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Chapter 2 The Measure of Time
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Chapter 2
The Measure of Time
1
 
So long as we do not go outside the domain1 of consciousness, the notion of time is relatively2 clear. Not only do we distinguish without difficulty present sensation from the remembrance of past sensations or the anticipation3 of future sensations, but we know perfectly4 well what we mean when we say that of two conscious phenomena5 which we remember, one was anterior6 to the other; or that, of two foreseen conscious phenomena, one will be anterior to the other.
 
When we say that two conscious facts are simultaneous, we mean that they profoundly interpenetrate, so that analysis can not separate them without mutilating them.
 
The order in which we arrange conscious phenomena does not admit of any arbitrariness. It is imposed upon us and of it we can change nothing.
 
I have only a single observation to add. For an aggregate7 of sensations to have become a remembrance capable of classification in time, it must have ceased to be actual, we must have lost the sense of its infinite complexity8, otherwise it would have remained present. It must, so to speak, have crystallized around a center of associations of ideas which will be a sort of label. It is only when they thus have lost all life that we can classify our memories in time as a botanist9 arranges dried flowers in his herbarium.
 
But these labels can only be finite in number. On that score, psychologic time should be discontinuous. Whence comes the feeling that between any two instants there are others? We arrange our recollections in time, but we know that there remain empty compartments10. How could that be, if time were not a form pre-existent in our minds? How could we know there were empty compartments, if these compartments were revealed to us only by their content?
 
2
 
But that is not all; into this form we wish to put not only the phenomena of our own consciousness, but those of which other consciousnesses are the theater. But more, we wish to put there physical facts, these I know not what with which we people space and which no consciousness sees directly. This is necessary because without it science could not exist. In a word, psychologic time is given to us and must needs create scientific and physical time. There the difficulty begins, or rather the difficulties, for there are two.
 
Think of two consciousnesses, which are like two worlds impenetrable one to the other. By what right do we strive to put them into the same mold, to measure them by the same standard? Is it not as if one strove to measure length with a gram or weight with a meter? And besides, why do we speak of measuring? We know perhaps that some fact is anterior to some other, but not by how much it is anterior.
 
Therefore two difficulties: (1) Can we transform psychologic time, which is qualitative11, into a quantitative12 time? (2) Can we reduce to one and the same measure facts which transpire13 in different worlds?
3
 
The first difficulty has long been noticed; it has been the subject of long discussions and one may say the question is settled. We have not a direct intuition of the equality of two intervals14 of time. The persons who believe they possess this intuition are dupes of an illusion. When I say, from noon to one the same time passes as from two to three, what meaning has this affirmation?
 
The least reflection shows that by itself it has none at all. It will only have that which I choose to give it, by a definition which will certainly possess a certain degree of arbitrariness. Psychologists could have done without this definition; physicists15 and astronomers16 could not; let us see how they have managed.
 
To measure time they use the pendulum18 and they suppose by definition that all the beats of this pendulum are of equal duration. But this is only a first approximation; the temperature, the resistance of the air, the barometric19 pressure, make the pace of the pendulum vary. If we could escape these sources of error, we should obtain a much closer approximation, but it would still be only an approximation. New causes, hitherto neglected, electric, magnetic or others, would introduce minute perturbations.
 
In fact, the best chronometers20 must be corrected from time to time, and the corrections are made by the aid of astronomic22 observations; arrangements are made so that the sidereal23 clock marks the same hour when the same star passes the meridian24. In other words, it is the sidereal day, that is, the duration of the rotation25 of the earth, which is the constant unit of time. It is supposed, by a new definition substituted for that based on the beats of the pendulum, that two complete rotations26 of the earth about its axis27 have the same duration.
 
However, the astronomers are still not content with this definition. Many of them think that the tides act as a check on our globe, and that the rotation of the earth is becoming slower and slower. Thus would be explained the apparent acceleration28 of the motion of the moon, which would seem to be going more rapidly than theory permits because our watch, which is the earth, is going slow.
4
 
All this is unimportant, one will say; doubtless our instruments of measurement are imperfect, but it suffices that we can conceive a perfect instrument. This ideal can not be reached, but it is enough to have conceived it and so to have put rigor29 into the definition of the unit of time.
 
