万物简史 第77期:事物的测定(25)

 When assembled, Michell's apparatus¹ looked like nothing so much as an eighteenth-century version of a Nautilus weight-training machine. It incorporated weights, counterweights, pendulums², shafts³, and torsion wires.

装配完毕以后，米歇尔的仪器看上去很像是一台18世纪的鹦鹉螺牌举重练习机。它由重物、砝码、摆锤、轴和扭转钢丝组成。

At the heart of the machine were two 350-pound lead balls, which were suspended beside two smaller spheres. The idea was to measure the gravitational deflection of the smaller spheres by the larger ones, which would allow the first measurement of the elusive⁴ force known as the gravitational constant, and from which the weight (strictly speaking, the mass) of the Earth could be deduced.

仪器的核心是两个635千克重的铅球，悬在两个较小球体的两侧。装配这台设备的目的是要测量两个大球给小球造成的引力偏差。这将使首次测量一种难以捉摸的力--所谓的引力常数--成为可能，并由此推测地球的重量（严格来说是质量）。

To a physicist⁵, mass and weight are two quite different things. Your mass stays the same wherever you go, but your weight varies depending on how far you are from the center of some other massive object like a planet. Travel to the Moon and you will be much lighter⁶ but no less massive. On Earth, for all practical purposes, mass and weight are the same and so the terms can be treated as synonymous. at least outside the classroom.

对于物理学家而言，质量和重量是两个截然不同的概念。无论在哪儿，物体的质量总是不变的，但是物体重量大小的变化取决于其与另一个如行星那样的巨大物体的中心距离。在月球上我们会变得很轻，但是我们的质量却不变。在地球上，为了实用起见，质量和重量数值上是相等的，因此可以用相近的办法处理，至少在教室外可以这么做。

Because gravity holds planets in orbit and makes falling objects land with a bang, we tend to think of it as a powerful force, but it is not really. It is only powerful in a kind of collective sense, when one massive object, like the Sun, holds on to another massive object, like the Earth. At an elemental level gravity is extraordinarily⁷ unrobust. Each time you pick up a book from a table or a dime⁸ from the floor you effortlessly overcome the combined gravitational exertion⁹ of an entire planet. What Cavendish was trying to do was measure gravity at this extremely featherweight level.

引力使行星保持在轨道上，使物体砰然坠落，因此很容易被认为是一种强大的力，其实不然。它只是在整体意义上强大：一个巨大的物体，比如太阳，牵住另一个巨大的物体，比如地球。在基础的层面上，引力极小。每次你从桌子上拿起一本书，或从地板上拾起一枚硬币，你毫不费劲就克服了整个行星施加的引力。卡文迪许想要做的，就是在极轻的层面上测量引力。

 

1 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。

2 pendulums   

n.摆，钟摆( pendulum的名词复数 )；摇摆不定的事态（或局面）

参考例句：

• An alternative approach using pendulums and dashpots is often used. 叠代法中往往使用单摆和冲击板。 来自辞典例句
• Good clocks have pendulums which are automatically compensated for temperature changes. 好钟的钟摆可以自动补偿温度变化。 来自互联网

3 shafts   

n.轴( shaft的名词复数 )；（箭、高尔夫球棒等的）杆；通风井；一阵（疼痛、害怕等）

参考例句：

• He deliberately jerked the shafts to rock him a bit. 他故意的上下颠动车把，摇这个老猴子几下。 来自汉英文学 - 骆驼祥子
• Shafts were sunk, with tunnels dug laterally. 竖井已经打下，并且挖有横向矿道。 来自辞典例句

4 elusive   

adj.难以表达(捉摸)的；令人困惑的；逃避的

参考例句：

• Try to catch the elusive charm of the original in translation.翻译时设法把握住原文中难以捉摸的风韵。
• Interpol have searched all the corners of the earth for the elusive hijackers.国际刑警组织已在世界各地搜查在逃的飞机劫持者。

5 physicist   

n.物理学家，研究物理学的人

参考例句：

• He is a physicist of the first rank.他是一流的物理学家。
• The successful physicist never puts on airs.这位卓有成就的物理学家从不摆架子。

6 lighter   

n.打火机，点火器；驳船；v.用驳船运送；light的比较级

参考例句：

• The portrait was touched up so as to make it lighter.这张画经过润色，色调明朗了一些。
• The lighter works off the car battery.引燃器利用汽车蓄电池打火。

7 extraordinarily   

adv.格外地；极端地

参考例句：

• She is an extraordinarily beautiful girl.她是个美丽非凡的姑娘。
• The sea was extraordinarily calm that morning.那天清晨，大海出奇地宁静。

8 dime   

n.（指美国、加拿大的钱币）一角

参考例句：

• A dime is a tenth of a dollar.一角银币是十分之一美元。
• The liberty torch is on the back of the dime.自由火炬在一角硬币的反面。

9 exertion   

n.尽力，努力

参考例句：

• We were sweating profusely from the exertion of moving the furniture.我们搬动家具大费气力，累得大汗淋漓。
• She was hot and breathless from the exertion of cycling uphill.由于用力骑车爬坡，她浑身发热。