' journeys; that from earth to sun is so many times the earth's diameter, etc.; and of longer distances still we may be said to have no adequate mental image whatever, but only numerical verbal symbols. But the symbol will often give us the emotional effect of the perception. Such expressions as the abysmal⁴⁰⁰ vault⁴⁰¹ of heaven, the endless expanse of ocean, etc., summarize many computations to the imagination, and give the sense of an enormous horizon. So it seems with the blind. They multiply mentally the amount of a distinctly felt freedom to move, anti gain the immediate sense of a vaster freedom still. Thus it is that blind men are never without the consciousness of their horizon. They all enjoy travelling, especially with a companion. On the prairies the feel the great openness; in valleys they feel closed in; and one has told me that he thought few seeing people could enjoy the view from a mountain-top more than he. A blind person on entering a house or room immediately receives, from the reverberations of his voice and steps, an impression of its dimensions, and to a certain extent of its arrangement. The tympanic sense noticed on p. 140, supra, comes in to help here, and possibly other forms of tactile sensibility not yet understood. Mr. Hank Levy⁴⁰², the blind author of 'Blindness and the Blind' (London), gives the following account of his powers of perception:

"Whether within a house or in the open air, whether walking or standing still, I can tell, although quite blind, when I am opposite an object, and can perceive whether it be tall or short, slender or bulky. I can also detect whether it be a solitary object or a continuous fence; whether it be a close fence or composed of open rails; and often whether it be a wooden fence, a brick or stone wall, or a quick-set hedge. I cannot usually perceive objects if much lower than my shoulder, but sometimes very low objects can be detected. This may depend on the nature of the objects, or on some abnormal state of the atmosphere. The currents of air can have nothing to do with this power, as the state of the wind does not directly affect it; the sense of hearing has nothing to do with it, as when snow lies thickly on the ground objects are more distinct, although the footfall cannot be heard. I seem to perceive objects through the skin of my face, and to have the impressions immediately transmitted to the brain. The only part of my body possessing this power is my face; this I have ascertained⁴⁰³ by suitable experiments. Stopping my ears does not interfere with it, but covering my face with a thick veil destroys it altogether. None of the five senses have anything to do with the existence of this power, and the circumstances above named induce me to call this unrecognized sense by the name of 'facial perception.' . . . When passing along a street I can distinguish shops from private houses, and even point out the doors and windows, etc., and this whether the doors be shut or open. When a window consists of one entire sheet of glass, it is more difficult to discover than one composed of a number of small panes⁴⁰⁴. From this it would appear that glass is a bad conductor of sensation, or at any rate of the sensation specially⁴⁴ connected with this sense. When objects below the face are perceived, the sensation seems to come in an oblique line from the object to the upper part of the face. While walking with a friend in Forest Lane, Stratford, I said, pointing to a fence which separated the road from a Field, 'Those rails are not quite as high as my shoulder.' He looked at them, and said they were higher. We, however, measured, and found them about, three inches lower than my shoulder. At the time of making this observation I was about four feet from the rails. Certainly in this instance facial perception was more accurate than sight. When the lower part of a. fence is brick-work, and the upper part rails, the fact can be detected, and the line where the two meet easily perceived. Irregularities in height, and projections⁴⁰⁶ and indentations in walls, call also be discovered."

According to Mr. Levy, this power of seeing with the face is diminished by a fog, but not by ordinary darkness. At one time he could tell when a cloud obscured the horizon, but he has now lost that power, which he has known several persons to possess who are totally blind. These effects of aqueous vapor⁴⁰⁷ suggest immediately that fluctuations⁴⁰⁸ in the heat radiated by the objects may be the source of the perception. One blind gentleman, Mr. Kilburne, an instructor⁴⁰⁹ in the Perkins Institution in South Boston, who has the power spoken of in an unusual degree, proved, however, to have no more delicate a sense of temperature in his face than ordinary persons. He himself supposed that his ears had nothing to do with the faculty until a complete stoppage of them, not only with cotton but with putty on top of it, by abolishing the perception entirely, proved his first impression to be erroneous. Many blind men say immediately that their ears are concerned in the matter. Sounds certainly play a far more prominent part in the mental Life of the blind than in our own. In taking a walk through the country, the mutations of sound, far and near, constitute their chief delight. And to a, great extent their imagination of distance and of objects moving from one distant spot to another seems to consist in thinking how a certain sonority⁴¹⁰ would be modified by the change of place. It is unquestionable that the semi-circular-canal feelings play a great part in determining the points of the compass and the direction of distant spots, in the blind as in us. We start towards them by feelings of this sort; and so many directions, so many different-feeling starts. 66

The only point that offers any theoretic difficulty is the prolongation into space of the direction, after the start. We saw, ten pages back, that for extradition to occur beyond the skin, the portion of skin in question and the space beyond must form a common object for some other sensory surface. The eyes are for most of us this sensory surface; for the blind it can only be other parts of the skin, coupled or not with motion. But the mere gropings of the hands in every direction must end by surrounding the whole body with a sphere of felt space. And this sphere must become enlarged with every movement of locomotion, these movements gaining their space-values from the semi-circular-canal feelings which accompany them, and from the farther and farther parts of large fixed objects (such as the bed, the wainscoting, or a fence) which they bring within the grasp. It might be supposed that a knowledge of space acquired by so many successive discrete⁴¹¹ acts would always retain a somewhat jointed⁴¹² and so to speak, granulated character. When we who are gifted with sight think of a space too large to come into a single field of view, we are apt to imagine it as composite, and fined with more or less jerky stoppings and startings (think, for instance, of the space from here to San Francisco), or else we reduce the scale symbolically⁴¹³ and imagine how much larger on a map the distance would look than others with whose totality we are familiar.

I am disposed to believe, after interrogating⁴¹⁴ many blind persons, that the use of imaginary maps on a reduced scale is less frequent with them than With the rest of us. Possibly the extraordinary changeableness of the visual magnitudes of things makes this habit natural to us, while the fixity of tactile magnitudes keeps them from falling into it. (When the blind young mall operated on by Dr. Franz was shown a, portrait in a locket, he was vastly surprised that the face could be put into so small a compass: it would have seemed to him, he said, as impossible as to put a bushel into a pint⁴¹⁵.) Be this as it may, however, the space which each blind man feels to extend beyond his body is felt by him as one smooth continuum -- all trace of those muscular startings and stoppings and reversals which presided over its formation having been eliminated from the memory. It seems, in other words, a generic image of the space-element common to all these experiences, with the unessential particularities of each left out. In truth, where in this space a start or a, stop may have occurred was quite accidental. It may never occur just there again, and so the attention lets it drops altogether. Even as long a space as that traversed in a several-mile walk will not necessarily appear to a blind man's thought in the guise⁴¹⁶ of a series of locomotor acts. Only where there is some distinct locomotor difficulty, such as a, step to ascend⁴¹⁷, a difficult crossing, or a disappearance of the path, will distinct locomotor images constitute the idea. Elsewhere the space seems continuous, and its parts may even all seem coexistent; though, as a very intelligent blind friend once remarked to me, 'To think of such distances involves probably more mental wear and tear and brain-waste in the blind than in the seeing.' This seems to point to a greater element of successive addition and construction in the blind mans idea.

Our own visual explorations go on by means of innumerable stoppings and startings of the eyeballs. Yet these are all effaced⁴¹⁸ from the final space-sphere of our visual imagination. They have neutralized⁴¹⁹ each other. We can even distribute our attention to the right and left side simultaneously, and think of those two quarters of space as coexistent. Does the smoothing out of the locomotor interruptions from the blind man's tactile space-sphere offer any greater paradox⁴²⁰? Surely not. And it is curious to note that both in him and in us there is one particular locomotor feeling that is apt to assert itself obstinately⁴²¹ to the last. We and he alike spontaneously imagine space as lying in front of us, for reasons too obvious to enumerate⁴²². If we think of the space behind us, we, as a rule, have to turn round mentally, and in doing so the front space vanishes. But in this, as in the other things of which we have been talking, individuals differ widely. Some, in imagining a room, can think of all its six surfaces at once. Others mentally turn round, or, at least, imagine the room in several successive and mutually exclusive acts (cf. p. 54, above).

Sir William Hamilton, and J. S. Mill after him have quoted approvingly an opinion of Platner (an eighteenth-century philosopher) regarding the space-perceptions of the blind. Platner says:

"The attentive⁵⁷ observation of it person born blind . . . has convinced me that the sense of touch by itself is altogether incompetent⁴²³ to afford us the representation of extension and space. . . . In fact, to those born blind, time serves instead of space. Vicinity and distance mean in their mouths nothing more than the shorter or longer time . . . necessary to attain³⁵⁰ from some one feeling to some other."

After my own observation of blind people, I should hardly have considered this as anything but an eccentric opinion, worthy to pair off with that other belief that color is primitively seen without extent, had it not been for the remarkable Essay on Tactile and Visual Space by M. Ch. Dunan, which appeared in the Revue Philosophique for 1888. This author quotes 67 three very competent witnesses, all officials in institutions for the blind [it does not appear from the text that more than one of them was blind himself], who say that blind people only live in time. M. Dunan himself does not share exactly this belief, but he insists that the blind man's and the seeing man's representation of space have absolutely naught⁴²⁴ in common, and that we are deceived into believing that what they mean by space is analogous to what we mean, by the fact that so many of them are but semi-blind and still think in visual terms, and from the farther fact that they all talk in visual terms just like ourselves. But on examining M. Dunan's reasons one finds that they all rest on the groundless logical assumption that the perception of a geometrical form which we get with our eyes, and that which a blind man gets with his fingers, must either be absolutely identical or absolutely unlike. They cannot be similar in diversity, "for they are simple notions, and it is of the essence of such to enter the mind or leave it all at once, so that one who has a simple notion at all, possesses it in all its completeness. . . . Therefore, since it is impossible that the blind should have of the forms in question ideas completely identical with our seeing ones, it follows that their ideas must be radically⁴²⁶ different from and wholly irreducible to our own." 69 Hereupon M. Dunan has no difficulty in finding a blind man who still preserves a crude sensation of diffused⁴²⁷ light, and who says when questioned that this light has no extent. Having 'no extent' appears, however, on farther questioning, to signify merely not enveloping any particular tactile objects, nor being located within their outline; so that (allowing for latitude⁴²⁸ of expression) the result tallies⁴²⁹ perfectly with our own view. A relatively stagnant⁴³⁰ retinal sensation of diffused light, not varying when different objects are handled, would naturally remain an object quite apart. If the word 'extent' were habitually used to denote tactile extent, this sensation, having no tactile associates whatever, would naturally have 'extent' denied of it. And yet all the while it would be analogous to the tactile sensations in having the quality of bigness. Of course it would have no other tactile qualities, just as the tactile objects have no other optical qualities than bigness. All sorts of analogies obtain between the spheres of sensibility. Why are 'sweet' and 'soft' used so synonymously in most languages? and why are both these adjectives applied⁴³¹ to objects of so many sensible kinds. Bough⁴³² sounds, heavy smells, hard lights, cold colors, are other examples. Nor does it follow from such analogies as these that the sensations compared need be composite and have some of their parts identical. We saw in Chapter XIII that likeness¹⁷⁰ and difference are an elementary relation, not to be resolved in every case into a mixture of absolute identity and absolute heterogeneity⁴³³ of content (cf. Vol. I, pp. 492-3).

I conclude, then, that although in its more superficial determinations the blind man's space is very different from space, yet a deep analogy remains between the two. 'Big' and 'little,' (far' and 'near,' are similar contents of consciousness in both of us. But the measure of the bigness and the farness is very different in him and in ourselves. He, for example, can have no notion of what we mean by objects appearing smaller as they move away, because he must always conceive of them as of their constant tactile size. Nor, whatever analogy the two extensions involve, should we expect that a, blind man receiving sight for the first time should recognize his new-given optical objects by their familiar tactile names. Molyneux wrote to Locke:

"Suppose a man born blind, and now adult, and taught by his touch to distinguish between a cube and a sphere, so as to tell, when he felt one and the other, which is the cube, which the sphere. Suppose then the cube and sphere placed on a table and the blind man to be made to see; query, whether by his sight, before he touched them, he could now distinguish and tell which is the globe, which the cube?"

This has remained in literature as 'Molyneux's query.' Molyneux answered 'No.' And Locke says: 70

"I agree with this thinking gentleman whom I am proud to call my friend, and am of opinion that the blind man at first sight would not be able to say which was the globe, which the cube, whilst he only saw them; though he could unerringly name them by his touch and certainly distinguish them by the difference of their figures felt."

This opinion has not lacked experimental confirmation⁴³⁴. From Chesselden's case downwards, patients operated for congenital cataract have been unable to name at first the things they saw. "So, Puss, I shall know you another time," said Chesselden's patient, after catching the cat, looking at her steadfastly⁴³⁵, and setting her down. Some of this incapacity is unquestionably due to general mental confusion at the new experience, and to the excessively unfavorable conditions for perception which an eye with its lens just extirpated⁴³⁶ affords. That the analogy of inner nature between the retinal and tactile sensations goes beyond mere extensity is proved by the cases where tile patients were the most intelligent, as in the young man operated on by Dr Franz, who named circular, triangular¹⁵², and quadrangular figures at first sight. 71
Visual Space.

It is when we come to analyze minutely the conditions of visual perception that difficulties arise which have made psychologists appeal to new and quasi-mythical mental powers. But I firmly believe that even here exact investigation will yield the same verdict as in the cases studied hitherto. This subject will close our survey of the facts; and if it give the result I foretell⁴³⁷, we shall be in the best of positions for a few banal⁴³⁸ pages of critically historical review.

If a common person is asked how he is enabled to see things as they are, he will simply reply, by opening his eyes and looking. This innocent answer has, however, long since been impossible for science. There are various paradoxes⁴³⁹ and irregularities about what we appear to perceive under seemingly identical optical conditions, which immediately raise questions. To say nothing now of the time-honored conundrums⁴⁴⁰ of why we see upright with an inverted retinal picture, and why we do not see double; and to leave aside the whole field of color-contrasts and ambiguities⁴⁴¹, as not directly relevant to the space-problem, -- it is certain that the same retinal image makes us see quite differently-sized and differently-shaped objects at different times, and it is equally certain that the same ocular movement varies in its perceptive import. It ought to be possible, were the act of perception completely and simply intelligible⁴⁴², to assign for every distinct judgment of size, shape, and position a distinct optical modification¹⁹⁶ of some kind as its occasion. And the connection between the two ought to be so constant that, given the same modification, we should always have the same judgment. But if we study the facts closely we soon and no such constant connection between either judgment and retinal modification, or judgment and muscular modification, to exist. The judgment seems to result from the combination of retinal, muscular and intellectual factors with each other; and any one of them may occasionally overpower the rest in a way which seems to leave the matter subject to no simple law. The scientific study of the subject, if we omit Descartes, began with Berkeley, and the particular perception he analyzed⁴⁴³ in his New Theory of Vision was that of distance or depth. Starting with the physical assumption that a difference in the distance of a point can make no difference in the nature of its retinal image, since "distance being a line directed endwise to the eye, it projects only one point in the fund of the eye -- which point remains invariably the same, whether the distance be longer or shorter," he concluded that distance could not possibly be a visual sensation, but must be an intellectual 'suggestion ' from 'custom' of some non-visual experience. According to Berkeley this experience was tactile. His whole treatment of the subject was excessively vague, -- no shame to him, as a breaker of fresh ground, -- but as it has been adopted and enthusiastically hugged in all its vagueness by nearly the whole line of British psychologists who have succeeded him, it will be well for us to begin our study of vision by refuting his notion that depth cannot possibly be perceived in terms of purely visual feeling.
The Third Dimension.

Berkeleyans unanimously assume that no retinal sensation can primitively be of volume; if it be of extension at all (which they are barely disposed to admit), it call be only of two-, not of three-, dimensional extension. At the beginning of the present chapter we denied this, and adduced facts to show that all objects of sensation are voluminous in three dimensions (cf. p. 136 if.). It is impossible to lie on one's back on a hill, to let tile empty abyss of blue one's whole visual field, and to sink deeper and deeper into the merely sensational mode of consciousness regarding it, without feeling: that an indeterminate, palpitating, circling depth is as indefeasibly one of its attributes as its breadth. We may artificially exaggerate this sensation of depth. Rise and look from the hill-top at the distant view; represent to yourself as vividly as possible the distance of the uttermost horizon; and then with inverted head look at the same. There will be a startling increase in the perspective, a most sensible recession of the maximum distance; and as you raise the head you can actually see the horizon-line again draw near. 72

Mind, I say nothing as yet about our estimate of the 'real' amount of this depth or distance. I only want to confirm its existence as a natural and inevitable⁴⁴⁴ optical consort⁴⁴⁵ of the two other optical dimensions. The held of view is always a volume-unit. Whatever be supposed to be its absolute and 'real' size, the relative sizes of its dimensions are functions of each other. Indeed, it happens perhaps most often that the breadth- and height-feeling take their absolute measure from the depth-feeling. If we plunge⁴⁴⁶ our head into a wash-basin, the felt nearness of the bottom makes us feel the lateral expanse to be small. If, on the contrary, we are on a mountain-top, the distance of the horizon carries with it in our judgment a proportionate height and length in the mountain-chains that bound it to our view. But as aforesaid, let us not consider the question of absolute size now, -- it must later be taken up in a thorough way. Let us confine ourselves to the way in which the three dimensions which are seen, get their values fixed relatively to each other.

Reid, in his Inquiry into tile Human Mind, has a section 'Of the Geometry of Visibles,' in which he assumes to trace what the perceptions would be of a race of 'Idomenians' reduced to the sole sense of sight. Agreeing with Berkeley that sight alone can give no knowledge of the third dimension, he humorously deduces various ingenious absurdities⁴⁴⁷ in their interpretations⁴⁴⁹ of the material appearances before their eyes.

Now I firmly believe, on the contrary, that one of Reid's Idomenians would frame precisely the same conception of the external world that we do, if he had our intellectual powers. 73 Even were his very eyeballs fixed and not movable like ours, that would only retard⁴⁵⁰, not frustrate⁴⁵¹, his education. For the same object, by alternately covering in its lateral movements different parts of his retina, would determine the mutual equivalencies of the first two dimensions of the held of view; and by exciting the physiological cause of his perception of depth in various degrees, it would establish a scale of equivalency between the first two and the third.

First of all, one of the sensations given by the object is chosen to represent its 'real' size and shape, in accordance with the principles laid down on pp. 178 and 179. One sensation measures the 'thing' present, and the 'thing' then measures the other sensations. The peripheral parts of the retina are equated⁴⁵² with the central by receiving the image of the same object. This needs no elucidation⁴⁵³ in case the object does not change its distance or its front. But suppose, to take a more complicated case, that the object is a stick, seen first in its whole length, and then rotated round one of its ends; let this fixed end be the one near the eye. In this movement the stick's image will grow progressively shorter; its farther end will appear less and less separated laterally⁴⁵⁴ from its fixed near end; soon it will be screened by the latter, and then reappear on the opposite side, and finally on that side resume its original length. Suppose this movement to become a familiar experience; the mind will presumably react upon it after its usual fashion (which is that of unifying⁴⁵⁵ all data which it is in any way possible to unify), and consider it the movement of a constant object rather than the transformation⁴⁵⁶ of a fluctuating one. Now, the sensation of depth which it receives during the experience is awakened more by the far than by the near end of the object. But how much depth? What shall measure its amount? Why, at the moment the far end is ready to be eclipsed, the difference of its distance from the near end's distance must be judged equal to the stick's whole length; but that length has already been judged equal to a certain optical sensation of breadth. Thus we find that given amounts of the visual depth-feeling become signs of given amounts of the visual depth-feeling. The measurement of distance is, as Berkeley truly said, a result of suggestion and experience. But visual experience alone is adequate to produce it, and this he erroneously denied.

Suppose a colonel in front of his regiment⁴⁵⁷ at dress-parade, and suppose he walks at right angles towards the midmost mall of the line. As he advances, and surveys the line in either direction, he looks more and more down it and less and less at it, until, when abreast⁴⁵⁸ of the midmost man, he feels the end men to be most distant; then when the line casts hardly any lateral image on his retina at all, what distance shall lie judge to be that of the end men? Why, half the length of the regiment as it was originally seen, of course; but this length was a moment ago a retinal object spread out laterally before his sight. He has now merely equated a retinal depth-feeling with a retinal breadth-feeling. If the regiment moved, and the near end of the object. colonel stood still, the result would be the same. In such ways as these a creature endowed with eyes alone could hardly fail of measuring out all three dimensions of the space he inhabited. And we ourselves, I think, although we may often 'realize' distance in locomotor terms (as Berkeley says we must always do), yet do so no less often in terms of our retinal map, and always in this the more spontaneously. Were this not so, the three visual dimensions could not possibly feel to us as homogeneous as they do, nor as commensurable inter se.

Let us then admit distance to be at least as genuinely optical a content of consciousness as either height or breadth. The question immediately returns, Can any of them be said in any strictness to be optical sensations? We have contended all along for the affirmative reply to this question, but must now cope with difficulties greater than any that have assailed⁴⁵⁹ us hitherto.
Helmholtz and Reid on Sensations

.

A sensation is, as we have seen in Chapter XVII, the mental affection that follows most immediately upon the stimulation of the sense-tract. Its antecedent is directly physical, no psychic links, no acts of memory, inference, or association intervening. Accordingly, if suppose the nexus⁴⁶⁰ between neural⁴ process in the sense-organ, on the one hand, and conscious affection, on the other, to be by nature uniform, the same process ought always to give the same sensation; and conversely, if what seems to be a sensation varies whilst the process in the sense-organ remains unchanged, the reason is presumably that it is really not a sensation but a higher mental product, whereof the variations depend on events occurring in the system of higher cerebral centres.

Now the size of the field of view varies enormously in all three dimensions, without our being able to assign with any definiteness the process in the visual tract on which the variation depends. We just saw how impossible such assignment was in the case where turning down the head produces the enlargement. In general, the maximum feeling of depth or distance seems to take the lead in determining the apparent magnitude of the whole field, and the two other dimensions seem to follow. If, to use the former instance, I look close into a wash-basin, the lateral extent of the field shrinks proportionately to its nearness. If I look from a mountain, the things seen are vast in height and breadth, in proportion to the farness of the horizon. But when we ask what changes in the eye determine how great this maximum feeling of depth or distance (which is undoubtedly felt as a unitary vastness) shall be, we find ourselves unable to point to any one of them as being its absolutely regular concomitant. Convergence, accommodation, double and disparate images, differences in the parallactic displacement³⁷² when we move our head, faintness of tint⁴⁶², dimness of outline, and smallness of the retinal image of objects named and known, are all processes that have something to do with the perception of 'far' and of 'near'; but the effect of each and ally one of them in determining such a perception at one moment may at another moment be reversed by the presence of some other sensible quality in the object, that makes us, evidently by reminding us of past experience, judge it to be at a different distance and of another shape. If we paint the inside of a pasteboard-mask like the outside, and look at it with one eye, the accommodation- and parallax-feelings ape there, but fail to make us see it hollow, as it is. Our mental knowledge of the fact that human faces are always convex overpowers them, and we directly perceive the nose to be nearer to us than the cheek instead of farther of.

The other organic tokens of farness and nearness are proved by similar experiments (of which we shall ere long speak more in detail) to have an equally fluctuating import. They lose all their value whenever the collateral⁴⁶³ circumstances favor a strong intellectual conviction that the object presented to the gaze is improbable -- cannot be either what or where they would make us perceive it to be.

Now the query immediately arises: Can the feelings of these processes in the eye, since they are so easily neutralized and reversed by intellectual suggestions, ever have been direct sensations of distance at all? Ought we not rather to assume, since the distances which me see in spite of them are conclusions from past experience, that the distances which we see by means of them are equally such conclusions? Ought we not, in short, to say "unhesitatingly that distance must be an intellectual and not a sensible content of consciousness? and that each of these eye-feelings serves as a mere signal to awaken this content, our intellect being so framed that sometimes it notices one signal more readily and sometimes another?

Reid long ago (Inquiry, c. vi sec. 17) said:

"It may be taken for a general rule that things which are produced by custom may be undone⁴⁶⁴ or changed by disuse or by contrary custom. On the other hand, it is a strong argument that an effect is not owning to custom, but to the constitution of nature, when a contrary custom is found neither nor to weaken it."

More briefly, a way of seeing things that can be unlearned was presumably learned, and only what we cannot unlearn is instinctive.

This seems to be Helmholtz's view, for he confirms Reid's maxim³⁰ by saying in emphatic print:

"No elements in our perception can he sensational which may be overcome or reversed by factors of demonstrably experimental origin. Whatever can be overcome by suggestions of experience must be regarded as itself a product of experience and custom. If we follow this rule it will appear that only qualities are sensational, whilst almost all spatial attributes are results of habit and experience." 74

This passage of Helmholtz's has obtained, it seems to me, an almost deplorable celebrity⁴⁶⁵. The reader will please observe its very radical⁴²⁵ import. Not only would he, and does he, for the reasons we have just been ourselves considering, deny distance to be an optical sensation; but, extending the same method of criticism to judgments⁴⁶⁶ of size, shape, and direction, and finding no single retinal or muscular process in the eyes to be indissolubly linked with any one of these, he goes so far as to say that all optical space-perceptions whatsoever must have an intellectual origin, and a content that no items of visual sensibility can account for. 75

As Wundt and others agree with Helmholtz here, and as their conclusions, if true, are irreconcilable⁴⁶⁷ with all the sensationalism which I have been teaching hitherto, it clearly devolves upon me to defend my position against this new attack. But as this chapter on Space is already so overgrown with episodes and details, I think it best to reserve the refutation of their general principle for the next chapter, and simply to assume at this point its untenability. This has of course an arrogant⁴⁶⁸ look; but if the reader will bear with me for not very many pages more, I shall hope to appease⁴⁶⁹ his mind. Meanwhile I affirm confidently that the same outer objects actually FEEL different to us according as our brain reacts on them in one way or another by making us perceive them as this or as that sort of thing. So true is this that one may well, with Stumpf, 76 reverse Helmholtz's query, and ask: "What would become of our sense-perceptions in case experience were not able so to transform them?" Stumpf adds: "All wrong perceptions that depend on peculiarities in the organs are more or less perfectly corrected by the influence of imagination following the guidance of experience."

If, therefore, among the facts of optical space-perception (which we must now proceed to consider in more detail) we find instances of an identical organic eye-process, giving us different perceptions at different times, in consequence of different collateral circumstances suggesting different objective facts to our imagination, we must not hastily conclude, with the school of Helmholtz and Wundt, that the organic eye-process pure and simple, without the collateral circumstances, is incapable⁴⁷⁰ of giving us any sensation of a spatial kind at all. We must rather seek to discover by what means the circumstances can so have transformed a space-sensation, which, but for their presence, would probably have been felt in its natural purity. And I may as well say now in advance that we shall find the means to be nothing more or less than association -- the suggestion to the mind of optical objects not actually present, but more habitually associated with the 'collateral circumstances' than the sensation which they now displace and being imagined now with a quasi-hallucinatory strength. But before this conclusion emerges, it will be necessary to have reviewed the most important facts of optical space-perception, in relation to the organic conditions on which they depend. Readers acquainted with German optics will excuse what is already familiar to them in the following section. 77 Let us begin the long and rather tedious inquiry by the most important case. Physiologists have long sought for a simple law by which to connect the seen direction and distance of objects with the retinal impressions they produce. Two principal theories have been held of this matter, the 'theory of identical points', and the 'theory of projection' -- each incompatible⁴⁷¹ with each other, and each beyond certain limits becoming inconsistent with the facts.
The Theory of Identical Points.

This theory starts from the truth that on both retinæ an impression on the upper half makes us perceive an object as below, on the lower half as above, the horizon; and
 

on the right half an object to the left, on the left half one to the right, of the median line. Thus each quadrant of one retina corresponds as a whole to the similar quadrant of the other; and within two similar quadrants, al and ar for example, there should, if the correspondence were consistently carried out, be geometrically similar points which, if impressed at the same time by light emitted from the same object, should cause that object to appear in the same direction to either eye. Experiment verifies this surmise⁴⁷². I we look at the starry⁴⁷³ vault with parallel eyes, the stars all seem single; and the laws of perspective show that under the circumstances the parallel light-rays coming from each star must impinge on points within either retina which are geometrically similar to each other. The same result may be more artificially obtained. If we take two exactly similar pictures, smaller, or at least no larger, than those on an ordinary stereoscopic slide, and if we look at them as stereoscopic slides are looked at, that is, at one with each eye (a median partition confining the view of either eye to the picture opposite it), we shall see but one flat picture, all of whose parts appear sharp and single. 78 Identical points being impressed, both eyes see their object in the same direction, and the two objects consequently coalesce into one.

The same thing may be shown in still another way. With fixed head converge²²⁸ the eyes upon some conspicuous objective point behind a pane⁴⁰⁵ of glass; then close either eye alternately and make a little ink-mark on the glass, 'covering' the object as seen by the eye which is momentarily open. On looking now with both eyes the ink-marks will seem single, and in the same direction as the objective point. Conversely, let the eyes converge on a single inkspot on the glass, and then by alternate shutting of them let it be noted what objects behind the glass the spot covers to the right and left eye respectively. Now with both eyes open, both these objects and the spot will appear in the same place, one or other of the three becoming distinct according to the fluctuations of retinal attention. 79

Now what is the direction of this common place? The only way of defining the direction of an object is by pointing to it. Most people, if asked to look at an object over the horizontal edge of a sheet of paper which conceals⁴⁷⁵ their hand and arm, and then to point their finger at it (raising the hand gradually so that at lest a finger-tip will appear above the sheet of paper), are found to place the finger not between either eye and the object, but between the latter and the root of the nose, and this whether both eyes or either alone be used. Hering and Helmholtz express this by saying that we judge of the direction of objects as they would appear to an imaginary cyclopean eye, situated⁴⁷⁶ between our two real eyes, and with its optical axis⁴⁷⁷ bisecting the angle of convergence of the latter. Our two retinæ act, according to Hering, as if they were superposed in the place of this Imaginary double-eye; we see by the corresponding points of each, situated far asunder as they really are, just as we should see if they were superposed and could both be excited together.

The judgment of objective singleness and that of identical direction seem to hang necessarily together. And that of identical direction seems to carry with it the necessity of a common origin, between the eyes or elsewhere, from which all the directions felt may seem to be estimated. This is why the cyclopean eye is really a fundamental part of the formulation of the theory of identical retinal points, and why Hering, the greatest champion of this theory, lays so much stress upon it.

It is an immediate consequence of the law of identical projection of images on geometrically similar points that images which fall upon geometrically DISPARATE points of the two retinæ should be projected in DISPARATE directions, and that their objects should consequently appear in TWO places, or LOOK DOUBLE . Take the parallel rays from a star falling upon two eyes which converge upon a near object, 0, instead of being parallel, as in the previously instanced case. If SL and SR in Fig⁸⁵. 55 be the parallel rays, each of them will fall upon the nasal half of the retina which it strikes.
 

But the two nasal halves are disparate, geometrically symmetrical, not geometrically similar. The image on the left one will therefore appear as if lying in a direction leftward of the cyclopean eye's line of sight; the image of the right one will appear far to the right of the same direction. The star will, in short, be seen double, -- 'homonymously' double.

Conversely, if the star be looked at directly with parallel axes, O will be seen double, because its images will effect the outer or cheek halves of the two retinæ, instead of one outer and one nasal half. The position of the images will here be reversed from that of the previous case. The right eye's image will now appear to the left, the left eye's to the right -- the double images will be 'heteronymous.'

The same reasoning and the same result ought to apply where the object's place with respect to the direction of the two optic axes is such as to make its images fall not on non-similar retinal halves, but on non-similar parts of similar halves. Here, of course, the directions of projection will be less widely disparate than in the other case, and the double images will appear to lie less widely apart.

Careful experiments made by many observers according to the so-called haploscopic method confirm this law, and show that corresponding points of single visual direction, exist upon the two retinæ. For the detail of these one must consult the special treatises⁴⁷⁸.

Note now an important consequence, If we take a stationary object and allow the eyes to vary their direction and convergence, a purely geometrical study will show that there will be some positions in which its two images impress corresponding retinal points, but more in which they impress disparate points. The former constitute the so-called horopter, and their discovery has been attended with great mathematical difficulty. Objects or parts of objects which lie in the eyes' horopter at any given time cannot appear double. Objects lying out of the horopter would seem, if the theory of identical points were strictly true, necessarily and always to appear double.

Here comes the first great conflict of the identity-theory with experience. Were the theory true, we ought ail⁴⁶ to have an intuitive knowledge of the horopter as the line of distinctest vision. Objects placed elsewhere ought to seem, if not actually double, at least blurred. And yet no living man makes any such distinction between the parts of his field of vision. To most of us the whole field appears single, and it is only by rare accident or by special education that we ever catch a glimpse of a double image. In 1838, Wheatstone, in his truly classical memoir⁴⁷⁹ on binocular vision and the stereoscope, 80 showed that the disparateness of the points on which the two images of an object fall does not within certain limits affect its seen singleness at all, but rather the distance at which it shell appear. Wheatstone made an observation, moreover, which subsequently became the bone of much hot contention⁴⁸⁰, in which he strove to show that not only might disparate images fuse, but images on corresponding or identical points might be seen double. 81

I am unfortunately prevented by the weakness of my own eyes from experimenting enough to form a decided personal opinion on the matter. It seems to me, however, that the balance of evidence is against the Wheatstonian interpretation⁴⁴⁸, and that disparate points may fuse, without identical points for that reason ever giving double images. The two questions, "Can we see single with disparate points?" and "Can we see double with identical points?" although at the first blush they may appear, as to Helmholtz they appear, to be but two modes of expressing the same inquiry, are in reality distinct. The first may quite well be answered affirmatively and the second negatively.

Add to this that the experiment quoted from Helmholtz above by no means always succeeds, but that many individuals place their finger between the object and one of their eyes, oftenest the right; 82 finally, observe that the identity-theory, with its Cyclopean starting point for all lines of direction, gives by itself no ground for the distance on any line at which an object shall appear, and has to be helped out in this respect by subsidiary hypotheses, which, in the hands of Hering and others, have become so complex as easily to fall a prey to critical attacks; and it will soon seem as if the law of identical seen directions by corresponding points, although a simple formula for expressing concisely⁴⁸¹ many fundamental phenomena, is by no means an adequate account of the whole matter of retinal perception. 83
The Projection-Theory.

Does the theory of projection fare any better? This theory admits that each eye sees the object in a different direction from the other, along the line, namely, passing from the object through the middle of the pupil to the retina. A point directly which these two optical axes have in common, and that is the point to which they converge. Everything directly looked at is seen at this point, and is thus seen both single and at its proper distance. It is easy to show the incompatibility⁴⁸² of this theory with the theory of identity. Take an objective point (like O in Fig. 50, when the star is looked at) casting its images R' and L' on geometrically dissimilar parts of the two retinæ and affecting the outer half of each eye. On the identity-theory it ought necessarily to appear double, whilst on the projection-theory there is no reason whatever why it should not appear single, provided only it be located by the judgment on each line of visible direction, neither nearer nor farther than its point of intersection⁴⁸³ with the other line.

Every point in the field of view ought, in truth, if the projection-theory were uniformly valid⁴⁸⁴, to appear single, entirely irrespective of the varying positions of the eyes, for from every point of space two lines of visible direction pass to the two retinæ and at the intersection of these lines, or just where the point is, there, according to the theory, it should appear. The objection to this theory is thus precisely the reverse of the objection to the identity-theory. If the latter ruled, we ought to see most things double all the time. If the projection-theory ruled, we ought never to see anything double. As a matter of fact we get too few double images for the identity-theory, and too many for the projection-theory.

