CHAPTER XXXVII. STANDARD MEASURES.

Machines are composed of parts connected together by rigid¹ and movable joints²; rigid joints are necessary because of the expense, and in most cases the impossibility, of constructing framing and other fixed³ detail in one piece.
 
All moving parts must of course be independent of fixed parts, the relation between the two being maintained by what has been called running joints.

It is evident that when the parts of a machine are joined together, each piece which has contact on more than one side must have specific dimensions; it is farther evident that as many of the joints in a machine as are to accommodate the exigencies⁴ of construction must be without space, that is, they represent continued sections of what should be solid material, if it were possible to construct the parts in that manner. This also demands specific dimensions.

In arranging the details of machines, it is impossible to have a special standard of dimensions for each case, or even for each shop; the dimensions employed are therefore made to conform to some general standard, which by custom becomes known and familiar to workmen and to a country, or as we may now say to all countries.

A standard of lineal measures, however, cannot be taken from one country to another, or even transferred from one shop to another without the risk of variation; and it is therefore necessary that such a standard be based upon something in nature to which reference can be made in cases of doubt.

In ages past, various attempts were made to find some constant in nature on which measures could be based. Some of these attempts were ludicrous, and all of them failures, until the vibrations⁵ of a pendulum⁷ connected length and space with time. The problem was then more easy. The changes of seasons and the movement of heavenly bodies had established measures of time, so that days, hours, and minutes became constants, proved and maintained by the unerring laws of nature.

A pendulum vibrating in uniform time regardless of distance, but always as its length, if arranged to perform one vibration⁶ in a given time, gave a constant measure of length. Thus lineal measure comes from time; cubic or solid measures from lineal measure, and standards of weight from the same source; because when a certain quantity of a substance of any kind could be determined⁸ by lineal measurement, and this quantity was weighed, a standard of weight would be reached, provided there was some substance sufficiently⁹ uniform, to which reference could be made in different countries. Such a substance is sea or pure water; weighed in vacuo, or with the air at an assumed density¹⁰, water gives a result constant enough for a standard of [147] weight.

It is a strange thought that with all the order, system, and regularity¹¹, existing in nature, there is nothing but the movements of the heavenly bodies constant enough to form a base for gauging¹² tests. The French standard based upon the calculated length of the meridian¹³ may be traced to this source.

Nothing animate¹⁴ or inanimate in nature is uniform; plants, trees, animals, are all different; even the air we breathe and the temperature around us is constantly changing; only one thing is constant, that is time, and to this must we go for all our standards.

I am not aware that the derivation of our standard measures has been, in an historical way, as the foregoing remarks will indicate, nor is it the purpose here to follow such history. A reader, whose attention is directed to the subject, will find no trouble in tracing the matter from other sources. The present object is to show what a wonderful series of connections can be traced from so simple a tool as a measuring gauge¹⁵, and how abstruse¹⁶, in fact, are many apparently¹⁷ simple things, often regarded as not worth a thought beyond their practical application.

(1.) Why are machine frames constructed in sections, instead of being in one piece?—(2.) Why must parts which have contact on opposite sides have specific dimensions?—(3.) What are standards of measure based upon in England, America, and France?—(4.) How can weight be measured by time?—(5.) Has the French metre proved a standard admitting of test reference?

1 rigid   

adj.严格的，死板的；刚硬的，僵硬的

参考例句：

• She became as rigid as adamant.她变得如顽石般的固执。
• The examination was so rigid that nearly all aspirants were ruled out.考试很严，几乎所有的考生都被淘汰了。

2 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。

3 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。

4 exigencies   

n.急切需要

参考例句：

• Many people are forced by exigencies of circumstance to take some part in them. 许多人由于境况所逼又不得不在某种程度上参与这种活动。
• The people had to accept the harsh exigencies of war. 人们要承受战乱的严酷现实。

5 vibrations   

n.摆动( vibration的名词复数 )；震动；感受；（偏离平衡位置的）一次性往复振动

参考例句：

• We could feel the vibrations from the trucks passing outside. 我们可以感到外面卡车经过时的颤动。
• I am drawn to that girl; I get good vibrations from her. 我被那女孩吸引住了，她使我产生良好的感觉。 来自《简明英汉词典》

6 vibration   

n.颤动，振动；摆动

参考例句：

• There is so much vibration on a ship that one cannot write.船上的震动大得使人无法书写。
• The vibration of the window woke me up.窗子的震动把我惊醒了。

7 pendulum   

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。

8 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。

9 sufficiently   

adv.足够地，充分地

参考例句：

• It turned out he had not insured the house sufficiently.原来他没有给房屋投足保险。
• The new policy was sufficiently elastic to accommodate both views.新政策充分灵活地适用两种观点。

10 density   

n.密集，密度，浓度

参考例句：

• The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
• The region has a very high population density.该地区的人口密度很高。

11 regularity   

n.规律性，规则性；匀称，整齐

参考例句：

• The idea is to maintain the regularity of the heartbeat.问题就是要维持心跳的规律性。
• He exercised with a regularity that amazed us.他锻炼的规律程度令我们非常惊讶。

12 gauging   

n.测量[试]，测定，计量v.（用仪器）测量( gauge的现在分词 )；估计；计量；划分

参考例句：

• The method is especially attractive for gauging natural streams. 该方法对于测量天然的流注具有特殊的吸引力。 来自辞典例句
• Incommunicative as he was, some time elapsed before I had an opportunity of gauging his mind. 由于他不爱说话，我过了一些时候才有机会探测他的心灵。 来自辞典例句

13 meridian   

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。

14 animate   

v.赋于生命，鼓励；adj.有生命的，有生气的

参考例句：

• We are animate beings,living creatures.我们是有生命的存在，有生命的动物。
• The girls watched,little teasing smiles animating their faces.女孩们注视着，脸上挂着调皮的微笑，显得愈加活泼。

15 gauge   

v.精确计量；估计；n.标准度量；计量器

参考例句：

• Can you gauge what her reaction is likely to be?你能揣测她的反应可能是什么吗？
• It's difficult to gauge one's character.要判断一个人的品格是很困难的。

16 abstruse   

adj.深奥的，难解的

参考例句：

• Einstein's theory of relativity is very abstruse.爱因斯坦的相对论非常难懂。
• The professor's lectures were so abstruse that students tended to avoid them.该教授的课程太深奥了，学生们纷纷躲避他的课。

17 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。