万物简史 第66期:事物的测定(14)(在线收听

 Bouguer and La Condamine thus had spent nearly a decade working toward a result they didn't wish to find only to learn now that they weren't even the first to find it. Listlessly, they completed their survey, which confirmed that the first French team was correct. Then, still not speaking, they returned to the coast and took separate ships home.

因此,布格和孔达米纳花了将近10年时间,得出了一个他们不希望得出的结果,而且发现这个结果还不是他们第一个得出的。他们没精打采地结束了测量工作,只是证明第一个法国小组是正确的。然后,他们依然默不作声地回到海边,分别乘船踏上了归途。 Something else conjectured by Newton in the Principia was that a plumb bob hung near a mountain would incline very slightly toward the mountain, affected by the mountain's gravitational mass as well as by the Earth's. This was more than a curious fact. If you measured the deflection accurately and worked out the mass of the mountain, you could calculate the universal gravitational constant—that is, the basic value of gravity, known as G—and along with it the mass of the Earth.
牛顿在《原理》中作的另一个推测是:一根挂在大山附近的铅锤线,会受到大山和地球引力质量的影响,稍稍向着大山倾斜。这个推测很有意思。要是你精确测量那个偏差,计算大山的质量,你可以算出万有引力的常数--即引力的基本值,叫做G--同时还可以算出地球的质量。
Bouguer and La Condamine had tried this on Peru's Mount Chimborazo, but had been defeated by both the technical difficulties and their own squabbling, and so the notion lay dormant for another thirty years until resurrected in England by Nevil Maskelyne, the astronomer royal. In Dava Sobel's popular book Longitude, Maskelyne is presented as a ninny and villain for failing to appreciate the brilliance of the clockmaker John Harrison, and this may be so, but we are indebted to him in other ways not mentioned in her book, not least for his successful scheme to weigh the Earth. Maskelyne realized that the nub of the problem lay with finding a mountain of sufficiently regular shape to judge its mass.
布格和孔达米纳在秘鲁的钦博拉索山做过这种试验,但是没有成功,一方面是因为技术难度很大,一方面是因为他们内部吵得不可开交。因此,这件事被暂时搁置下来,30年后才在英国由皇家天文学家内维尔·马斯基林重新启动。达娃·索贝尔在她的畅销书《经线》中,把马斯基林说成是个傻瓜和坏蛋,不会欣赏钟匠约翰·哈里森的卓越才华,这话也许没错儿。但是,我们要在她书里没有提到的其他方面感激马斯基林,尤其要感激他制定了称地球质量的成功方案。马斯基林意识到,问题的关键在于找到一座形状规则的山,能够估测它的质量。
 
  原文地址:http://www.tingroom.com/lesson/syysdw/wwwjs/350860.html