The partisans⁴⁸⁵ of the projection-theory, beginning with

Aguilonius, have always explained double images as the result of an erroneous judgment of the distance of the object, the images of the latter being projected by the imagination along the two lines of visible direction either nearer or farther than the point of intersection of the latter. diagram will make this clear.

Let O be the point looked at, M an object farther, and N an object nearer, than it. Then M and N will send the lines of visible direction MM and NN to the two retinæ. If N be judged as far as O, it must necessarily lie where the two lines of visible direction NN intersect the plane of the arrow, or in two places, at N' and at N". If M be judged as near as O, it must for the same reason form two images at M' and M".

It is, as a matter of fact, true that we often misjudge the distance in the way alleged⁴⁸⁶. If the reader will hold his forefingers, one beyond the other, in the median line, and fixate them alternately, he will see the one not looked at, double; and he will also notice that it appears nearer to the plane of the one looked at, whichever the latter may be, than it really is. Its changes of apparent size, as the convergence of the eyes, alter also prove the change of apparent distance. The distance at which the axes converge seems, in fact, to exert a sort of attraction upon objects situated elsewhere. Being the distance of which we are most acutely sensible, it invades, so to speak, the whole held of our perception. If two half-dollars be laid on the table an inch or two apart, and the eyes fixate steadily the point of a pen held in the median line at varying distances between the coins and the face, there will come a distance at which the pen stands between the left half-dollar and the right eye, and the right half-dollar and the left eye. The two half-dollars will then coalesce into one; and this one will show its apparent approach to the pen-point by seeming Suddenly much reduced in size. 84

Yet, in spite of this tendency to inaccuracy we are never actually mistaken about the half-dollar being behind the pen-point. It may not seem far enough off, but still it is farther than the point. In general it may be said that where the objects are known to us, no such inclusion of distance occurs in any one as the theory would require. And in some observers, Hering for example, it seems hardly to occur at all. If I look into infinite distance and get my finger in double images, they do not seem infinitely far off. To make objects at different distances seem equidistant, careful precautions must be taken to have them alike in appearance, and to exclude all outward reasons for ascribing to the one a different location from that ascribed to the other. Thus Donders tries to prove the law of projection by taking two similar electric sparks, one behind the other on a dark ground, one seen double; or an iron rod placed so near to the eyes that its double images seem as broad as that of a fixated stove-pipe, the top and bottom of the objects being cut off by screens, so as to prevent all suggestions of perspective, etc. The three objects in each experiment seem in the same plane. 85

Add to this the impossibility, recognized by all observers, of ever seeing double with the foveæ, and the fact that authorities as able as those quoted in the note on Wheatstone's observation deny that they can see double then with identical points, and we are forced to conclude that the projection-theory, like its predecessor⁴⁸⁷, breaks down. Neither formulates⁴⁸⁸ exactly or exhaustively a law for all our perceptions.
Ambiguity of Retinal Impressions
 

What does each theory try to do? To make of seen location a fixed function of retinal impressions. Other facts may be brought forward to show how far from fixed are the perceptive functions of retinal impressions. We alluded⁴⁸⁹ a while ago to the extraordinary ambiguity of the retinal image as a revealer of magnitude. Produce an after-image of the sun and look at your finger-tip: it will be smaller than your nail. Project it on the table, and it will be as big as a strawberry; on the wall, as large as a plate; on yonder mountain, bigger than a house. And yet it is an unchanged retinal impression. Prepare a sheet with the figures shown in Fig. 57 strongly marked upon it, and get by direct fixation a distinct after-image of each.

Project the after-image of the cross upon the upper left- hand part of the well, it min appear as in Fig. 58; on the upper right-hand it will appear as in Fig. 59. The circle

similarly projected will be distorted into two different ellipses⁴⁹⁰. If the two parallel lines be projected upon the ceiling or floor far in front, the farther ends will diverge; and if the three parallel lines be thrown on the same surfaces, the upper pair will seem farther apart than the lower. Adding certain lines to others has the same distorting effect. In what is known as Zöllner's pattern (Pig. 60), the long parallels tip towards each other the moment we draw the short slanting⁴⁹¹ lines over them yet their retinal images

are the same they always were. A similar distortion of parallels appears in Pig 61. Drawing a square inside the circle (Fig. 52) gives to the outline of the latter an indented⁴⁹² appearance where the square's corners touch it. Drawing the radii of one

of the right angles in the same figure makes it seem larger than the other. In Fig. 63, the retinal image of the space between the extreme dots is in all three lines the same, yet it seems much larger the moment it is filled up with other dots.

In the stereoscope certain pairs of lines which look single under ordinary circumstances immediately seem double when we add certain other lines to them.


Ambiguous Import of Eye-movements.

These facts show the indeterminateness of the space-import of various retinal impressions. Take now the eye's movements, and we find a similar vacillation⁴⁹³. When we follow a moving object with our gaze, the motion is 'voluntary'; when our eyes oscillate to and fro after we have made ourselves dizzy by spinning around, it is 'reflex'; and when the eyeball is pushed with the finger, it is 'passive.' Now, in all three of these cases we get a feeling from the movement as it effects itself. But the objective perceptions to which the feeling assists us are by no means the same. In the worst case we may see a stationary field of view with one moving object in it; in the second, the total held swimming more or less steadily in one direction in the third, a sudden lump or twist of the same total held.

The feelings of convergence of the eyeballs permit of the same ambiguous interpretation. When objects are near we converge strongly upon them in order to see them; when far, we set our optic axes parallel. But the exact degree of convergence fails to be felt; or rather, being felt, fails to tell us the absolute distance of the object we are regarding. Wheatstone arranged his stereoscope in such a way that the size of the retinal images might change without the convergence altering; or conversely, the convergence might change without the retinal image altering. Under these circumstances, he says, 87 the object seemed to approach or recede in the first case, without altering its size; in the second, to change its size without altering its distance -- just But the objective total same the reverse of what might have been expected. Wheatstone adds, however, that 'fixing the attention' converted each of these perceptions into its opposite. The same perplexity occurs in looking through prismatic glasses, which alter the eyes' convergence. He cannot decide whether the object has come nearer, or grown larger, or both, or neither; and our judgment vacillates in the most surprising way. We may even make our eyes diverge, and the object will none the less appear at a definite distance. When we look through the stereoscope, the picture seems at no determinate distance. These and other facts have led Helmholtz to deny that the feeling of convergence has any very exact value as a distance-measurer. 88

With the feelings of accommodation it is very much the same. Donders has shown 89 that the apparent magnifying power of spectacles of moderate convexity hardly depends at all upon their enlargement of the retinal image, but rather on the relaxation⁴⁹⁴ they permit of the muscle of accommodation. This suggests an object farther off, and consequently a much larger one, since its retinal size rather increases than diminishes. But in this case the same vacillation of judgment as in the previously mentioned case of convergence takes place. The recession made the object seem larger, but the apparent growth in size of the object now makes it look as if it came nearer instead of receding³⁵³. The effect thus contradicts its own cause. Everyone is conscious, on first putting on a pair of spectacles, of a doubt whether the field of view draws near or retreats. 90

There is still another deception⁴⁹⁵, occurring in persons who have had one eye-muscle suddenly paralyzed. has led Wundt to affirm that the eyeball-feeling proper, the incoming sensation of effected rotation, tells us only of the direction of our eye-movements, but not of their whole extent. 91 For this reason, and because not only Wundt, but many other authors, think the phenomena in these partial paralyses demonstrate the existence of a feeling of innervation, a feeling of the outgoing nervous current, opposed to every different sensation whatever, it seems proper to note the facts with a certain degree of detail.

Suppose a man wakes up some morning with the external rectus muscle of his right eye half paralyzed, what will be the result? He will be enabled only with great effort to rotate the eye so as to look at objects lying far off to the right. Something in the effort he makes will make him feel as if the object lay much farther to the right than it really is. If the left and sound eye be closed, and he be asked to touch rapidly with his finger an object situated towards his right, he will point the finger to the right of it. The current explanation of the 'something' in the effort which causes this deception is that it is the sensation of the outgoing discharge from the nervous centres, the 'feeling of innervation,' to use Wundt's expression, requisite for bringing the open eye with its weakened muscle to bear upon the object to be touched. If that object be situated 20 degrees to the right, the patient has now to innervate as powerfully to turn the eye those 20 degrees as formerly he did to turn the eye 30 degrees. He consequently believes as before that he has turned it 30 degrees; until, by a newly-acquired custom, he learns the altered spatial import of all the discharges his brain makes into his right abducens nerve. The 'feeling of innervation' maintained to exist by this and other observations, plays an immense part in the space-theories of certain philosophers, especially Wundt. I shall elsewhere try to show that the observations by no means warrant the conclusions drawn from them, and that the feeling in question is probably a wholly fictitious⁴⁹⁶ entity¹⁹¹. 92 Meanwhile it suffices to point out that even those who set most store by it are compelled, by the readiness with which the translocation of the field of view becomes corrected and further errors avoided, to admit that the precise space-import of the supposed sensation of outgoing energy is as ambiguous and indeterminate as that of any other of the eye-feelings we have considered hitherto.

I have now given what no one will call an understatement of the facts and arguments by which it is sought to banish⁴⁹⁷ the credit of directly revealing space from each and every kind of eye-sensation taken by itself. The reader will confess that they make a very plausible⁴⁹⁸ show, and most likely wonder whether my own theory of the matter can rally from their damaging evidence. But the case is far from being hopeless; and the introduction of a discrimination hitherto unmade will, if I mistake not, easily vindicate⁴⁹⁹ the view adopted in these pages, Whilst at the same time it makes ungrudging allowance for all the ambiguity and illusion on which so much stress is laid by the advocates of the intellectualist-theory.
The Choice of the Visual Reality.

We have native and fixed optical space-sensations; but experience leads us to select certain one from among them to be the exclusive bearers of reality: the rest become mere signs and suggesters of these. The factor of selection, on which we have already laid so much stress, here as elsewhere is the solving word of the enigma⁵⁰⁰. If Helmholtz, Wundt, and the rest, with an ambiguous retinal sensation before them, meaning now one size and distance, and now another, had not contented⁵⁰¹ themselves with merely saying: -- The size and distance are not this sensation, they are something beyond it which it merely calls up, and whose own birthplace is afar -- in 'synthesis' (Wundt) or in 'experience' (Helmholtz) as the case may be; if they had gone on definitely to ask and definitely to answer the question, What are the size and distance in their proper selves? they would not only have escaped the present deplorable vagueness of their space-theories, but they would have seen that the objective spatial attributes 'signified' are simply and solely certain other optical sensations now absent, but which the present sensations suggest.

What, for example, is the slant-legged cross which we think we see on the well when we project the rectangular after-image high up towards our right or left (Figs. 58 and 59)? Is it not in very sooth a retinal sensation itself? An imagined sensation, not a felt one, it is true, but none the less essentially and originally sensational or retinal for that, -- the sensation, namely, which we should receive if a 'real' slant-legged cross stood on the wall in front of us and threw its image on our eye. That image is not the one our retina now holds. Our retina now holds the image which a cross of square shape throws when in front, but which a cross of the slant-legged pattern would throw, provided it were actually on the wall in the distant place at which we look. Call this actual retinal image the 'square' image. The square image is then one of the innumerable images the slant-legged cross can throw Why should another one, and that an absent one, of those innumerable images be picked out to represent exclusively the slant-legged cross's 'true' shape? Why should that absent and imagined slant-legged image displace the present and felt square image from our mind? Why, when the objective cross gives us so many shapes, as it varies its position, should we think we feel the true shape only when the cross is directly in front? And when that question is answered, how can the absent and represented feeling of a slant-legged figure so successfully intrude⁵⁰² itself into the place of a presented square one?

Before answering either question, let us be doubly sure about our facts, and see how true it is that in our dealings with objects we always do pick out one of the visual images they yield, to constitute the real form or size.

The matter of size has been already touched upon, so that no more need be said of it here. As regards shape, almost all the retinal shapes that objects throw are perspective 'distortions.' Square table-tops constantly present two acute and two obtuse angles; circles drawn on our wall-papers, our carpets, or on sheets of paper, usually show like ellipses; parallels approach as they recede; human bodies are foreshortened; and the transitions from one to another of these altering forms are infinite and continual. Out of the flux⁵⁰³, however, one phase always stands prominent. It is the form the object has when we see it easiest and best: and that is when our eyes and the object both are in what may be called the normal position. In this position our head is upright and our optic axes either parallel or symmetrically convergent⁵⁰⁴; the plane of the object is perpendicular to the visual plane; and if the object is one containing many lines it is turned so as to make them, as far as possible, either parallel or perpendicular to the visual plane. In this situation it is that we compare all shapes with each other; here every exact measurement and decision is made. 93

It is very easy to see why the normal situation should have this extraordinary pre-eminence. First, it is the position in which we easiest hold anything we are examining in our hands; second, it is a turning-point between all right- and all left-hand perspective views of a given object; third, it is the only position in which symmetrical figures seem symmetrical and equal angles seem equal; fourth, it is often that starting-point of movements from which the eye is least troubled by axial rotations, by which superposition 94 of the retinal images of different lines and different parts of the same line is easiest produced, and consequently by which the eye can make the best comparative measurements in its sweeps. All these merits single the normal position out to be chosen. No other point of view offers so many aesthetic and practical advantages. Here we believe we see the object as it is; elsewhere, only as it seems. Experience and custom soon teach us, however, that the seeming appearance passes into the real one by continuous gradations. They teach us, moreover, that seeming and being may be strangely interchanged. Now a real circle may slide into a seeming ellipse; now an ellipse may, by sliding in the same direction, become a seeming circle; now a rectangular cross grows slant-legged; now a slant-legged one grows rectangular.

Almost any form in oblique vision may be thus a derivative of almost any other in 'primary' vision; and we must learn, when we get one of the former appearance, to translate it into the appropriate one of the latter class; we must learn of what optical 'reality' it is one of the optical signs. Having learned this, me do but obey that law of economy or simplification which dominates our whole psychic life, when we attend exclusively to the 'reality' and ignore as much as our consciousness will let us the 'sign' by which we came to apprehend it. The signs of each probable real thing being multiple and the thing itself one and fixed, we gain the same mental relief by abandoning the former for the latter that we do when we abandon mental images, with all their fluctuating characters, for the definite and unchangeable names which they suggest. The selection of the several 'normal' appearances from out of the jungle of our optical experiences, to serve as the real sights of which we shall think, is psychologically a, parallel phenomenon to the habit of thinking in words, and has a like use. Both are substitutions of terms few and fixed for terms manifold and vague. Sensations which we Ignore.

This service of sensations as mere signs, to be ignored when they have evoked⁵⁰⁶ the other sensations which are their significates, was noticed first by Berkeley and remarked in many passages, as the following:

"Signs, being little considered in themselves, or for their own sake, but only in their relative capacity and for the sake of those things whereof they are signs, it comes to pass that the mind overlooks them, so as to carry its attention immediately on to the things signified . . . which in truth and strictness are not seen, but only suggested and apprehended by means of the proper objects of sight which alone are seen." (Divine Visual Language, &§12.)

Berkeley of course erred¹⁸⁶ in supposing that the thing suggested was not even originally an object of sight, as the sign now is which calls it up. Reid expressed Berkeley's principle in yet clearer language:

" The visible appearances of objects are intended by nature only as signs or indications, and the mind passes instantly to the things signified, without making the least reflection upon the sign, or even perceiving that there is any such thing. . . . The mind has acquired a confirmed and inveterate habit of inattention to them (the signs). For they no sooner appear than, quick as lightning, the thing signified succeeds and engrosses⁵⁰⁷ all our regard. They have no name in language; and although we are conscious of them when they pass through the mind, yet their passage is so quick and so familiar that it is absolutely unheeded; nor do they leave any footsteps of themselves, either in the memory or imagination." (Inquiry, chap. v. &§&§2, 3.)

If we review the facts we shall find every grade of non-attention between the extreme form of overlooking mentioned by Reid (or forms even more extreme still) and complete conscious perception of the sensation present. Sometimes it is literally⁵⁰⁸ impossible to become aware of the latter. Sometimes a little artifice⁵⁰⁹ or effort easily leads us to discern it together, or in alternation, with the 'object' it reveals. Sometimes the present sensation is held to be the object or to reproduce its features in undistorted shape, and then, of course, it receives the mind's full glare.

The deepest inattention is to subjective optical sensations, strictly so called, or those which are not signs of outer objects at all. Helmholtz's treatment of these phenomena, muscæ volitantes, negative after-images, double images, etc., is very satisfactory. He says:

" We only attend with any ease and exactness to our sensations in so far forth as they can be utilized⁵¹⁰ for the knowledge of outward things; and we are accustomed to neglect all those portions of them which have no significance as regards the external world. So much is this the case that for the most part special artifices⁵¹¹ and practice are required for the observation of these latter more subjective feelings. Although it might seem that nothing should be easier than to be conscious of one's own sensations, experience nevertheless shows that often enough either a special talent like that showed in eminent⁵¹² degree by Purkinje, or accident or theoretic speculation⁵¹³, are necessary conditions for the discovery of subjective phenomena. Thus, for example, the blind spot on the retina was discovered by Mariotte by the theoretic way; similarly by me the existence of 'summation'-tones in acoustics⁵¹⁴. In the majority of cases accident is what first led observers whose attention was especially exercised on subjective phenomena to discover this one or that; only where the subjective appearances are so intense that they interfere with the perception of objects are they noticed by all men alike. But if they have once been discovered it is for the most part easy for subsequent observers who place themselves in proper conditions and bend their attention in the right direction to perceive them. But in many cases -- for example, in the phenomena of the blind spot, in the discrimination of over-tones and combination-tones from the ground- tone of musical sounds, etc. -- such a strain of the attention is required, even with appropriate instrumental aids, that most persons fail. The very after-images of bright objects are by most men perceived only under exceptionally favorable conditions, and it takes steady practice to see the fainter images of this kind. It is a, commonly recurring⁵¹⁵ experience that persons smitten⁵¹⁶ with some eye-disease which impairs⁵¹⁷ vision suddenly remark for the first time the muscæ volitantes which all through life their vitreous humor has contained, but which they now firmly believe to have arisen since their malady⁵¹⁸; the truth being that the latter has only made them more observant of all their visual sensations. There are also cases where one eye has gradually grown blind, and the patient lived for an indefinite time without knowing it, until, through the accidental closure of the healthy eye alone, the blindness of the other was brought to attention.

"Most people, when first made aware of binocular double images, are uncommonly⁵¹⁹ astonished that they should never have noticed them before, although all through their life they had been in the habit of seeing singly only those few objects which were about equally distant with the point of fixation, and the rest, those nearer and farther, which constitute the great majority, had always been double.

"We must then learn to turn our attention to our particular sensations, and we learn this commonly only for such sensations as are means of cognition of tile outer world. Only so far as they serve this end hale our sensations any importance for us in ordinary life. Subjective feelings are mostly interesting only to scientific investigators⁵²⁰; were they remarked in the ordinary use of the senses, they could only cause disturbance⁹⁷. Whilst, therefore, we reach an extraordinary degree of dryness and security in objective observation, we not only do not reach this where subjective phenomena are concerned, but we actually attain in a high degree the faculty of overlooking these altogether, and keeping ourselves independent of their influence in judging of objects, even in cases where their strength might lend them easily to attract our attention." (Physiol. Optik, pp. 431-2.)

Even where the sensation is not merely subjective, as in the cases of which Helmholtz speaks, but is a sign of something outward, we are also liable, as Reid says, to overlook its intrinsic quality and attend exclusively to the image of the 'thing' it suggests. But here everyone can easily notice the sensation itself if he will. Usually we see a sheet of paper as uniformly white, although a part of it may be in shadow. But we can in an instant, if we please, notice the shadow as local color. A man walking towards us does not usually seem to alter his size; but we can, by setting which impairs our attention in a peculiar way make him appear to do so. The whole education of the artist consists in his learning to see the presented signs as well as the represented things. No matter what the held of view means, he sees it also as it feels -- that is, as a collection of patches of color bounded by lines -- the whole terming an optical diagram of whose intrinsic proportions one who is not an artist has hardly a conscious inkling. The ordinary man's attention passes over them to their import; the artist's turns back and dwells upon them for their own sake. 'Don't draw the thing as it is, but as it looks!' is the endless advice of every teacher to his pupil; forgetting that what it 'is' is what it would also 'look,' provided it were placed in what we have called the 'normal' situation for vision. In this situation the sensation as 'sign' and the sensation as 'object' coalesce into one, and there is no contrast between them.
Sensations which seem Suppressed.

But a great difficulty has been made of certain peculiar cases which we must now turn to consider. They are cases in which a present sensation, whose existence is supposed to be proved by its outward conditions being there, seems absolutely suppressed or changed by the image of the 'thing' it suggests.

This matter carries us back to what was said on p. 218. The passage there quoted from Helmholtz refers to these cases. He thinks they conclusively⁵²¹ disprove the original and intrinsic spatiality of any of our retinal sensations; for if such a one, actually present, had an immanent and essential space-determination of its own, that might well be added to and overlaid or even momentarily eclipsed by suggestions of its sensation, but how could it possibly be altered or completely suppressed thereby⁵²²? Of actually present sensations, he says, being suppressed by suggestions of experience --

"We have not a single well-attested example. In all those illusions which are provoked by sensations in the absence of their usually exciting objects, the mistake never vanishes by the better understanding of the object really present, and by insight into the cause of deception. Phosphenes provoked by pressure on the eyeball, by traction²⁹³ on the entrance of the optic nerve, after-images, etc., remain projected into their apparent place in the held of vision, just as the image projected from a mirror's surface continues to be seen behind the mirror, although we know that to all these appearances no outward reality corresponds. True enough, we can remove our attention, and keep it removed, from sensations that have no reference to the outer world, those, e.g., of the weaker after-images, and of entoptic objects, etc. . . . But what would become of our perceptions at all if we had the power not only of ignoring, but of transforming into their opposites, any part of them that differed from that outward experience, the image of which, as that of a present reality, accompanies them in the mind?" 95

And again:

"On the analogy of all other experience, we should expect that the conquered feelings would persist to our perception, even if only in the shape of recognized illusions. But this is not the case. One does not see how the assumption of originally spatial sensations can explain our optical cognitions, when in the last resort those who believe in these very sensations and themselves obliged to assume that they are overcome by our better judgment, based on experience."

These words, coming from such a quarter, necessarily carry great weight. But the authority even of a Helmholtz ought not to shake one's critical composure. And the moment one abandons abstract generalities and comes to close quarters with the particulars, I think one easily sees that no such conclusions as those we have quoted follow from the latter. But probably to conduct the discussion we must divide the alleged instances into groups.

(a) With Helmholtz, color-perception is equally with space-perception an intellectual affair. The so-called simultaneous color-contrast, by which one color modifies another alongside of which it is said, is explained by him as an unconscious inference. In Chapter XVII we discussed the color-contrast problem; the principles which applied to its solution will prove also applicable to part of the present problem. In my opinion, Hering has definitively⁵²³ proved that, when one color is laid beside another, it modifies the sensation of the latter, not by virtue of any mere mental suggestion, as Helmholtz would have it but by actually exciting a new nerve-process, to which the modified feeling of color immediately corresponds. The explanation is physiological, not psychological. The transformation of the original color by the inducing color is due to the disappearance of the physiological conditions under which the first color was produced, and to the induction, under the new conditions, of a genuine new sensation, with which the (suggestions of experience' have naught to do.

That processes in the visual apparatus propagate themselves laterally, if one may so express it, is also shown by the phenomena of contrast which occur after looking upon motions of various kinds. Here are a few examples. If, over the rail of a moving vessel⁵²⁴, we look at the water rushing along the side, and then transfer our gaze to the deck, a band of planks⁵²⁵ will appear to us, moving in the opposite direction to that in which, a moment previously, we had been seeing the water move, whilst on either side of this band another band of planks will move as the water did. Looking at a waterfall, or at the road from out of a car-window in a moving train, produces the same illusion, which may be easily verified in the laboratory by a simple piece of apparatus. A board with a window five or six inches wide and of any convenient length is supported upright on two feet. On the back side of the board, above and below the window, are two rollers, one of which is provided with a crank. An endless band of any figured stuff is passed over these rollers (one of which can be so adjusted on its bearings as to keep the stuff always taut⁵²⁶ and not liable to slip), and the surface of the front board is also covered with stuff or paper of a nature to catch the eye. Turning the crank now sets the central band in continuous motion, whilst the margins of the field remain really at rest, but after a while appear moving in the contrary way. Stopping the crank results in an illusory appearance of motion in reverse directions all over the field.

A disk with an Archimedean spiral drawn upon it, whirled round on an ordinary rotating machine, produces still more startling effects.
 

"If the revolution is in the direction in which the spiral line approaches the centre of the disk the entire surface of the latter seems to expand during revolution and to contract after it has ceased; and vice⁵⁰⁵ versâ if the movement of revolution is in the opposite direction. If in the former case the eyes of the observers are turned from the rotating disk towards any familiar object -- e. g. the face of a friend -- the latter seems to contract or recede in a somewhat striking manner, and to expand or approach after the opposite motion of the spiral." 96

An elementary form of these motor illusions seems to be the one described by Helmholtz on pp. 568-571 of his Optik. The motion of anything in the field of vision along an acute angle towards a straight line sensibly distorts
 

that line. Thus in Fig. 66: Let AB be a line drawn on paper, CDE the tracing made over this line by the point of a compass steadily followed by the eve, as it moves. As the compass-point passes from C to D, the line appears to move downwards; as it passes from D to E, the line appears to move upwards; at the same time the whole line seems to incline itself in the direction FG during the first half of the compass's movement; and in the direction HI during its last half; the change from one inclination⁵²⁷ to another being quite distinct as the compass-point passes over D.

Any line across which we draw a pencil-point appears to be animated⁵²⁸ by a, rapid movement of its own towards the pencil-point. This apparent movement of both of two things in relative motion to each other, even when one of them is absolutely still, reminds us of the instances quoted from Vierordt on page 188, and seems to take us back to a primitive stage of perception, in which the discriminations we now make when we feel a movement have not yet been made. If we draw the point of a pencil through 'Zöllner's pattern' (Fig. 60, p. 232), and follow it with the eye, the whole figure becomes the scene of the most singular apparent unrest, of which Helmholtz has very carefully noted the conditions. The illusion of Zöllner's figure vanishes entirely, or almost so, with most people, if they steadily look at one point of it with an unmoving eye; and the same is the case with many other illusions.

Now all these facts taken together seen, to show -- vaguely it is true, but certainly -- that present excitements and after- effects of former excitements may alter the result of processes occurring simultaneously at a distance from them in the retina or other portions of the apparatus for optical sensation. In the cases last considered, the moving eye, as it sweeps the fovea over certain parts of the figure, seems thereby to determine a modification in the feeling which the other parts confer, which modification is the figure's 'distortion.' It is true that this statement explains nothing. It only keeps the cases to which it applies from being explained spuriously. The spurious account of these illusions is that they are intellectual, not sensational, that they are secondary, not primary, mental facts. The distorted figure is said to be one which the mind is led to imagine, by falsely drawing an unconscious inference from certain premises⁵²⁹ of which it is not distinctly aware. And the imagined figure is supposed to be strong enough to suppress the perception of whatever real sensations there may be. But Helmholtz, Wundt, Delboeuf, Zöllner, and all the advocates of unconscious inference are at variance⁵³⁰ with each other when it comes to the question what these unconscious premises and inferences may be. That small angles look proportionally larger than larger ones is, in brief, the fundamental illusion to which almost all authors would reduce the peculiarity of Fig. 67, 89 of Figs. 60, 61, 62 (pp. 232, 233). This peculiarity of small angles is by Wundt treated as the case of a fined space seeming larger than an empty one, as in Fig. 68; and this, according to both Delboeuf and Wundt is owing to the fact that more muscular innervation is needed for the eye to traverse a filled space than so empty one, because the points and lines

in the filled space inevitably⁵³¹ arrest and constrain⁵³² the eye, and this makes us feel as if it were doing more work, i.e. traversing a longer distance.  When, however, we recol-

lect that muscular movements are positively⁵³³ proved to have no share in the waterfall and revolving⁵³⁴-spirals illusions. and that it is hard to see how Wundt's and Delboeuf's particular form of muscle-explanation can possibly apply to the compass-point illusion considered a moment ago, we must conclude that these writers have probably exaggerated, to say the least, the reach of their muscle-explanation in the case of the subdivided angles and lines. Never do we get such strong muscular feelings as when, against the course of nature, we oblige our eyes to be still; but fixing the eyes on one point of the figure, so far from making that part of the latter seem larger, dispels⁵³⁵, in most persons, the illusion of these diagrams altogether.

As for Helmholtz, he invokes⁵³⁶, to explain the enlargement of small angles, 98 what he calls a 'law of contrast' between directions and distances of lines, analogous to that between colors and intensities of light. Lines cutting another line make the latter seem more inclined away from them than it really is. Moreover, clearly recognizable magnitudes appear greater than equal magnitudes which we but vaguely apprehend. But this is surely a sensationalistic law, a native function of our seeing-apparatus, Quite as little as the negative after-image of the revolving spiral could such contrast be deduced from any association of ideas or recall of past objects. The principle of contrast is criticised by Wundt, 99 who says that by it small spaces ought to appear to us smaller, and not larger, than they really are. Helmholtz might have retorted (had not the retort been as fatal to the uniformity of his own principle as to Wundt's) that if the muscle-explanation were true, it ought not to give rise to just the opposite illusions in the skin. We saw on p. 141 that subdivided spaces appear shorter than empty ones upon the skin. To the instances there given add this: Divide a line on paper into equal halves, puncture⁵³⁷ the extremities, and make punctures⁵³⁸ all along one of the halves; then, with the finger-tip on the opposite side of the paper, follow the line of punctures, the empty half will seem much longer than the punctured⁵³⁹ half. This seems to bring things back to unanalyzable laws, by reason of which our feeling of size is determined differently in the skin and in the retina, even when the objective conditions are the same. Hering's explanation of Zöllner's figure is to be found in Hermann's Handb. d. Physiologie, III. I, p. 579. Lipps 100 gives another reason why lines cutting another line make the latter seem to bend away from them more than is really the case. If, he says, we draw (Fig. 69) the line pm upon the line ab, and follow the latter with our eye, we shall, on reaching the point m, tend for a moment to slip off ab and to follow mp, without distinctly realizing that we are not still on the main line. This makes us feel as if the remainder mb of the main line were bent⁵⁴⁰ a little away from its original direction. The illusion is apparent in the shape of a seeming
 

approach of the ends b, b, of the two main lines. This to my mind would be a more satisfactory explanation of this class of illusions than any of those given by previous authors, were it not again for what happens in the skin.

Considering all the circumstances, I feel justified⁵⁴¹ in, discarding his entire batch⁵⁴² of illusions as irrelevant⁵⁴³ to our present inquiry. Whatever they may prove, they do not prove that our visual percepts of form and movement may not be sensations strictly so called. They much more probably fall into line with the phenomena of irradiation and of color-contrast, and with Vierordt's primitive illusions of movement. They show us, if anything, a, realm of sensations in which our habitual experience has not yet made traces, and which persist in spite of our better knowledge, unsuggestive of those other space-sensations which we all the time know from extrinsic⁵⁴⁴ evidence to constitute the real space-determinations of the diagram. Very likely, if these sensations were as frequent and as practically important as they now are insignificant⁵⁴⁵ and dare, we should end by substituting their significates -- the real space-values of the diagrams -- for them. These latter me should then seem to see directly, and the illusions would disappear like that of the side of a tooth-socket when the tooth has been out a week.

(b) Another batch of cases which we may discard is that of double images. A thoroughgoing anti-sensationalist ought to deny all native tendency to see double images when disparate retinal points are stimulated, because, he should say, most people never get them, but see all things single which experience has led them to believe to be single. Can a doubleness, so easily neutralized by our knowledge, ever be a datum of sensation at all?" such an anti-sensationalist might ask.

To which the answer is that it is a datum of sensation, but a datum which, like many other data, must first be discriminated. As a rule, no sensible qualities are discriminated without a motive⁵⁴⁶. 101 And those that later we learn to discriminate were originally felt confused. As well pretend that a voice, or an odor, which we have learned to pick out, is no sensation now. One may easily acquire skin in discriminating⁵⁴⁷ double images, though, as Hering somewhere says, it is an art of which one cannot become master in one year or in two. For masters like Hering himself, or Le Conte, the ordinary stereoscopic diagrams are of little use. Instead of combining into one solid appearance, they simply cross each other with their doubled
 

lines. Volkmann has shown a great variety of ways in which the addition of secondary lines, differing in the two fields, helps us to see the primary lines double. The effect is analogous to that shown in the cases which we despatched [sic] a moment ago, where given lines have their space-value changed by the addition of new lines, without our being able to say why, except that a certain mutual adhesion of the lines and modification of the resultant feeling takes place by psychophysiologica1 laws. Thus, if in Fig. 66, l and r be crossed by an horizontal line at the same level, and viewed stereoscopically, they appear as a single pair of lines, l, in space. But if the horizontal be at different levels, as in l', r', three lines appear, as in s'. 102 Let us then say no more about double images. All that the facts prove is what Volkmann says, 103 that, although there may be sets of retinal fibres so organized as to give an impression of two separate spots, yet the excitement of other retinal fibres may inhibit⁵⁴⁸ the effect of the first excitement, and prevent us from actually making the discrimination. Still farther retinal processes may, however, bring the doubleness to the eye of attention; and, once there, it is as genuine a sensation as any that our life affords. 104

(c) These groups of illusions being eliminated, either as cases of defective⁵⁴⁹ discrimination, or as changes of one space-sensation into another when the total retinal process changes, there remain but two other groups to puzzle us. The first is that of the after-images distorted by projection on to oblique planes; the second relates to the instability of our judgments of relative distance and size by the eye, and Includes especially what are known as pseudoscopic illusions.

The phenomena of the first group were described on page 232. A. W. Volkmann has studied them with his accustomed clearness and care. 105 Even an imaginarily inclined wall, in a picture, will, if an after-image be thrown upon it, distort the shape thereof, and make us see a form of which our after-image would be the natural projection on the retina, were that form laid upon the wall. Thus a, signboard is painted in perspective on a screen, and the eye, after steadily looking at a rectangular cross, is turned to the painted signboard. The after-image appears as an oblique-legged cross upon the signboard. It is the converse⁴⁶¹ phenomenon of a perspective drawing like Fig. 71, in which
 

really oblique-legged figures are seen as rectangular crosses.

The unstable⁵⁵⁰ judgments of relative distance and size were also mentioned on pp. 231-2. Whatever the size may be of the retinal image which an object makes, the object is seen as of its own normal size. A man moving towards us is not sensibly perceived to grow, for example; and my finger, of which a single joint may more than conceal⁴⁷⁴ him from my view, is nevertheless seen as a much smaller object than the man. As for distances, it is often possible to make the farther part of an object seem near and the nearer part far. A human profile in intaglio⁵⁵¹, looked at steadily with one eye, or even both, soon appears irresistibly⁵⁵² as a bas- relief. The inside of a common pasteboard mask, painted like the outside, and viewed with one eye in a direct light, also looks convex instead of hollow. So strong is the illusion, after long fixation, that a friend who painted such a mask for me told me it soon became difficult to see how to apply the brush. Bend a visiting-card across the middle, so that its halves form an angle of 90° more or less; set it upright on the table, as in Fig. 72, and view it with one eye.
 

You can make it appear either as if it opened towards you or away from you. In the former case, the angle ab lies

upon the table, b being nearer to you than a; in the latter case ab seems vertical to the table -- as indeed it really is -- with a nearer to you than b. 106 Again, look, with either one or two eyes, at the opening of a wine-glass or tumbler (Fig. 73), held either above or below the eye's level. The retinal image of the opening is an oval, but we can see the oval in either of two ways, as if it were the perspective view of a circle whose edge b were farther from us than its edge a (in which case we should seem to be looking down on the circle), or as if its edge a were the more distant edge (in which case we should be looking up at it through the b side of the glass). As the manner of seeing the edge changes, the glass itself alters its form in space and looks straight or seems bent towards or from the eye, 107 according as the latter is placed beneath or above it.