The trouble is that there is no rigor in the definition. When we use the pendulum to measure time, what postulate30 do we implicitly31 admit? It is that the duration of two identical phenomena is the same; or, if you prefer, that the same causes take the same time to produce the same effects.
 
And at first blush, this is a good definition of the equality of two durations. But take care. Is it impossible that experiment may some day contradict our postulate?
 
Let me explain myself. I suppose that at a certain place in the world the phenomenon α happens, causing as consequence at the end of a certain time the effect α′. At another place in the world very far away from the first, happens the phenomenon β, which causes as consequence the effect β′. The phenomena α and β are simultaneous, as are also the effects α′ and β′.
 
Later, the phenomenon α is reproduced under approximately the same conditions as before, and simultaneously32 the phenomenon β is also reproduced at a very distant place in the world and almost under the same circumstances. The effects α′ and β′ also take place. Let us suppose that the effect α′ happens perceptibly before the effect β′.
 
If experience made us witness such a sight, our postulate would be contradicted. For experience would tell us that the first duration αα′ is equal to the first duration ββ′ and that the second duration αα′ is less than the second duration ββ′. On the other hand, our postulate would require that the two durations αα′ should be equal to each other, as likewise the two durations ββ′. The equality and the inequality deduced from experience would be incompatible33 with the two equalities deduced from the postulate.
 
Now can we affirm that the hypotheses I have just made are absurd? They are in no wise contrary to the principle of contradiction. Doubtless they could not happen without the principle of sufficient reason seeming violated. But to justify34 a definition so fundamental I should prefer some other guarantee.
5
 
But that is not all. In physical reality one cause does not produce a given effect, but a multitude of distinct causes contribute to produce it, without our having any means of discriminating35 the part of each of them.
 
Physicists seek to make this distinction; but they make it only approximately, and, however they progress, they never will make it except approximately. It is approximately true that the motion of the pendulum is due solely36 to the earth’s attraction; but in all rigor every attraction, even of Sirius, acts on the pendulum.
 
Under these conditions, it is clear that the causes which have produced a certain effect will never be reproduced except approximately. Then we should modify our postulate and our definition. Instead of saying: ‘The same causes take the same time to produce the same effects,’ we should say: ‘Causes almost identical take almost the same time to produce almost the same effects.’
 
Our definition therefore is no longer anything but approximate. Besides, as M. Calinon very justly remarks in a recent memoir:7
 
One of the circumstances of any phenomenon is the velocity37 of the earth’s rotation; if this velocity of rotation varies, it constitutes in the reproduction of this phenomenon a circumstance which no longer remains38 the same. But to suppose this velocity of rotation constant is to suppose that we know how to measure time.
 
7 Etude sur les diverses grandeurs, Paris, Gauthier-Villars, 1897.
 
Our definition is therefore not yet satisfactory; it is certainly not that which the astronomers of whom I spoke39 above implicitly adopt, when they affirm that the terrestrial rotation is slowing down.
 
What meaning according to them has this affirmation? We can only understand it by analyzing40 the proofs they give of their proposition. They say first that the friction41 of the tides producing heat must destroy vis viva. They invoke42 therefore the principle of vis viva, or of the conservation of energy.
 
They say next that the secular43 acceleration of the moon, calculated according to Newton’s law, would be less than that deduced from observations unless the correction relative to the slowing down of the terrestrial rotation were made. They invoke therefore Newton’s law. In other words, they define duration in the following way: time should be so defined that Newton’s law and that of vis viva may be verified. Newton’s law is an experimental truth; as such it is only approximate, which shows that we still have only a definition by approximation.
 
If now it be supposed that another way of measuring time is adopted, the experiments on which Newton’s law is founded would none the less have the same meaning. Only the enunciation44 of the law would be different, because it would be translated into another language; it would evidently be much less simple. So that the definition implicitly adopted by the astronomers may be summed up thus: Time should be so defined that the equations of mechanics may be as simple as possible. In other words, there is not one way of measuring time more true than another; that which is generally adopted is only more convenient. Of two watches, we have no right to say that the one goes true, the other wrong; we can only say that it is advantageous45 to conform to the indications of the first.
 
