Vlll ADVERTISEMENT. 



in order to make our tides rc-afcend a very great 

 way toward the North. The fîmple aftion of the 

 general Current of the Atlantic, which defcends 

 from the North Pole and ruflhes toward the South, 

 difplacing by it's impetuofity a vaft mafs of water, 

 which it repels to the right and to the left, is fuffi- 

 cient to produce, through the whole length of it*s 

 courfe, thofe lateral re-adions which occafion our 

 tides, and make them flow to the North. 



I had quoted, on this fubjed, two obfervations, 

 the firft of which is level to every capacity. It is 

 that of a fource which, on difcharging itlelf into a 

 bafon, produces, at the fides of that bafon, a back- 

 ward motion or counter- current, which carries 

 ftraws and other floating fubflances up toward the 

 fource. 



The fécond obfervation is extraded from the 

 Tïiilory of New-France by Father Charlevoix. He 

 tells us that, though the wind was contrary, he 

 failed at the rate of eight good leagues a day up 

 lake Michigan, againft it's general Current, with 

 the afliftance of it's lateral counter- currents. 



But M. de Crevecœwy Author of the Letters of 

 an American Farmer, goes fl.ill further; for he af- 

 fures us, (^Vol. III. page 433) that in failing up the 

 Ohio, along it's banks, he made 42a miles in four- 

 teen 