Plane diagrams also can be conceived as solids, and that in more than one way. Figs. 74, 75, 76, for example, are am-
 

biguous perspective projections, and may each of them remind us of two different natural objects. Whichever of these objects we conceive clearly at the moment of looking at the figure, we seem to see in all its solidity before us. A little practice will enable us to flap the figures, so to speak, backwards end forwards from one object to the other at will. We need only attend to one of the angles represented, and imagine it either solid or hollow -- pulled towards us out of the plane of the paper, or pushed back behind the same -- and the whole figure obeys the cue and is instantaneously transformed beneath our gaze. 108

The peculiarity of all these cases is the ambiguity of the perception to which the fixed retinal impression gives rise. With our retina excited in exactly the same way, whether by after-image, mask or diagram, we see now this object and now that, as if the retinal image per se had no essential space-import. Surely if form and length were originally retinal sensations, retinal rectangles ought not to become acute or obtuse, and lines ought not to alter their relative lengths as they do. If relief were an optical feeling, it ought not to flap to and fro, with every optical condition unchanged. Here, if anywhere, the deniers of space-sensation ought to be able to make their final stand. 109

It must be confessed that their plea is plausible at first sight. But it is one thing to throw out retinal sensibility altogether as a space-yielding function the moment we find an ambiguity in its deliverances, and another thing to examine candidly⁵⁵³ the conditions which may have brought the ambiguity about. The former way is cheap, wholesale⁵⁵⁴, shallow; the latter difficult and complicated, but full of instruction in the end. Let us try it for ourselves. In the case of the diagrams 72, 73, 74, 75, 76, the real object, lines meeting or crossing each other on a plane, is replaced by an imagined solid which we describe as seen. Really it is not seen but only so vividly conceived as to approach a vision of reality. We feel all the while, however, that the solid suggested is not solidly there. The reason why one solid may seem more easily suggested than another, and why it is easier in generally to perceive the diagram, solid than flat, seems due to probability. 110 Those lines have countless⁵⁵⁵ times in our past experience been drawn on our retina by solids for once that we have seen them flat on paper. And hundreds of times we have looked down upon the upper surface of parallelopipeds, stairs and glasses, for once that we have looked upwards at their bottom -- hence we see the solids easiest as if from above.

Habit or probability seems also to govern the illusion of the intaglio profile, and of the hollow mask. We have never seen a human face except in relief -- hence the case with which the present sensation is overpowered. Hence, too, the obstinacy⁵⁵⁶ with which human faces and forms, and other extremely familiar convex objects, refuse to appear hollow when viewed through Wheatstone's pseudoscope. Our perception seems wedded⁵⁵⁷ to certain total ways of seeing certain objects. The moment the object is suggested at all, it takes possession of the mind in the fulness of its stereotyped⁵⁵⁸ habitual form. This explains the suddenness of the transformations⁵⁵⁹ when the perceptions change. The object shoots back and forth completely from this to that familiar thing, and doubtful, indeterminate, and composite things are excluded, apparently because we are unused to their existence.

When we turn from the diagrams to the actual folded visiting-card and to the real glass, the imagined form seems fully as real as the correct one. The card flaps over; tile glass rim³⁵ tilts⁵⁶⁰ this may or that, as if some inward spring suddenly became released in our eye. In these changes the actual retinal image receives different comments from the mind. But the remarkable thing is that the complement⁵⁶¹ and the image combine so completely that the twain are one flesh, as it were, and cannot be discriminated in the result. If the complement be, as we have called it (on pp. 237-8), a set of imaginary absent eye-sensations, they seem no whit less vividly there than the sensation which the eye now receives from without.

The case of the after-images distorted by projection upon an oblique plane is even more strange, for the imagined perspective figure, lying in the plane, seems less to combine with the one a moment previously seen by the eye than to suppress it and take its place. 111 The point needing explanation, then, in all this, is how it comes to pass that, when imagined sensations are usually so inferior in vivacity⁵⁶² to reel ones, they should in these few experiences prove to be almost or quite their match.

The mystery is solved when we note the class to which all these experiences belong. They are 'perceptions' of definite 'things,' definitely situated in tridimensional space. The mind uniformly uses its sensations to identify things by. The sensation is invariably apperceived by the idea, name, or 'normal' aspect (p. 238) of the thing. The peculiarity of the optical signs of things is their extraordinary mutability. A 'thing' which we follow with the eye, never doubting of its physical identity, will change its retinal image incessantly. A cross, a ring, waved about in the air, will pass through every conceivable angular and elliptical form. All the while, however, as we look at them, we hold fast to the perception of their 'real' shape, by mentally combining the pictures momentarily received with the notion of peculiar positions in space. It is not the cross and ring pure and simple which we perceive, but the cross so held, the ring so held. From the day of our birth we have sought every hour of our lives to correct the apparent form of things, and transit¹⁵⁹ into the real form by keeping note of the way they are placed or held. In no other class of sensations does this incessant correction occur. What wonder, then, that the notion 'so placed' should invincibly exert its habitual corrective effect, even when the object with which it combines is only an after-image, and make us perceive the latter under a changed but more 'real' form? The 'real' form is also a sensation conjured⁵⁶⁴ up by memory; but it is one so probable, so habitually conjured up when we have just this combination of optical experiences, that it partakes of the invincible⁵⁶⁵ freshness of reality, and seems to break through that law which elsewhere condemns⁵⁶⁶ reproductive processes to being so much fainter than sensations.

Once more, these cases form an extreme. Somewhere, in the list of our imaginations of absent feelings, there must be found the vividest of all. These optical reproductions of real forms are the vividest of all. It is foolish to reason from cases lower in the scale, to prove that the scale can contain no such extreme cases as these; and particularly foolish since we can definitely see why these imaginations ought to be more vivid than any others, whenever they recall the forms of habitual and probable things. These latter, by incessantly repeated presence and reproduction, will plough deep grooves⁵⁶⁷ in the nervous system. There will be developed, to correspond to them, paths of least resistance, of unstable equilibrium⁵⁶⁸, liable to become active in their totality when any point is touched off. Even when the objective stimulus is imperfect, we shall still see the full convexity of a human face, the correct inclination of an angle or sweep of a curve, or the distance of two lines. Our mind will be like a polyhedron, whose facets⁵⁶⁹ are the attitudes of perception in which it can most easily rest. These are worn upon it by habitual objects, and from one of these it can pass only by tumbling over into another. 112

Hering has well accounted for the sensationally⁵⁷⁰ vivid character of these habitually reproduced forms. He says, after reminding us that every visual sensation is correlated to a physical process in the nervous apparatus: "If this psychophysical process is aroused, as usually happens, by light-rays impinging on the retina, its form depends not only on the nature of these rays, but on the constitution of the entire nervous apparatus which is connected with the organ of vision, and on the state in which it finds itself. The same stimulus may excite widely different sensations according to this state.

"The constitution of the nervous apparatus depends naturally in part upon innate⁵⁷¹ predisposition; but the ensemble⁵⁷³ of effects wrought by stimuli⁵⁷⁴ upon it in the course of life, whether these come through the eyes or from elsewhere, is a co-factor of its development. To express it otherwise, involuntary and voluntary experience and exercise assist in determining the material structure of the nervous organ of vision, and hence the ways in which it may react on a retinal image as an outward stimulus. That experience and exercise should be possible at all in vision is a consequence of the reproductive power, or memory, of its nerve-substance. Every particular activity of the organ makes it more suited to a repetition of the same; ever slighter touches are required to make the repetition occur. The organ habituates itself to the repeated activity. . . .

"Suppose now that, in the first experience of a complex sensation produced by a particular retinal image, certain portions were made the special objects of attention. In a repetition of the sensible experience it will happen that notwithstanding the identity of the outward stimulus these portions will be more easily and strongly reproduced; and when this happens a hundred times the inequality with which the various constituents⁵⁷⁵ of the complex sensation appeal to consciousness grows ever greater.

"Now in the present state of our knowledge we cannot assert that in both the first and the last occurrence of the retinal image in question the same pure sensation is provoked, but that the mind interprets it differently the last time in consequence of experience; for the only open thing we know are on the one hand the retinal image which is both times the same, and on the other the mental percept which is both times different; of a third thing, such as a pure sensation, interpolated between image and percept, we know nothing. We ought, therefore, if we wish to avoid hypotheses, simply to say that the nervous apparatus reacts the last time differently from the first, and gives us in consequence it different group of sensations.

"But not only by repetition of the same retinal image, but by that of similar ones, will the law obtain. Portions of the image common to the successive experiences will awaken, as it were, a stronger echo in the nervous apparatus than other portions. Hence it results that reproduction is usually elective: the more strongly reverberating⁵⁷⁶ parts of the picture yield stronger feelings than the rest. This may result in the latter being quite overlooked and, as it were, eliminated from perception. It may even come to pass that instead of these parts eliminated by election a feeling of entirely different elements comes to consciousness -- elements not objectively contained in the stimulus. A group of sensations, namely, for which a strong tendency to reproduction has become, by frequent repetition, ingrained in the nervous system will easily revive as a whole when, not its whole retinal image, but only an essential part thereof, returns. In this case we get some sensations to which no adequate stimulus exists in the retinal image, and which owe their being solely to the reproductive power of the nervous apparatus. This is complementary (ergänzende) reproduction.

"Thus a few points and disconnected strokes are sufficient to make us see a human face, and without specially directed attention we fail to note that we see much that really is not drawn on the paper. Attention will show that the outlines were deficient⁵⁷⁷ in spots where we thought them complete. . . . The portions of the percept supplied by complementary reproduction depend, however, just as much as its other portions, on the reaction of the nervous apparatus upon the retinal image, indirect though this reaction may, in the case of the supplied portions, be. And so long as they are present, we have a perfect right to call them sensations, for they differ in no wise from such sensations as correspond to an actual stimulus in the retina. Often, however, they are not persistent; many of them may be expelled by more close observation, but this is not proved to be the case with all. . . . In vision with one eye . . . the distribution of parts within the third dimension is essentially the work of this complementary reproduction, i.e. of former experience. . . . When a certain way of localizing a particular group of sensations has become with us a second nature, our better knowledge, our judgment, our logic¹⁰⁰, are of no avail. . . . Things actually diverse may give similar or almost identical retinal images; e.g., an object extended in three dimensions, and its hat perspective picture. In such cases it often depends on small accidents, and especially on our will, whether the one or the other group of sensations shall be excited. . . . We can see a relief hollow, as a mould, or vice versâ; for a relief illuminated from the left can look just like its mould illuminated from the right. Reflecting upon this, one may infer from the direction of the shadows that one has a relief before one, and the idea of the relief will guide the nerve-processes into the right path, so that the feeling of the relief is suddenly aroused. . . . Whenever the retinal image is of such a nature that two diverse modes of reaction on the part of the nervous apparatus are, so to speak, equally, or nearly equally, imminent⁵⁷⁸, it must depend on small accidents whether the one or the other reaction is realized. In these cases our previous knowledge often has a decisive effect, and helps the correct perception to victory. The bare idea of the right object is itself a feeble reproduction which with the help of the proper retinal picture develops into clear and lively sensation. But if there be not already in the nervous apparatus a disposition⁵⁷² to the production of that percept which our judgment tells us is right, our knowledge strives in vain to conjure⁵⁶³ up the feeling of it; we then know that we see something to which no reality corresponds, but we see it all the same. 113

Note that no object not probable, no object which we are not incessantly practised in reproducing, can acquire this vividness in imagination. Objective corners are ever changing their angles to the eyes, spaces their apparent size, lines their distance. But by no transmutation of position in space does an objective straight line appear bent, and only in one position out of an infinity⁵⁷⁹ does a broken line look straight. Accordingly, it is impossible by projecting the after-image
 

of a straight line upon two surfaces which make a. solid angle with each other to give the line itself a sensible 'kink.' Look with it at the corner of your room: the after-image, which may overlap²⁶⁹ all three surfaces of the corner, still continues straight. Volkmann constructed a complicated surface of projection like that drawn in Fig. 77, but he found it impossible so to throw a straight after- image upon it as to alter its visible form.

One of the situations in which we oftenest see things is spread out on the ground before us. We are incessantly drilled in making allowance for this perspective, and reducing things to their real form in spite of optical foreshortening. Hence if the preceding explanations are true, we ought to find this habit inveterate. The lower half of the retina, which habitually sees the farther half of things spread out on the ground, ought to have acquired a habit of enlarging its pictures by imagination, so as to make them more than equal to those which fall on the upper retinal surface; and this habit ought to be hard to escape from, even when both halves of the object are equidistant from the eye, as in a, vertical line on paper. Delboeuf has found, accordingly, that if we try to bisect such a line we place the point of division about 1/16 of its length too high. 114

Similarly, a square cross, or a square, drawn on paper, should look higher than it is broad. And that this is actually the case, the reader may verify by a glance at Fig 78.
 

For analogous reasons the upper and lower halves of the letter S, or of the figure 8, hardly seem to differ. But when turned upside down, as the upper half looks much the larger. 

Hering has tried to explain our exaggeration of small angles in the same way. We have more to do with right angles than with any others: right angles, in fact, have an altogether unique sort of interest for the human mind. Nature almost never begets⁵⁸⁰ them, but we think space by means of them and put them everywhere. Consequently obtuse and acute ones, liable always to be the images of right ones foreshortened, particularly easily revive right ones in memory. It is hard to look at such figures as a, b, c, in Fig. 79, without seeing them in perspective, as

approximations, at least, to foreshortened rectangular forms. 116

At the same time the genuine sensational form of the lines before us can, in all the cases of distortion by suggested perspective, be felt correctly by a mind able to abstract from the notion of perspective altogether. Individuals differ in this abstracting power. Artistic⁵⁸¹ training improves it, so that after a little while errors in vertical bi-section, in estimating height relatively to breadth, etc., become impossible. In other words, we learn to take the optical sensation before us pure. 117

We may then sum up our study of illusions by saying that they in no wise undermine our view that every spatial determination of things is originally given in the shape of a sensation of the eyes. They only show how very potent¹¹⁴ certain imagined sensations of the eyes may become.

These sensations, so far as they bring definite forms to the mind, appear to be retinal exclusively. The movements of the eyeballs play a great part in educating our perception, it is true; but they have nothing to do with constituting any one feeling of form. Their function is limited to exciting the various feelings of form, by tracing retinal streaks; and to comparing them, and measuring them off against each other, by applying different parts of the retinal surface to the same objective thing. Helmholtz's analysis of the facts of our 'measurement of the field of view' is, bating a lapse or two, masterly, and seems to prove that the movements of the eye have had some part in bringing our sense of retinal equivalencies about -- equivalencies, mind, of different retinal forms and sizes, not forms and sizes themselves. Superposition is the way in which the eye-movements accomplish this result. An object traces the line AB on a peripheral tract of the retina. Quickly we move the eye so that the same object traces the line ab on a central tract. Forthwith, to our mind, AB and ab are judged equivalent. But, as Helmholtz admits, the equivalence-judgment is independent of the way in which we may feel the form and length of the several retinal pictures themselves:

"The retina is like a pair of compasses, whose points we apply in succession to the ends of several lines to see whether they agree or not in length. All we need know meanwhile about the compasses is that the distance of their points remains unchanged. What that distance is, and what is the shape of the compasses, is a matter of no account." 118

Measurement implies a stuff to measure. Retinal sensations give the stuff; objective things form the yard-stick; motion does the measuring operation; which can, of course, be well performed only where it is possible to make the same object fall on many retinal tracts. This is practically im possible where the tracts make a wide angle with each other. But there are certain directions in the held of view, certain retinal lines, along which it is particularly easy to make the image of an object slide. The object then be- comes 'ruler' for these lines, as Helmholtz; puts it, 119 making them seem straight throughout if the object looked straight to us in that pert of them at which it was most distinctly seen.

But all this need of superposition shows how devoid of exact space-import the feelings of movement are per se. As we compare the space-value of two retinal tracts by super- posing them successively upon the same objective line, so we also hare to compare the space-value of objective angles and lines by superposing them on the same retinal tract. Neither procedure would be required if our eye-movements were apprehended immediately, by pure muscular feeling or innervation, for example, as distinct lengths and directions in space. To compare retinal tracts, it would then suffice simply to notice how it feels to move any image over them. And two objective lines could be compared as well by moving different retinal tracts along them as by laying them along the same. It would be as easy to compare non-parallel figures as it now is to judge of those which are parallel. 120 Those which it took the same amount of movement to traverse would be equal, in whatever direction the movement occurred.
General Summary.

With this we may end our long and, I fear to many readers, tediously minute survey. The facts of vision form a jungle of intricacy; and those who penetrate²⁵⁹ deeply into physiological optics will be more struck by our omissions⁵⁸² than by our abundance of detail. But for students who may have lost sight of the forest for the trees, I will recapitulate⁵⁸³ briefly the points of our whole argument from the beginning, and then proceed to a short historical survey, which will set them in relief.

All our sensations are positively and inexplicably⁵⁸⁴ extensive wholes.

The sensations contributing to space-perception seem exclusively to be the surface of skin, retina, and joints. 'Muscular' feelings play no appreciable⁵⁸⁵ part in the generation of our feelings of form, direction, etc.

The total bigness of a cutaneous or retinal feeling soon becomes subdivided by discriminative attention.

Movements assist this discrimination by reason of the peculiarly exciting quality of the sensations which stimuli moving over surfaces arouse.

Subdivisions, once discriminated, acquire definite relations of position towards each other within the total space. These 'relations' are themselves feelings of the subdivisions that intervene. When these subdivisions are not the seat of stimuli, the relations are only reproduced in imaginary form.

The various sense-spaces are, in the first instance, incoherent with each other; and primitively both they and their subdivisions are but vaguely comparable in point of bulk and form.

The education of our space-perception consists largely of two processes -- reducing the various sense-feelings to a common measure, and adding them together into the single all-including space of the real world.

Both the measuring and the adding are performed by the aid of things.

The imagined aggregate⁵⁸⁶ of positions occupied by all the actual or possible, moving or stationary, things which we know, is our notion of 'real' space -- a very incomplete and vague conception in all minds.

The measuring of our space-feelings against each other mainly comes about through the successive arousal of different ones by the same thing, by our selection of certain ones as feelings of its real size and shape, and by the degradation⁵⁸⁷ of others to the status of being merely signs of these.

For the successive application of the same thing to different space-giving surfaces motion is indispensable, and hence plays a great pert in our space-education, especially in that of the eye. Abstractly considered, the motion of the object over the sensitive surface would educate us quite as well as that of the surface over the object. But the self- mobility of the organ carrying the surface accelerates immensely the result.

In completely educated space-perception, the present sensation is usually just what Helmholtz (Physiol. Optik, p. 797) calls it, 'a sign, the interpretation of whose meaning is left to the understanding'. But the understanding is exclusively reproductive and never productive in the process; and its function is limited to the recall of previous space-sensations with which the present one has been associated and which may be judged more real than it.

Finally, this reproduction may in the case of certain visual forms be as vivid, or almost so, as actual sensation is.

The third dimension forms an original element of all our space-sensations. In the eye it is subdivided by various discriminations. The more distant subdivisions are often shut out altogether, and, in being suppressed, have the effort of diminishing the absolute space-value of the total field of view. 121
Historical

Let us now close with a brief historical survey. The first achievement of note in the study of space-perception was Berkeley's theory of vision. This undertook to establish two points, first that distance was not a visual but a tactile form of consciousness, suggested by visual signs; secondly⁵⁸⁸, that there is no one quality or 'idea' common to the sensations of touch and sight, such that prior to experience one might possibly anticipate from the look of an object anything about its felt size, shape, or position, or from the touch of it anything about its look.

In other words, that primitively chaotic or semi-chaotic condition of our various sense-spaces which we have demonstrated, was established for good by Berkeley; and he bequeathed to psychology the problem of describing the manner in which the deliverances are harmonized so as all to refer to one and the same extended world.

His disciples⁵⁸⁹ in Great Britain have solved this problem after Berkeley's own fashion, and to a great extent as we have done ourselves, by the ideas of the various senses suggesting each other in consequence of Association. But, either because they were intoxicated⁵⁹⁰ with the principle of association, or because in the number of details they lost their general bearings, they have forgotten, as a rule, to state under what sensible form the primitive spatial experiences are found which later became associated with so many other sensible signs. Heedless of their master Locke's precept⁵⁹¹, that the mind can frame unto itself no one new simple idea, they seem for the most part to be trying to explain the extensive plurality itself, account for it, and evolve it, by the mere association together of feelings which originally possessed⁵⁹² it not. They first evaporate the nature of extension by making it tantamount to mere 'coexistence,' and then they explain coexistence as being the same thing as succession, provided it be an extremely rapid or a reversible succession. Space-perception thus emerges without being anywhere postulated⁵⁹³. The only things postulated are unextended feelings and time. Says Thomas Brown (lecture XXIII.): "I am inclined to reverse exactly the process commonly supposed; and instead of deriving⁵⁹⁴ the measure of time from extension, to derive the knowledge and original measure of extension from time." Brown and both the Mills think that retinal sensations, colors, in their primitive condition, are felt with no extension and that the latter merely becomes inseparably associated with them. John Mill says: "Whatever may be the retinal impression conveyed by a line which bounds two colors, I see no ground for thinking that by the eye alone we could acquire the conception of what we now mean when we say that one of the colors is outside [beside] the other." 123

Whence does the extension come which gets so inseparably associated with these non-extended colored sensations? From the 'sweep and movements' of the eye -- from muscular feelings. But, as Prof. Bain says, if movement-feelings give us any property of things, "it would seem to be not space, but time." 124 And John Min says that "the idea of space is, at bottom, one of time." 125 Space, then, is not to be found in any elementary sensation, but, in Bain's words, "as a quality, it has no other origin and no other meaning then the association of these different [non-spatial] motor and sensitive effects." 127

This phrase is mystical-sounding enough to one who understands association as producing nothing, but only as knitting together things already produced in separate ways. The truth is that the English Associationist school, in trying to show how much their principle can accomplish, have altogether overshot the mark and espoused⁵⁹⁵ a kind of theory in respect to space-perception which the general tenor⁵⁹⁶ of their philosophy should lead them to abhor⁵⁹⁷. Really there are but three possible kinds of theory concerning space. Either (1) there is no spatial quality of sensation at all, and space is a mere symbol of succession; or (2) there is an extensive quality given immediately in certain particular sensations; or, finally, (3) there is a quality produced out of the inward resources of the mind, to envelop¹³³ sensations which, as given originally, are not spatial, but which, on being cast into the spatial form, become united and orderly. This last is the Kantian view. Stumpf admirably designates it as the 'psychic stimulus' theory, the crude sensations being considered as goads⁵⁹⁸ to the mind to put forth its slumbering⁵⁹⁹ power.

Brown, the Mills, and Bain, amid these possibilities, seem to have gone astray like lost sheep. With the 'mental chemistry' of which the Mills speak -- precisely the same thing as the 'psychical⁶⁰⁰ synthesis' of Wundt, which, as we shall soon see, is a principle expressly intended to do what Association can never perform -- they hold the third view, but again in other places imply the first. And, between the impossibility of getting from mere association anything not contained in the sensations associated and the dislike to allow spontaneous mental productivity, they flounder in a dismal⁶⁰¹ dilemma⁶⁰². Mr. Sully joins them there in what I must call a vague and vacillating way. Mr. Spencer of course is bound to pretend to 'evolve' all mental qualities out of antecedents different from themselves, so that we need perhaps not wonder at his refusal to accord the spatial quality to any of the several elementary sensations out of which our space-perception grows. Thus (Psychology, ii. 168, 172, 218):

"No idea of extension can arise from a simultaneous excitation" of a multitude of nerve-terminations like those of the skin or the retina, since this would imply a "knowledge of their relative positions" -- that is, "a pre-existent idea of a special extension, which is absurd." "No relation between successive states of consciousness gives in itself any idea of extension." "The muscular sensations accompanying motion are quite distinct from the notions of space and time associated with them."

Mr. Spencer none the less inveighs⁶⁰³ vociferously⁶⁰⁴ against the Kantian position that space is produced by the mind's own resources. And yet he nowhere denies space to be a, specific affection of consciousness different from time!

Such incoherency is pitiful. The fact is that, at bottom, all these authors are really 'psychical stimulists,' or Kantists. The space they speak of is a super-sensational mental product. This position appears to me thoroughly⁶⁰⁵ mythological⁶⁰⁶. But let us see how it is held by those who know more definitely what they mean. Schopenhauer expresses the Kantian view with more vigor⁶⁰⁷ and clearness than anyone else. He says:

"A man must be forsaken⁶⁰⁸ by all the gods to dream that the world we see outside of us, fining space in its three dimensions, moving down the inexorable stream of time, governed at each step by Causality's invariable law, -- but in all this only following rules which we may prescribe for it in advance of all experience, -- to dream, I say, that such a world should stand there outside of us, quite objectively real with no complicity of ours, and thereupon by a subsequent act, through the instrumentality of mere sensation, that it should enter our head and reconstruct a duplicate of itself as it was outside. For what a poverty-stricken thing is this mere sensation! Even in the noblest organs of sense it is nothing more than a local and specific feeling, susceptible within its kind of a few variations, but always strictly subjective and containing in itself nothing objective, nothing resembling a perception. For sensation of every sort is and remains a process in the organism itself. As such it is limited to the territory inside the skin and can never, accordingly, per se contain anything that lies outside the skin or outside ourselves. . . . Only when the Understanding . . . is roused to activity and brings its sole and only form, the law of Causality, into play, only then does the mighty⁶⁰⁹ transformation take place which makes out of subjective sensation objective intuition. The Understanding, namely, grasps by means of its innate, a priori, ante-experiential form, the given sensation of the body as an effect which as such must necessarily have a cause. At the same time the Understanding summons to Its aid the form of the outer sense which similarly lies already preformed in the intellect (or brain), and which is Space, in order to locate that cause outside of the organism. . . . In this process the Understanding, as I shall soon show, takes note of the most minute peculiarities of the given sensation in order to construct in the outer space a cause which shall completely account for them. This operation of the Understanding is, however, not one that takes place discursively⁶¹⁰, reflectively, in abstracto, by means of words and concepts; but is intuitive and immediate. . . . Thus the Understanding must drat create the objective world; never can the latter, already complete in se, simply promenade⁶¹¹ into our heads through the senses and organic apertures⁶¹². For the senses yield us nothing further than the raw material which must be first elaborated into the objective conception of an orderly physical world-system by means of the aforesaid simple forms of Space, Time, and Causality. . . . Let me show the great chasm⁶¹³ between sensation and perception by showing how raw the material is out of which the fair structure is upreared [sic]. Only two senses serve objective perception: touch and sight. They alone furnish the data on the basis whereof the Understanding, by the process indicated, erects⁶¹⁴ the objective world. . . . These data in themselves are still no perception; that is the Understanding's work. If I press with my hand against the table, the sensation I receive has no analogy with the idea of the firm cohesion⁶¹⁵ of the parts of this mass: only when my Understanding passes from the sensation to its cause does it create for itself a body with the properties of solidity, impenetrability, and hardness. When in the dark I lay my hand on a surface, or grasp a ball of three inches diameter, in either case the same parts of the band receive the impression: but out of the different contraction of the hand in the two cases my Understanding constructs the form of the body whose contact caused the feeling, and confirms its construction by leading me to move my hand over the body. If one born blind handles a cubical body, the sensations of his hand are quite uniform on all sides and in all directions, -- only the corners press upon a smaller part of his skin. In these sensations, as such, there is nothing whatever analogous to a cube. But from the felt resistance his Understanding infers immediately and intuitively a cause thereof, which now presents itself as a solid body; and from the movements of exploration which the arms made whilst the feelings of the hands remained constant he constructs, in the space known to him a priori, the body's cubical shape. Did he not bring with him ready-made the idea of a cause and of a space, with the laws thereof, there never could arise, out. of those successive feelings in his hand, the image of a cube. If we let a string run through our closed hand, we immediately construct as the cause of the friction⁶¹⁶ and its duration in such an attitude of the hand, a long cylindrical⁶¹⁷ body moving uniformly in one direction. But never out of the pure sensation in the hand could the idea of movement, that is, of change of position in space by means of time, arise: such a content can never lie in sensation, nor come out of it. Our Intellect, antecedently to all experience, must bear in itself the intuitions of Space and Time, and therewithal of the possibility of motion, and no less the idea of Causality, to pass from the empirically given feeling to its cause, and to construct the latter as a so moving body of the designated shape. For how great is the abyss between the mere sensation in the hand and the ideas of causality, materiality, and movement through Space, occurring in Time! The feeling in the hand, even with different contacts and positions, is something far too uniform and poor in content for it to be possible to construct out of it the idea of Space with its three dimensions, of the action of bodies on each other, with the properties of extension, impenetrability, cohesion, shape, hardness, softness, rest, and motion -- in short, the foundations of the objective world. This is only possible through Space, Time, and Causality . . . being preformed in the Intellect itself, . . . from whence it again follows that the perception of the external world is essentially an intellectual process, a work of the Understanding, to which sensation furnishes merely the occasion, and the data to be interpreted in each particular case." 128

I call this view mythological, because I am conscious of no such Kantian machine-shop in my mind, and feel no call to disparage⁶¹⁸ the powers of poor sensation in this merciless way. I have no introspective experience of mentally producing or creating space. My space-intuitions occur not in two times but in one. There is not one moment of passive inextensive sensation, succeeded by another of active extensive perception, but the form I see is as immediately felt as the color which fins it out. That the higher parts of the mind come in, who can deny? They add and subtract, they compare and measure, they reproduce and abstract. They inweave the space-sensations with intellectual relations; but these relations are the same when they obtain between the elements of the space-system as when they obtain between any of the other elements of which the world is made.

The essence of the Kantian contention is that there are not spaces, but Space -- one infinite continuous Unit -- and that our knowledge of this cannot be a piecemeal sensational affair, produced by summation and abstraction. To which the obvious reply is that, if any known thing bears on its front the appearance of piecemeal construction and abstraction, it is this very notion of the infinite unitary space of the world. It is a notion, if ever there was one; and no intuition. Most of us apprehend it in the barest symbolic abridgment⁶¹⁹: and if perchance we ever do try to make it more adequate, we just add one image of sensible extension to another until we are tired. Most of us are obliged to turn round and drop the thought of the space in front of us when we think of that behind. And the space represented as near to us seems more minutely subdivisible than that we think of as lying far away.

The other prominent German writers on space are also 'psychical stimulists.' Herbert, whose influence has been widest, says 'the resting eye sees no space,' 129 and ascribes visual extension to the influence of movements combining with the non-spatial retinal feelings so as to form graduated series of the latter. A given sensation of such a series reproduces the idea of its associates in regular order, and its idea is similarly reproduced by any one of them with the order reversed. Out of the fusion of these two contrasted reproductions comes the form of space 130 -- Heaven knows how.

The obvious objection is that mere serial order is a genus, and space-order a very peculiar species of that genus; and that, if the terms of reversible series became by that fact coexistent terms in space, the musical scale, the degrees of warmth and cold, and all other ideally graded series ought to appear to us in the shape of extended corporeal aggregates⁶²⁰, -- which they notoriously do not, though we may of course symbolize⁶²¹ their order by a spatial scheme. W. Volkmann von Volkmar, the Herbartian, takes the bull here by the horns, and says the musical scale is spatially extended, though he admits that its space does not belong to the real world. 131 I am unacquainted with any other Herbartian so bold.

To Lotze we owe the much-used term 'local sign.' He insisted that space could not emigrate directly into the mind from without, but must be reconstructed by the soul; and he seemed to think that the first reconstructions⁶²² of it by the soul must be super-sensational, But why sensations themselves might not be the soul's original spatial reconstructive acts Lotze fails to explain.

Wundt has all his life devoted⁶²³ himself to the elaboration of a space-theory, of which the neatest and most final expression is to be found in his Logik (ii. 457-60). He says:

"In the eye, space-perception has certain constant peculiarities which prove that no single optical sensation by itself possesses the extensive form, but that everywhere in our perception of space heterogeneous⁶²⁴ feelings combine. If we simply suppose that luminous sensations per se feel extensive, our supposition is shattered by that influence of movement in vision which is so clearly to be traced in many normal errors in the measurement, of the field of view. If we assume, on the other hand, that the movements and their feelings are alone possessed of the extensive quality, we make an unjustified hypothesis, for the phenomena compel us, it is true, to accord an influence to movement, but give us no right, to call the retinal sensations indifferent, for there are no visual ideas without retinal sensations. If then we wish rigorously to express the given facts, we can ascribe a spatial constitution only to combinations of retinal sensations with those of movement."

Thus Wundt, dividing theories into 'nativistic' and 'genetic⁶²⁵,' calls his own a genetic theory. To distinguish it from other theories of the same class, he names it a 'theory of complex local signs."

"It supposes two systems of local signs, whose relations -- taking the eye as an example -- we may think as . . . the measuring of the manifold local-sign system of the retina by the simple local-sign system of the movements. In its psychological nature this is a process of associative synthesis: it consists in the fusion of both groups of sensations into a product, whose elementary components are no longer separable from each other in idea. In melting wholly away into the product which they create they become consciously undistinguishable, and the mind apprehends⁶²⁶ only their resultant, the intuition of space. Thus there obtains a certain analogy between this psychic synthesis and that chemical synthesis which out of simple bodies generates a compound that appears to our immediate perception as a homogeneous whole with new properties."

Now let no modest reader think that if this sounds obscure to him it is because he does not know the full context; and that if a, wise professor like Wundt can talk so fluently and plausibly⁶²⁷ about 'combination' and 'psychic synthesis,' it must surely be because those words convey a so much greater fulness of positive meaning to the scholarly than to the unlearned mind. Really it is quite the reverse; all the virtue of the phrase lies in its mere sound and skin. Learning does but make one the more sensible of its inward unintelligibility⁶²⁸. Wundt's 'theory' is the flimsiest thing in the world. It starts by an untrue assumption, and then corrects it by an unmeaning phrase. Retinal sensations are spatial; and were they not, no amount of 'synthesis' with equally spaceless motor sensations could intelligibly⁶²⁹ make them so. Wundt's theory is, in short, but an avowal⁶³⁰ of impotence, and an appeal to the inscrutable powers of the soul. 132 It confesses that we cannot analyse the constitution or give the genesis of the spatial quality in consciousness. But at the same time it says the antecedents thereof are psychical and not cerebral facts. In calling the quality in question a sensational quality, our own account equally disclaimed⁶³¹ ability to analyse it, but said its antecedents were cerebral, not psychical -- in other words, that it was a first psychical thing. This is merely a question of probable fact, which the reader may decide.

And now what shall be said of Helmholtz? Can I find fault with a book which, on the whole, I imagine to be one of the four or five greatest monuments of human genius in the scientific line? If truth impels⁶³² I must fain try, and take the risks. It seems to me that Helmholtz's genius moves most securely when it keeps close to particular facts. At any rate, it shows least strong in purely speculative⁶³³ passages, which in the Optics, in spite of many beauties, seem to me fundamentally vacillating and obscure. The 'empiristic' view which Helmholtz defends is that the space-determinations we perceive are in every case products of a process of unconscious inference. 133 The inference is similar to one from induction or analogy. 134 We always see that form before us which habitually would have caused the sensation we now have. 135 But the latter sensation can never be intrinsically spatial, or its intrinsic space-determinations would never be overcome as they are so often by the 'illusory' space-determinations it so often suggests. 136 Since the illusory determination can be traced to a suggestion of Experience, the 'real' one must also be such a suggestion: so that all space intuitions are due solely to Experience. 137 The only psychic activity required for this is the association of ideas. 138

But how, it may be asked, can association produce a. space-quality not in the things associated? How can we by induction or analogy infer what we do not already generically know? Can 'suggestions of experience' reproduce elements which no particular experience originally contained? This is the point by which Helmholtz's 'empiristic' theory, as a theory, must he judged. No theory is worthy of the name which leaves such a point obscure.