The difficulty which has just occupied us has been, as I have said, often pointed46 out; among the most recent works in which it is considered, I may mention, besides M. Calinon’s little book, the treatise47 on mechanics of Andrade.
6
 
The second difficulty has up to the present attracted much less attention; yet it is altogether analogous48 to the preceding; and even, logically, I should have spoken of it first.
 
Two psychological phenomena happen in two different consciousnesses; when I say they are simultaneous, what do I mean? When I say that a physical phenomenon, which happens outside of every consciousness, is before or after a psychological phenomenon, what do I mean?
 
In 1572, Tycho Brahe noticed in the heavens a new star. An immense conflagration49 had happened in some far distant heavenly body; but it had happened long before; at least two hundred years were necessary for the light from that star to reach our earth. This conflagration therefore happened before the discovery of America. Well, when I say that; when, considering this gigantic phenomenon, which perhaps had no witness, since the satellites of that star were perhaps uninhabited, I say this phenomenon is anterior to the formation of the visual image of the isle50 of Espa?ola in the consciousness of Christopher Columbus, what do I mean?
 
A little reflection is sufficient to understand that all these affirmations have by themselves no meaning. They can have one only as the outcome of a convention.
7
 
We should first ask ourselves how one could have had the idea of putting into the same frame so many worlds impenetrable to one another. We should like to represent to ourselves the external universe, and only by so doing could we feel that we understood it. We know we never can attain51 this representation: our weakness is too great. But at least we desire the ability to conceive an infinite intelligence for which this representation could be possible, a sort of great consciousness which should see all, and which should classify all in its time, as we classify, in our time, the little we see.
 
This hypothesis is indeed crude and incomplete, because this supreme52 intelligence would be only a demigod; infinite in one sense, it would be limited in another, since it would have only an imperfect recollection of the past; and it could have no other, since otherwise all recollections would be equally present to it and for it there would be no time. And yet when we speak of time, for all which happens outside of us, do we not unconsciously adopt this hypothesis; do we not put ourselves in the place of this imperfect god; and do not even the atheists put themselves in the place where god would be if he existed?
 
What I have just said shows us, perhaps, why we have tried to put all physical phenomena into the same frame. But that can not pass for a definition of simultaneity, since this hypothetical intelligence, even if it existed, would be for us impenetrable. It is therefore necessary to seek something else.
8
 
The ordinary definitions which are proper for psychologic time would suffice us no more. Two simultaneous psychologic facts are so closely bound together that analysis can not separate without mutilating them. Is it the same with two physical facts? Is not my present nearer my past of yesterday than the present of Sirius?
 
It has also been said that two facts should be regarded as simultaneous when the order of their succession may be inverted54 at will. It is evident that this definition would not suit two physical facts which happen far from one another, and that, in what concerns them, we no longer even understand what this reversibility would be; besides, succession itself must first be defined.
 
9
 
Let us then seek to give an account of what is understood by simultaneity or antecedence55, and for this let us analyze56 some examples.
 
I write a letter; it is afterward57 read by the friend to whom I have addressed it. There are two facts which have had for their theater two different consciousnesses. In writing this letter I have had the visual image of it, and my friend has had in his turn this same visual image in reading the letter. Though these two facts happen in impenetrable worlds, I do not hesitate to regard the first as anterior to the second, because I believe it is its cause.
 
I hear thunder, and I conclude there has been an electric discharge; I do not hesitate to consider the physical phenomenon as anterior to the auditory image perceived in my consciousness, because I believe it is its cause.
 
Behold58 then the rule we follow, and the only one we can follow: when a phenomenon appears to us as the cause of another, we regard it as anterior. It is therefore by cause that we define time; but most often, when two facts appear to us bound by a constant relation, how do we recognize which is the cause and which the effect? We assume that the anterior fact, the antecedent, is the cause of the other, of the consequent. It is then by time that we define cause. How save ourselves from this petitio principii?
 
We say now post hoc, ergo propter hoc; now propter hoc, ergo post hoc; shall we escape from this vicious circle?
10
 
Let us see, not how we succeed in escaping, for we do not completely succeed, but how we try to escape.
 
I execute a voluntary act A and I feel afterward a sensation D, which I regard as a consequence of the act A; on the other hand, for whatever reason, I infer that this consequence is not immediate59, but that outside my consciousness two facts B and C, which I have not witnessed, have happened, and in such a way that B is the effect of A, that C is the effect of B, and D of C.
 
