17．Certainly Newton considered some theoretical aspects of it in his writings, but he was reluctant to go to sea to further his work.

　　18．For most people the sea was remote, and with the exception of early intercontinental travellers or others who earned a living from the sea, there was little reason to ask many questions about it , let alone to ask what lay beneath the surface.

　　19． The first time that the question “ What is at the bottom of the oceans?” had to be answered with any commercial consequence was when the laying of a telegraph cable from Europe to America was proposed.

　　20． At the early attempts, the cable failed and when it was taken out for repairs it was found to be covered in living growths, a fact which defied contemporary scientific opinion that there was no life in the deeper parts of the sea.
 

　　译文

　　17．当然牛顿在他的作品中写到了一些理论方面的东西，但他不愿进行更加深刻的研究。

　　18．除了一些洲际旅行者和以大海为生的人，对于大多数人来说，大海是遥远的，没有什么必要提出太多问题，更别说思考大海海底的东西了。

　　19．当铺设一条从欧洲到美洲的海底电报光缆的时候，出于商业动机，人们第一次不得不回答这个问题“海底是什么东西”。

　　20．在早期的尝试中，光缆铺设失败，不得不取出来维修。这时人们发现上面覆盖有生物，这推翻了当时科学界认为深海没有生命的理论。