Well, Helmholtz does so leave it. At one time he seems to fall back on inscrutable powers of the soul, and to range himself with the 'psychical stimulists.' He speaks of gent as having made the essential step in the matter in distinguishing the content of experience from that form -- space, course -- which is given it by the peculiar faculties⁶³⁴ of the mind. 139 But elsewhere, again, 140 speaking of sensationalistic theories which would connect spatially determinate feelings directly with certain neural events, he says it is better to assume only such simple psychic activities as we know to exist, and gives the association of ideas as an instance of what he means. Later, 141 he reinforces this remark by confessing that he does not see how any neural process can give rise without antecedent experience to a ready-made (fertige) perception of space. And, finally, in a single momentous⁶³⁵ sentence, he speaks of sensations of touch as if they might be the original material of our space-percepts -- which thus, from the optical point of view, 'may be assumed as given.' 142

Of course the eye-man has a right to fall back on the skin-man for help at a pinch. But doesn't this means that he is a mere eye-man and not a complete psychologist? In other words, Helmholtz's Optics and the 'empiristic theory' there professed⁶³⁶ are not to be understood as attempts at answering the general question of how space-consciousness enters the mind. They simply deny that it enters with the first optical sensations. 143 Our own account has affirmed stoutly⁶³⁷ that it enters then; but no more than Helmholtz have we pretended to show why. Who calls a thing a first sensation admits he has no theory of its production. Helmholtz, though all the while without an articulate theory, makes the world thing he has one. He beautifully traces the immense part which reproductive processes play in our vision of space, and never -- except in that one pitiful little sentence about touch -- does he tell us just what it is they reproduce. He limits himself to denying that they reproduce originals of a visual sort. And so difficult is the subject, and so magically do catch-words work on the popular-scientist ear, that most likely, had he written 'physiological' instead of 'nativistic,' and 'spiritualistic' instead of 'empiristic' (which synonyms⁶³⁸ Hering suggests), numbers of his present empirical evolutionary⁶³⁹ followers⁶⁴⁰ would fail to find in his teaching anything worthy of praise. But since he wrote otherwise, they hurrah⁶⁴¹ for him as a sort of second Locke, dealing another death-blow at the old bugaboo of 'innate ideas.' His 'nativistic' adversary⁶⁴² Hering, they probably imagine, -- Heaven save the mark! -- to be a scholastic⁶⁴³ in modern disguise.

After Wundt and Helmholtz, the most important anti-sensationalist space-philosopher in Germany is Professor Lipps, whose deduction⁶⁴⁴ of space from an order of non-spatial differences, continuous yet separate, is a wonderful piece of subtlety⁶⁴⁵ and logic. And yet he has to confess that continuous differences form in the first instance only a logical series, which need not appear spatial, and that whenever it does so appear, this must be accounted a 'fact,' due merely 'to the nature of the soul.' 144

Lipps, and almost all the anti-sensationalist theorists except Helmholtz, seem guilty of that confusion which Mr. Shadworth Hodgson has done so much to clear away, viz., the confounding the analysis of an idea with the means of its production. Lipps, for example, finds that every space we think of can be broken up into positions, and concludes that in some undefined way the several positions must have pre-existed in thought before the aggregate space could have appeared to perception. Similarly Mr. Spencer, defining extension as an 'aggregate of relations of coexistent position,' says "every cognition of magnitude is a cognition of relations of position," 145 and "no idea of extension can arise from the simultaneous excitation" of many nerves "unless there is a knowledge of their relative positions." 146 Just so Prof. Bain insists that the very meaning of space is scope for movement, 147 and that therefore distance and magnitude can be no original attributes of the eye's sensibility. Similarly because movement is analyzable into positions occupied at successive moments by the mover, philosophers (e.g. Schopenhauer, as quoted above) have repeatedly denied the possibility of its being an immediate sensation. We have, however, seen that it is the most immediate of all our space-sensations. Because it can only occur in a definite direction the impossibility of perceiving it without perceiving its direction has been decreed -- a decree which the simplest experiment overthrows⁶⁴⁶. 148 It is a case of what I have called the 'psychologist's fallacy': mere acquaintance with space is treated as tantamount to every sort of knowledge about it, the conditions of the latter are demanded of the former state of mind, and all sorts of mythological processes are brought in to help. 149 As well might one say that because the world consists of all its parts, therefore we can only apprehend it at all by having unconsciously summed these up in our head. It is the old idea of our actual knowledge being drawn out from a pre-existent potentiality, an idea which, whatever worth it may metaphysically possess, does no good in psychology.

My own sensationalistic account has derived most aid and comfort from the writings of Hering, A. W. Volkmann, Stumpf, Leconte, and Schön. All these authors allow ample scope to that Experience which Berkeley's genius saw to be a present factor in all our visual acts. But they give Experience some grist to grind, which the soi-distant 'empiristic' school forgets to do. Stumpf seems to me the most philosophical⁶⁴⁷ and profound of all these writers; and I owe him much. I should doubtless have owed almost as much to Mr. James Ward, had his article on Psychology in the Encyclopædia Britannica appeared before my own thoughts were written down. The literature of the question is in all languages very voluminous. I content myself with referring to the bibliography⁶⁴⁸ in Helmholtz's and Aubert's works on Physiological Optics for the visual part of the subject, and with naming in a note the ablest works in the English tongue which have treated of the subject in a general way.

 

 

 

 

 

 

 

 

 

 

 

 

 

1 luminous   

adj.发光的，发亮的；光明的；明白易懂的；有启发的

参考例句：

• There are luminous knobs on all the doors in my house.我家所有门上都安有夜光把手。
• Most clocks and watches in this shop are in luminous paint.这家商店出售的大多数钟表都涂了发光漆。

2 squeaking   

v.短促地尖叫( squeak的现在分词 )；吱吱叫；告密；充当告密者

参考例句：

• Squeaking floorboards should be screwed down. 踏上去咯咯作响的地板应用螺钉钉住。 来自《简明英汉词典》
• Can you hear the mice squeaking? 你听到老鼠吱吱叫吗？ 来自《简明英汉词典》

3 prick   

v.刺伤，刺痛，刺孔；n.刺伤，刺痛

参考例句：

• He felt a sharp prick when he stepped on an upturned nail.当他踩在一个尖朝上的钉子上时，他感到剧烈的疼痛。
• He burst the balloon with a prick of the pin.他用针一戳，气球就爆了。

4 neural   

adj.神经的，神经系统的

参考例句：

• The neural network can preferably solve the non- linear problem.利用神经网络建模可以较好地解决非线性问题。
• The information transmission in neural system depends on neurotransmitters.信息传递的神经途径有赖于神经递质。

5 fin   

n.鳍；(飞机的)安定翼

参考例句：

• They swim using a small fin on their back.它们用背上的小鳍游动。
• The aircraft has a long tail fin.那架飞机有一个长长的尾翼。

6 discomfort   

n.不舒服，不安，难过，困难，不方便

参考例句：

• One has to bear a little discomfort while travelling.旅行中总要忍受一点不便。
• She turned red with discomfort when the teacher spoke.老师讲话时她不好意思地红着脸。

7 solitary   

adj.孤独的，独立的，荒凉的；n.隐士

参考例句：

• I am rather fond of a solitary stroll in the country.我颇喜欢在乡间独自徜徉。
• The castle rises in solitary splendour on the fringe of the desert.这座城堡巍然耸立在沙漠的边际，显得十分壮美。

8 subjective   

a.主观(上)的，个人的

参考例句：

• The way they interpreted their past was highly subjective. 他们解释其过去的方式太主观。
• A literary critic should not be too subjective in his approach. 文学评论家的看法不应太主观。

9 investigation   

n.调查，调查研究

参考例句：

• In an investigation,a new fact became known, which told against him.在调查中新发现了一件对他不利的事实。
• He drew the conclusion by building on his own investigation.他根据自己的调查研究作出结论。

10 stimulation   

n.刺激，激励，鼓舞

参考例句：

• The playgroup provides plenty of stimulation for the children.幼儿游戏组给孩子很多启发。
• You don't get any intellectual stimulation in this job.你不能从这份工作中获得任何智力启发。

11 spatial   

adj.空间的，占据空间的

参考例句：

• This part of brain judges the spatial relationship between objects.大脑的这部分判断物体间的空间关系。
• They said that time is the feeling of spatial displacement.他们说时间是空间位移的感觉。

12 adjourn   

v.（使）休会，（使）休庭

参考例句：

• The motion to adjourn was carried.休会的提议通过了。
• I am afraid the court may not adjourn until three or even later.我担心法庭要到3点或更晚时才会休庭。

13 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

14 tract   

n.传单，小册子，大片(土地或森林)

参考例句：

• He owns a large tract of forest.他拥有一大片森林。
• He wrote a tract on this subject.他曾对此写了一篇短文。

15 thigh   

n.大腿；股骨

参考例句：

• He is suffering from a strained thigh muscle.他的大腿肌肉拉伤了，疼得很。
• The thigh bone is connected to the hip bone.股骨连着髋骨。

16 twitch   

v.急拉，抽动，痉挛，抽搐；n.扯，阵痛，痉挛

参考例句：

• The smell made my dog's nose twitch.那股气味使我的狗的鼻子抽动着。
• I felt a twitch at my sleeve.我觉得有人扯了一下我的袖子。

17 eyelid   

n.眼睑，眼皮

参考例句：

• She lifted one eyelid to see what he was doing.她抬起一只眼皮看看他在做什么。
• My eyelid has been tumid since yesterday.从昨天起，我的眼皮就肿了。

18 musk   

n.麝香, 能发出麝香的各种各样的植物，香猫

参考例句：

• Musk is used for perfume and stimulant.麝香可以用作香料和兴奋剂。
• She scented her clothes with musk.她用麝香使衣服充满了香味。

19 epithet   

n.（用于褒贬人物等的）表述形容词，修饰语

参考例句：

• In "Alfred the Great","the Great"is an epithet.“阿尔弗雷德大帝”中的“大帝”是个称号。
• It is an epithet that sums up my feelings.这是一个简洁地表达了我思想感情的形容词。

20 streak   

n.条理，斑纹，倾向，少许，痕迹；v.加条纹，变成条纹，奔驰，快速移动

参考例句：

• The Indians used to streak their faces with paint.印第安人过去常用颜料在脸上涂条纹。
• Why did you streak the tree?你为什么在树上刻条纹？

21 derived   

vi.起源；由来；衍生；导出v.得到( derive的过去式和过去分词 )；（从…中）得到获得；源于；（从…中）提取

参考例句：

• Many English words are derived from Latin and Greek. 英语很多词源出于拉丁文和希腊文。 来自《简明英汉词典》
• He derived his enthusiasm for literature from his father. 他对文学的爱好是受他父亲的影响。 来自《简明英汉词典》

22 derive   

v.取得；导出；引申；来自；源自；出自

参考例句：

• We derive our sustenance from the land.我们从土地获取食物。
• We shall derive much benefit from reading good novels.我们将从优秀小说中获得很大好处。

23 ward   

n.守卫，监护，病房，行政区，由监护人或法院保护的人（尤指儿童）；vt.守护，躲开

参考例句：

• The hospital has a medical ward and a surgical ward.这家医院有内科病房和外科病房。
• During the evening picnic,I'll carry a torch to ward off the bugs.傍晚野餐时，我要点根火把，抵挡蚊虫。

24 repletion   

n.充满，吃饱

参考例句：

• It is better to die of repletion than to endure hunger.饱死胜过挨饿。
• A baby vomits milk from repletion.婴儿吃饱会吐奶。

25 suffocation   

n.窒息

参考例句：

• The greatest dangers of pyroclastic avalanches are probably heat and suffocation. 火成碎屑崩落的最大危害可能是炽热和窒息作用。 来自辞典例句
• The room was hot to suffocation. 房间热得闷人。 来自辞典例句

26 nausea   

n.作呕，恶心；极端的憎恶(或厌恶)

参考例句：

• Early pregnancy is often accompanied by nausea.怀孕期常有恶心的现象。
• He experienced nausea after eating octopus.吃了章鱼后他感到恶心。

27 drowsiness   

n.睡意；嗜睡

参考例句：

• A feeling of drowsiness crept over him. 一种昏昏欲睡的感觉逐渐袭扰着他。 来自《简明英汉词典》
• This decision reached, he finally felt a placid drowsiness steal over him. 想到这，来了一点平安的睡意。 来自汉英文学 - 骆驼祥子

28 fatigue   

n.疲劳，劳累

参考例句：

• The old lady can't bear the fatigue of a long journey.这位老妇人不能忍受长途旅行的疲劳。
• I have got over my weakness and fatigue.我已从虚弱和疲劳中恢复过来了。

29 pulsation   

n.脉搏，悸动，脉动；搏动性

参考例句：

• At low frequencies, such as 10 per sec., pulsation is sensed rather than vibration. 在低频率（譬如每秒十次）时，所感觉到的是脉冲而非振动。 来自辞典例句
• If the roller pulsation, the pressure on paper as cause misregister. 如果滚子径向跳不静，则差纸的不张辛有不小有小，致使套印禁绝。 来自互联网

30 maxim   

n.格言，箴言

参考例句：

• Please lay the maxim to your heart.请把此格言记在心里。
• "Waste not,want not" is her favourite maxim.“不浪费则不匮乏”是她喜爱的格言。

31 subdivide   

vt.细分（细区分，再划分，重分，叠分，分小类）

参考例句：

• You can use sales organizations to subdivide markets into regions.用销售组织将市场细分为区域。
• The verbs were subdivided into transitive and intransitive categories.动词可细分为及物动词和不及物动词。

32 lesser   

adj.次要的，较小的；adv.较小地，较少地

参考例句：

• Kept some of the lesser players out.不让那些次要的球员参加联赛。
• She has also been affected,but to a lesser degree.她也受到波及，但程度较轻。

33 simultaneously   

adv.同时发生地，同时进行地

参考例句：

• The radar beam can track a number of targets almost simultaneously.雷达波几乎可以同时追着多个目标。
• The Windows allow a computer user to execute multiple programs simultaneously.Windows允许计算机用户同时运行多个程序。

34 considerably   

adv.极大地；相当大地；在很大程度上

参考例句：

• The economic situation has changed considerably.经济形势已发生了相当大的变化。
• The gap has narrowed considerably.分歧大大缩小了。

35 rim   

n.(圆物的)边，轮缘；边界

参考例句：

• The water was even with the rim of the basin.盆里的水与盆边平齐了。
• She looked at him over the rim of her glass.她的目光越过玻璃杯的边沿看着他。

36 intensity   

n.强烈，剧烈；强度；烈度

参考例句：

• I didn't realize the intensity of people's feelings on this issue.我没有意识到这一问题能引起群情激奋。
• The strike is growing in intensity.罢工日益加剧。

37 entirely   

ad.全部地，完整地；完全地，彻底地

参考例句：

• The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
• His life was entirely given up to the educational work. 他的一生统统献给了教育工作。

38 peculiar   

adj.古怪的，异常的；特殊的，特有的

参考例句：

• He walks in a peculiar fashion.他走路的样子很奇特。
• He looked at me with a very peculiar expression.他用一种很奇怪的表情看着我。

39 sensational   

adj.使人感动的，非常好的，轰动的，耸人听闻的

参考例句：

• Papers of this kind are full of sensational news reports.这类报纸满是耸人听闻的新闻报道。
• Their performance was sensational.他们的演出妙极了。

40 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

41 inter   

v.埋葬

参考例句：

• They interred their dear comrade in the arms.他们埋葬了他们亲爱的战友。
• The man who died in that accident has been interred.在那次事故中死的那个人已经被埋葬了。

42 qualitative   

adj.性质上的，质的，定性的

参考例句：

• There are qualitative differences in the way children and adults think.孩子和成年人的思维方式有质的不同。
• Arms races have a quantitative and a qualitative aspects.军备竞赛具有数量和质量两个方面。

43 cataract   

n.大瀑布，奔流，洪水，白内障

参考例句：

• He is an elderly gentleman who had had a cataract operation.他是一位曾经动过白内障手术的老人。
• The way is blocked by the tall cataract.高悬的大瀑布挡住了去路。

44 specially   

adv.特定地；特殊地；明确地

参考例句：

• They are specially packaged so that they stack easily.它们经过特别包装以便于堆放。
• The machine was designed specially for demolishing old buildings.这种机器是专为拆毁旧楼房而设计的。

45 cannon   

n.大炮，火炮；飞机上的机关炮

参考例句：

• The soldiers fired the cannon.士兵们开炮。
• The cannon thundered in the hills.大炮在山间轰鸣。

46 ail   

v.生病，折磨，苦恼

参考例句：

• It may provide answers to some of the problems that ail America.这一点可能解答困扰美国的某些问题。
• Seek your sauce where you get your ail.心痛还须心药治。

47 strictly   

adv.严厉地，严格地；严密地

参考例句：

• His doctor is dieting him strictly.他的医生严格规定他的饮食。
• The guests were seated strictly in order of precedence.客人严格按照地位高低就座。

48 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

49 vaguely   

adv.含糊地，暖昧地

参考例句：

• He had talked vaguely of going to work abroad.他含糊其词地说了到国外工作的事。
• He looked vaguely before him with unseeing eyes.他迷迷糊糊的望着前面，对一切都视而不见。

50 fins   

[医]散热片；鱼鳍；飞边；鸭掌

参考例句：

• The level of TNF-α positively correlated with BMI,FPG,HbA1C,TG,FINS and IRI,but not with SBP and DBP. TNF-α水平与BMI、FPG、HbA1C、TG、FINS和IRI呈显著正相关，与SBP、DBP无相关。 来自互联网
• Fins are a feature specific to fish. 鱼鳍是鱼类特有的特征。 来自辞典例句

51 mere   

adj.纯粹的；仅仅，只不过

参考例句：

• That is a mere repetition of what you said before.那不过是重复了你以前讲的话。
• It's a mere waste of time waiting any longer.再等下去纯粹是浪费时间。

52 transparent   

adj.明显的，无疑的；透明的

参考例句：

• The water is so transparent that we can see the fishes swimming.水清澈透明，可以看到鱼儿游来游去。
• The window glass is transparent.窗玻璃是透明的。

53 opaque   

adj.不透光的；不反光的，不传导的；晦涩的

参考例句：

• The windows are of opaque glass.这些窗户装着不透明玻璃。
• Their intentions remained opaque.他们的意图仍然令人费解。

54 perfectly   

adv.完美地，无可非议地，彻底地

参考例句：

• The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
• Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。

55 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

56 attentively   

adv.聚精会神地；周到地；谛；凝神

参考例句：

• She listened attentively while I poured out my problems. 我倾吐心中的烦恼时，她一直在注意听。 来自《简明英汉词典》
• She listened attentively and set down every word he said. 她专心听着，把他说的话一字不漏地记下来。 来自《简明英汉词典》

57 attentive   

adj.注意的，专心的；关心(别人)的，殷勤的

参考例句：

• She was very attentive to her guests.她对客人招待得十分周到。
• The speaker likes to have an attentive audience.演讲者喜欢注意力集中的听众。

58 discriminate   

v.区别，辨别，区分；有区别地对待

参考例句：

• You must learn to discriminate between facts and opinions.你必须学会把事实和看法区分出来。
• They can discriminate hundreds of colours.他们能分辨上百种颜色。

59 vividly   

adv.清楚地，鲜明地，生动地

参考例句：

• The speaker pictured the suffering of the poor vividly.演讲者很生动地描述了穷人的生活。
• The characters in the book are vividly presented.这本书里的人物写得栩栩如生。

60 analogous   

adj.相似的；类似的

参考例句：

• The two situations are roughly analogous.两种情況大致相似。
• The company is in a position closely analogous to that of its main rival.该公司与主要竞争对手的处境极为相似。

61 retract   

vt.缩回，撤回收回，取消

参考例句：

• The criminals should stop on the precipice, retract from the wrong path and not go any further.犯罪分子应当迷途知返，悬崖勒马，不要在错误的道路上继续走下去。
• I don't want to speak rashly now and later have to retract my statements.我不想现在说些轻率的话，然后又要收回自己说过的话。

62 backwards   

adv.往回地，向原处，倒，相反，前后倒置地

参考例句：

• He turned on the light and began to pace backwards and forwards.他打开电灯并开始走来走去。
• All the girls fell over backwards to get the party ready.姑娘们迫不及待地为聚会做准备。

63 undo   

vt.解开，松开；取消，撤销

参考例句：

• His pride will undo him some day.他的傲慢总有一天会毁了他。
• I managed secretly to undo a corner of the parcel.我悄悄地设法解开了包裹的一角。

64 undoubtedly   

adv.确实地，无疑地

参考例句：

• It is undoubtedly she who has said that.这话明明是她说的。
• He is undoubtedly the pride of China.毫无疑问他是中国的骄傲。

65 projection   

n.发射，计划，突出部分

参考例句：

• Projection takes place with a minimum of awareness or conscious control.投射在最少的知觉或意识控制下发生。
• The projection of increases in number of house-holds is correct.对户数增加的推算是正确的。

66 fluctuation   

n.(物价的)波动，涨落；周期性变动；脉动

参考例句：

• The erratic fluctuation of market prices are in consequence of unstable economy.经济波动致使市场物价忽起忽落。
• Early and adequate drainage is essential if fluctuation occurs.有波动感时，应及早地充分引流。

67 crater   

n.火山口，弹坑

参考例句：

• With a telescope you can see the huge crater of Ve-suvius.用望远镜你能看到巨大的维苏威火山口。
• They came to the lip of a dead crater.他们来到了一个死火山口。

68 socket   

n.窝，穴，孔，插座，插口

参考例句：

• He put the electric plug into the socket.他把电插头插入插座。
• The battery charger plugs into any mains socket.这个电池充电器可以插入任何类型的电源插座。

69 monstrous   

adj.巨大的；恐怖的；可耻的，丢脸的

参考例句：

• The smoke began to whirl and grew into a monstrous column.浓烟开始盘旋上升，形成了一个巨大的烟柱。
• Your behaviour in class is monstrous!你在课堂上的行为真是丢人！

70 membrane   

n.薄膜，膜皮，羊皮纸

参考例句：

• A vibrating membrane in the ear helps to convey sounds to the brain.耳膜的振动帮助声音传送到大脑。
• A plastic membrane serves as selective diffusion barrier.一层塑料薄膜起着选择性渗透屏障的作用。

71 cuticle   

n.表皮

参考例句：

• You'd never puncture the cuticle.你无法刺穿表皮。
• The reform has hardly made a scratch upon the cuticle of affairs.改革几乎还没有触到事物的表皮。

72 nostrils   

鼻孔( nostril的名词复数 )

参考例句：

• Her nostrils flared with anger. 她气得两个鼻孔都鼓了起来。
• The horse dilated its nostrils. 马张大鼻孔。

73 immediate   

adj.立即的；直接的，最接近的；紧靠的

参考例句：

• His immediate neighbours felt it their duty to call.他的近邻认为他们有责任去拜访。
• We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。

74 discriminated   

分别，辨别，区分( discriminate的过去式和过去分词 )； 歧视，有差别地对待

参考例句：

• His great size discriminated him from his followers. 他的宽广身材使他不同于他的部下。
• Should be a person that has second liver virus discriminated against? 一个患有乙肝病毒的人是不是就应该被人歧视？

75 sieve   

n.筛，滤器，漏勺

参考例句：

• We often shake flour through a sieve.我们经常用筛子筛面粉。
• Finally,it is like drawing water with a sieve.到头来，竹篮打水一场空。

76 enumeration   

n.计数，列举；细目；详表；点查

参考例句：

• Predictive Categoriesinclude six categories of prediction, namely Enumeration, Advance Labeling, Reporting,Recapitulation, Hypotheticality, and Question. 其中预设种类又包括列举(Enumeration)、提前标示(Advance Labeling)、转述(Reporting)、回顾(Recapitulation)、假设(Hypotheticality)和提问(Question)。 来自互联网
• Here we describe a systematic procedure which is basically "enumeration" in nature. 这里介绍一个本质上是属于“枚举法”的系统程序。 来自辞典例句

77 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

78 sensory   

adj.知觉的，感觉的，知觉器官的

参考例句：

• Human powers of sensory discrimination are limited.人类感官分辨能力有限。
• The sensory system may undergo long-term adaptation in alien environments.感觉系统对陌生的环境可能经过长时期才能适应。

79 lateral   

adj.侧面的，旁边的

参考例句：

• An airfoil that controls lateral motion.能够控制横向飞行的机翼。
• Mr.Dawson walked into the court from a lateral door.道森先生从一个侧面的门走进法庭。

80 forefinger   

n.食指

参考例句：

• He pinched the leaf between his thumb and forefinger.他将叶子捏在拇指和食指之间。
• He held it between the tips of his thumb and forefinger.他用他大拇指和食指尖拿着它。

81 forefingers   

n.食指( forefinger的名词复数 )

参考例句：

• When her eyes were withdrawn, he secretly crossed his two forefingers. 一等她的眼睛转过去，他便偷偷用两个食指交叠成一个十字架。 来自辞典例句
• The ornithologists made Vs with their thumbs and forefingers, measuring angles. 鸟类学家们用大拇指和食指构成V形量测角度。 来自互联网

82 crumb   

n.饼屑，面包屑，小量

参考例句：

• It was the only crumb of comfort he could salvage from the ordeal.这是他从这场磨难里能找到的唯一的少许安慰。
• Ruth nearly choked on the last crumb of her pastry.鲁斯几乎被糕点的最后一块碎屑所噎住。

83 drawn   

v.拖，拉，拔出；adj.憔悴的，紧张的

参考例句：

• All the characters in the story are drawn from life.故事中的所有人物都取材于生活。
• Her gaze was drawn irresistibly to the scene outside.她的目光禁不住被外面的风景所吸引。

84 diverge   

v.分叉，分歧，离题，使...岔开，使转向

参考例句：

• This is where our opinions diverge from each other.这就是我们意见产生分歧之处。
• Don't diverge in your speech.发言不要离题。

85 fig   

n.无花果(树)

参考例句：

• The doctor finished the fig he had been eating and selected another.这位医生吃完了嘴里的无花果，又挑了一个。
• You can't find a person who doesn't know fig in the United States.你找不到任何一个在美国的人不知道无花果的。

86 figs   

figures 数字，图形，外形

参考例句：

• The effect of ring dyeing is shown in Figs 10 and 11. 环形染色的影响如图10和图11所示。
• The results in Figs. 4 and 5 show the excellent agreement between simulation and experiment. 图4和图5的结果都表明模拟和实验是相当吻合的。

87 manlier   

manly（有男子气概的）的比较级形式

参考例句：

• The man did work that was thought to be manlier. He was a logger. 老先生做的是一般认为较适合男性的工作-当一名樵夫。

88 extremities   

n.端点( extremity的名词复数 )；尽头；手和足；极窘迫的境地

参考例句：

• She was most noticeable, I thought, in respect of her extremities. 我觉得她那副穷极可怜的样子实在太惹人注目。 来自辞典例句
• Winters may be quite cool at the northwestern extremities. 西北边区的冬天也可能会相当凉。 来自辞典例句

89 touching   

adj.动人的，使人感伤的

参考例句：

• It was a touching sight.这是一幅动人的景象。
• His letter was touching.他的信很感人。

90 circumscribed   

adj.[医]局限的：受限制或限于有限空间的v.在…周围划线( circumscribe的过去式和过去分词 )；划定…范围；限制；限定

参考例句：

• The power of the monarchy was circumscribed by the new law. 君主统治的权力受到了新法律的制约。
• His activities have been severely circumscribed since his illness. 自生病以来他的行动一直受到严格的限制。 来自《简明英汉词典》

91 opacity   

n.不透明；难懂

参考例句：

• He insisted that the mineral content of the water determined the opacity.他坚持认为水的清澈程度取决于其中矿物质的含量。
• Opacity of the eye lens can be induced by deficiency of certain vitamins.眼球晶状体的混浊可由缺乏某些维生素造成。

92 inverse   

adj.相反的，倒转的，反转的；n.相反之物；v.倒转

参考例句：

• Evil is the inverse of good.恶是善的反面。
• When the direct approach failed he tried the inverse.当直接方法失败时，他尝试相反的做法。

93 perversions   

n.歪曲( perversion的名词复数 )；变坏；变态心理

参考例句：

• Many practices commonly regarded as perversions were widespread. 许多通常认为是性变态的行为的做法实际上是广泛存在的。 来自辞典例句

94 recede   

vi.退(去)，渐渐远去；向后倾斜，缩进

参考例句：

• The colleges would recede in importance.大学的重要性会降低。
• He saw that the dirty water had begun to recede.他发现那污浊的水开始往下退了。

95 physiologist   

n.生理学家

参考例句：

• Russian physiologist who observed conditioned salivary responses in dogs (1849-1936). （1849-1936）苏联生理学家，在狗身上观察到唾液条件反射，曾获1904年诺贝尔生理学-医学奖。
• The physiologist recently studied indicated that evening exercises beneficially. 生理学家新近研究表明，傍晚锻炼最为有益。

96 cerebral   

adj.脑的，大脑的；有智力的，理智型的

参考例句：

• Your left cerebral hemisphere controls the right-hand side of your body.你的左半脑控制身体的右半身。
• He is a precise,methodical,cerebral man who carefully chooses his words.他是一个一丝不苟、有条理和理智的人，措辞谨慎。

97 disturbance   

n.动乱，骚动；打扰，干扰；(身心)失调

参考例句：

• He is suffering an emotional disturbance.他的情绪受到了困扰。
• You can work in here without any disturbance.在这儿你可不受任何干扰地工作。

98 disturbances   

n.骚乱( disturbance的名词复数 )；打扰；困扰；障碍

参考例句：

• The government has set up a commission of inquiry into the disturbances at the prison. 政府成立了一个委员会来调查监狱骚乱事件。
• Extra police were called in to quell the disturbances. 已调集了增援警力来平定骚乱。

99 physiological   

adj.生理学的，生理学上的

参考例句：

• He bought a physiological book.他买了一本生理学方面的书。
• Every individual has a physiological requirement for each nutrient.每个人对每种营养成分都有一种生理上的需要。

100 logic   

n.逻辑(学)；逻辑性

参考例句：

• What sort of logic is that?这是什么逻辑？
• I don't follow the logic of your argument.我不明白你的论点逻辑性何在。

101 awaken   

vi.醒，觉醒；vt.唤醒，使觉醒，唤起，激起

参考例句：

• Old people awaken early in the morning.老年人早晨醒得早。
• Please awaken me at six.请于六点叫醒我。

102 awakens   

v.（使）醒( awaken的第三人称单数 )；（使）觉醒；弄醒；（使）意识到

参考例句：

• The scene awakens reminiscences of my youth. 这景象唤起我年轻时的往事。 来自《现代英汉综合大词典》
• The child awakens early in the morning. 这个小孩早晨醒得早。 来自辞典例句

103 illuminated   

adj.被照明的；受启迪的

参考例句：

• Floodlights illuminated the stadium. 泛光灯照亮了体育场。
• the illuminated city at night 夜幕中万家灯火的城市

104 celebrated   

adj.有名的，声誉卓著的

参考例句：

• He was soon one of the most celebrated young painters in England.不久他就成了英格兰最负盛名的年轻画家之一。
• The celebrated violinist was mobbed by the audience.观众团团围住了这位著名的小提琴演奏家。

105 spatially   

空间地，存在于空间地

参考例句：

• A well-defined array of stable fringes results and the field is spatially coherent. 结果得到一组完全确定的稳定条纹，而光场是空间相干的。
• The units are collaged together by a serial tectonic spatially and temporally. 这些构造单元是由构造原因，依一定的时空序列拼贴在一起的。

106 analyze   

vt.分析，解析 (=analyse)

参考例句：

• We should analyze the cause and effect of this event.我们应该分析这场事变的因果。
• The teacher tried to analyze the cause of our failure.老师设法分析我们失败的原因。

107 spatiality   

空间性

参考例句：

• The 20th century witnessed the timeliness took the place of the spatiality. 摘要20世纪预示着一个空间时代的到来。
• The floor levels are relative and spatiality is perceived differently according to one's position. 楼面是相对而言的，站立地点不同就会感觉到不同的空间性。

108 peculiarities   

n. 特质, 特性, 怪癖, 古怪

参考例句：

• the cultural peculiarities of the English 英国人的文化特点
• He used to mimic speech peculiarities of another. 他过去总是模仿别人讲话的特点。

109 recollected   

adj.冷静的；镇定的；被回忆起的；沉思默想的v.记起，想起( recollect的过去式和过去分词 )

参考例句：

• I recollected that she had red hair. 我记得她有一头红发。 来自《简明英汉词典》
• His efforts, the Duke recollected many years later, were distinctly half-hearted. 据公爵许多年之后的回忆，他当时明显只是敷衍了事。 来自辞典例句

110 psychic   

n.对超自然力敏感的人；adj.有超自然力的

参考例句：

• Some people are said to have psychic powers.据说有些人有通灵的能力。
• She claims to be psychic and to be able to foretell the future.她自称有特异功能，能预知未来。

111 primitively   

最初地，自学而成地

参考例句：

• Result: The histological structure of anencephalus differentiates primitively and grows very slowly. 结果：无脑儿食管的组织学结构较正常胎儿分化较低，发育迟缓。
• Another primitively for horse's hoof Dutch. 另一个原始属为马蹄荷属。

112 primitive   

adj.原始的；简单的；n.原(始)人，原始事物

参考例句：

• It is a primitive instinct to flee a place of danger.逃离危险的地方是一种原始本能。
• His book describes the march of the civilization of a primitive society.他的著作描述了一个原始社会的开化过程。

113 reigns   

n.君主的统治( reign的名词复数 )；君主统治时期；任期；当政期

参考例句：

• In these valleys night reigns. 夜色笼罩着那些山谷。 来自《现代汉英综合大词典》
• The Queen of Britain reigns, but she does not rule or govern. 英国女王是国家元首，但不治国事。 来自辞典例句

114 potent   

adj.强有力的，有权势的；有效力的

参考例句：

• The medicine had a potent effect on your disease.这药物对你的病疗效很大。
• We must account of his potent influence.我们必须考虑他的强有力的影响。

115 apprehended   

逮捕，拘押( apprehend的过去式和过去分词 )； 理解

参考例句：

• She apprehended the complicated law very quickly. 她很快理解了复杂的法律。
• The police apprehended the criminal. 警察逮捕了罪犯。

116 apprehend   

vt.理解，领悟，逮捕，拘捕，忧虑

参考例句：

• I apprehend no worsening of the situation.我不担心局势会恶化。
• Police have not apprehended her killer.警察还未抓获谋杀她的凶手。

117 primordial   

adj.原始的；最初的

参考例句：

• It is the primordial force that propels us forward.它是推动我们前进的原始动力。
• The Neanderthal Man is one of our primordial ancestors.的尼安德特人是我们的原始祖先之一.