But why? If I think I have reason to regard the four facts A, B, C, D, as bound to one another by a causal connection, why range them in the causal order A B C D, and at the same time in the chronologic order A B C D, rather than in any other order?
 
I clearly see that in the act A I have the feeling of having been active, while in undergoing the sensation D I have that of having been passive. This is why I regard A as the initial cause and D as the ultimate effect; this is why I put A at the beginning of the chain and D at the end; but why put B before C rather than C before B?
 
If this question is put, the reply ordinarily is: we know that it is B which is the cause of C because we always see B happen before C. These two phenomena, when witnessed, happen in a certain order; when analogous phenomena happen without witness, there is no reason to invert53 this order.
 
Doubtless, but take care; we never know directly the physical phenomena B and C. What we know are sensations B′ and C′ produced respectively by B and C. Our consciousness tells us immediately that B′ precedes C′ and we suppose that B and C succeed one another in the same order.
 
This rule appears in fact very natural, and yet we are often led to depart from it. We hear the sound of the thunder only some seconds after the electric discharge of the cloud. Of two flashes of lightning, the one distant, the other near, can not the first be anterior to the second, even though the sound of the second comes to us before that of the first?
11
 
Another difficulty; have we really the right to speak of the cause of a phenomenon? If all the parts of the universe are interchained in a certain measure, any one phenomenon will not be the effect of a single cause, but the resultant of causes infinitely60 numerous; it is, one often says, the consequence of the state of the universe a moment before. How enunciate61 rules applicable to circumstances so complex? And yet it is only thus that these rules can be general and rigorous.
 
Not to lose ourselves in this infinite complexity, let us make a simpler hypothesis. Consider three stars, for example, the sun, Jupiter and Saturn62; but, for greater simplicity63, regard them as reduced to material points and isolated64 from the rest of the world. The positions and the velocities65 of three bodies at a given instant suffice to determine their positions and velocities at the following instant, and consequently at any instant. Their positions at the instant t determine their positions at the instant t + h as well as their positions at the instant t ? h.
 
Even more; the position of Jupiter at the instant t, together with that of Saturn at the instant t + a, determines the position of Jupiter at any instant and that of Saturn at any instant.
 
The aggregate of positions occupied by Jupiter at the instant t + e and Saturn at the instant t + a + e is bound to the aggregate of positions occupied by Jupiter at the instant t and Saturn at the instant t + a, by laws as precise as that of Newton, though more complicated. Then why not regard one of these aggregates66 as the cause of the other, which would lead to considering as simultaneous the instant t of Jupiter and the instant t + a of Saturn?
 
In answer there can only be reasons, very strong, it is true, of convenience and simplicity.
12
 
But let us pass to examples less artificial; to understand the definition implicitly supposed by the savants, let us watch them at work and look for the rules by which they investigate simultaneity.
 
I will take two simple examples, the measurement of the velocity of light and the determination of longitude67.
 
When an astronomer17 tells me that some stellar phenomenon, which his telescope reveals to him at this moment, happened, nevertheless, fifty years ago, I seek his meaning, and to that end I shall ask him first how he knows it, that is, how he has measured the velocity of light.
 
He has begun by supposing that light has a constant velocity, and in particular that its velocity is the same in all directions. That is a postulate without which no measurement of this velocity could be attempted. This postulate could never be verified directly by experiment; it might be contradicted by it if the results of different measurements were not concordant. We should think ourselves fortunate that this contradiction has not happened and that the slight discordances which may happen can be readily explained.
 
The postulate, at all events, resembling the principle of sufficient reason, has been accepted by everybody; what I wish to emphasize is that it furnishes us with a new rule for the investigation68 of simultaneity, entirely69 different from that which we have enunciated70 above.
 
This postulate assumed, let us see how the velocity of light has been measured. You know that Roemer used eclipses of the satellites of Jupiter, and sought how much the event fell behind its prediction. But how is this prediction made? It is by the aid of astronomic laws; for instance Newton’s law.
 
