THE EARTH. 



195 



covered witli vegetables, which make it look as green as a mea- 

 dow, and beneath are seen thousands of turtles, and other sea- 

 animals feeding thereon. 



In order to extend our knowledge of the sea to greater depths, 

 recoiu-se has been had to the plummet •, which is generally made 

 of a lump of lead of about forty pounds weight, fastened to a 

 cord.- This, however, only answers in moderate depths -, for 

 when a deep sea is to be sounded, the matter of which the cord 

 is composed, being lighter than the water, floats upon it, and 

 when let down to a considerable depth, its length so increases its 

 surface, that it is often sufficient to prevent the lead from sink- 

 ing ; so that this may be the reason why some parts of the sea 

 are said to have no bottom. 



Ill general, we learn from the plummet, that the bottom of 

 the sea is tolerably even where it has been examined; and that the 

 farther from the shore, the sea is in general the deeper. Not- 

 withstanding, in the midst of a great and imfathomable ocean, 

 we often find an island raising its head, and singly braving its 

 fury. Such islands may be considered as the mountains of the 

 deep ; and, could we for a moment imagine the waters of the 

 ocean removed or dried away, we should probably fina the ine- 

 qualities of its bed resembling those that are found at land. 

 Here extensive plains, there valleys, and, in many places, moun - 

 tains of amazing height. M. Buache has actually given us a 

 map of that part of its bottom, which lies between Africa and 

 America, taken from the several soundings of mariners : in it 

 we find the same uneven surface that we do upon land, the same 

 eminences, and the same depressions. In such an imaginary 

 prospect, howev.'r, there would be this difference, that as the 

 tops of land-mountains appear the most barren and rocky, the 

 tups of sea-mountains would be found the most verdant and 

 fruitful. 



The plummet, which thus gives us some idea of the inequali- 

 ties of the bottom, leaves us totally in the dark as to every other 

 particular ; recourse, therefore, has been had to divers : these, 

 either behig bred up in this dangerous way of life, and accus- 

 tomed to remain sometime under water without breathing, or 

 assisted by means of a diving-bell, have been able to return some 



2 Boyle, vol- ii. n 5 

 k2 • 