118 subdivided   

再分，细分( subdivide的过去式和过去分词 )

参考例句：

• The compound was subdivided into four living areas. 那个区域被划分成4个居住小区。
• This part of geologic calendar has not been satisfactorily subdivided. 这部分地质年代表还没有令人满意地再细分出来。

119 shuffle   

n.拖著脚走，洗纸牌；v.拖曳，慢吞吞地走

参考例句：

• I wish you'd remember to shuffle before you deal.我希望在你发牌前记得洗牌。
• Don't shuffle your feet along.别拖着脚步走。

120 chaotic   

adj.混沌的，一片混乱的，一团糟的

参考例句：

• Things have been getting chaotic in the office recently.最近办公室的情况越来越乱了。
• The traffic in the city was chaotic.这城市的交通糟透了。

121 chaotically   

参考例句：

• His thoughts churned chaotically in his brain like snowflakes whirling about in the north wind. 头脑里，情思弥漫纷乱像个北风飘雪片的天空。 来自汉英文学 - 围城
• In metal the atoms are arranged not chaotically but in even rows, forming a crystal lattice. 在金属里，原子并不是杂乱无章地排列而是排成平整的行列，构成一个晶格。 来自辞典例句

122 sentient   

adj.有知觉的，知悉的；adv.有感觉能力地

参考例句：

• The living knew themselves just sentient puppets on God's stage.生还者认识到，他们不过是上帝的舞台上有知觉的木偶而已。
• It teaches us to love all sentient beings equally.它教导我们应该平等爱护一切众生。

123 intercourse   

n.性交；交流，交往，交际

参考例句：

• The magazine becomes a cultural medium of intercourse between the two peoples.该杂志成为两民族间文化交流的媒介。
• There was close intercourse between them.他们过往很密。

124 brook   

n.小河，溪；v.忍受，容让

参考例句：

• In our room we could hear the murmur of a distant brook.在我们房间能听到远处小溪汩汩的流水声。
• The brook trickled through the valley.小溪涓涓流过峡谷。

125 cedars   

雪松，西洋杉( cedar的名词复数 )

参考例句：

• The old cedars were badly damaged in the storm. 风暴严重损害了古老的雪松。
• Open thy doors, O Lebanon, that the fire may devour thy cedars. 1黎巴嫩哪，开开你的门，任火烧灭你的香柏树。

126 corporeal   

adj.肉体的，身体的；物质的

参考例句：

• The body is the corporeal habitation of the soul.身体为灵魂之有形寓所。
• He is very religious;corporeal world has little interest for him.他虔信宗教，对物质上的享受不感兴趣。

127 dispersing   

adj. 分散的 动词disperse的现在分词形式

参考例句：

• Whereas gasoline fumes linger close to the ground before dispersing. 而汽油烟气却靠近地面迟迟不散。
• Earthworms may be instrumental in dispersing fungi or bacteria. 蚯蚓可能是散布真菌及细菌的工具。

128 impartially   

adv.公平地，无私地

参考例句：

• Employers must consider all candidates impartially and without bias. 雇主必须公平而毫无成见地考虑所有求职者。
• We hope that they're going to administer justice impartially. 我们希望他们能主持正义，不偏不倚。

129 partially   

adv.部分地，从某些方面讲

参考例句：

• The door was partially concealed by the drapes.门有一部分被门帘遮住了。
• The police managed to restore calm and the curfew was partially lifted.警方设法恢复了平静，宵禁部分解除。

130 remarkable   

adj.显著的，异常的，非凡的，值得注意的

参考例句：

• She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
• These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。

131 constructiveness   

组织，构造

参考例句：

• This learning style has characteristics of subjectivity, openness, process and constructiveness. 它具有主体性、开放性、过程性、建构性的特点。 来自互联网
• With the constructiveness of maternity, Rosamund satisfies her need for maternal love and self respect. 经过母爱的洗礼，罗丝蒙德不仅满足了自己母性的需要，而且也满足了对自尊的需要。 来自互联网

132 tortuous   

adj.弯弯曲曲的，蜿蜒的

参考例句：

• We have travelled a tortuous road.我们走过了曲折的道路。
• They walked through the tortuous streets of the old city.他们步行穿过老城区中心弯弯曲曲的街道。

133 envelop   

vt.包，封，遮盖；包围

参考例句：

• All combine to form a layer of mist to envelop this region.织成一层烟雾又笼罩着这个地区。
• The dust cloud will envelop the planet within weeks.产生的尘云将会笼罩整个星球长达几周。

134 enveloping   

v.包围，笼罩，包住( envelop的现在分词 )

参考例句：

• Always the eyes watching you and the voice enveloping you. 那眼睛总是死死盯着你，那声音总是紧紧围着你。 来自英汉文学
• The only barrier was a mosquito net, enveloping the entire bed. 唯一的障碍是那顶蚊帐罩住整个床。 来自辞典例句

135 rudiment   

n.初步；初级；基本原理

参考例句：

• The rudiment with the capitalism,new developing citizens stratum appeared in the society in the ming dynasty.伴随着资本主义的萌芽，明代社会出现了新兴的市民阶层。
• It do not take me long to pick up the rudiment of the language.我没有费多少时间就学会了这一语言的初步知识。

136 cataracts   

n.大瀑布( cataract的名词复数 )；白内障

参考例句：

• The rotor cataracts water over the top of the machines. 回转轮将水从机器顶上注入。 来自《现代英汉综合大词典》
• Cataracts of rain flooded the streets. 倾盆大雨弄得街道淹水。 来自辞典例句

137 vertical   

adj.垂直的，顶点的，纵向的；n.垂直物，垂直的位置

参考例句：

• The northern side of the mountain is almost vertical.这座山的北坡几乎是垂直的。
• Vertical air motions are not measured by this system.垂直气流的运动不用这种系统来测量。

138 obtuse   

adj.钝的；愚钝的

参考例句：

• You were too obtuse to take the hint.你太迟钝了，没有理解这种暗示。
• "Sometimes it looks more like an obtuse triangle,"Winter said.“有时候它看起来更像一个钝角三角形。”温特说。

139 lengthen   

vt.使伸长，延长

参考例句：

• He asked the tailor to lengthen his coat.他请裁缝把他的外衣放长些。
• The teacher told her to lengthen her paper out.老师让她把论文加长。

140 whatsoever   

adv.（用于否定句中以加强语气）任何；pron.无论什么

参考例句：

• There's no reason whatsoever to turn down this suggestion.没有任何理由拒绝这个建议。
• All things whatsoever ye would that men should do to you,do ye even so to them.你想别人对你怎样，你就怎样对人。

141 psychology   

n.心理，心理学，心理状态

参考例句：

• She has a background in child psychology.她受过儿童心理学的教育。
• He studied philosophy and psychology at Cambridge.他在剑桥大学学习哲学和心理学。

142 disciple   

n.信徒，门徒，追随者

参考例句：

• Your disciple failed to welcome you.你的徒弟没能迎接你。
• He was an ardent disciple of Gandhi.他是甘地的忠实信徒。

143 extraneous   

adj.体外的；外来的；外部的

参考例句：

• I can choose to ignore these extraneous thoughts.我可以选择无视这些外来的想法。
• Reductant from an extraneous source is introduced.外来的还原剂被引进来。

144 coordinates   

n.相配之衣物；坐标( coordinate的名词复数 )；（颜色协调的）配套服装；[复数]女套服；同等重要的人（或物）v.使协调，使调和( coordinate的第三人称单数 )；协调；协同；成为同等

参考例句：

• The town coordinates on this map are 695037. 该镇在这幅地图上的坐标是695037。 来自《简明英汉词典》
• The UN Office for the Coordination of Humanitarian Affairs, headed by the Emergency Relief Coordinator, coordinates all UN emergency relief. 联合国人道主义事务协调厅在紧急救济协调员领导下，负责协调联合国的所有紧急救济工作。 来自《简明英汉词典》

145 datum   

n.资料；数据；已知数

参考例句：

• The author has taught foreigners Chinese manyand gathered rich language and datum.作者长期从事对外汉语教学，积累了丰富的语言资料。
• Every theory,datum,or fact is generated by purpose.任何理论，资料、事实都来自于一定的目的。

146 riddle   

n.谜，谜语，粗筛；vt.解谜，给…出谜，筛，检查，鉴定，非难，充满于；vi.出谜

参考例句：

• The riddle couldn't be solved by the child.这个谜语孩子猜不出来。
• Her disappearance is a complete riddle.她的失踪完全是一个谜。

147 dealing   

n.经商方法，待人态度

参考例句：

• This store has an excellent reputation for fair dealing.该商店因买卖公道而享有极高的声誉。
• His fair dealing earned our confidence.他的诚实的行为获得我们的信任。

148 ambiguity   

n.模棱两可；意义不明确

参考例句：

• The telegram was misunderstood because of its ambiguity.由于电文意义不明确而造成了误解。
• Her answer was above all ambiguity.她的回答毫不含糊。

149 poetical   

adj.似诗人的；诗一般的；韵文的；富有诗意的

参考例句：

• This is a poetical picture of the landscape. 这是一幅富有诗意的风景画。 来自《简明英汉词典》
• John is making a periphrastic study in a worn-out poetical fashion. 约翰正在对陈腐的诗风做迂回冗长的研究。 来自辞典例句

150 perpendicular   

adj.垂直的，直立的；n.垂直线，垂直的位置

参考例句：

• The two lines of bones are set perpendicular to one another.这两排骨头相互垂直。
• The wall is out of the perpendicular.这墙有些倾斜。

151 extremity   

n.末端，尽头；尽力；终极；极度

参考例句：

• I hope you will help them in their extremity.我希望你能帮助在穷途末路的他们。
• What shall we do in this extremity?在这种极其困难的情况下我们该怎么办呢？

152 triangular   

adj.三角（形）的，三者间的

参考例句：

• It's more or less triangular plot of land.这块地略成三角形。
• One particular triangular relationship became the model of Simone's first novel.一段特殊的三角关系成了西蒙娜第一本小说的原型。

153 triangularity   

成三角形

参考例句：

154 locus   

n.中心

参考例句：

• Barcelona is the locus of Spanish industry.巴塞罗那是西班牙工业中心。
• Thereafter,the military remained the locus of real power.自此之后，军方一直掌握着实权。

155 generically   

adv.一般地

参考例句：

• The so-called critics are generically mentioned, but not individually mentioned. 当所谓的批评提及时总是一笔带过，从不指名道姓。 来自互联网
• We market these drugs generically. 我们推广的这些药是未经注册的。 来自互联网

156 generic   

adj.一般的，普通的，共有的

参考例句：

• I usually buy generic clothes instead of name brands.我通常买普通的衣服，不买名牌。
• The generic woman appears to have an extraordinary faculty for swallowing the individual.一般妇女在婚后似乎有特别突出的抑制个性的能力。

157 intensities   

n.强烈( intensity的名词复数 )；（感情的）强烈程度；强度；烈度

参考例句：

• At very high intensities, nuclear radiations cause itching and tingling of the skin. 当核辐射强度很高时，它能使皮肤感到发痒和刺痛。 来自辞典例句
• They ask again and again in a variety of ways and intensities. 他们会以不同的方式和强度来不停地问，直到他得到自己想要的答案为止。 来自互联网

158 tune   

n.调子；和谐，协调；v.调音，调节，调整

参考例句：

• He'd written a tune,and played it to us on the piano.他写了一段曲子，并在钢琴上弹给我们听。
• The boy beat out a tune on a tin can.那男孩在易拉罐上敲出一首曲子。

159 transit   

n.经过，运输；vt.穿越，旋转；vi.越过

参考例句：

• His luggage was lost in transit.他的行李在运送中丢失。
• The canal can transit a total of 50 ships daily.这条运河每天能通过50条船。

160 synthetic   

adj.合成的，人工的；综合的；n.人工制品

参考例句：

• We felt the salesman's synthetic friendliness.我们感觉到那位销售员的虚情假意。
• It's a synthetic diamond.这是人造钻石。

161 analytic   

adj.分析的，用分析方法的

参考例句：

• The boy has an analytic mind. 这男孩有分析的头脑。
• Latin is a synthetic language,while English is analytic.拉丁文是一种综合性语言，而英语是一种分析性语言。

162 envisaged   

想像，设想( envisage的过去式和过去分词 )

参考例句：

• He envisaged an old age of loneliness and poverty. 他面对着一个孤独而贫困的晚年。
• Henry Ford envisaged an important future for the motor car. 亨利·福特为汽车设想了一个远大前程。

163 indirectly   

adv.间接地，不直接了当地

参考例句：

• I heard the news indirectly.这消息我是间接听来的。
• They were approached indirectly through an intermediary.通过一位中间人，他们进行了间接接触。

164 standing   

n.持续，地位；adj.永久的，不动的，直立的，不流动的

参考例句：

• After the earthquake only a few houses were left standing.地震过后只有几幢房屋还立着。
• They're standing out against any change in the law.他们坚决反对对法律做任何修改。

165 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

166 unity   

n.团结，联合，统一；和睦，协调

参考例句：

• When we speak of unity,we do not mean unprincipled peace.所谓团结，并非一团和气。
• We must strengthen our unity in the face of powerful enemies.大敌当前，我们必须加强团结。

167 interval   

n.间隔，间距；幕间休息，中场休息

参考例句：

• The interval between the two trees measures 40 feet.这两棵树的间隔是40英尺。
• There was a long interval before he anwsered the telephone.隔了好久他才回了电话。

168 pointed   

adj.尖的，直截了当的

参考例句：

• He gave me a very sharp pointed pencil.他给我一支削得非常尖的铅笔。
• She wished to show Mrs.John Dashwood by this pointed invitation to her brother.她想通过对达茨伍德夫人提出直截了当的邀请向她的哥哥表示出来。

169 distinguished   

adj.卓越的，杰出的，著名的

参考例句：

• Elephants are distinguished from other animals by their long noses.大象以其长长的鼻子显示出与其他动物的不同。
• A banquet was given in honor of the distinguished guests.宴会是为了向贵宾们致敬而举行的。

170 likeness   

n.相像，相似（之处）

参考例句：

• I think the painter has produced a very true likeness.我认为这位画家画得非常逼真。
• She treasured the painted likeness of her son.她珍藏她儿子的画像。

171 faculty   

n.才能；学院，系；(学院或系的)全体教学人员

参考例句：

• He has a great faculty for learning foreign languages.他有学习外语的天赋。
• He has the faculty of saying the right thing at the right time.他有在恰当的时候说恰当的话的才智。

172 quail   

n.鹌鹑；vi.畏惧，颤抖

参考例句：

• Cowards always quail before the enemy.在敌人面前，胆小鬼们总是畏缩不前的。
• Quail eggs are very high in cholesterol.鹌鹑蛋胆固醇含量高。

173 awakened   

v.（使）醒( awaken的过去式和过去分词 )；（使）觉醒；弄醒；（使）意识到

参考例句：

• She awakened to the sound of birds singing. 她醒来听到鸟的叫声。
• The public has been awakened to the full horror of the situation. 公众完全意识到了这一状况的可怕程度。 来自《简明英汉词典》

174 virtue   

n.德行，美德；贞操；优点；功效，效力

参考例句：

• He was considered to be a paragon of virtue.他被认为是品德尽善尽美的典范。
• You need to decorate your mind with virtue.你应该用德行美化心灵。

175 isolated   

adj.与世隔绝的

参考例句：

• His bad behaviour was just an isolated incident. 他的不良行为只是个别事件。
• Patients with the disease should be isolated. 这种病的患者应予以隔离。

176 heed   

v.注意，留意；n.注意，留心

参考例句：

• You must take heed of what he has told.你要注意他所告诉的事。
• For the first time he had to pay heed to his appearance.这是他第一次非得注意自己的外表不可了。

177 devoid   

adj.全无的，缺乏的

参考例句：

• He is completely devoid of humour.他十分缺乏幽默。
• The house is totally devoid of furniture.这所房子里什么家具都没有。

178 mutual   

adj.相互的，彼此的；共同的，共有的

参考例句：

• We must pull together for mutual interest.我们必须为相互的利益而通力合作。
• Mutual interests tied us together.相互的利害关系把我们联系在一起。

179 precisely   

adv.恰好，正好，精确地，细致地

参考例句：

• It's precisely that sort of slick sales-talk that I mistrust.我不相信的正是那种油腔滑调的推销宣传。
• The man adjusted very precisely.那个人调得很准。

180 anterior   

adj.较早的；在前的

参考例句：

• We've already finished the work anterior to the schedule.我们已经提前完成了工作。
• The anterior part of a fish contains the head and gills.鱼的前部包括头和鳃。

181 alteration   

n.变更，改变；蚀变

参考例句：

• The shirt needs alteration.这件衬衣需要改一改。
• He easily perceived there was an alteration in my countenance.他立刻看出我的脸色和往常有些不同。

182 delicacy   

n.精致，细微，微妙，精良；美味，佳肴

参考例句：

• We admired the delicacy of the craftsmanship.我们佩服工艺师精巧的手艺。
• He sensed the delicacy of the situation.他感觉到了形势的微妙。

183 joint   

adj.联合的，共同的；n.关节，接合处；v.连接，贴合

参考例句：

• I had a bad fall,which put my shoulder out of joint.我重重地摔了一跤，肩膀脫臼了。
• We wrote a letter in joint names.我们联名写了封信。

184 joints   

接头( joint的名词复数 )； 关节； 公共场所（尤指价格低廉的饮食和娱乐场所） （非正式）； 一块烤肉 （英式英语）

参考例句：

• Expansion joints of various kinds are fitted on gas mains. 各种各样的伸缩接头被安装在煤气的总管道上了。
• Expansion joints of various kinds are fitted on steam pipes. 各种各样的伸缩接头被安装在蒸气管道上了。

185 membranes   

n.（动物或植物体内的）薄膜( membrane的名词复数 )；隔膜；（可起防水、防风等作用的）膜状物

参考例句：

• The waste material is placed in cells with permeable membranes. 废液置于有渗透膜的槽中。 来自辞典例句
• The sarcoplasmic reticulum is a system of intracellular membranes. 肌浆网属于细胞内膜系统。 来自辞典例句

186 erred   

犯错误，做错事( err的过去式和过去分词 )

参考例句：

• He erred in his judgement. 他判断错了。
• We will work on those who have erred and help them do right. 我们将对犯了错误的人做工作，并帮助他们改正。

187 peculiarity   

n.独特性，特色；特殊的东西；怪癖

参考例句：

• Each country has its own peculiarity.每个国家都有自己的独特之处。
• The peculiarity of this shop is its day and nigth service.这家商店的特点是昼夜服务。

188 proximity   

n.接近，邻近

参考例句：

• Marriages in proximity of blood are forbidden by the law.法律规定禁止近亲结婚。
• Their house is in close proximity to ours.他们的房子很接近我们的。

189 asunder   

adj.分离的，化为碎片

参考例句：

• The curtains had been drawn asunder.窗帘被拉向两边。
• Your conscience,conviction,integrity,and loyalties were torn asunder.你的良心、信念、正直和忠诚都被扯得粉碎了。

190 sunder   

v.分开；隔离；n.分离，分开

参考例句：

• Lightning tore the tree in sunder.闪电把树劈成两半。
• Nothing can sunder our friendship.什么也不能破坏我们的友谊。

191 entity   

n.实体，独立存在体，实际存在物

参考例句：

• The country is no longer one political entity.这个国家不再是一个统一的政治实体了。
• As a separate legal entity,the corporation must pay taxes.作为一个独立的法律实体，公司必须纳税。

192 revert   

v.恢复，复归，回到

参考例句：

• Let us revert to the earlier part of the chapter.让我们回到本章的前面部分。
• Shall we revert to the matter we talked about yesterday?我们接着昨天谈过的问题谈，好吗？

193 query   

n.疑问，问号，质问；vt.询问，表示怀疑

参考例句：

• I query very much whether it is wise to act so hastily.我真怀疑如此操之过急地行动是否明智。
• They raised a query on his sincerity.他们对他是否真诚提出质疑。

194 propounded   

v.提出（问题、计划等）供考虑[讨论]，提议( propound的过去式和过去分词 )

参考例句：

• the theory of natural selection, first propounded by Charles Darwin 查尔斯∙达尔文首先提出的物竞天择理论
• Indeed it was first propounded by the ubiquitous Thomas Young. 实际上，它是由尽人皆知的杨氏首先提出来的。 来自辞典例句

195 modifications   

n.缓和( modification的名词复数 )；限制；更改；改变

参考例句：

• The engine was pulled apart for modifications and then reassembled. 发动机被拆开改型，然后再组装起来。 来自《简明英汉词典》
• The original plan had undergone fairly extensive modifications. 原计划已经作了相当大的修改。 来自《简明英汉词典》

196 modification   

n.修改，改进，缓和，减轻

参考例句：

• The law,in its present form,is unjust;it needs modification.现行的法律是不公正的，它需要修改。
• The design requires considerable modification.这个设计需要作大的修改。

197 tempted   

v.怂恿（某人）干不正当的事；冒…的险（tempt的过去分词）

参考例句：

• I was sorely tempted to complain, but I didn't. 我极想发牢骚，但还是没开口。
• I was tempted by the dessert menu. 甜食菜单馋得我垂涎欲滴。

198 evoke   

vt.唤起，引起，使人想起

参考例句：

• These images are likely to evoke a strong response in the viewer.这些图像可能会在观众中产生强烈反响。
• Her only resource was the sympathy she could evoke.她以凭借的唯一力量就是她能从人们心底里激起的同情。

199 evokes   

产生，引起，唤起( evoke的第三人称单数 )

参考例句：

• The film evokes chilling reminders of the war. 这部电影使人们回忆起战争的可怕场景。
• Each type evokes antibodies which protect against the homologous. 每一种类型都能产生抗同种病毒的抗体。

200 dormant   

adj.暂停活动的；休眠的；潜伏的

参考例句：

• Many animals are in a dormant state during winter.在冬天许多动物都处于睡眠状态。
• This dormant volcano suddenly fired up.这座休眠火山突然爆发了。

201 machinery   

n.(总称)机械，机器；机构

参考例句：

• Has the machinery been put up ready for the broadcast?广播器材安装完毕了吗？
• Machinery ought to be well maintained all the time.机器应该随时注意维护。

202 perceptive   

adj.知觉的，有洞察力的，感知的

参考例句：

• This is a very perceptive assessment of the situation.这是一个对该情况的极富洞察力的评价。
• He is very perceptive and nothing can be hidden from him.他耳聪目明，什么事都很难瞒住他。

203 subjectively   

主观地； 臆

参考例句：

• Subjectively, the demand of interest is the desire of human being. 荀子所说的对利的需要从主观上说就是人的欲望。
• A sound also has an amplitude, a property subjectively heard as loudness. 声音有振幅，振幅的主观感觉是声音的大小。

204 habitually   

ad.习惯地，通常地

参考例句：

• The pain of the disease caused him habitually to furrow his brow. 病痛使他习惯性地紧皱眉头。
• Habitually obedient to John, I came up to his chair. 我已经习惯于服从约翰，我来到他的椅子跟前。

205 habitual   

adj.习惯性的；通常的，惯常的

参考例句：

• He is a habitual criminal.他是一个惯犯。
• They are habitual visitors to our house.他们是我家的常客。

206 irritation   

n.激怒，恼怒，生气

参考例句：

• He could not hide his irritation that he had not been invited.他无法掩饰因未被邀请而生的气恼。
• Barbicane said nothing,but his silence covered serious irritation.巴比康什么也不说，但是他的沉默里潜伏着阴郁的怒火。

207 tinged   

v.（使）发丁丁声( ting的过去式和过去分词 )

参考例句：

• memories tinged with sadness 略带悲伤的往事
• white petals tinged with blue 略带蓝色的白花瓣

208 gastric   

adj.胃的

参考例句：

• Miners are a high risk group for certain types of gastric cancer.矿工是极易患某几种胃癌的高风险人群。
• That was how I got my gastric trouble.我的胃病就是这么得的。

209 dermal   

adj.皮肤的，真皮的

参考例句：

• Dermal hypersensitivity usually does not develop until three to four weeks after onset. 皮肤过敏通常在起病后三、四周内不会出现。 来自辞典例句
• The doctor said permanent dermal pigmentation is a form of microsurgery. 医生说永久的皮肤染色是一种显微手术。 来自互联网

210 briefly   

adv.简单地，简短地

参考例句：

• I want to touch briefly on another aspect of the problem.我想简单地谈一下这个问题的另一方面。
• He was kidnapped and briefly detained by a terrorist group.他被一个恐怖组织绑架并短暂拘禁。

211 revival   

n.复兴，复苏，（精力、活力等的）重振

参考例句：

• The period saw a great revival in the wine trade.这一时期葡萄酒业出现了很大的复苏。
• He claimed the housing market was showing signs of a revival.他指出房地产市场正出现复苏的迹象。

212 wrought   

v.引起；以…原料制作；运转；adj.制造的

参考例句：

• Events in Paris wrought a change in British opinion towards France and Germany.巴黎发生的事件改变了英国对法国和德国的看法。
• It's a walking stick with a gold head wrought in the form of a flower.那是一个金质花形包头的拐杖。

213 requisite   

adj.需要的，必不可少的；n.必需品

参考例句：

• He hasn't got the requisite qualifications for the job.他不具备这工作所需的资格。
• Food and air are requisite for life.食物和空气是生命的必需品。

214 apprehending   

逮捕，拘押( apprehend的现在分词 )； 理解

参考例句：

• China has not been totally unsuccessful apprehending corruption suspects. 在逮捕腐化分子方面，中国并非毫无进展。
• Apprehending violence is not an easy task. 惧怕暴力不是一件容易的事。

215 belly   

n.肚子，腹部；(像肚子一样)鼓起的部分，膛

参考例句：

• The boss has a large belly.老板大腹便便。
• His eyes are bigger than his belly.他眼馋肚饱。

216 instinctive   

adj.(出于)本能的；直觉的；(出于)天性的

参考例句：

• He tried to conceal his instinctive revulsion at the idea.他试图饰盖自己对这一想法本能的厌恶。
• Animals have an instinctive fear of fire.动物本能地怕火。

217 discriminative   

有判别力

参考例句：

• The measures are non-discriminative and not targeted at Mexican citizens. 有关措施并非针对墨西哥公民，没有歧视性。
• The Discriminative Common Vector (DCV) successfully overcomes this problem for FLDA. 近年来针对此问题提出了不同的解决方法，其中基于共同鉴别矢量(DCV)的方法成功克服了已有各种方法存在的缺点，有较好的数值稳定性和较低的计算复杂度。

218 glides   

n.滑行( glide的名词复数 )；滑音；音渡；过渡音v.滑动( glide的第三人称单数 )；掠过；（鸟或飞机 ） 滑翔

参考例句：

• The new dance consists of a series of glides. 这种新舞蹈中有一连串的滑步。 来自《简明英汉词典》
• The stately swan glides gracefully on the pond. 天鹅在池面上优美地游动。 来自《简明英汉词典》

219 forth   

adv.向前；向外，往外

参考例句：

• The wind moved the trees gently back and forth.风吹得树轻轻地来回摇晃。
• He gave forth a series of works in rapid succession.他很快连续发表了一系列的作品。

220 awakening   

n.觉醒，醒悟 adj.觉醒中的；唤醒的

参考例句：

• the awakening of interest in the environment 对环境产生的兴趣
• People are gradually awakening to their rights. 人们正逐渐意识到自己的权利。

221 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。

222 exquisite   

adj.精美的；敏锐的；剧烈的，感觉强烈的

参考例句：

• I was admiring the exquisite workmanship in the mosaic.我当时正在欣赏镶嵌画的精致做工。
• I still remember the exquisite pleasure I experienced in Bali.我依然记得在巴厘岛所经历的那种剧烈的快感。

223 conspicuous   

adj.明眼的，惹人注目的；炫耀的，摆阔气的

参考例句：

• It is conspicuous that smoking is harmful to health.很明显，抽烟对健康有害。
• Its colouring makes it highly conspicuous.它的色彩使它非常惹人注目。

224 abject   

adj.极可怜的，卑屈的

参考例句：

• This policy has turned out to be an abject failure.这一政策最后以惨败而告终。
• He had been obliged to offer an abject apology to Mr.Alleyne for his impertinence.他不得不低声下气，为他的无礼举动向艾莱恩先生请罪。

225 margin   

n.页边空白；差额；余地，余裕；边，边缘

参考例句：

• We allowed a margin of 20 minutes in catching the train.我们有20分钟的余地赶火车。
• The village is situated at the margin of a forest.村子位于森林的边缘。

226 volition   

n.意志；决意

参考例句：

• We like to think that everything we do and everything we think is a product of our volition.我们常常认为我们所做和所想的一切都出自自己的意愿。
• Makin said Mr Coombes had gone to the police of his own volition.梅金说库姆斯先生是主动去投案的。

227 steadily   

adv.稳定地；不变地；持续地

参考例句：

• The scope of man's use of natural resources will steadily grow.人类利用自然资源的广度将日益扩大。
• Our educational reform was steadily led onto the correct path.我们的教学改革慢慢上轨道了。

228 converge   

vi.会合；聚集，集中；(思想、观点等)趋近

参考例句：

• The results converge towards this truth.其结果趋近于这个真理。
• Parallel lines converge at infinity.平行线永不相交。

229 converged   

v.（线条、运动的物体等）会于一点( converge的过去式 )；（趋于）相似或相同；人或车辆汇集；聚集

参考例句：

• Thousands of supporters converged on London for the rally. 成千上万的支持者从四面八方汇聚伦敦举行集会。
• People converged on the political meeting from all parts of the city. 人们从城市的四面八方涌向这次政治集会。 来自《简明英汉词典》

230 invincibly   

adv.难战胜地，无敌地

参考例句：

• Invincibly, the troops moved forward. 这支军队一路前进，所向披靡。 来自互联网

231 contemplate   

vt.盘算，计议；周密考虑；注视，凝视

参考例句：

• The possibility of war is too horrifying to contemplate.战争的可能性太可怕了，真不堪细想。
• The consequences would be too ghastly to contemplate.后果不堪设想。

232 speck   

n.微粒，小污点，小斑点

参考例句：

• I have not a speck of interest in it.我对它没有任何兴趣。
• The sky is clear and bright without a speck of cloud.天空晴朗，一星星云彩也没有。

233 catching   

adj.易传染的，有魅力的，迷人的，接住

参考例句：

• There are those who think eczema is catching.有人就是认为湿疹会传染。
• Enthusiasm is very catching.热情非常富有感染力。

234 oblique   

adj.斜的，倾斜的，无诚意的，不坦率的

参考例句：

• He made oblique references to her lack of experience.他拐弯抹角地说她缺乏经验。
• She gave an oblique look to one side.她向旁边斜看了一眼。

235 upwards   

adv.向上，在更高处...以上

参考例句：

• The trend of prices is still upwards.物价的趋向是仍在上涨。
• The smoke rose straight upwards.烟一直向上升。

236 downwards   

adj./adv.向下的（地），下行的（地）

参考例句：

• He lay face downwards on his bed.他脸向下伏在床上。
• As the river flows downwards,it widens.这条河愈到下游愈宽。

237 incessant   

adj.不停的，连续的

参考例句：

• We have had incessant snowfall since yesterday afternoon.从昨天下午开始就持续不断地下雪。
• She is tired of his incessant demands for affection.她厌倦了他对感情的不断索取。

238 incessantly   

ad.不停地

参考例句：

• The machines roar incessantly during the hours of daylight. 机器在白天隆隆地响个不停。
• It rained incessantly for the whole two weeks. 雨不间断地下了整整两个星期。

239 peripheral   

adj.周边的，外围的

参考例句：

• We dealt with the peripheral aspects of a cost reduction program.我们谈到了降低成本计划的一些外围问题。
• The hotel provides the clerk the service and the peripheral traveling consultation.旅舍提供票务服务和周边旅游咨询。

240 radii   

n.半径；半径（距离）( radius的名词复数 )；用半径度量的圆形面积；半径范围；桡骨

参考例句：

• Hence, the damage radii can not be determined from overpressure alone. 因此，破坏半径不能单单由超压力大小来决定。 来自辞典例句
• It is now necessary to introduce a sign convention for radii of curvature. 现在必须介绍曲率半径的正负号规则。 来自辞典例句

241 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

242 streaks   

n.（与周围有所不同的）条纹( streak的名词复数 )；（通常指不好的）特征（倾向）；（不断经历成功或失败的）一段时期v.快速移动( streak的第三人称单数 )；使布满条纹

参考例句：

• streaks of grey in her hair 她头上的绺绺白发
• Bacon has streaks of fat and streaks of lean. 咸肉中有几层肥的和几层瘦的。 来自《现代英汉综合大词典》

243 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

244 divers   

adj.不同的；种种的

参考例句：

• He chose divers of them,who were asked to accompany him.他选择他们当中的几个人，要他们和他作伴。
• Two divers work together while a standby diver remains on the surface.两名潜水员协同工作，同时有一名候补潜水员留在水面上。

245 inquiry   

n.打听，询问，调查，查问

参考例句：

• Many parents have been pressing for an inquiry into the problem.许多家长迫切要求调查这个问题。
• The field of inquiry has narrowed down to five persons.调查的范围已经缩小到只剩5个人了。

246 fusion   

n.溶化；熔解；熔化状态，熔和；熔接

参考例句：

• Brass is formed by the fusion of copper and zinc. 黄铜是通过铜和锌的熔合而成的。
• This alloy is formed by the fusion of two types of metal.这种合金是用两种金属熔合而成的。

247 invoking   

v.援引( invoke的现在分词 )；行使（权利等）；祈求救助；恳求

参考例句：

• You can customise the behavior of the Asynchronous Server and hence re-brand it by defining your own command set for invoking services. 通过定义自己调用服务的命令集，您可以定制自定义异步服务器的行为，通过为调用服务定义自己的命令集从而对它重新标记。 来自《简明英汉词典》
• You can customize the behavior of the Asynchronous Server and hence re-brand it by defining your own command set for invoking services. 通过定义自己调用服务的命令集，您可以定制自定义异步服务器的行为，通过为调用服务定义自己的命令集从而对它重新标记。 来自辞典例句

248 immersion   

n.沉浸；专心

参考例句：

• The dirt on the bottom of the bath didn't encourage total immersion.浴缸底有污垢，不宜全身浸泡于其中。
• The wood had become swollen from prolonged immersion.因长时间浸泡，木头发胀了。

249 apex   

n.顶点，最高点

参考例句：

• He reached the apex of power in the early 1930s.他在三十年代初达到了权力的顶峰。
• His election to the presidency was the apex of his career.当选总统是他一生事业的顶峰。

250 integument   

n.皮肤

参考例句：

• The first protector against the entry of microorganisms is the integument.抗御微生物进入体内的第一道防线是皮肤。
• The cells of the integument and nucellus of some plants form perfectly normal embryos.某些植物的珠被和珠心细胞形成完全正常的胚。

251 exquisitely   

adv.精致地；强烈地；剧烈地；异常地

参考例句：

• He found her exquisitely beautiful. 他觉得她异常美丽。 来自《简明英汉词典》
• He wore an exquisitely tailored gray silk and accessories to match. 他穿的是做工非常考究的灰色绸缎衣服，还有各种配得很协调的装饰。 来自教父部分

252 periphery   

n.(圆体的)外面；周围

参考例句：

• Geographically, the UK is on the periphery of Europe.从地理位置上讲，英国处于欧洲边缘。
• The periphery of the retina is very sensitive to motion.视网膜的外围对运动非常敏感。

253 vernacular   

adj.地方的，用地方语写成的；n.白话；行话；本国语；动植物的俗名

参考例句：

• The house is built in a vernacular style.这房子按当地的风格建筑。
• The traditional Chinese vernacular architecture is an epitome of Chinese traditional culture.中国传统民居建筑可谓中国传统文化的缩影。

254 adventitious   

adj.偶然的

参考例句：

• The strike was broken,of course,but mainly by a series of adventitious developments.罢工是中断了，但主要还是由于发生了一系列意外事件。
• His knowledge of this particular bishop was somewhat adventitious.他对主教当中这一位的了解，似乎多少事出偶然。

255 lust   

n.性(淫)欲；渴(欲)望；vi.对…有强烈的欲望

参考例句：

• He was filled with lust for power.他内心充满了对权力的渴望。
• Sensing the explorer's lust for gold, the chief wisely presented gold ornaments as gifts.酋长觉察出探险者们垂涎黄金的欲念，就聪明地把金饰品作为礼物赠送给他们。