Could not the observed facts be just as well explained if we attributed to the velocity of light a little different value from that adopted, and supposed Newton’s law only approximate? Only this would lead to replacing Newton’s law by another more complicated. So for the velocity of light a value is adopted, such that the astronomic laws compatible with this value may be as simple as possible. When navigators or geographers71 determine a longitude, they have to solve just the problem we are discussing; they must, without being at Paris, calculate Paris time. How do they accomplish it? They carry a chronometer21 set for Paris. The qualitative problem of simultaneity is made to depend upon the quantitative problem of the measurement of time. I need not take up the difficulties relative to this latter problem, since above I have emphasized them at length.
 
Or else they observe an astronomic phenomenon, such as an eclipse of the moon, and they suppose that this phenomenon is perceived simultaneously from all points of the earth. That is not altogether true, since the propagation of light is not instantaneous; if absolute exactitude were desired, there would be a correction to make according to a complicated rule.
 
Or else finally they use the telegraph. It is clear first that the reception of the signal at Berlin, for instance, is after the sending of this same signal from Paris. This is the rule of cause and effect analyzed72 above. But how much after? In general, the duration of the transmission is neglected and the two events are regarded as simultaneous. But, to be rigorous, a little correction would still have to be made by a complicated calculation; in practise it is not made, because it would be well within the errors of observation; its theoretic necessity is none the less from our point of view, which is that of a rigorous definition. From this discussion, I wish to emphasize two things: (1) The rules applied73 are exceedingly various. (2) It is difficult to separate the qualitative problem of simultaneity from the quantitative problem of the measurement of time; no matter whether a chronometer is used, or whether account must be taken of a velocity of transmission, as that of light, because such a velocity could not be measured without measuring a time.
13
 
To conclude: We have not a direct intuition of simultaneity, nor of the equality of two durations. If we think we have this intuition, this is an illusion. We replace it by the aid of certain rules which we apply almost always without taking count of them.
 
But what is the nature of these rules? No general rule, no rigorous rule; a multitude of little rules applicable to each particular case.
 
These rules are not imposed upon us and we might amuse ourselves in inventing others; but they could not be cast aside without greatly complicating74 the enunciation of the laws of physics, mechanics and astronomy.
 
We therefore choose these rules, not because they are true, but because they are the most convenient, and we may recapitulate75 them as follows: “The simultaneity of two events, or the order of their succession, the equality of two durations, are to be so defined that the enunciation of the natural laws may be as simple as possible. In other words, all these rules, all these definitions are only the fruit of an unconscious opportunism.”

