l68 STUDIES OF NATURE. 



th,e map, whether the rivers which water any 

 country are flow or rapid, and whether that coun- 

 try is flat or elevated, by the angle which the conr 

 fluent rivers form with their courfes. 



Thus, moft of thofe which throw themfelves 

 into the Rhone, form right angles with that rapid 

 river, to check its impetuofity. Some of thefe con- 

 fluent rivers are real dikes, which crofs the main 

 river from fide to fide, in fueh a manner, that the 

 river crofled, which was running very rapidly 

 ^bove the confluence, flows very gently below it. 

 This obfervation applies to many of the rivers of 

 America, and remarkably to the Mechafllpi. From 

 thefe fimple perceptions, which I have, at prefent, 

 only time to indicate, it may be concluded, that it* 

 is eafy to retard, or accelerate the eourfe of a river, 

 by fimply changing the angle of incidence of it's 

 confluent rivers. I produce this not as a matter of 

 advice, but as a very curious fpeculation ; for it is 

 always dangerous for Man to derange the plans of 

 Nature. 



The rivers, on throwing themfelves into the 

 Sea, produce, in their turn, by the direction of 

 their mouths, acceleration, or retardation, in the 

 ÇGVirfe ©f the tides. But I muft not launch farther 

 out into the fludy of thefe grand and fublime har-r 

 monies, J fatisfy myfelf with having faid enough 



to 