256 withdrawn   

vt.收回；使退出；vi.撤退，退出

参考例句：

• Our force has been withdrawn from the danger area.我们的军队已从危险地区撤出。
• All foreign troops should be withdrawn to their own countries.一切外国军队都应撤回本国去。

257 stimulated   

a.刺激的

参考例句：

• The exhibition has stimulated interest in her work. 展览增进了人们对她作品的兴趣。
• The award has stimulated her into working still harder. 奖金促使她更加努力地工作。

258 olfactory   

adj.嗅觉的

参考例句：

• He is to develop a sensor to substitute for the olfactory abilities of dogs.克罗克将研制一种传感器用以代替狗的嗅觉功能。
• Based on these findings, Keller suspects that each person has an olfactory blind spot.根据这些发现，凯勒推断，每个人都有一个嗅觉盲区。

259 penetrate   

v.透(渗)入；刺入，刺穿；洞察，了解

参考例句：

• Western ideas penetrate slowly through the East.西方观念逐渐传入东方。
• The sunshine could not penetrate where the trees were thickest.阳光不能透入树木最浓密的地方。

260 hesitation   

n.犹豫，踌躇

参考例句：

• After a long hesitation, he told the truth at last.踌躇了半天，他终于直说了。
• There was a certain hesitation in her manner.她的态度有些犹豫不决。

261 susceptible   

adj.过敏的，敏感的；易动感情的，易受感动的

参考例句：

• Children are more susceptible than adults.孩子比成人易受感动。
• We are all susceptible to advertising.我们都易受广告的影响。

262 questionably   

adv.可疑地；不真实地；有问题地

参考例句：

• These were estates his father questionably acquired. 这些财产不一定是他父亲努力获得的。 来自互联网

263 infinitely   

adv.无限地，无穷地

参考例句：

• There is an infinitely bright future ahead of us.我们有无限光明的前途。
• The universe is infinitely large.宇宙是无限大的。

264 whit   

n.一点，丝毫

参考例句：

• There's not a whit of truth in the statement.这声明里没有丝毫的真实性。
• He did not seem a whit concerned.他看来毫不在乎。

265 worthy   

adj.(of)值得的，配得上的；有价值的

参考例句：

• I did not esteem him to be worthy of trust.我认为他不值得信赖。
• There occurred nothing that was worthy to be mentioned.没有值得一提的事发生。

266 physiologists   

n.生理学者( physiologist的名词复数 )；生理学( physiology的名词复数 )；生理机能

参考例句：

• Quite unexpectedly, vertebrate physiologists and microbial biochemists had found a common ground. 出乎意外，脊椎动物生理学家和微生物生化学家找到了共同阵地。 来自辞典例句
• Physiologists are interested in the workings of the human body. 生理学家对人体的功能感兴趣。 来自辞典例句

267 second-hand   

adj.用过的，旧的，二手的

参考例句：

• I got this book by chance at a second-hand bookshop.我赶巧在一家旧书店里买到这本书。
• They will put all these second-hand goods up for sale.他们将把这些旧货全部公开出售。

268 tracts   

大片土地( tract的名词复数 )； 地带； （体内的）道； （尤指宣扬宗教、伦理或政治的）短文

参考例句：

• vast tracts of forest 大片大片的森林
• There are tracts of desert in Australia. 澳大利亚有大片沙漠。

269 overlap   

v.重叠，与…交叠；n.重叠

参考例句：

• The overlap between the jacket and the trousers is not good.夹克和裤子重叠的部分不好看。
• Tiles overlap each other.屋瓦相互叠盖。

270 overlapped   

_adj.重叠的v.部分重叠( overlap的过去式和过去分词 )；（物体）部份重叠；交叠；（时间上）部份重叠

参考例句：

• His visit and mine overlapped. 他的访问期与我的访问期有几天重叠。 来自《现代汉英综合大词典》
• Our visits to the town overlapped. 我们彼此都恰巧到那小城观光。 来自辞典例句

271 persistent   

adj.坚持不懈的，执意的；持续的

参考例句：

• Albert had a persistent headache that lasted for three days.艾伯特连续头痛了三天。
• She felt embarrassed by his persistent attentions.他不时地向她大献殷勤，使她很难为情。

272 stationary   

adj.固定的，静止不动的

参考例句：

• A stationary object is easy to be aimed at.一个静止不动的物体是容易瞄准的。
• Wait until the bus is stationary before you get off.你要等公共汽车停稳了再下车。

273 irresistible   

adj.非常诱人的，无法拒绝的，无法抗拒的

参考例句：

• The wheel of history rolls forward with an irresistible force.历史车轮滚滚向前，势不可挡。
• She saw an irresistible skirt in the store window.她看见商店的橱窗里有一条叫人着迷的裙子。

274 abducting   

劫持，诱拐( abduct的现在分词 )； 使（肢体等）外展

参考例句：

• She was charged with abducting a six-month-old child. 她被控诱拐一个6个月大的孩子。
• At the same time, the rate of abducting foreigners is going down. 同时，发生在外国人身上的绑架案正在下降。

275 actively   

adv.积极地，勤奋地

参考例句：

• During this period all the students were actively participating.在这节课中所有的学生都积极参加。
• We are actively intervening to settle a quarrel.我们正在积极调解争执。

276 components   

（机器、设备等的）构成要素，零件，成分； 成分( component的名词复数 )； [物理化学]组分； [数学]分量； （混合物的）组成部分

参考例句：

• the components of a machine 机器部件
• Our chemistry teacher often reduces a compound to its components in lab. 在实验室中化学老师常把化合物分解为各种成分。

277 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

278 victorious   

adj.胜利的，得胜的

参考例句：

• We are certain to be victorious.我们定会胜利。
• The victorious army returned in triumph.获胜的部队凯旋而归。

279 shamming   

假装，冒充( sham的现在分词 )

参考例句：

• He is not really ill, he is shamming. 他不是生病，他在装病。
• He is only shamming. 他只是假装罢了。

280 paralysis   

n.麻痹(症)；瘫痪(症)

参考例句：

• The paralysis affects his right leg and he can only walk with difficulty.他右腿瘫痪步履维艰。
• The paralysis affects his right leg and he can only walk with difficulty.他右腿瘫痪步履维艰。

281 crustacean   

n.甲壳动物；adj.甲壳纲的

参考例句：

• Seafood is a valuable lobster crustacean section.名贵海珍品龙虾属甲壳科。
• The illustrious Cuvier did not perceive that a barnacle was a crustacean.大名鼎鼎的居维叶也未看出藤壶是一种甲壳动物。

282 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

283 mobility   

n.可动性，变动性，情感不定

参考例句：

• The difference in regional house prices acts as an obstacle to mobility of labour.不同地区房价的差异阻碍了劳动力的流动。
• Mobility is very important in guerrilla warfare.机动性在游击战中至关重要。

284 conspicuity   

显著的

参考例句：

285 tickling   

反馈，回授，自旋挠痒法

参考例句：

• Was It'spring tickling her senses? 是不是春意撩人呢？
• Its origin is in tickling and rough-and-tumble play, he says. 他说，笑的起源来自于挠痒痒以及杂乱无章的游戏。

286 blurred   

v.（使）变模糊( blur的过去式和过去分词 )；（使）难以区分；模模糊糊；迷离

参考例句：

• She suffered from dizziness and blurred vision. 她饱受头晕目眩之苦。
• Their lazy, blurred voices fell pleasantly on his ears. 他们那种慢吞吞、含糊不清的声音在他听起来却很悦耳。 来自《简明英汉词典》

287 labors   

v.努力争取(for)( labor的第三人称单数 )；苦干；详细分析；（指引擎）缓慢而困难地运转

参考例句：

• He was tiresome in contending for the value of his own labors. 他老为他自己劳动的价值而争强斗胜，令人生厌。 来自辞典例句
• Farm labors used to hire themselves out for the summer. 农业劳动者夏季常去当雇工。 来自辞典例句

288 inveterate   

adj.积习已深的，根深蒂固的

参考例句：

• Hitler was not only an avid reader but also an inveterate underliner.希特勒不仅酷爱读书，还有写写划划的习惯。
• It is hard for an inveterate smoker to give up tobacco.要一位有多年烟瘾的烟民戒烟是困难的。

289 twitching   

n.颤搐

参考例句：

• The child in a spasm kept twitching his arms and legs. 那个害痉挛的孩子四肢不断地抽搐。 来自《现代汉英综合大词典》
• My eyelids keep twitching all the time. 我眼皮老是跳。 来自《现代汉英综合大词典》

290 imprints   

n.压印( imprint的名词复数 )；痕迹；持久影响

参考例句：

• With each step he took, his boots left muddy imprints on the floor. 她父亲的毡靴一移动，就在地板上压了几个泥圈圈。 来自汉英文学 - 中国现代小说
• In Freudian theory, the imprints are memories, albeit unconscious ones. 在佛洛伊德理论中，这些痕迹就是记忆，只不过它们是无意识的。 来自互联网

291 contractions   

n.收缩( contraction的名词复数 )；缩减；缩略词；（分娩时）子宫收缩

参考例句：

• Contractions are much more common in speech than in writing. 缩略词在口语里比在书写中常见得多。 来自《简明英汉词典》
• Muscle contractions are powered by the chemical adenosine triphosphate(ATP ). 肌肉收缩是由化学物质三磷酸腺苷(ATP)提供动力的。 来自辞典例句

292 contraction   

n.缩略词，缩写式，害病

参考例句：

• The contraction of this muscle raises the lower arm.肌肉的收缩使前臂抬起。
• The forces of expansion are balanced by forces of contraction.扩张力和收缩力相互平衡。

293 traction   

n.牵引；附着摩擦力

参考例句：

• I'll show you how the traction is applied.我会让你看如何做这种牵引。
• She's injured her back and is in traction for a month.她背部受伤，正在作一个月的牵引治疗。

294 fathoms   

英寻( fathom的名词复数 )

参考例句：

• The harbour is four fathoms deep. 港深为四英寻。
• One bait was down forty fathoms. 有个鱼饵下沉到四十英寻的深处。

295 waned   

v.衰落( wane的过去式和过去分词 )；（月）亏；变小；变暗淡

参考例句：

• However,my enthusiasm waned.The time I spent at exercises gradually diminished. 然而，我的热情减退了。我在做操上花的时间逐渐减少了。 来自《用法词典》
• The bicycle craze has waned. 自行车热已冷下去了。 来自《现代汉英综合大词典》

296 glided   

v.滑动( glide的过去式和过去分词 )；掠过；（鸟或飞机 ） 滑翔

参考例句：

• The President's motorcade glided by. 总统的车队一溜烟开了过去。
• They glided along the wall until they were out of sight. 他们沿着墙壁溜得无影无踪。 来自《简明英汉词典》

297 illustrate   

v.举例说明，阐明；图解，加插图

参考例句：

• The company's bank statements illustrate its success.这家公司的银行报表说明了它的成功。
• This diagram will illustrate what I mean.这个图表可说明我的意思。

298 innocence   

n.无罪；天真；无害

参考例句：

• There was a touching air of innocence about the boy.这个男孩有一种令人感动的天真神情。
• The accused man proved his innocence of the crime.被告人经证实无罪。

299 aesthetic   

adj.美学的，审美的，有美感

参考例句：

• My aesthetic standards are quite different from his.我的审美标准与他的大不相同。
• The professor advanced a new aesthetic theory.那位教授提出了新的美学理论。

300 propitious   

adj.吉利的；顺利的

参考例句：

• The circumstances were not propitious for further expansion of the company.这些情况不利于公司的进一步发展。
• The cool days during this week are propitious for out trip.这种凉爽的天气对我们的行程很有好处。

301 equating   

v.认为某事物（与另一事物）相等或相仿( equate的现在分词 )；相当于；等于；把（一事物） 和（另一事物）等同看待

参考例句：

• [ Ray ] I definitely started equating crossword puzzles with songwriting. 我已经干脆开始把字谜游戏等同于歌曲写作了。 来自电影对白
• But they have a hard time equating plural marriage with those evils. 但是他们很难把这种多妻婚姻与上面说的那些坏事联系起来。 来自互联网

302 anticipatory   

adj.预想的，预期的

参考例句：

• An anticipatory story is a trap to the teller.对于讲故事的人而言，事先想好的故事是个框框。
• Data quality is a function of systematic usage,not anticipatory design.数据质量是系统使用的功能，不是可预料的设计。

303 versed   

adj. 精通，熟练

参考例句：

• He is well versed in history.他精通历史。
• He versed himself in European literature. 他精通欧洲文学。

304 tactile   

adj.触觉的，有触觉的，能触知的

参考例句：

• Norris is an expert in the tactile and the tangible.诺里斯创作最精到之处便是，他描绘的人物使人看得见摸得着。
• Tactile communication uses touch rather than sight or hearing.触觉交流，是用触摸感觉，而不是用看或听来感觉。

305 felon   

n.重罪犯；adj.残忍的

参考例句：

• He's a convicted felon.他是个已定罪的重犯。
• Hitler's early "successes" were only the startling depredations of a resolute felon.希特勒的早期“胜利 ”，只不过是一个死心塌地的恶棍出人意料地抢掠得手而已。

306 arteries   

n.动脉( artery的名词复数 )；干线，要道

参考例句：

• Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
• This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》

307 fleeting   

adj.短暂的，飞逝的

参考例句：

• The girls caught only a fleeting glimpse of the driver.女孩们只匆匆瞥了一眼司机。
• Knowing the life fleeting,she set herself to enjoy if as best as she could.她知道这种日子转瞬即逝，于是让自已尽情地享受。

308 summation   

n.总和；最后辩论

参考例句：

• The exhibition was a summation of his life's work.这次展览汇集了他一生中典型的作品。
• The defense attorney phrased his summation at last.最后，辩护律师作了辩论总结。

309 consolidated   

a.联合的

参考例句：

• With this new movie he has consolidated his position as the country's leading director. 他新执导的影片巩固了他作为全国最佳导演的地位。
• Those two banks have consolidated and formed a single large bank. 那两家银行已合并成一家大银行。

310 chaos   

n.混乱，无秩序

参考例句：

• After the failure of electricity supply the city was in chaos.停电后，城市一片混乱。
• The typhoon left chaos behind it.台风后一片混乱。

311 extricating   

v.使摆脱困难，脱身( extricate的现在分词 )

参考例句：

• First, this will not bring on disorder and, second, it will not make extricating oneself impossible. 大鸣大放，一不会乱，二不会下不得台。 来自互联网
• Idea of Multhus "Two Control" and System Conditions of Extricating from "Population Trap " 马尔萨斯“两种抑制”的观点及解脱“人口陷阱”的制度条件。 来自互联网

312 accurately   

adv.准确地，精确地

参考例句：

• It is hard to hit the ball accurately.准确地击中球很难。
• Now scientists can forecast the weather accurately.现在科学家们能准确地预报天气。

313 excavates   

v.挖掘( excavate的第三人称单数 )；开凿；挖出；发掘

参考例句：

• Biblical criticism excavates the various deposits that have been gathered in successive layers in these writings. “圣经”考证把向来积聚于这些作品的各层中的各种堆积物掘开。 来自辞典例句
• Why excavates K-V5's archaeology one not to die a violent death? 为什么发掘K-V5的考古者们没有一个死于非命呢？ 来自互联网

314 margins   

边( margin的名词复数 )； 利润； 页边空白； 差数

参考例句：

• They have always had to make do with relatively small profit margins. 他们不得不经常设法应付较少的利润额。
• To create more space between the navigation items, add left and right margins to the links. 在每个项目间留更多的空隙，加左或者右的margins来定义链接。

315 embed   

vt.把…嵌(埋、插)入，扎牢；使深留脑中

参考例句：

• The harpoon struck but did not embed.鱼叉击中了但并没有插入。
• This photo showed us how did the root of plant embed the soil deeply.这张照片显示植物的根是如何深入到土壤里去的。

316 rotation   

n.旋转；循环，轮流

参考例句：

• Crop rotation helps prevent soil erosion.农作物轮作有助于防止水土流失。
• The workers in this workshop do day and night shifts in weekly rotation.这个车间的工人上白班和上夜班每周轮换一次。

317 rotations   

旋转( rotation的名词复数 )； 转动； 轮流； 轮换

参考例句：

• Farmers traditionally used long-term rotations of hay, pasture, and corn. 农民以往长期实行干草、牧草和玉米轮作。
• The crankshaft makes three rotations for each rotation of the rotor. 转子每转一周，曲轴转3周。

318 unnatural   

adj.不自然的；反常的

参考例句：

• Did her behaviour seem unnatural in any way?她有任何反常表现吗？
• She has an unnatural smile on her face.她脸上挂着做作的微笑。

319 perplexed   

adj.不知所措的

参考例句：

• The farmer felt the cow,went away,returned,sorely perplexed,always afraid of being cheated.那农民摸摸那头牛，走了又回来，犹豫不决，总怕上当受骗。
• The child was perplexed by the intricate plot of the story.这孩子被那头绪纷繁的故事弄得迷惑不解。

320 cravat   

n.领巾，领结；v.使穿有领结的服装，使结领结

参考例句：

• You're never fully dressed without a cravat.不打领结，就不算正装。
• Mr. Kenge adjusting his cravat,then looked at us.肯吉先生整了整领带，然后又望着我们。

321 inverted   

adj.反向的，倒转的v.使倒置，使反转( invert的过去式和过去分词 )

参考例句：

• Only direct speech should go inside inverted commas. 只有直接引语应放在引号内。
• Inverted flight is an acrobatic manoeuvre of the plane. 倒飞是飞机的一种特技动作。 来自《简明英汉词典》

322 utterly   

adv.完全地，绝对地

参考例句：

• Utterly devoted to the people,he gave his life in saving his patients.他忠于人民，把毕生精力用于挽救患者的生命。
• I was utterly ravished by the way she smiled.她的微笑使我完全陶醉了。

323 apparently   

adv.显然地；表面上，似乎

参考例句：

• An apparently blind alley leads suddenly into an open space.山穷水尽，豁然开朗。
• He was apparently much surprised at the news.他对那个消息显然感到十分惊异。

324 rectifies   

改正，矫正( rectify的第三人称单数 )； 精馏

参考例句：

• A diode rectifies alternating current. 二极管调整交流电。

325 judgment   

n.审判；判断力，识别力，看法，意见

参考例句：

• The chairman flatters himself on his judgment of people.主席自认为他审视人比别人高明。
• He's a man of excellent judgment.他眼力过人。

326 subsists   

v.（靠很少的钱或食物）维持生活，生存下去( subsist的第三人称单数 )

参考例句：

• This plant subsists in water holes only during the rainy season. 这种植物只有雨季在水坑里出现。 来自辞典例句
• The hinge is that the enterprise subsists on suiting the development of data communication. 适应数据通信的发展是通信企业生存的关键。 来自互联网

327 apprehension   

n.理解，领悟；逮捕，拘捕；忧虑

参考例句：

• There were still areas of doubt and her apprehension grew.有些地方仍然存疑，于是她越来越担心。
• She is a girl of weak apprehension.她是一个理解力很差的女孩。

328 lapse   

n.过失，流逝，失效，抛弃信仰，间隔；vi.堕落，停止，失效，流逝；vt.使失效

参考例句：

• The incident was being seen as a serious security lapse.这一事故被看作是一次严重的安全疏忽。
• I had a lapse of memory.我记错了。

329 outskirts   

n.郊外，郊区

参考例句：

• Our car broke down on the outskirts of the city.我们的汽车在市郊出了故障。
• They mostly live on the outskirts of a town.他们大多住在近郊。

330 unify   

vt.使联合，统一；使相同，使一致

参考例句：

• How can we unify such scattered islands into a nation?我们怎么才能把如此分散的岛屿统一成一个国家呢？
• It is difficult to imagine how the North and South could ever agree on a formula to unify the divided peninsula.很难想象南北双方在统一半岛的方案上究竟怎样才能达成一致。

331 coalesce   

v.联合，结合，合并

参考例句：

• And these rings of gas would then eventually coalesce and form the planets.这些气体环最后终于凝结形成行星。
• They will probably collide again and again until they coalesce.他们可能会一次又一次地发生碰撞，直到他们合并。

332 coalescence   

n.合并，联合

参考例句：

• It is formed by the coalescence of the first three neuromeres in the embryo .它是由胚胎时的前三个神经原节愈合而成的。
• The other process of droplet growth is by collision and coalescence.云滴增长的另一个过程是各云滴间的碰撞和并合。

333 coalescing   

v.联合，合并( coalesce的现在分词 )

参考例句：

• A mental model begins coalescing in their minds. 一个意识模型开始结合到他们的脑子里。 来自互联网
• On the basis of coalescing this kind of element can separate oil from compressed air. 采用凝聚原理，分离压缩空气中的油份。 来自互联网

334 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

335 phenomena   

n.现象

参考例句：

• Ade couldn't relate the phenomena with any theory he knew.艾德无法用他所知道的任何理论来解释这种现象。
• The object of these experiments was to find the connection,if any,between the two phenomena.这些实验的目的就是探索这两种现象之间的联系，如果存在着任何联系的话。

336 overflowing   

n. 溢出物,溢流 adj. 充沛的，充满的 动词overflow的现在分词形式

参考例句：

• The stands were overflowing with farm and sideline products. 集市上农副产品非常丰富。
• The milk is overflowing. 牛奶溢出来了。

337 interfere   

v.(in)干涉，干预；(with)妨碍，打扰

参考例句：

• If we interfere, it may do more harm than good.如果我们干预的话，可能弊多利少。
• When others interfere in the affair,it always makes troubles. 别人一卷入这一事件，棘手的事情就来了。

338 serial   

n.连本影片，连本电视节目；adj.连续的

参考例句：

• A new serial is starting on television tonight.今晚电视开播一部新的电视连续剧。
• Can you account for the serial failures in our experiment?你能解释我们实验屡屡失败的原因吗？

339 exteriority   

n.在外，外在性

参考例句：

340 piecemeal   

adj.零碎的；n.片，块；adv.逐渐地；v.弄成碎块

参考例句：

• A lack of narrative drive leaves the reader with piecemeal vignettes.叙述缺乏吸引力，读者读到的只是一些支离破碎的片段。
• Let's settle the matter at one stroke,not piecemeal.把这事一气儿解决了吧，别零敲碎打了。

341 disappearance   

n.消失，消散，失踪

参考例句：

• He was hard put to it to explain her disappearance.他难以说明她为什么不见了。
• Her disappearance gave rise to the wildest rumours.她失踪一事引起了各种流言蜚语。

342 abides   

容忍( abide的第三人称单数 )； 等候； 逗留； 停留

参考例句：

• He abides by his friends. 他忠于朋友。
• He always abides by the law. 他素来守法。

343 locomotion   

n.运动，移动

参考例句：

• By land,air or sea,birds are masters of locomotion.无论是通过陆地，飞越空中还是穿过海洋，鸟应算是运动能手了。
• Food sources also elicit oriented locomotion and recognition behavior patterns in most insects.食物源也引诱大多数昆虫定向迁移和识别行为。

344 blister   

n.水疱；(油漆等的)气泡；v.(使)起泡

参考例句：

• I got a huge blister on my foot and I couldn't run any farther.我脚上长了一个大水泡，没办法继续跑。
• I have a blister on my heel because my shoe is too tight.鞋子太紧了，我脚后跟起了个泡。

345 protracted   

adj.拖延的；延长的v.拖延“protract”的过去式和过去分词

参考例句：

• The war was protracted for four years. 战争拖延了四年。 来自《简明英汉词典》
• We won victory through protracted struggle. 经过长期的斗争，我们取得了胜利。 来自《简明英汉词典》

346 emphatic   

adj.强调的，着重的；无可置疑的，明显的

参考例句：

• Their reply was too emphatic for anyone to doubt them.他们的回答很坚决，不容有任何人怀疑。
• He was emphatic about the importance of being punctual.他强调严守时间的重要性。

347 blisters   

n.水疱( blister的名词复数 )；水肿；气泡

参考例句：

• My new shoes have made blisters on my heels. 我的新鞋把我的脚跟磨起泡了。 来自《现代汉英综合大词典》
• His new shoes raised blisters on his feet. 他的新鞋把他的脚磨起了水疱。 来自《简明英汉词典》

348 glade   

n.林间空地，一片表面有草的沼泽低地

参考例句：

• In the midst of a glade were several huts.林中的空地中间有几间小木屋。
• The family had their lunch in the glade.全家在林中的空地上吃了午饭。

349 attained   

（通常经过努力）实现( attain的过去式和过去分词 )； 达到； 获得； 达到（某年龄、水平、状况）

参考例句：

• She has attained the degree of Master of Arts. 她已获得文学硕士学位。
• Lu Hsun attained a high position in the republic of letters. 鲁迅在文坛上获得崇高的地位。

350 attain   

vt.达到，获得，完成

参考例句：

• I used the scientific method to attain this end. 我用科学的方法来达到这一目的。
• His painstaking to attain his goal in life is praiseworthy. 他为实现人生目标所下的苦功是值得称赞的。

351 flexing   

n.挠曲，可挠性v.屈曲( flex的现在分词 )；弯曲；（为准备大干而）显示实力；摩拳擦掌

参考例句：

• Flexing particular muscles allows snakes to move in several ways. 可弯曲的特殊的肌肉使蛇可以用几种方式移动。 来自电影对白
• China has become an economic superpower and is flexing its muscles. 中国已经成为了一个经济巨人而且在展示他的肌肉。 来自互联网

352 purely   

adv.纯粹地，完全地

参考例句：

• I helped him purely and simply out of friendship.我帮他纯粹是出于友情。
• This disproves the theory that children are purely imitative.这证明认为儿童只会单纯地模仿的理论是站不住脚的。

353 receding   

v.逐渐远离( recede的现在分词 )；向后倾斜；自原处后退或避开别人的注视；尤指问题

参考例句：

• Desperately he struck out after the receding lights of the yacht. 游艇的灯光渐去渐远，他拼命划水追赶。 来自辞典例句
• Sounds produced by vehicles receding from us seem lower-pitched than usual. 渐渐远离我们的运载工具发出的声似乎比平常的音调低。 来自辞典例句

354 postponed   

vt.& vi.延期，缓办，（使）延迟vt.把…放在次要地位；[语]把…放在后面（或句尾）vi.（疟疾等）延缓发作（或复发）

参考例句：

• The trial was postponed indefinitely. 审讯无限期延迟。
• The game has already been postponed three times. 这场比赛已经三度延期了。

355 solely   

adv.仅仅，唯一地

参考例句：

• Success should not be measured solely by educational achievement.成功与否不应只用学业成绩来衡量。
• The town depends almost solely on the tourist trade.这座城市几乎完全靠旅游业维持。

356 derivative   

n.派(衍)生物；adj.非独创性的，模仿他人的

参考例句：

• His paintings are really quite derivative.他的画实在没有创意。
• Derivative works are far more complicated.派生作品更加复杂。

357 reiterated   

反复地说，重申( reiterate的过去式和过去分词 )

参考例句：

• "Well, I want to know about it,'she reiterated. “嗯，我一定要知道你的休假日期，"她重复说。 来自英汉文学 - 嘉莉妹妹
• Some twenty-two years later President Polk reiterated and elaborated upon these principles. 大约二十二年之后，波尔克总统重申这些原则并且刻意阐释一番。

358 hush   

int.嘘，别出声；n.沉默，静寂；v.使安静

参考例句：

• A hush fell over the onlookers.旁观者们突然静了下来。
• Do hush up the scandal!不要把这丑事声张出去！

359 formerly   

adv.从前，以前

参考例句：

• We now enjoy these comforts of which formerly we had only heard.我们现在享受到了过去只是听说过的那些舒适条件。
• This boat was formerly used on the rivers of China.这船从前航行在中国内河里。

360 triumphant   

adj.胜利的，成功的；狂欢的，喜悦的

参考例句：

• The army made a triumphant entry into the enemy's capital.部队胜利地进入了敌方首都。
• There was a positively triumphant note in her voice.她的声音里带有一种极为得意的语气。

361 invoke   

v.求助于(神、法律)；恳求，乞求

参考例句：

• Let us invoke the blessings of peace.让我们祈求和平之福。
• I hope I'll never have to invoke this clause and lodge a claim with you.我希望我永远不会使用这个条款向你们索赔。

362 practitioners   

n.习艺者，实习者( practitioner的名词复数 )；从业者（尤指医师）

参考例句：

• one of the greatest practitioners of science fiction 最了不起的科幻小说家之一
• The technique is experimental, but the list of its practitioners is growing. 这种技术是试验性的，但是采用它的人正在增加。 来自辞典例句

363 flexed   

adj.[医]曲折的，屈曲v.屈曲( flex的过去式和过去分词 )；弯曲；（为准备大干而）显示实力；摩拳擦掌

参考例句：

• He stretched and flexed his knees to relax himself. 他伸屈膝关节使自己放松一下。 来自辞典例句
• He flexed his long stringy muscles manfully. 他孔武有力地弯起膀子，显露出细长条的肌肉。 来自辞典例句

364 impaired   

adj.受损的；出毛病的；有（身体或智力）缺陷的v.损害，削弱( impair的过去式和过去分词 )

参考例句：

• Much reading has impaired his vision. 大量读书损害了他的视力。 来自《现代汉英综合大词典》
• His hearing is somewhat impaired. 他的听觉已受到一定程度的损害。 来自《现代汉英综合大词典》

365 imprinted   

v.盖印（imprint的过去式与过去分词形式）

参考例句：

• The terrible scenes were indelibly imprinted on his mind. 那些恐怖场面深深地铭刻在他的心中。
• The scene was imprinted on my mind. 那个场面铭刻在我的心中。 来自《简明英汉词典》

366 exclusion   

n.拒绝，排除，排斥，远足，远途旅行

参考例句：

• Don't revise a few topics to the exclusion of all others.不要修改少数论题以致排除所有其他的。
• He plays golf to the exclusion of all other sports.他专打高尔夫球，其他运动一概不参加。

367 testimony   

n.证词；见证，证明

参考例句：

• The testimony given by him is dubious.他所作的证据是可疑的。
• He was called in to bear testimony to what the police officer said.他被传入为警官所说的话作证。

368 appreciation   

n.评价；欣赏；感谢；领会，理解；价格上涨

参考例句：

• I would like to express my appreciation and thanks to you all.我想对你们所有人表达我的感激和谢意。
• I'll be sending them a donation in appreciation of their help.我将送给他们一笔捐款以感谢他们的帮助。

369 apparatus   

n.装置，器械；器具，设备

参考例句：

• The school's audio apparatus includes films and records.学校的视听设备包括放映机和录音机。
• They had a very refined apparatus.他们有一套非常精良的设备。

370 velocity   

n.速度，速率

参考例句：

• Einstein's theory links energy with mass and velocity of light.爱因斯坦的理论把能量同质量和光速联系起来。
• The velocity of light is about 300000 kilometres per second.光速约为每秒300000公里。

371 minimal   

adj.尽可能少的，最小的

参考例句：

• They referred to this kind of art as minimal art.他们把这种艺术叫微型艺术。
• I stayed with friends, so my expenses were minimal.我住在朋友家，所以我的花费很小。

372 displacement   

n.移置，取代，位移，排水量

参考例句：

• They said that time is the feeling of spatial displacement.他们说时间是空间位移的感觉。
• The displacement of all my energy into caring for the baby.我所有精力都放在了照顾宝宝上。

373 displacements   

n.取代( displacement的名词复数 )；替代；移位；免职

参考例句：

• The laws of physics are symmetrical for translational displacements. 物理定律对平移是对称的。 来自辞典例句
• We encounter only displacements of the first type. 我们只遇到第一类的驱替。 来自辞典例句

374 induction   

n.感应，感应现象

参考例句：

• His induction as a teacher was a turning point in his life.他就任教师工作是他一生的转折点。
• The magnetic signals are sensed by induction coils.磁信号由感应线圈所检测。

375 countenance   

n.脸色，面容；面部表情；vt.支持，赞同

参考例句：

• At the sight of this photograph he changed his countenance.他一看见这张照片脸色就变了。
• I made a fierce countenance as if I would eat him alive.我脸色恶狠狠地，仿佛要把他活生生地吞下去。

376 insipid   

adj.无味的，枯燥乏味的，单调的

参考例句：

• The food was rather insipid and needed gingering up.这食物缺少味道，需要加点作料。
• She said she was a good cook,but the food she cooked is insipid.她说她是个好厨师，但她做的食物却是无味道的。

377 configuration   

n.结构，布局，形态，(计算机)配置

参考例句：

• Geographers study the configuration of the mountains.地理学家研究山脉的地形轮廓。
• Prices range from $119 to $199,depending on the particular configuration.价格因具体配置而异，从119美元至199美元不等。

378 presumption   

n.推测，可能性，冒昧，放肆，[法律]推定

参考例句：

• Please pardon my presumption in writing to you.请原谅我很冒昧地写信给你。
• I don't think that's a false presumption.我认为那并不是错误的推测。

379 engendering   

v.产生（某形势或状况），造成，引起( engender的现在分词 )

参考例句：

• Certain soluble extracts of B pertussis may prove to be effective without engendering serious side effects. 某些可溶性百日咳杆菌提取物，可证明用之有效，也不产生严重副作用。 来自辞典例句
• The engendering, classification, path and control of environmental pollution transference were discussed. 对环境污染转嫁的产生、分类、途径及其控制与防范进行了分析。 来自互联网

380 merged   

（使）混合( merge的过去式和过去分词 )； 相融； 融入； 渐渐消失在某物中

参考例句：

• Turf wars are inevitable when two departments are merged. 两个部门合并时总免不了争争权限。
• The small shops were merged into a large market. 那些小商店合并成为一个大商场。

381 inflamed   

adj.发炎的，红肿的v.（使）变红，发怒，过热( inflame的过去式和过去分词 )

参考例句：

• His comments have inflamed teachers all over the country. 他的评论激怒了全国教师。
• Her joints are severely inflamed. 她的关节严重发炎。 来自《简明英汉词典》

382 extradition   

n.引渡（逃犯）

参考例句：

• The smuggler is in prison tonight,awaiting extradition to Britain.这名走私犯今晚在监狱，等待引渡到英国。
• He began to trouble concerning the extradition laws.他开始费尽心思地去想关于引渡法的问题。

383 cane   

n.手杖，细长的茎，藤条；v.以杖击，以藤编制的

参考例句：

• This sugar cane is quite a sweet and juicy.这甘蔗既甜又多汁。
• English schoolmasters used to cane the boys as a punishment.英国小学老师过去常用教鞭打男学生作为惩罚。

384 symbolic   

adj.象征性的，符号的，象征主义的

参考例句：

• It is symbolic of the fighting spirit of modern womanhood.它象征着现代妇女的战斗精神。
• The Christian ceremony of baptism is a symbolic act.基督教的洗礼仪式是一种象征性的做法。

385 stimulus   

n.刺激，刺激物，促进因素，引起兴奋的事物

参考例句：

• Regard each failure as a stimulus to further efforts.把每次失利看成对进一步努力的激励。
• Light is a stimulus to growth in plants.光是促进植物生长的一个因素。

386 judicious   

adj.明智的，明断的，能作出明智决定的

参考例句：

• We should listen to the judicious opinion of that old man.我们应该听取那位老人明智的意见。
• A judicious parent encourages his children to make their own decisions.贤明的父亲鼓励儿女自作抉择。

387 ribs   

n.肋骨( rib的名词复数 )；（船或屋顶等的）肋拱；肋骨状的东西；（织物的）凸条花纹

参考例句：

• He suffered cracked ribs and bruising. 他断了肋骨还有挫伤。
• Make a small incision below the ribs. 在肋骨下方切开一个小口。

388 physiologically   

ad.生理上，在生理学上

参考例句：

• Therefore, the liver and gallbladder cannot be completely separated physiologically and pathologically. 因此，肝胆在生理和病理上不能完全分离。
• Therefore, the liver and gallbladder are closely related physiologically and pathologically. 因此，肝胆在生理和病理上紧密联系。