点击收听单词发音收听单词发音  

1 domain ys8xC     
n.(活动等)领域,范围;领地,势力范围
参考例句:
  • This information should be in the public domain.这一消息应该为公众所知。
  • This question comes into the domain of philosophy.这一问题属于哲学范畴。
2 relatively bkqzS3     
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。
3 anticipation iMTyh     
n.预期,预料,期望
参考例句:
  • We waited at the station in anticipation of her arrival.我们在车站等着,期待她的到来。
  • The animals grew restless as if in anticipation of an earthquake.各种动物都变得焦躁不安,像是感到了地震即将发生。
4 perfectly 8Mzxb     
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。
5 phenomena 8N9xp     
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。
6 anterior mecyi     
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。
7 aggregate cKOyE     
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。
8 complexity KO9z3     
n.复杂(性),复杂的事物
参考例句:
  • Only now did he understand the full complexity of the problem.直到现在他才明白这一问题的全部复杂性。
  • The complexity of the road map puzzled me.错综复杂的公路图把我搞糊涂了。
9 botanist kRTyL     
n.植物学家
参考例句:
  • The botanist introduced a new species of plant to the region.那位植物学家向该地区引入了一种新植物。
  • I had never talked with a botanist before,and I found him fascinating.我从没有接触过植物学那一类的学者,我觉得他说话极有吸引力。
10 compartments 4e9d78104c402c263f5154f3360372c7     
n.间隔( compartment的名词复数 );(列车车厢的)隔间;(家具或设备等的)分隔间;隔层
参考例句:
  • Your pencil box has several compartments. 你的铅笔盒有好几个格。 来自《简明英汉词典》
  • The first-class compartments are in front. 头等车室在前头。 来自《简明英汉词典》
11 qualitative JC4yi     
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。
12 quantitative TCpyg     
adj.数量的,定量的
参考例句:
  • He said it was only a quantitative difference.他说这仅仅是数量上的差别。
  • We need to do some quantitative analysis of the drugs.我们对药物要进行定量分析。
13 transpire dqayZ     
v.(使)蒸发,(使)排出 ;泄露,公开
参考例句:
  • We do not know what may transpire when we have a new boss.当新老板来后,我们不知会有什么发生。
  • When lack of water,commonly plants would transpire as a way for cool.在缺乏水分时,植物一般用蒸发作为降温的手段。
14 intervals f46c9d8b430e8c86dea610ec56b7cbef     
n.[军事]间隔( interval的名词复数 );间隔时间;[数学]区间;(戏剧、电影或音乐会的)幕间休息
参考例句:
  • The forecast said there would be sunny intervals and showers. 预报间晴,有阵雨。
  • Meetings take place at fortnightly intervals. 每两周开一次会。
15 physicists 18316b43c980524885c1a898ed1528b1     
物理学家( physicist的名词复数 )
参考例句:
  • For many particle physicists, however, it was a year of frustration. 对于许多粒子物理学家来说,这是受挫折的一年。 来自英汉非文学 - 科技
  • Physicists seek rules or patterns to provide a framework. 物理学家寻求用法则或图式来构成一个框架。
16 astronomers 569155f16962e086bd7de77deceefcbd     
n.天文学者,天文学家( astronomer的名词复数 )
参考例句:
  • Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
  • Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪,为什么只有土星有光环。 来自《简明英汉词典》
17 astronomer DOEyh     
n.天文学家
参考例句:
  • A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
  • He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。
18 pendulum X3ezg     
n.摆,钟摆
参考例句:
  • The pendulum swung slowly to and fro.钟摆在慢慢地来回摆动。
  • He accidentally found that the desk clock did not swing its pendulum.他无意中发现座钟不摇摆了。
19 barometric 8f9aa910b267a0dd0a4a3f7ad83555f5     
大气压力
参考例句:
  • Electricity compensates for barometric pressure as well as system pressure variations. 用电补偿大气压和系统压力的变化。
  • A barometric altimeter indicates height above sea level or some other selected elevation. 气压高度表用以指示海平面或另外某个被选定高度以上的高度。
20 chronometers 8e186a56fecc328d887fd633a4861ebf     
n.精密计时器,航行表( chronometer的名词复数 )
参考例句:
  • Chronometers have been adjusted to the correct time. 天文钟已经调整到正确时间。 来自互联网
21 chronometer CVWyh     
n.精密的计时器
参考例句:
  • Murchison followed with his eye the hand of his chronometer.莫奇生的眼睛追随着他的时计的秒针。
  • My watch is more expensive because it's a chronometer.我的手表是精密型的,所以要比你的贵。
22 astronomic 4ab55ff07e93847cd0218918df5c1505     
天文学的,星学的
参考例句:
  • The environmental impact of this population increase is bound to be astronomic. 这个人口增长对环境的影响必然是天文数字。
  • Eclipse is a very intriguing astronomic phenomenon. 日食是非常引人入胜的天文现象。
23 sidereal yy0wA     
adj.恒星的
参考例句:
