萬物簡史 第88期:敲石頭的人們(20)

One of the better early attempts at dating theplanet came from the ever-reliable Edmond Halley,who in 1715 suggested that if you divided the totalamount of salt in the world's seas by the amountadded each year, you would get the number of yearsthat the oceans had been in existence, which wouldgive you a rough idea of Earth's age. The logic wasappealing, but unfortunately no one knew howmuch salt was in the sea or by how much it increasedeach year, which rendered the experimentimpracticable.

在確定這顆行星的年齡的問題上，早期有個比較合理的看法。它是由始終可靠的埃德蒙·哈雷提出來的。1715年，他提出，要是你把全世界海洋里的鹽的總量，除以每年增加的量，你就會得出海洋存在的年數(shù)，從而可以大致知道地球的年齡。這個道理很吸引人，但不幸的是，誰也不知道海洋里究竟有多少鹽，也不知道每年到底增加多少，這就使得這項(xiàng)實(shí)驗(yàn)無法付諸實(shí)施。

The first attempt at measurement that could be called remotely scientific was made by theFrenchman Georges-Louis Leclerc, Comte de Buffon, in the 1770s. It had long been known thatthe Earth radiated appreciable amounts of heat—that was apparent to anyone who wentdown a coal mine—but there wasn't any way of estimating the rate of dissipation.

第一次稱得上比較符合科學(xué)的嘗試是由法國的布豐伯爵喬治-路易·勒克萊爾進(jìn)行的，那是在18世紀(jì)70年代。很長時間以來，大家都知道，地球釋放出相當(dāng)可觀的熱量——下過煤礦的人都清楚——但是，沒有辦法來估計(jì)散逸率。

Buffon's experiment consisted of heating spheres until they glowed white hot and thenestimating the rate of heat loss by touching them (presumably very lightly at first) as theycooled. From this he guessed the Earth's age to be somewhere between 75,000 and 168,000years old. This was of course a wild underestimate, but a radical notion nonetheless, andBuffon found himself threatened with excommunication for expressing it. A practical man, heapologized at once for his thoughtless heresy, then cheerfully repeated the assertionsthroughout his subsequent writings.

布豐在實(shí)驗(yàn)過程中先把球體加熱到白熾的程度，然后在其冷卻的過程中用觸摸的辦法(可能開頭是輕輕的)來估計(jì)熱的損耗率。根據(jù)這項(xiàng)實(shí)驗(yàn)，他推測地球的年齡在75000——168000年之間。這當(dāng)然是大大地低估了;但是，這是一種很激進(jìn)的見解。布豐發(fā)現(xiàn)，要是把這見解加以發(fā)表，他有被開除教籍的危險。他是個講究實(shí)際的人，連忙為自己缺乏考慮的邪說表示歉意，然后輕松愉快地在隨后的著作中不斷重復(fù)他的看法。