389 nay   

adv.不；n.反对票，投反对票者

参考例句：

• He was grateful for and proud of his son's remarkable,nay,unique performance.他为儿子出色的，不，应该是独一无二的表演心怀感激和骄傲。
• Long essays,nay,whole books have been written on this.许多长篇大论的文章，不，应该说是整部整部的书都是关于这件事的。

390 corroborate   

v.支持，证实，确定

参考例句：

• He looked at me anxiously,as if he hoped I'd corroborate this.他神色不安地看着我，仿佛他希望我证实地的话。
• It appeared that what he said went to corroborate my account.看来他所说的和我叙述的相符。

391 gaping   

adj.口的；张口的；敞口的；多洞穴的v.目瞪口呆地凝视( gape的现在分词 )；张开，张大

参考例句：

• Ahead of them was a gaping abyss. 他们前面是一个巨大的深渊。
• The antelope could not escape the crocodile's gaping jaws. 那只羚羊无法从鱷鱼张开的大口中逃脱。 来自《简明英汉词典》

392 mucous   

adj. 黏液的，似黏液的

参考例句：

• Healthy,skin,mucous membranes,and cilia are natural barriers to many viruses.健康的皮肤，粘膜和纤毛是许多病毒的天然屏障。
• Seromucous glands contain both mucous and serous cells.浆粘液腺既含有粘液性细胞，又含有浆液性细胞。

393 permanently   

adv.永恒地，永久地，固定不变地

参考例句：

• The accident left him permanently scarred.那次事故给他留下了永久的伤疤。
• The ship is now permanently moored on the Thames in London.该船现在永久地停泊在伦敦泰晤士河边。

394 humble   

adj.谦卑的，恭顺的；地位低下的；v.降低，贬低

参考例句：

• In my humble opinion,he will win the election.依我拙见，他将在选举中获胜。
• Defeat and failure make people humble.挫折与失败会使人谦卑。

395 multiplication   

n.增加，增多，倍增；增殖，繁殖；乘法

参考例句：

• Our teacher used to drum our multiplication tables into us.我们老师过去老是让我们反覆背诵乘法表。
• The multiplication of numbers has made our club building too small.会员的增加使得我们的俱乐部拥挤不堪。

396 landmark   

n.陆标，划时代的事，地界标

参考例句：

• The Russian Revolution represents a landmark in world history.俄国革命是世界历史上的一个里程碑。
• The tower was once a landmark for ships.这座塔曾是船只的陆标。

397 exalting   

a.令人激动的，令人喜悦的

参考例句：

• To exert an animating, enlivening, encouraging or exalting influence on someone. 使某人充满活力，对他进行启发，鼓励，或施加影响。
• One of the key ideas in Isaiah 2 is that of exalting or lifting up. 以赛亚书2章特点之一就是赞颂和提升。

398 condemned   

adj. 被责难的, 被宣告有罪的 动词condemn的过去式和过去分词

参考例句：

• He condemned the hypocrisy of those politicians who do one thing and say another. 他谴责了那些说一套做一套的政客的虚伪。
• The policy has been condemned as a regressive step. 这项政策被认为是一种倒退而受到谴责。

399 computed   

adj.[医]计算的，使用计算机的v.计算，估算( compute的过去式和过去分词 )

参考例句：

• He computed that the project would take seven years to complete. 他估计这项计划要花七年才能完成。 来自《简明英汉词典》
• Resolving kernels and standard errors can also be computed for each block. 还可以计算每个块体的分辨核和标准误差。 来自辞典例句

400 abysmal   

adj.无底的，深不可测的，极深的；糟透的，极坏的；完全的

参考例句：

• The film was so abysmal that I fell asleep.电影太糟糕，看得我睡着了。
• There is a historic explanation for the abysmal state of Chinese cuisine in the United States.中餐在美国的糟糕状态可以从历史上找原因。

401 vault   

n.拱形圆顶，地窖，地下室

参考例句：

• The vault of this cathedral is very high.这座天主教堂的拱顶非常高。
• The old patrician was buried in the family vault.这位老贵族埋在家族的墓地里。

402 levy   

n.征收税或其他款项，征收额

参考例句：

• They levy a tax on him.他们向他征税。
• A direct food levy was imposed by the local government.地方政府征收了食品税。

403 ascertained   

v.弄清，确定，查明( ascertain的过去式和过去分词 )

参考例句：

• The previously unidentified objects have now been definitely ascertained as being satellites. 原来所说的不明飞行物现在已证实是卫星。 来自《简明英汉词典》
• I ascertained that she was dead. 我断定她已经死了。 来自《简明英汉词典》

404 panes   

窗玻璃( pane的名词复数 )

参考例句：

• The sun caught the panes and flashed back at him. 阳光照到窗玻璃上，又反射到他身上。
• The window-panes are dim with steam. 玻璃窗上蒙上了一层蒸汽。

405 pane   

n.窗格玻璃，长方块

参考例句：

• He broke this pane of glass.他打破了这块窗玻璃。
• Their breath bloomed the frosty pane.他们呼出的水气，在冰冷的窗玻璃上形成一层雾。

406 projections   

预测( projection的名词复数 )； 投影； 投掷； 突起物

参考例句：

• Their sales projections are a total thumbsuck. 他们的销售量预测纯属估计。
• The council has revised its projections of funding requirements upwards. 地方议会调高了对资金需求的预测。

407 vapor   

n.蒸汽，雾气

参考例句：

• The cold wind condenses vapor into rain.冷风使水蒸气凝结成雨。
• This new machine sometimes transpires a lot of hot vapor.这部机器有时排出大量的热气。

408 fluctuations   

波动，涨落，起伏( fluctuation的名词复数 )

参考例句：

• He showed the price fluctuations in a statistical table. 他用统计表显示价格的波动。
• There were so many unpredictable fluctuations on the Stock Exchange. 股票市场瞬息万变。

409 instructor   

n.指导者，教员，教练

参考例句：

• The college jumped him from instructor to full professor.大学突然把他从讲师提升为正教授。
• The skiing instructor was a tall,sunburnt man.滑雪教练是一个高高个子晒得黑黑的男子。

410 sonority   

n.响亮，宏亮

参考例句：

• Vowels possess greater sonority than consonants.元音比辅音响亮。
• The introduction presents arpeggios on the harp against a string tremolo--an enchanting sonority.引子在弦乐的震音上竖琴奏出了琶音，一种迷人的音响。

411 discrete   

adj.个别的，分离的，不连续的

参考例句：

• The picture consists of a lot of discrete spots of colour.这幅画由许多不相连的色点组成。
• Most staple fibers are discrete,individual entities.大多数短纤维是不联系的单独实体。

412 jointed   

有接缝的

参考例句：

• To embrace her was like embracing a jointed wooden image. 若是拥抱她，那感觉活像拥抱一块木疙瘩。 来自英汉文学
• It is possible to devise corresponding systematic procedures for rigid jointed frames. 推导出适合于钢架的类似步骤也是可能的。

413 symbolically   

ad.象征地，象征性地

参考例句：

• By wearing the ring on the third finger of the left hand, a married couple symbolically declares their eternal love for each other. 将婚戒戴在左手的第三只手指上，意味着夫妻双方象征性地宣告他们的爱情天长地久，他们定能白头偕老。
• Symbolically, he coughed to clear his throat. 周经理象征地咳一声无谓的嗽，清清嗓子。

414 interrogating   

n.询问技术v.询问( interrogate的现在分词 )；审问；（在计算机或其他机器上）查询

参考例句：

• She was no longer interrogating but lecturing. 她已经不是在审问而是在教训人了。 来自辞典例句
• His face remained blank, interrogating, slightly helpless. 他的面部仍然没有表情，只带有询问的意思，还有点无可奈何。 来自辞典例句

415 pint   

n.品脱

参考例句：

• I'll have a pint of beer and a packet of crisps, please.我要一品脱啤酒和一袋炸马铃薯片。
• In the old days you could get a pint of beer for a shilling.从前，花一先令就可以买到一品脱啤酒。

416 guise   

n.外表，伪装的姿态

参考例句：

• They got into the school in the guise of inspectors.他们假装成视察员进了学校。
• The thief came into the house under the guise of a repairman.那小偷扮成个修理匠进了屋子。

417 ascend   

vi.渐渐上升，升高；vt.攀登，登上

参考例句：

• We watched the airplane ascend higher and higher.我们看着飞机逐渐升高。
• We ascend in the order of time and of development.我们按时间和发展顺序向上溯。

418 effaced   

v.擦掉( efface的过去式和过去分词 )；抹去；超越；使黯然失色

参考例句：

• Someone has effaced part of the address on his letter. 有人把他信上的一部分地址擦掉了。 来自《现代英汉综合大词典》
• The name of the ship had been effaced from the menus. 那艘船的名字已经从菜单中删除了。 来自辞典例句

419 neutralized   

v.使失效( neutralize的过去式和过去分词 )；抵消；中和；使（一个国家）中立化

参考例句：

• Acidity in soil can be neutralized by spreading lime on it. 土壤的酸性可以通过在它上面撒石灰来中和。 来自《简明英汉词典》
• This strategy effectively neutralized what the Conservatives had hoped would be a vote-winner. 这一策略有效地冲淡了保守党希望在选举中获胜的心态。 来自《简明英汉词典》

420 paradox   

n.似乎矛盾却正确的说法；自相矛盾的人(物)

参考例句：

• The story contains many levels of paradox.这个故事存在多重悖论。
• The paradox is that Japan does need serious education reform.矛盾的地方是日本确实需要教育改革。

421 obstinately   

ad.固执地，顽固地

参考例句：

• He obstinately asserted that he had done the right thing. 他硬说他做得对。
• Unemployment figures are remaining obstinately high. 失业数字仍然顽固地居高不下。

422 enumerate   

v.列举，计算，枚举，数

参考例句：

• The heroic deeds of the people's soldiers are too numerous to enumerate.人民子弟兵的英雄事迹举不胜举。
• Its applications are too varied to enumerate.它的用途不胜枚举。

423 incompetent   

adj.无能力的，不能胜任的

参考例句：

• He is utterly incompetent at his job.他完全不能胜任他的工作。
• He is incompetent at working with his hands.他动手能力不行。

424 naught   

n.无，零 [=nought]

参考例句：

• He sets at naught every convention of society.他轻视所有的社会习俗。
• I hope that all your efforts won't go for naught.我希望你的努力不会毫无结果。

425 radical   

n.激进份子，原子团，根号；adj.根本的，激进的，彻底的

参考例句：

• The patient got a radical cure in the hospital.病人在医院得到了根治。
• She is radical in her demands.她的要求十分偏激。

426 radically   

ad.根本地，本质地

参考例句：

• I think we may have to rethink our policies fairly radically. 我认为我们可能要对我们的政策进行根本的反思。
• The health service must be radically reformed. 公共医疗卫生服务必须进行彻底改革。

427 diffused   

散布的，普及的，扩散的

参考例句：

• A drop of milk diffused in the water. 一滴牛奶在水中扩散开来。
• Gases and liquids diffused. 气体和液体慢慢混合了。

428 latitude   

n.纬度，行动或言论的自由(范围)，(pl.)地区

参考例句：

• The latitude of the island is 20 degrees south.该岛的纬度是南纬20度。
• The two cities are at approximately the same latitude.这两个城市差不多位于同一纬度上。

429 tallies   

n.账( tally的名词复数 )；符合；（计数的）签；标签v.计算，清点( tally的第三人称单数 )；加标签（或标记）于；（使）符合；（使）吻合

参考例句：

• Cash on hand tallies with the figure in the accounts. 现款跟账上的数目没有出入。 来自《现代汉英综合大词典》
• He tallies his own marks. 他把自己的得分记了下来。 来自《简明英汉词典》

430 stagnant   

adj.不流动的，停滞的，不景气的

参考例句：

• Due to low investment,industrial output has remained stagnant.由于投资少，工业生产一直停滞不前。
• Their national economy is stagnant.他们的国家经济停滞不前。

431 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

432 bough   

n.大树枝，主枝

参考例句：

• I rested my fishing rod against a pine bough.我把钓鱼竿靠在一棵松树的大树枝上。
• Every bough was swinging in the wind.每条树枝都在风里摇摆。

433 heterogeneity   

n.异质性；多相性

参考例句：

• The heterogeneity and uneven development of China's economy are rather advantageous in the war of resistance.中国经济的不统一、不平衡，对于抗日战争反为有利。
• In heterogeneity is creation of the world.世界产生自异质性。

434 confirmation   

n.证实，确认，批准

参考例句：

• We are waiting for confirmation of the news.我们正在等待证实那个消息。
• We need confirmation in writing before we can send your order out.给你们发送订购的货物之前，我们需要书面确认。

435 steadfastly   

adv.踏实地，不变地；岿然；坚定不渝

参考例句：

• So he sat, with a steadfastly vacant gaze, pausing in his work. 他就像这样坐着，停止了工作，直勾勾地瞪着眼。 来自英汉文学 - 双城记
• Defarge and his wife looked steadfastly at one another. 德伐日和他的妻子彼此凝视了一会儿。 来自英汉文学 - 双城记

436 extirpated   

v.消灭，灭绝( extirpate的过去式和过去分词 )；根除

参考例句：

• Many species have been extirpated from large areas. 许多种动物已在大片区域内灭绝。 来自辞典例句
• The brigands have never been really extirpated from the neighborhood of Rome. 罗马附近的土匪实际上从来没有真正被消灭干净过。 来自互联网

437 foretell   

v.预言，预告，预示

参考例句：

• Willow trees breaking out into buds foretell the coming of spring.柳枝绽青报春来。
• The outcome of the war is hard to foretell.战争胜负难以预卜。

438 banal   

adj.陈腐的，平庸的

参考例句：

• Making banal remarks was one of his bad habits.他的坏习惯之一就是喜欢说些陈词滥调。
• The allegations ranged from the banal to the bizarre.从平淡无奇到离奇百怪的各种说法都有。

439 paradoxes   

n.似非而是的隽语，看似矛盾而实际却可能正确的说法( paradox的名词复数 )；用于语言文学中的上述隽语；有矛盾特点的人[事物，情况]

参考例句：

• Contradictions and paradoxes arose in increasing numbers. 矛盾和悖论越来越多。 来自辞典例句
• As far as these paradoxes are concerned, the garden definitely a heterotopia. 就这些吊诡性而言，花园无疑地是个异质空间。 来自互联网

440 conundrums   

n.谜，猜不透的难题，难答的问题( conundrum的名词复数 )

参考例句：

• After all the conundrums of Hungary, the second Turkish Grand Prix promises much. 继匈牙利站所有猜不透的事之后，第二届土耳其大奖赛许诺了太多。 来自互联网
• I see conundrums, dilemmas, quandaries, impasses, gnarly thickets of fateful possibility with no obvious way out. 眼看问题经纬万端，进退两难、入困境，死路一条，盘根错节的命定可能性，但找不到明显的出路。 来自互联网

441 ambiguities   

n.歧义( ambiguity的名词复数 )；意义不明确；模棱两可的意思；模棱两可的话

参考例句：

• His reply was full of ambiguities. 他的答复非常暧昧。 来自《现代汉英综合大词典》
• Fortunately, no ambiguities hang about this word or about its opposite, indeterminism. 值得庆幸的是，关于这个词和它的反义词，非决定论都不存在多种解释。 来自哲学部分

442 intelligible   

adj.可理解的，明白易懂的，清楚的

参考例句：

• This report would be intelligible only to an expert in computing.只有计算机运算专家才能看懂这份报告。
• His argument was barely intelligible.他的论点不易理解。

443 analyzed   

v.分析( analyze的过去式和过去分词 )；分解；解释；对…进行心理分析

参考例句：

• The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
• The young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程，因为对他来说，爱是个不可分析的迷。 来自《简明英汉词典》

444 inevitable   

adj.不可避免的，必然发生的

参考例句：

• Mary was wearing her inevitable large hat.玛丽戴着她总是戴的那顶大帽子。
• The defeat had inevitable consequences for British policy.战败对英国政策不可避免地产生了影响。

445 consort   

v.相伴；结交

参考例句：

• They went in consort two or three together.他们三三两两结伴前往。
• The nurses are instructed not to consort with their patients.护士得到指示不得与病人交往。

446 plunge   

v.跳入，(使)投入，(使)陷入；猛冲

参考例句：

• Test pool's water temperature before you plunge in.在你跳入之前你应该测试水温。
• That would plunge them in the broil of the two countries.那将会使他们陷入这两国的争斗之中。

447 absurdities   

n.极端无理性( absurdity的名词复数 )；荒谬；谬论；荒谬的行为

参考例句：

• She has a sharp eye for social absurdities, and compassion for the victims of social change. 她独具慧眼，能够看到社会上荒唐的事情，对于社会变革的受害者寄以同情。 来自辞典例句
• The absurdities he uttered at the dinner party landed his wife in an awkward situation. 他在宴会上讲的荒唐话使他太太陷入窘境。 来自辞典例句

448 interpretation   

n.解释，说明，描述；艺术处理

参考例句：

• His statement admits of one interpretation only.他的话只有一种解释。
• Analysis and interpretation is a very personal thing.分析与说明是个很主观的事情。

449 interpretations   

n.解释( interpretation的名词复数 )；表演；演绎；理解

参考例句：

• This passage is open to a variety of interpretations. 这篇文章可以有各种不同的解释。 来自《简明英汉词典》
• The involved and abstruse passage makes several interpretations possible. 这段艰涩的文字可以作出好几种解释。 来自《现代汉英综合大词典》

450 retard   

n.阻止，延迟；vt.妨碍，延迟，使减速

参考例句：

• Lack of sunlight will retard the growth of most plants.缺乏阳光会妨碍大多数植物的生长。
• Continuing violence will retard negotiations over the country's future.持续不断的暴力活动会阻碍关系到国家未来的谈判的进行。

451 frustrate   

v.使失望；使沮丧；使厌烦

参考例句：

• But this didn't frustrate Einstein.He was content to go as far as he could.但这并没有使爱因斯坦灰心，他对能够更深入地研究而感到满意。
• They made their preparations to frustrate the conspiracy.他们作好准备挫败这个阴谋。

452 equated   

adj.换算的v.认为某事物（与另一事物）相等或相仿( equate的过去式和过去分词 )；相当于；等于；把（一事物） 和（另一事物）等同看待

参考例句：

• Production costs for the movie equated to around 30% of income. 这部电影的制作成本相当于收益的30%。
• Politics cannot be equated with art. 政治不能同艺术等同起来。

453 elucidation   

n.说明，阐明

参考例句：

• The advertising copy is the elucidation text,which must be written according to the formula of AIDA. 文案是说明文，应基本遵照AIDA公式来写作。 来自互联网
• Fourth, a worm hole, elucidation space-time can stretch, compression, rent, also is deduced time-travel this idea. 第四，有了虫洞，就说明时空可以被拉伸、压缩、撕裂，也就推导出了时空旅行这个想法。 来自互联网

454 laterally   

ad.横向地；侧面地；旁边地

参考例句：

• Shafts were sunk, with tunnels dug laterally. 竖井已经打下，并且挖有横向矿道。
• When the plate becomes unstable, it buckles laterally. 当板失去稳定时，就发生横向屈曲。

455 unifying   

使联合( unify的现在分词 )； 使相同； 使一致； 统一

参考例句：

• In addition, there were certain religious bonds of a unifying kind. 此外，他们还有某种具有一种统一性质的宗教上的结合。
• There is a unifying theme, and that is the theme of information flow within biological systems. 我们可以用一个总的命题，把生物学系统内的信息流来作为这一研究主题。

456 transformation   

n.变化；改造；转变

参考例句：

• Going to college brought about a dramatic transformation in her outlook.上大学使她的观念发生了巨大的变化。
• He was struggling to make the transformation from single man to responsible husband.他正在努力使自己由单身汉变为可靠的丈夫。

457 regiment   

n.团，多数，管理；v.组织，编成团，统制

参考例句：

• As he hated army life,he decide to desert his regiment.因为他嫌恶军队生活，所以他决心背弃自己所在的那个团。
• They reformed a division into a regiment.他们将一个师整编成为一个团。

458 abreast   

adv.并排地；跟上(时代)的步伐，与…并进地

参考例句：

• She kept abreast with the flood of communications that had poured in.她及时回复如雪片般飞来的大批信件。
• We can't keep abreast of the developing situation unless we study harder.我们如果不加强学习，就会跟不上形势。

459 assailed   

v.攻击( assail的过去式和过去分词 )；困扰；质问；毅然应对

参考例句：

• He was assailed with fierce blows to the head. 他的头遭到猛烈殴打。
• He has been assailed by bad breaks all these years. 这些年来他接二连三地倒霉。 来自《用法词典》

460 nexus   

n.联系；关系

参考例句：

• Shared ambition is the vital nexus between them.共同的志向是把他们联结在一起的重要纽带。
• Either way,the nexus between the consumer and consumer prices is important.无论那个方面，消费者与消费价格之间的关系是至关重要的。

461 converse   

vi.谈话，谈天，闲聊；adv.相反的，相反

参考例句：

• He can converse in three languages.他可以用3种语言谈话。
• I wanted to appear friendly and approachable but I think I gave the converse impression.我想显得友好、平易近人些,却发觉给人的印象恰恰相反。

462 tint   

n.淡色，浅色；染发剂；vt.着以淡淡的颜色

参考例句：

• You can't get up that naturalness and artless rosy tint in after days.你今后不再会有这种自然和朴实无华的红润脸色。
• She gave me instructions on how to apply the tint.她告诉我如何使用染发剂。

463 collateral   

adj.平行的；旁系的；n.担保品

参考例句：

• Many people use personal assets as collateral for small business loans.很多人把个人财产用作小额商业贷款的抵押品。
• Most people here cannot borrow from banks because they lack collateral.由于拿不出东西作为抵押，这里大部分人无法从银行贷款。

464 undone   

a.未做完的，未完成的

参考例句：

• He left nothing undone that needed attention.所有需要注意的事他都注意到了。

465 celebrity   

n.名人，名流；著名，名声，名望

参考例句：

• Tom found himself something of a celebrity. 汤姆意识到自己已小有名气了。
• He haunted famous men, hoping to get celebrity for himself. 他常和名人在一起, 希望借此使自己获得名气。

466 judgments   

判断( judgment的名词复数 )； 鉴定； 评价； 审判

参考例句：

• A peculiar austerity marked his judgments of modern life. 他对现代生活的批评带着一种特殊的苛刻。
• He is swift with his judgments. 他判断迅速。

467 irreconcilable   

adj.（指人）难和解的，势不两立的

参考例句：

• These practices are irreconcilable with the law of the Church.这种做法与教规是相悖的。
• These old concepts are irreconcilable with modern life.这些陈旧的观念与现代生活格格不入。

468 arrogant   

adj.傲慢的，自大的

参考例句：

• You've got to get rid of your arrogant ways.你这骄傲劲儿得好好改改。
• People are waking up that he is arrogant.人们开始认识到他很傲慢。

469 appease   

v.安抚，缓和，平息，满足

参考例句：

• He tried to appease the crying child by giving him candy.他试图给那个啼哭的孩子糖果使他不哭。
• The government tried to appease discontented workers.政府试图安抚不满的工人们。

470 incapable   

adj.无能力的，不能做某事的

参考例句：

• He would be incapable of committing such a cruel deed.他不会做出这么残忍的事。
• Computers are incapable of creative thought.计算机不会创造性地思维。

471 incompatible   

adj.不相容的，不协调的，不相配的

参考例句：

• His plan is incompatible with my intent.他的计划与我的意图不相符。
• Speed and safety are not necessarily incompatible.速度和安全未必不相容。

472 surmise   

v./n.猜想，推测

参考例句：

• It turned out that my surmise was correct.结果表明我的推测没有错。
• I surmise that he will take the job.我推测他会接受这份工作。

473 starry   

adj.星光照耀的, 闪亮的

参考例句：

• He looked at the starry heavens.他瞧着布满星星的天空。
• I like the starry winter sky.我喜欢这满天星斗的冬夜。

474 conceal   

v.隐藏，隐瞒，隐蔽

参考例句：

• He had to conceal his identity to escape the police.为了躲避警方，他只好隐瞒身份。
• He could hardly conceal his joy at his departure.他几乎掩饰不住临行时的喜悦。

475 conceals   

v.隐藏，隐瞒，遮住( conceal的第三人称单数 )

参考例句：

• He conceals his worries behind a mask of nonchalance. 他装作若无其事，借以掩饰内心的不安。 来自《简明英汉词典》
• Drunkenness reveals what soberness conceals. 酒醉吐真言。 来自《简明英汉词典》

476 situated   

adj.坐落在...的，处于某种境地的

参考例句：

• The village is situated at the margin of a forest.村子位于森林的边缘。
• She is awkwardly situated.她的处境困难。

477 axis   

n.轴，轴线，中心线；坐标轴，基准线

参考例句：

• The earth's axis is the line between the North and South Poles.地轴是南北极之间的线。
• The axis of a circle is its diameter.圆的轴线是其直径。

478 treatises   

n.专题著作，专题论文，专著( treatise的名词复数 )

参考例句：

• Many treatises in different languages have been published on pigeons. 关于鸽类的著作，用各种文字写的很多。 来自辞典例句
• Many other treatises incorporated the new rigor. 许多其它的专题论文体现了新的严密性。 来自辞典例句

479 memoir   

n.[pl.]回忆录，自传；记事录

参考例句：

• He has just published a memoir in honour of his captain.他刚刚出了一本传记来纪念他的队长。
• In her memoir,the actress wrote about the bittersweet memories of her first love.在那个女演员的自传中，她写到了自己苦乐掺半的初恋。

480 contention   

n.争论，争辩，论战；论点，主张

参考例句：

• The pay increase is the key point of contention. 加薪是争论的焦点。
• The real bone of contention,as you know,is money.你知道，争论的真正焦点是钱的问题。

481 concisely   

adv.简明地

参考例句：

• These equations are written more concisely as a single columnmatrix equation. 这些方程以单列矩阵方程表示会更简单。 来自辞典例句
• The fiber morphology can be concisely summarized. 可以对棉纤维的形态结构进行扼要地归纳。 来自辞典例句

482 incompatibility   

n.不兼容

参考例句：

• One cause may be an Rh incompatibility causing kernicterus in the newborn. 一个原因可能是Rh因子不相配引起新生儿的脑核性黄疸。
• Sexual incompatibility is wide-spread in the apple. 性的不亲合性在苹果中很普遍。

483 intersection   

n.交集，十字路口，交叉点；[计算机] 交集

参考例句：

• There is a stop sign at an intersection.在交叉路口处有停车标志。
• Bridges are used to avoid the intersection of a railway and a highway.桥用来避免铁路和公路直接交叉。

484 valid   

adj.有确实根据的；有效的；正当的，合法的

参考例句：

• His claim to own the house is valid.他主张对此屋的所有权有效。
• Do you have valid reasons for your absence?你的缺席有正当理由吗？

485 partisans   

游击队员( partisan的名词复数 )； 党人； 党羽； 帮伙

参考例句：

• Every movement has its partisans. 每一运动都有热情的支持者。
• He was rescued by some Italian partisans. 他被几名意大利游击队员所救。

486 alleged   

a.被指控的，嫌疑的

参考例句：

• It was alleged that he had taken bribes while in office. 他被指称在任时收受贿赂。
• alleged irregularities in the election campaign 被指称竞选运动中的不正当行为

487 predecessor   

n.前辈，前任

参考例句：

• It will share the fate of its predecessor.它将遭受与前者同样的命运。
• The new ambassador is more mature than his predecessor.新大使比他的前任更成熟一些。

488 formulates   

v.构想出( formulate的第三人称单数 )；规划；确切地阐述；用公式表示

参考例句：

• Article Eleven SEPA formulates the overall plans of the training. 第十一条环保总局统筹规划培训工作。 来自互联网
• This paper carries on the experimental analysis and formulates some anti-disturbance measures. 文章对电磁干扰进行了实验分析，并有针对性地制定一些抗干扰措施。 来自互联网

489 alluded   

提及，暗指( allude的过去式和过去分词 )

参考例句：

• In your remarks you alluded to a certain sinister design. 在你的谈话中，你提到了某个阴谋。
• She also alluded to her rival's past marital troubles. 她还影射了对手过去的婚姻问题。

490 ellipses   

n.椭园，省略号；椭圆( ellipse的名词复数 )；（语法结构上的）省略( ellipsis的名词复数 )

参考例句：

• The planets move around the sun in ellipses. 各行星围绕太阳按椭圆形运转。 来自《简明英汉词典》
• Summations are almost invariably indicated ellipses instead of the more prevalent sigma notation. 在表示“连加”的式子中，几乎一成不变地使用省略号来代替更为流行的“∑”符号。 来自辞典例句

491 slanting   

倾斜的，歪斜的

参考例句：

• The rain is driving [slanting] in from the south. 南边潲雨。
• The line is slanting to the left. 这根线向左斜了。

492 indented   

adj.锯齿状的，高低不平的；缩进排版

参考例句：

• His voyage was down Chile's indented coastline.他的航行沿智利参差曲折的海岸线行进。
• Each paragraph of the body is usually indented five blocks.正文每段开始，一般缩进五个英文字母。

493 vacillation   

n.动摇；忧柔寡断

参考例句：

• Vacillation is the cause of his failure.优柔寡断是他失败的原因。
• His constant vacillation made him an unfit administrator.他经常优柔寡断，这使他不适合当行政官员。

494 relaxation   

n.松弛，放松；休息；消遣；娱乐

参考例句：

• The minister has consistently opposed any relaxation in the law.部长一向反对法律上的任何放宽。
• She listens to classical music for relaxation.她听古典音乐放松。

495 deception   

n.欺骗，欺诈；骗局，诡计

参考例句：

• He admitted conspiring to obtain property by deception.他承认曾与人合谋骗取财产。
• He was jailed for two years for fraud and deception.他因为诈骗和欺诈入狱服刑两年。

496 fictitious   

adj.虚构的，假设的；空头的

参考例句：

• She invented a fictitious boyfriend to put him off.她虚构出一个男朋友来拒绝他。
• The story my mother told me when I was young is fictitious.小时候妈妈对我讲的那个故事是虚构的。

497 banish   

vt.放逐，驱逐；消除，排除

参考例句：

• The doctor advised her to banish fear and anxiety.医生劝她消除恐惧和忧虑。
• He tried to banish gloom from his thought.他试图驱除心中的忧愁。

498 plausible   

adj.似真实的，似乎有理的，似乎可信的

参考例句：

• His story sounded plausible.他说的那番话似乎是真实的。
• Her story sounded perfectly plausible.她的说辞听起来言之有理。

499 vindicate   

v.为…辩护或辩解，辩明；证明…正确

参考例句：

• He tried hard to vindicate his honor.他拼命维护自己的名誉。
• How can you vindicate your behavior to the teacher?你怎样才能向老师证明你的行为是对的呢？

500 enigma   

n.谜，谜一样的人或事

参考例句：

• I've known him for many years,but he remains something of an enigma to me.我与他相识多年，他仍然难以捉摸。
• Even after all the testimonies,the murder remained a enigma.即使听完了所有的证词，这件谋杀案仍然是一个谜。

501 contented   

adj.满意的，安心的，知足的

参考例句：

• He won't be contented until he's upset everyone in the office.不把办公室里的每个人弄得心烦意乱他就不会满足。
• The people are making a good living and are contented,each in his station.人民安居乐业。

502 intrude   

vi.闯入；侵入；打扰，侵扰

参考例句：

• I do not want to intrude if you are busy.如果你忙我就不打扰你了。
• I don't want to intrude on your meeting.我不想打扰你们的会议。

503 flux   

n.流动；不断的改变

参考例句：

• The market is in a constant state of flux.市场行情在不断变化。
• In most reactors,there is a significant flux of fast neutrons.在大部分反应堆中都有一定强度的快中子流。

504 convergent   

adj.会聚的

参考例句：

• A curved-inwards wall has a convergent effect on wall spray.凹型壁面对碰壁喷雾有聚集作用。
• If a sequence is not convergent,it is divergent.如果一个序列不收敛，我们称它发散。

505 vice   

n.坏事；恶习；[pl.]台钳，老虎钳；adj.副的

参考例句：

• He guarded himself against vice.他避免染上坏习惯。
• They are sunk in the depth of vice.他们堕入了罪恶的深渊。

506 evoked   

[医]诱发的

参考例句：

• The music evoked memories of her youth. 这乐曲勾起了她对青年时代的回忆。
• Her face, though sad, still evoked a feeling of serenity. 她的脸色虽然悲伤，但仍使人感觉安详。

507 engrosses   

v.使全神贯注( engross的第三人称单数 )

参考例句：

508 literally   

adv.照字面意义，逐字地；确实

参考例句：

• He translated the passage literally.他逐字逐句地翻译这段文字。
• Sometimes she would not sit down till she was literally faint.有时候，她不走到真正要昏厥了，决不肯坐下来。

509 artifice   

n.妙计，高明的手段；狡诈，诡计

参考例句：

• The use of mirrors in a room is an artifice to make the room look larger.利用镜子装饰房间是使房间显得大一点的巧妙办法。
• He displayed a great deal of artifice in decorating his new house.他在布置新房子中表现出富有的技巧。

510 utilized   

v.利用，使用( utilize的过去式和过去分词 )

参考例句：

• In the19th century waterpower was widely utilized to generate electricity. 在19世纪人们大规模使用水力来发电。 来自《简明英汉词典》
• The empty building can be utilized for city storage. 可以利用那栋空建筑物作城市的仓库。 来自《简明英汉词典》

511 artifices   

n.灵巧( artifice的名词复数 )；诡计；巧妙办法；虚伪行为

参考例句：

• These pure verbal artifices do not change the essence of the matter. 这些纯粹是文词上的花样，并不能改变问题的实质。 来自互联网
• There are some tools which realise this kind of artifices. 一些工具实现了这些方法。 来自互联网

512 eminent   

adj.显赫的，杰出的，有名的，优良的

参考例句：

• We are expecting the arrival of an eminent scientist.我们正期待一位著名科学家的来访。
• He is an eminent citizen of China.他是一个杰出的中国公民。

513 speculation   

n.思索，沉思；猜测；投机

参考例句：

• Her mind is occupied with speculation.她的头脑忙于思考。
• There is widespread speculation that he is going to resign.人们普遍推测他要辞职。

514 acoustics   

n.声学，(复)音响效果，音响装置

参考例句：

• The acoustics of the new concert hall are excellent.这座新音乐厅的音响效果极好。
• The auditorium has comfortable seating and modern acoustics.礼堂里有舒适的座椅和现代化的音响设备。

515 recurring   

adj.往复的，再次发生的

参考例句：

• This kind of problem is recurring often. 这类问题经常发生。
• For our own country, it has been a time for recurring trial. 就我们国家而言，它经过了一个反复考验的时期。

516 smitten   

猛打，重击，打击( smite的过去分词 )

参考例句：

• From the moment they met, he was completely smitten by her. 从一见面的那一刻起，他就完全被她迷住了。
• It was easy to see why she was smitten with him. 她很容易看出为何她为他倾倒。

517 impairs   

v.损害，削弱( impair的第三人称单数 )

参考例句：

• Smoking impairs our health. 吸烟会损害我们的健康。 来自《简明英汉词典》
• Almost anything that impairs liver function can cause hepatitis. 任何有损于肝功能的因素，几乎都会引起肝炎。 来自辞典例句

518 malady   

n.病，疾病(通常做比喻)

参考例句：

• There is no specific remedy for the malady.没有医治这种病的特效药。
• They are managing to control the malady into a small range.他们设法将疾病控制在小范围之内。

519 uncommonly   

adv. 稀罕(极，非常)

参考例句：

• an uncommonly gifted child 一个天赋异禀的儿童
• My little Mary was feeling uncommonly empty. 我肚子当时正饿得厉害。