  • The sidereal year is not used to construct a calendar. 恒星年不用于编制年历。
  • A sidereal day is about 4 minutes shorter than a solar day.一个恒星日比一个太阳日大约短4分钟。
24 meridian f2xyT     
adj.子午线的;全盛期的
参考例句:
  • All places on the same meridian have the same longitude.在同一子午线上的地方都有相同的经度。
  • He is now at the meridian of his intellectual power.他现在正值智力全盛期。
25 rotation LXmxE     
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。
26 rotations d52e30a99086786b005c11c05b280215     
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。
27 axis sdXyz     
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。
28 acceleration ff8ya     
n.加速,加速度
参考例句:
  • All spacemen must be able to bear acceleration.所有太空人都应能承受加速度。
  • He has also called for an acceleration of political reforms.他同时呼吁加快政治改革的步伐。
29 rigor as0yi     
n.严酷,严格,严厉
参考例句:
  • Their analysis lacks rigor.他们的分析缺乏严谨性。||The crime will be treated with the full rigor of the law.这一罪行会严格依法审理。
30 postulate oiwy2     
n.假定,基本条件;vt.要求,假定
参考例句:
  • Let's postulate that she is a cook.我们假定她是一位厨师。
  • 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。
31 implicitly 7146d52069563dd0fc9ea894b05c6fef     
adv. 含蓄地, 暗中地, 毫不保留地
参考例句:
  • Many verbs and many words of other kinds are implicitly causal. 许多动词和许多其他类词都蕴涵着因果关系。
  • I can trust Mr. Somerville implicitly, I suppose? 我想,我可以毫无保留地信任萨莫维尔先生吧?
32 simultaneously 4iBz1o     
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。
33 incompatible y8oxu     
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。
34 justify j3DxR     
vt.证明…正当(或有理),为…辩护
参考例句:
  • He tried to justify his absence with lame excuses.他想用站不住脚的借口为自己的缺席辩解。
  • Can you justify your rude behavior to me?你能向我证明你的粗野行为是有道理的吗?
35 discriminating 4umz8W     
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。
36 solely FwGwe     
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。
37 velocity rLYzx     
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。
38 remains 1kMzTy     
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。
39 spoke XryyC     
n.(车轮的)辐条;轮辐;破坏某人的计划;阻挠某人的行动 v.讲,谈(speak的过去式);说;演说;从某种观点来说
参考例句:
  • They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
  • The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。
40 analyzing be408cc8d92ec310bb6260bc127c162b     
v.分析;分析( analyze的现在分词 );分解;解释;对…进行心理分析n.分析
参考例句:
  • Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据,暴露出的问题甚至更大。 来自辞典例句
  • He undoubtedly was not far off the mark in analyzing its predictions. 当然,他对其预测所作的分析倒也八九不离十。 来自辞典例句
41 friction JQMzr     
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。
42 invoke G4sxB     
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。
43 secular GZmxM     
n.牧师,凡人;adj.世俗的,现世的,不朽的
参考例句:
  • We live in an increasingly secular society.我们生活在一个日益非宗教的社会。
  • Britain is a plural society in which the secular predominates.英国是个世俗主导的多元社会。
44 enunciation wtRzjz     
n.清晰的发音;表明,宣言;口齿
参考例句:
  • He is always willing to enunciate his opinions on the subject of politics. 他总是愿意对政治问题发表意见。> enunciation / I9nQnsI5eIFn; I9nQnsI`eFEn/ n [C, U]。 来自辞典例句
  • Be good at communicating,sense of responsibility,the work is careful,the enunciation is clear. 善于沟通,责任心强,工作细致,口齿清晰。 来自互联网
45 advantageous BK5yp     
adj.有利的;有帮助的
参考例句:
  • Injections of vitamin C are obviously advantageous.注射维生素C显然是有利的。
  • You're in a very advantageous position.你处于非常有利的地位。
46 pointed Il8zB4     
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。
47 treatise rpWyx     
n.专著;(专题)论文
参考例句:
  • The doctor wrote a treatise on alcoholism.那位医生写了一篇关于酗酒问题的论文。
  • This is not a treatise on statistical theory.这不是一篇有关统计理论的论文。
48 analogous aLdyQ     
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。
49 conflagration CnZyK     
n.建筑物或森林大火
参考例句:
  • A conflagration in 1947 reduced 90 percent of the houses to ashes.1947年的一场大火,使90%的房屋化为灰烬。
  • The light of that conflagration will fade away.这熊熊烈火会渐渐熄灭。
50 isle fatze     
n.小岛,岛
参考例句:
  • He is from the Isle of Man in the Irish Sea.他来自爱尔兰海的马恩岛。
