THE EAaiH- ''^' 



CHAP. XIV. 



OF THE ORIGIN OF RIVERS. 



" The sun ariseth, and the sun goeth down, and pants for the 

 place from whence he arose. All things are filled with labour, 

 and man cannot utter it. All rivers run into the sea, yet the sea 

 is not full. Unto the place whence the rivers come, thither they 

 return again. The eye is not satisfied with seeing, nor the ear 

 with hearing.'" Thus speaks the wisest of the Jews. And at 

 60 early a period was the curiosity of man employed in observing 

 these great circulations of nature. Every eye attempted to ex- 

 plain those appearances ; and every philosopher who has long 

 thougut upon the subject, seems to give a peculiar solution. 

 The inquiry whence rivers are produced ; whence they derive 

 those unceasing stores of water, which continually enrich the 

 world with fertility and verdure ; has been variously considered, 

 and divided the opinions of mankind more than any other topic 

 in natural history. 



In this contest the various champions may be classed under 

 two leaders ; Mr De la Hire, who contends that rivers must be 

 supplied from the sea, strained through the pores of the earth ; 

 and Dr Halley, who has endeavoured to demonstrate that the 

 clouds alone are sufficient for the supply. Both sides have 

 brought in mathematics to their aid ; and have shown that long 

 and laborious calculations can at any time be made to obscuie 

 both sides of a question. 



De la Hire' begins his proofs, that rain-water, evaporated 

 from the sea, is iuLufficient for the production of rivers : by show- 

 ing that rain never penetrates the surface of the ear*;h above six- 

 teen inches. From thence he infers, that it is impossible for 

 it in many cases, to sink so as to be found at such considerable 

 depths below. Rain-water, he grants, is often seen to mix with 

 rivers, and to swell their currents ; but a much greater part of 

 ir evaporates. " In fact," continues he, " if we suppose the 

 earth eveiy where covered with water, evaporation alone would 

 be sufficient to carry off two feet nine inches of it in a year ; and 



8 Kcclesiastes, chap. i. ver. 5. 7, 8 3 Hiot. dc 1' Acad. 1713, r>. 56 



M .3 