520 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》

521 conclusively   

adv.令人信服地，确凿地

参考例句：

• All this proves conclusively that she couldn't have known the truth. 这一切无可置疑地证明她不可能知道真相。 来自《简明英汉词典》
• From the facts,he was able to determine conclusively that the death was not a suicide. 根据这些事实他断定这起死亡事件并非自杀。 来自《简明英汉词典》

522 thereby   

adv.因此，从而

参考例句：

• I have never been to that city,,ereby I don't know much about it.我从未去过那座城市，因此对它不怎么熟悉。
• He became a British citizen,thereby gaining the right to vote.他成了英国公民，因而得到了投票权。

523 definitively   

adv.决定性地，最后地

参考例句：

• None of the three super-states could be definitively conquered even by the other two in combination. 三个超级国家中的任何一国都不可能被任何两国的联盟所绝对打败。 来自英汉文学
• Therefore, nothing can ever be definitively proved with a photograph. 因此，没有什么可以明确了一张照片。 来自互联网

524 vessel   

n.船舶；容器，器皿；管，导管，血管

参考例句：

• The vessel is fully loaded with cargo for Shanghai.这艘船满载货物驶往上海。
• You should put the water into a vessel.你应该把水装入容器中。

525 planks   

（厚）木板( plank的名词复数 )； 政纲条目，政策要点

参考例句：

• The house was built solidly of rough wooden planks. 这房子是用粗木板牢固地建造的。
• We sawed the log into planks. 我们把木头锯成了木板。

526 taut   

adj.拉紧的，绷紧的，紧张的

参考例句：

• The bowstring is stretched taut.弓弦绷得很紧。
• Scarlett's taut nerves almost cracked as a sudden noise sounded in the underbrush near them. 思嘉紧张的神经几乎一下绷裂了，因为她听见附近灌木丛中突然冒出的一个声音。

527 inclination   

n.倾斜；点头；弯腰；斜坡；倾度；倾向；爱好

参考例句：

• She greeted us with a slight inclination of the head.她微微点头向我们致意。
• I did not feel the slightest inclination to hurry.我没有丝毫着急的意思。

528 animated   

adj.生气勃勃的，活跃的，愉快的

参考例句：

• His observations gave rise to an animated and lively discussion.他的言论引起了一场气氛热烈而活跃的讨论。
• We had an animated discussion over current events last evening.昨天晚上我们热烈地讨论时事。

529 premises   

n.建筑物，房屋

参考例句：

• According to the rules,no alcohol can be consumed on the premises.按照规定，场内不准饮酒。
• All repairs are done on the premises and not put out.全部修缮都在家里进行，不用送到外面去做。

530 variance   

n.矛盾，不同

参考例句：

• The question of woman suffrage sets them at variance. 妇女参政的问题使他们发生争执。
• It is unnatural for brothers to be at variance. 兄弟之间不睦是不近人情的。

531 inevitably   

adv.不可避免地；必然发生地

参考例句：

• In the way you go on,you are inevitably coming apart.照你们这样下去，毫无疑问是会散伙的。
• Technological changes will inevitably lead to unemployment.技术变革必然会导致失业。

532 constrain   

vt.限制，约束；克制，抑制

参考例句：

• She tried to constrain herself from a cough in class.上课时她竭力忍住不咳嗽。
• The study will examine the factors which constrain local economic growth.这项研究将考查抑制当地经济发展的因素。

533 positively   

adv.明确地，断然，坚决地；实在，确实

参考例句：

• She was positively glowing with happiness.她满脸幸福。
• The weather was positively poisonous.这天气着实讨厌。

534 revolving   

adj.旋转的，轮转式的；循环的v.（使）旋转( revolve的现在分词 )；细想

参考例句：

• The theatre has a revolving stage. 剧院有一个旋转舞台。
• The company became a revolving-door workplace. 这家公司成了工作的中转站。

535 dispels   

v.驱散，赶跑( dispel的第三人称单数 )

参考例句：

• This landmark case dispels the absolute finality of this dreaded disease. 这个划时代的病例终于改观了这可怕疾病的绝对结局。 来自辞典例句
• Charles's experience--and that of all other researchers I have met--dispels many myths about water buffaloes. 查尔斯以及我所见到的其他研究人员的经验破除了关于水牛的许多奇谈。 来自辞典例句

536 invokes   

v.援引( invoke的第三人称单数 )；行使（权利等）；祈求救助；恳求

参考例句：

• The Roundtable statement invokes the principles of the free market system. 企业界圆桌会议的声明援用了自由市场制度的原则。 来自辞典例句
• When no more storage is available, the system invokes a garbage collector. 当没有可用的存贮时，系统就调用无用单元收集程序。 来自辞典例句

537 puncture   

n.刺孔，穿孔；v.刺穿，刺破

参考例句：

• Failure did not puncture my confidence.失败并没有挫伤我的信心。
• My bicycle had a puncture and needed patching up.我的自行车胎扎了个洞，需要修补。

538 punctures   

n.（尖物刺成的）小孔( puncture的名词复数 )；（尤指）轮胎穿孔；（尤指皮肤上被刺破的）扎孔；刺伤v.在（某物）上穿孔( puncture的第三人称单数 )；刺穿（某物）；削弱（某人的傲气、信心等）；泄某人的气

参考例句：

• My car has had two punctures this week. 这个星期我的汽车轮胎被戳破两次。 来自《简明英汉词典》
• SCULLY: Needle punctures, maybe. An animal bite. Electrocution of some kind. 针刺的，也许。动物的咬伤。某种电击。 来自互联网

539 punctured   

v.在（某物）上穿孔( puncture的过去式和过去分词 )；刺穿（某物）；削弱（某人的傲气、信心等）；泄某人的气

参考例句：

• Some glass on the road punctured my new tyre. 路上的玻璃刺破了我的新轮胎。 来自《简明英汉词典》
• A nail on the road punctured the tyre. 路上的钉子把车胎戳穿了。 来自《现代汉英综合大词典》

540 bent   

n.爱好，癖好；adj.弯的；决心的，一心的

参考例句：

• He was fully bent upon the project.他一心扑在这项计划上。
• We bent over backward to help them.我们尽了最大努力帮助他们。

541 justified   

a.正当的，有理的

参考例句：

• She felt fully justified in asking for her money back. 她认为有充分的理由要求退款。
• The prisoner has certainly justified his claims by his actions. 那个囚犯确实已用自己的行动表明他的要求是正当的。

542 batch   

n.一批(组，群)；一批生产量

参考例句：

• The first batch of cakes was burnt.第一炉蛋糕烤焦了。
• I have a batch of letters to answer.我有一批信要回复。

543 irrelevant   

adj.不恰当的，无关系的，不相干的

参考例句：

• That is completely irrelevant to the subject under discussion.这跟讨论的主题完全不相关。
• A question about arithmetic is irrelevant in a music lesson.在音乐课上，一个数学的问题是风马牛不相及的。

544 extrinsic   

adj.外部的；不紧要的

参考例句：

• Nowadays there are more extrinsic pressures to get married.现在来自外部的结婚压力多了。
• The question is extrinsic to our discussion.这个问题和我们的讨论无关。

545 insignificant   

adj.无关紧要的，可忽略的，无意义的

参考例句：

• In winter the effect was found to be insignificant.在冬季，这种作用是不明显的。
• This problem was insignificant compared to others she faced.这一问题与她面临的其他问题比较起来算不得什么。

546 motive   

n.动机，目的；adv.发动的，运动的

参考例句：

• The police could not find a motive for the murder.警察不能找到谋杀的动机。
• He had some motive in telling this fable.他讲这寓言故事是有用意的。

547 discriminating   

a.有辨别能力的

参考例句：

• Due caution should be exercised in discriminating between the two. 在区别这两者时应该相当谨慎。
• Many businesses are accused of discriminating against women. 许多企业被控有歧视妇女的做法。

548 inhibit   

vt.阻止，妨碍，抑制

参考例句：

• Don't let ego and greed inhibit clear thinking and hard work.不要让自我和贪婪妨碍清晰的思维和刻苦的工作。
• They passed a law to inhibit people from parking in the street.他们通过一项法令以阻止人们在街上停车。

549 defective   

adj.有毛病的，有问题的，有瑕疵的

参考例句：

• The firm had received bad publicity over a defective product. 该公司因为一件次品而受到媒体攻击。
• If the goods prove defective, the customer has the right to compensation. 如果货品证明有缺陷， 顾客有权索赔。

550 unstable   

adj.不稳定的，易变的

参考例句：

• This bookcase is too unstable to hold so many books.这书橱很不结实，装不了这么多书。
• The patient's condition was unstable.那患者的病情不稳定。

551 intaglio   

n.凹版雕刻；v.凹雕

参考例句：

• The picture shows the intaglio printing workshop of this company.图为该企业凹印制版车间。
• Other anti-counterfeiting features include the use of latent images,pearl ink,and intaglio printing.其他防伪特征，包括隐形图案、珍珠油墨和凹印。

552 irresistibly   

adv.无法抵抗地，不能自持地；极为诱惑人地

参考例句：

• Her gaze was drawn irresistibly to the scene outside. 她的目光禁不住被外面的风景所吸引。 来自《简明英汉词典》
• He was irresistibly attracted by her charm. 他不能自已地被她的魅力所吸引。 来自《简明英汉词典》

553 candidly   

adv.坦率地，直率而诚恳地

参考例句：

• He has stopped taking heroin now,but admits candidly that he will always be a drug addict.他眼下已经不再吸食海洛因了,不过他坦言自己永远都是个瘾君子。
• Candidly,David,I think you're being unreasonable.大卫，说实话我认为你不讲道理。

554 wholesale   

n.批发；adv.以批发方式；vt.批发，成批出售

参考例句：

• The retail dealer buys at wholesale and sells at retail.零售商批发购进货物，以零售价卖出。
• Such shoes usually wholesale for much less.这种鞋批发出售通常要便宜得多。

555 countless   

adj.无数的，多得不计其数的

参考例句：

• In the war countless innocent people lost their lives.在这场战争中无数无辜的人丧失了性命。
• I've told you countless times.我已经告诉你无数遍了。

556 obstinacy   

n.顽固；（病痛等）难治

参考例句：

• It is a very accountable obstinacy.这是一种完全可以理解的固执态度。
• Cindy's anger usually made him stand firm to the point of obstinacy.辛迪一发怒，常常使他坚持自见，并达到执拗的地步。

557 wedded   

adj.正式结婚的；渴望…的，执著于…的v.嫁，娶，（与…）结婚( wed的过去式和过去分词 )

参考例句：

• She's wedded to her job. 她专心致志于工作。
• I was invited over by the newly wedded couple for a meal. 我被那对新婚夫妇请去吃饭。 来自《简明英汉词典》

558 stereotyped   

adj.(指形象、思想、人物等)模式化的

参考例句：

• There is a sameness about all these tales. They're so stereotyped -- all about talented scholars and lovely ladies. 这些书就是一套子，左不过是些才子佳人，最没趣儿。
• He is the stereotyped monster of the horror films and the adventure books, and an obvious (though not perhaps strictly scientific) link with our ancestral past. 它们是恐怖电影和惊险小说中的老一套的怪物，并且与我们的祖先有着明显的（虽然可能没有科学的）联系。

559 transformations   

n.变化( transformation的名词复数 )；转换；转换；变换

参考例句：

• Energy transformations go on constantly, all about us. 在我们周围，能量始终在不停地转换着。 来自辞典例句
• On the average, such transformations balance out. 平均起来，这种转化可以互相抵消。 来自辞典例句

560 tilts   

（意欲赢得某物或战胜某人的）企图，尝试( tilt的名词复数 )

参考例句：

• As the kitten touches it, it tilts at the floor. 它随着击碰倾侧，头不动，眼不动，还呆呆地注视着地上。 来自汉英文学 - 散文英译
• The two writers had a number of tilts in print. 这两位作家写过一些文章互相攻击。

561 complement   

n.补足物，船上的定员；补语；vt.补充，补足

参考例句：

• The two suggestions complement each other.这两条建议相互补充。
• They oppose each other also complement each other.它们相辅相成。

562 vivacity   

n.快活，活泼，精神充沛

参考例句：

• Her charm resides in her vivacity.她的魅力存在于她的活泼。
• He was charmed by her vivacity and high spirits.她的活泼与兴高采烈的情绪把他迷住了。

563 conjure   

v.恳求，祈求；变魔术，变戏法

参考例句：

• I conjure you not to betray me.我恳求你不要背弃我。
• I can't simply conjure up the money out of thin air.我是不能像变魔术似的把钱变来。

564 conjured   

用魔术变出( conjure的过去式和过去分词 )； 祈求，恳求； 变戏法； （变魔术般地） 使…出现

参考例句：

• He conjured them with his dying breath to look after his children. 他临终时恳求他们照顾他的孩子。
• His very funny joke soon conjured my anger away. 他讲了个十分有趣的笑话，使得我的怒气顿消。

565 invincible   

adj.不可征服的，难以制服的

参考例句：

• This football team was once reputed to be invincible.这支足球队曾被誉为无敌的劲旅。
• The workers are invincible as long as they hold together.只要工人团结一致，他们就是不可战胜的。

566 condemns   

v.（通常因道义上的原因而）谴责( condemn的第三人称单数 )；宣判；宣布…不能使用；迫使…陷于不幸的境地

参考例句：

• Her widowhood condemns her to a lonely old age. 守寡使她不得不过着孤独的晚年生活。 来自《简明英汉词典》
• The public opinion condemns prostitution. 公众舆论遣责卖淫。 来自《现代汉英综合大词典》

567 grooves   

n.沟( groove的名词复数 )；槽；老一套；（某种）音乐节奏v.沟( groove的第三人称单数 )；槽；老一套；（某种）音乐节奏

参考例句：

• Wheels leave grooves in a dirt road. 车轮在泥路上留下了凹痕。 来自《简明英汉词典》
• Sliding doors move in grooves. 滑动门在槽沟中移动。 来自《现代汉英综合大词典》

568 equilibrium   

n.平衡，均衡，相称，均势，平静

参考例句：

• Change in the world around us disturbs our inner equilibrium.我们周围世界的变化扰乱了我们内心的平静。
• This is best expressed in the form of an equilibrium constant.这最好用平衡常数的形式来表示。

569 facets   

n.（宝石或首饰的）小平面( facet的名词复数 )；（事物的）面；方面

参考例句：

• The question had many facets. 这个问题是多方面的。 来自《简明英汉词典》
• A fully cut brilliant diamond has 68 facets. 经过充分切刻的光彩夺目的钻石有68个小平面。 来自《简明英汉词典》

570 sensationally   

参考例句：

• Newspapers reported the incident sensationally, making it appear worse than it really was. 报纸大肆渲染这件事，描述得更不像话。 来自辞典例句
• However Gattuso has sensationally come out against the 28-year-old's signature. 然而加图索已经公开的站出来反对签下这名28岁的球员。 来自互联网

571 innate   

adj.天生的，固有的，天赋的

参考例句：

• You obviously have an innate talent for music.你显然有天生的音乐才能。
• Correct ideas are not innate in the mind.人的正确思想不是自己头脑中固有的。

572 disposition   

n.性情，性格；意向，倾向；排列，部署

参考例句：

• He has made a good disposition of his property.他已对财产作了妥善处理。
• He has a cheerful disposition.他性情开朗。

573 ensemble   

n.合奏(唱)组；全套服装；整体，总效果

参考例句：

• We should consider the buildings as an ensemble.我们应把那些建筑物视作一个整体。
• It is ensemble music for up to about ten players,with one player to a part.它是最多十人演奏的合奏音乐，每人担任一部分。

574 stimuli   

n.刺激（物）

参考例句：

• It is necessary to curtail or alter normally coexisting stimuli.必需消除或改变正常时并存的刺激。
• My sweat glands also respond to emotional stimuli.我的汗腺对情绪刺激也能产生反应。

575 constituents   

n.选民( constituent的名词复数 )；成分；构成部分；要素

参考例句：

• She has the full support of her constituents. 她得到本区选民的全力支持。
• Hydrogen and oxygen are the constituents of water. 氢和氧是水的主要成分。 来自《简明英汉词典》

576 reverberating   

回响，回荡( reverberate的现在分词 )； 使反响，使回荡，使反射

参考例句：

• The words are still ringing [reverberating] in one's ears. 言犹在耳。
• I heard a voice reverberating: "Crawl out! I give you liberty!" 我听到一个声音在回荡：“爬出来吧，我给你自由！”

577 deficient   

adj.不足的，不充份的，有缺陷的

参考例句：

• The crops are suffering from deficient rain.庄稼因雨量不足而遭受损害。
• I always have been deficient in selfconfidence and decision.我向来缺乏自信和果断。

578 imminent   

adj.即将发生的，临近的，逼近的

参考例句：

• The black clounds show that a storm is imminent.乌云预示暴风雨即将来临。
• The country is in imminent danger.国难当头。

579 infinity   

n.无限，无穷，大量

参考例句：

• It is impossible to count up to infinity.不可能数到无穷大。
• Theoretically,a line can extend into infinity.从理论上来说直线可以无限地延伸。

580 begets   

v.为…之生父( beget的第三人称单数 )；产生，引起

参考例句：

• It begets at least seven standard type offspring from such matings. 这类交配中生下至少七个标准型后代。 来自辞典例句
• Violence begets violence until the innocent perish with the guilty. 暴力招致暴力直到这因罪行而无缘无故的毁灭。 来自电影对白

581 artistic   

adj.艺术(家)的，美术(家)的；善于艺术创作的

参考例句：

• The picture on this screen is a good artistic work.这屏风上的画是件很好的艺术品。
• These artistic handicrafts are very popular with foreign friends.外国朋友很喜欢这些美术工艺品。

582 omissions   

n.省略( omission的名词复数 )；删节；遗漏；略去或漏掉的事（或人）

参考例句：

• In spite of careful checking, there are still omissions. 饶这么细心核对，还是有遗漏。 来自《现代汉英综合大词典》
• It has many omissions; even so, it is quite a useful reference book. 那本书有许多遗漏之处，即使如此，尚不失为一本有用的参考书。 来自《现代汉英综合大词典》

583 recapitulate   

v.节述要旨，择要说明

参考例句：

• Let's recapitulate the main ideas.让我们来概括一下要点。
• It will be helpful to recapitulate them.在这里将其简要重述一下也是有帮助的。

584 inexplicably   

adv.无法说明地，难以理解地，令人难以理解的是

参考例句：

• Inexplicably, Mary said she loved John. 真是不可思议，玛丽说她爱约翰。 来自《简明英汉词典》
• Inexplicably, she never turned up. 令人不解的是，她从未露面。 来自辞典例句

585 appreciable   

adj.明显的，可见的，可估量的，可觉察的

参考例句：

• There is no appreciable distinction between the twins.在这对孪生子之间看不出有什么明显的差别。
• We bought an appreciable piece of property.我们买下的资产有增值的潜力。

586 aggregate   

adj.总计的，集合的；n.总数；v.合计；集合

参考例句：

• The football team had a low goal aggregate last season.这支足球队上个赛季的进球总数很少。
• The money collected will aggregate a thousand dollars.进帐总额将达一千美元。

587 degradation   

n.降级；低落；退化；陵削；降解；衰变

参考例句：

• There are serious problems of land degradation in some arid zones.在一些干旱地带存在严重的土地退化问题。
• Gambling is always coupled with degradation.赌博总是与堕落相联系。

588 secondly   

adv.第二，其次

参考例句：

• Secondly,use your own head and present your point of view.第二，动脑筋提出自己的见解。
• Secondly it is necessary to define the applied load.其次，需要确定所作用的载荷。

589 disciples   

n.信徒( disciple的名词复数 )；门徒；耶稣的信徒；（尤指）耶稣十二门徒之一

参考例句：

• Judas was one of the twelve disciples of Jesus. 犹大是耶稣十二门徒之一。 来自《简明英汉词典》
• "The names of the first two disciples were --" “最初的两个门徒的名字是——” 来自英汉文学 - 汤姆历险

590 intoxicated   

喝醉的，极其兴奋的

参考例句：

• She was intoxicated with success. 她为成功所陶醉。
• They became deeply intoxicated and totally disoriented. 他们酩酊大醉，东南西北全然不辨。

591 precept   

n.戒律；格言

参考例句：

• It occurs to me that example is always more efficacious than precept.我想到身教重于言教。
• The son had well profited by the precept and example of the father.老太爷的言传身教早已使他儿子获益无穷。

592 possessed   

adj.疯狂的；拥有的，占有的

参考例句：

• He flew out of the room like a man possessed.他像着了魔似地猛然冲出房门。
• He behaved like someone possessed.他行为举止像是魔怔了。

593 postulated   

v.假定，假设( postulate的过去式和过去分词 )

参考例句：

• They postulated a 500-year lifespan for a plastic container. 他们假定塑料容器的寿命为500年。
• Freud postulated that we all have a death instinct as well as a life instinct. 弗洛伊德曾假定我们所有人都有生存本能和死亡本能。 来自辞典例句

594 deriving   

v.得到( derive的现在分词 )；（从…中）得到获得；源于；（从…中）提取

参考例句：

• I anticipate deriving much instruction from the lecture. 我期望从这演讲中获得很多教益。 来自《简明英汉词典》
• He anticipated his deriving much instruction from the lecture. 他期望从这次演讲中得到很多教益。 来自辞典例句

595 espoused   

v.（决定）支持，拥护（目标、主张等）( espouse的过去式和过去分词 )

参考例句：

• They espoused the notion of equal opportunity for all in education. 他们赞同在教育方面人人机会均等的观念。
• The ideas she espoused were incomprehensible to me. 她所支持的意见令我难以理解。 来自《简明英汉词典》

596 tenor   

n.男高音（歌手），次中音（乐器），要旨，大意

参考例句：

• The tenor of his speech was that war would come.他讲话的大意是战争将要发生。
• The four parts in singing are soprano,alto,tenor and bass.唱歌的四个声部是女高音、女低音、男高音和男低音。

597 abhor   

v.憎恶；痛恨

参考例句：

• They abhor all forms of racial discrimination.他们憎恶任何形式的种族歧视。
• They abhor all the nations who have different ideology and regime.他们仇视所有意识形态和制度与他们不同的国家。

598 goads   

n.赶牲口的尖棒( goad的名词复数 )v.刺激( goad的第三人称单数 )；激励；（用尖棒）驱赶；驱使（或怂恿、刺激）某人

参考例句：

• They are motivated by the twin goads of punishment and reward. 他们受赏与罚的双重因素所激励。 来自互联网

599 slumbering   

微睡，睡眠（slumber的现在分词形式）

参考例句：

• It was quiet. All the other inhabitants of the slums were slumbering. 贫民窟里的人已经睡眠静了。
• Then soft music filled the air and soothed the slumbering heroes. 接着，空中响起了柔和的乐声，抚慰着安睡的英雄。

600 psychical   

adj.有关特异功能现象的；有关特异功能官能的；灵魂的；心灵的

参考例句：

• Conclusion: The Liuhe-lottery does harm to people, s psychical health and should be for bidden. 结论：“六合彩”赌博有害人们心理卫生，应予以严禁。 来自互联网

601 dismal   

adj.阴沉的，凄凉的，令人忧郁的，差劲的

参考例句：

• That is a rather dismal melody.那是一支相当忧郁的歌曲。
• My prospects of returning to a suitable job are dismal.我重新找到一个合适的工作岗位的希望很渺茫。

602 dilemma   

n.困境，进退两难的局面

参考例句：

• I am on the horns of a dilemma about the matter.这件事使我进退两难。
• He was thrown into a dilemma.他陷入困境。

603 inveighs   

v.猛烈抨击，痛骂，谩骂( inveigh的第三人称单数 )

参考例句：

604 vociferously   

adv.喊叫地，吵闹地

参考例句：

• They are arguing vociferously over who should pay the bill. 他们为谁该付账单大声争吵。 来自《简明英汉词典》
• Annixter had cursed him so vociferously and tersely that even Osterman was cowed. 安尼克斯特骂了他的声音之大，语气之凶，连奥斯特曼也不禁吓了一跳。 来自辞典例句

605 thoroughly   

adv.完全地，彻底地，十足地

参考例句：

• The soil must be thoroughly turned over before planting.一定要先把土地深翻一遍再下种。
• The soldiers have been thoroughly instructed in the care of their weapons.士兵们都系统地接受过保护武器的训练。

606 mythological   

adj.神话的

参考例句：

• He is remembered for his historical and mythological works. 他以其带有历史感和神话色彩的作品而著称。
• But even so, the cumulative process had for most Americans a deep, almost mythological significance. 不过即使如此，移民渐增的过程，对于大部分美国人，还是意味深长的，几乎有不可思议的影响。

607 vigor   

n.活力，精力，元气

参考例句：

• The choir sang the words out with great vigor.合唱团以极大的热情唱出了歌词。
• She didn't want to be reminded of her beauty or her former vigor.现在，她不愿人们提起她昔日的美丽和以前的精力充沛。

608 Forsaken   

adj. 被遗忘的, 被抛弃的 动词forsake的过去分词

参考例句：

• He was forsaken by his friends. 他被朋友们背弃了。
• He has forsaken his wife and children. 他遗弃了他的妻子和孩子。

609 mighty   

adj.强有力的；巨大的

参考例句：

• A mighty force was about to break loose.一股巨大的力量即将迸发而出。
• The mighty iceberg came into view.巨大的冰山出现在眼前。

610 discursively   

adv.东拉西扯地，推论地

参考例句：

• They were chattering (discursively on a variety of topics) over their needlework. 她们一边做针线活一边闲扯个不停。 来自《现代汉英综合大词典》

611 promenade   

n./v.散步

参考例句：

• People came out in smarter clothes to promenade along the front.人们穿上更加时髦漂亮的衣服，沿着海滨散步。
• We took a promenade along the canal after Sunday dinner.星期天晚饭后我们沿着运河散步。

612 apertures   

n.孔( aperture的名词复数 )；隙缝；（照相机的）光圈；孔径

参考例句：

• These apertures restrict the amount of light that can reach the detector. 这些光阑将会限制到达探测器的光线的总量。 来自互联网
• The virtual anode formation time and propagation velocity at different pressure with different apertures are investigated. 比较了在不同气压和空心阴极孔径下虚阳极的形成时间和扩展速度。 来自互联网

613 chasm   

n.深坑，断层，裂口，大分岐，利害冲突

参考例句：

• There's a chasm between rich and poor in that society.那社会中存在着贫富差距。
• A huge chasm gaped before them.他们面前有个巨大的裂痕。

614 erects   

v.使直立，竖起( erect的第三人称单数 )；建立

参考例句：

• You're at present on a different footing-property erects a kind of barrier. 你现在的地位不同了--财产已在你周围建立起一道屏障。 来自互联网
• When oneself small JJ erects, not be too hard, how to do? 自己的小JJ勃起时不是太硬，怎么办？ 来自互联网

615 cohesion   

n.团结，凝结力

参考例句：

• I had to bring some cohesion into the company.我得使整个公司恢复凝聚力。
• The power of culture is deeply rooted in the vitality,creativity and cohesion of a nation. 文化的力量，深深熔铸在民族的生命力、创造力和凝聚力之中。

616 friction   

n.摩擦，摩擦力

参考例句：

• When Joan returned to work,the friction between them increased.琼回来工作后，他们之间的摩擦加剧了。
• Friction acts on moving bodies and brings them to a stop.摩擦力作用于运动着的物体，并使其停止。

617 cylindrical   

adj.圆筒形的

参考例句：

• huge cylindrical gas tanks 巨大的圆柱形贮气罐
• Beer cans are cylindrical. 啤酒罐子是圆筒形的。

618 disparage   

v.贬抑，轻蔑

参考例句：

• Your behaviour will disparage the whole family.你的行为将使全家丢脸。
• Never disparage yourself or minimize your strength or power.不要贬低你自己或降低你的力量或能力。

619 abridgment   

n.删节，节本

参考例句：

• An abridgment of the book has been published for young readers.他们为年轻读者出版了这本书的节本。
• This abridgment provides a concise presentation of this masterpiece of Buddhist literature.这个删节本提供了简明介绍佛教文学的杰作。

620 aggregates   

数( aggregate的名词复数 )； 总计； 骨料； 集料（可成混凝土或修路等用的）

参考例句：

• Snowflakes are loose aggregates of ice crystals. 雪花是冰晶的松散凝结。
• Our airplanes based in Europe should be included in the aggregates. 我们驻欧飞机应包括在总数内。

621 symbolize   

vt.作为...的象征，用符号代表

参考例句：

• Easter eggs symbolize the renewal of life.复活蛋象征新生。
• Dolphins symbolize the breath of life.海豚象征着生命的气息。

622 reconstructions   

重建( reconstruction的名词复数 )； 再现； 重建物； 复原物

参考例句：

• Multicolored reconstructions have been formed using (black and white) volume holographic plates. 利用黑白体积全息片已经做成了彩色重建象。
• The method gives ways to evaluate collision speed in traffic accident reconstructions. 该模型为交通事故再现推算碰撞速度提供了有效实用的方法。

623 devoted   

adj.忠诚的，忠实的，热心的，献身于...的

参考例句：

• He devoted his life to the educational cause of the motherland.他为祖国的教育事业贡献了一生。
• We devoted a lengthy and full discussion to this topic.我们对这个题目进行了长时间的充分讨论。

624 heterogeneous   

adj.庞杂的；异类的

参考例句：

• There is a heterogeneous mass of papers in the teacher's office.老师的办公室里堆满了大批不同的论文。
• America has a very heterogeneous population.美国人口是由不同种族组成的。

625 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

626 apprehends   

逮捕，拘押( apprehend的第三人称单数 )； 理解

参考例句：

• A guilty man apprehends danger in every sound. 犯了罪的人对每一个声音都感到风声鹤唳。
• The police maintain order in the city, help prevent crime, apprehends lawbreakers and directs traffic. 警察维持城市的秩序，协助防止犯罪，逮捕犯法者及指挥交通。

627 plausibly   

似真地

参考例句：

• The case was presented very plausibly. 案情的申述似很可信。
• He argued very plausibly for its acceptance. 他为使之认可辩解得头头是道。

628 unintelligibility   

不可懂度，不清晰性

参考例句：

• Thus, they argue: "'Unintelligibility' resulting from faithfulness is worse than faithlessness that makes translation 'intelligible'." 故此主张“与其忠实而使人看不懂，毋宁不很忠实而看得懂。” 来自汉英文学 - 散文英译

629 intelligibly   

adv.可理解地，明了地，清晰地

参考例句：

• The foreigner spoke to us quite intelligibly. 这个外国人对我们讲的话理解很好。 来自《简明英汉词典》
• Logically or intelligibly ordered or presented; coherent. 有逻辑或理性地排列或表现的；协调的。 来自互联网

630 avowal   

n.公开宣称，坦白承认

参考例句：

• The press carried his avowal throughout the country.全国的报纸登载了他承认的消息。
• This was not a mere empty vaunt,but a deliberate avowal of his real sentiments.这倒不是一个空洞的吹牛，而是他真实感情的供状。

631 disclaimed   

v.否认( disclaim的过去式和过去分词 )

参考例句：

• She disclaimed any knowledge of her husband's whereabouts. 她否认知道丈夫的下落。
• He disclaimed any interest in the plan. 他否认对该计划有任何兴趣。 来自《简明英汉词典》

632 impels   

v.推动、推进或敦促某人做某事( impel的第三人称单数 )

参考例句：

• The development of production impels us continuously to study technique. 生产的发展促使我们不断地钻研技术。 来自《现代汉英综合大词典》
• Instinct impels the cuckoo to migrate. 本能促使杜鹃迁徒。 来自辞典例句

633 speculative   

adj.思索性的，暝想性的，推理的

参考例句：

• Much of our information is speculative.我们的许多信息是带推测性的。
• The report is highly speculative and should be ignored.那个报道推测的成分很大，不应理会。

634 faculties   

n.能力( faculty的名词复数 )；全体教职员；技巧；院

参考例句：

• Although he's ninety, his mental faculties remain unimpaired. 他虽年届九旬，但头脑仍然清晰。
• All your faculties have come into play in your work. 在你的工作中，你的全部才能已起到了作用。 来自《简明英汉词典》

635 momentous   

adj.重要的，重大的

参考例句：

• I am deeply honoured to be invited to this momentous occasion.能应邀出席如此重要的场合，我深感荣幸。
• The momentous news was that war had begun.重大的新闻是战争已经开始。

636 professed   

公开声称的，伪称的，已立誓信教的

参考例句：

• These, at least, were their professed reasons for pulling out of the deal. 至少这些是他们自称退出这宗交易的理由。
• Her manner professed a gaiety that she did not feel. 她的神态显出一种她并未实际感受到的快乐。

637 stoutly   

adv.牢固地，粗壮的

参考例句：

• He stoutly denied his guilt.他断然否认自己有罪。
• Burgess was taxed with this and stoutly denied it.伯杰斯为此受到了责难，但是他自己坚决否认有这回事。

638 synonyms   

同义词( synonym的名词复数 )

参考例句：

• If you want to grasp English, you must carefully discriminate synonyms. 如果你想掌握好英语，你必须仔细区分同义词。
• Study the idioms and synonyms l wrote down before your test. 学考试前我给你写的习惯用语和同义字。

639 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

640 followers   

追随者( follower的名词复数 )； 用户； 契据的附面； 从动件

参考例句：

• the followers of Mahatma Gandhi 圣雄甘地的拥护者
• The reformer soon gathered a band of followers round him. 改革者很快就获得一群追随者支持他。

641 hurrah   

int.好哇，万岁，乌拉

参考例句：

• We hurrah when we see the soldiers go by.我们看到士兵经过时向他们欢呼。
• The assistants raised a formidable hurrah.助手们发出了一片震天的欢呼声。

642 adversary   

adj.敌手，对手

参考例句：

• He saw her as his main adversary within the company.他将她视为公司中主要的对手。
• They will do anything to undermine their adversary's reputation.他们会不择手段地去损害对手的名誉。

643 scholastic   

adj.学校的，学院的，学术上的

参考例句：

• There was a careful avoidance of the sensitive topic in the scholastic circles.学术界小心地避开那个敏感的话题。
• This would do harm to students' scholastic performance in the long run.这将对学生未来的学习成绩有害。

644 deduction   

n.减除，扣除，减除额；推论，推理，演绎

参考例句：

• No deduction in pay is made for absence due to illness.因病请假不扣工资。
• His deduction led him to the correct conclusion.他的推断使他得出正确的结论。

645 subtlety   

n.微妙，敏锐，精巧；微妙之处，细微的区别

参考例句：

• He has shown enormous strength,great intelligence and great subtlety.他表现出充沛的精力、极大的智慧和高度的灵活性。
• The subtlety of his remarks was unnoticed by most of his audience.大多数听众都没有觉察到他讲话的微妙之处。

646 overthrows   

n.推翻，终止，结束( overthrow的名词复数 )v.打倒，推翻( overthrow的第三人称单数 )；使终止

参考例句：

• Newly-elected French President Charles Louis Bonaparte overthrows the Second Republic. 1851年，新选出来的法国总统查尔斯·路易斯·波拿巴推翻了第二次共和。 来自互联网
• With unexpected innovative elements, the Next Step overthrows your knowledge for percussion! 意想不到的创新元素，颠覆你对打击乐的印象。 来自互联网

647 philosophical   

adj.哲学家的，哲学上的，达观的

参考例句：

• The teacher couldn't answer the philosophical problem.老师不能解答这个哲学问题。
• She is very philosophical about her bad luck.她对自己的不幸看得很开。

648 bibliography   

n.参考书目；(有关某一专题的)书目

参考例句：

• There is a useful bibliography at the end of each chapter.在每一章后附有一份有用的参考书目。
• The production of this bibliography is totally automated.这个目录的编制过程全是自动化的。