  • The boat left for the paradise isle of Bali.小船驶向天堂一般的巴厘岛。
51 attain HvYzX     
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。
52 supreme PHqzc     
adj.极度的,最重要的;至高的,最高的
参考例句:
  • It was the supreme moment in his life.那是他一生中最重要的时刻。
  • He handed up the indictment to the supreme court.他把起诉书送交最高法院。
53 invert HRuzr     
vt.使反转,使颠倒,使转化
参考例句:
  • She catch the insect by invert her cup over it.她把杯子倒扣在昆虫上,将它逮住了。
  • Invert the cake onto a cooling rack.把蛋糕倒扣在冷却架上。
54 inverted 184401f335d6b8661e04dfea47b9dcd5     
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》
55 antecedence iefyk     
n.居先,优先
参考例句:
  • Creative thinking is the antecedence of design.创新性设计,必须有创新性思维。
  • Electric power is antecedence to the development of the national economic.国家经济的发展,电力是先行。
56 analyze RwUzm     
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。
57 afterward fK6y3     
adv.后来;以后
参考例句:
  • Let's go to the theatre first and eat afterward. 让我们先去看戏,然后吃饭。
  • Afterward,the boy became a very famous artist.后来,这男孩成为一个很有名的艺术家。
58 behold jQKy9     
v.看,注视,看到
参考例句:
  • The industry of these little ants is wonderful to behold.这些小蚂蚁辛勤劳动的样子看上去真令人惊叹。
  • The sunrise at the seaside was quite a sight to behold.海滨日出真是个奇景。
59 immediate aapxh     
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。
60 infinitely 0qhz2I     
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。
61 enunciate jovxd     
v.发音;(清楚地)表达
参考例句:
  • Actors learn how to enunciate clearly in the theatrical college.演员在戏剧学院学习怎样清晰地发音。
  • He is always willing to enunciate his opinions on the subject of politics.他总是愿意对政治问题发表意见。
62 Saturn tsZy1     
n.农神,土星
参考例句:
  • Astronomers used to ask why only Saturn has rings.天文学家们过去一直感到奇怪,为什么只有土星有光环。
  • These comparisons suggested that Saturn is made of lighter materials.这些比较告诉我们,土星由较轻的物质构成。
63 simplicity Vryyv     
n.简单,简易;朴素;直率,单纯
参考例句:
  • She dressed with elegant simplicity.她穿着朴素高雅。
  • The beauty of this plan is its simplicity.简明扼要是这个计划的一大特点。
64 isolated bqmzTd     
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。
65 velocities 64d80206fdcbbf917808c5b00e0a8ff5     
n.速度( velocity的名词复数 );高速,快速
参考例句:
  • In experimenting we find out that sound travels with different velocities through different substances. 在实验中,我们发现声音以不同的速度通过不同的物质而传播。 来自《现代汉英综合大词典》
  • A gas in thermal equilibrium has particles of all velocities. 处于热平衡的气体,其粒子有一切速度。 来自辞典例句
66 aggregates 46710fe77f663864a23e02a880a9ae53     
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。
67 longitude o0ZxR     
n.经线,经度
参考例句:
  • The city is at longitude 21°east.这个城市位于东经21度。
  • He noted the latitude and longitude,then made a mark on the admiralty chart.他记下纬度和经度,然后在航海图上做了个标记。
68 investigation MRKzq     
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。
69 entirely 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。
70 enunciated 2f41d5ea8e829724adf2361074d6f0f9     
v.(清晰地)发音( enunciate的过去式和过去分词 );确切地说明
参考例句:
  • She enunciated each word slowly and carefully. 她每个字都念得又慢又仔细。
  • His voice, cold and perfectly enunciated, switched them like a birch branch. 他的话口气冰冷,一字一板,有如给了他们劈面一鞭。 来自辞典例句
71 geographers 30061fc34de34d8b0b96ee99d3c9f2ea     
地理学家( geographer的名词复数 )
参考例句:
  • Geographers study the configuration of the mountains. 地理学家研究山脉的地形轮廓。
  • Many geographers now call this landmass Eurasia. 许多地理学家现在把这块陆地叫作欧亚大陆。
72 analyzed 483f1acae53789fbee273a644fdcda80     
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》
73 applied Tz2zXA     
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。
74 complicating 53d55ae4c858e224b98a8187fa34fb04     
使复杂化( complicate的现在分词 )
参考例句:
  • High spiking fever with chills is suggestive of a complicating pylephlebitis. 伴有寒战的高热,暗示合并门静脉炎。
  • In America these actions become executive puberty rites, complicating relationships that are already complicated enough. 在美国,这些行动成了行政青春期的惯例,使本来已经够复杂的关系变得更复杂了。
75 recapitulate CU9xx     
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。


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