kXPLÀNATION QF THE PLATES. Il 



V)erceptîble in India, becaufe of the vaft circuit which it is 

 t)bh'ged to make round the Cape of Good-Hope ; whereas 

 that of the South Pole, which commences in the month of 

 Septeihber, arrives much fooner, becaufe it has no circuit 

 to make : and, finally, that the era of thefe verfatile revo- 

 lutions commences precifely at the Equinoxes, that is, the 

 very moment when the Sun withdraws from the one Pole, 

 ton his way to warm the other» 



It is manifeft, therefore, that the half-yearly and alter- 

 hate Currents of the Indian Ocean derive their origin from 

 the half-yearly and alternate fufion of the ices of the North 

 and South Poles ; and that their direilion from Eaft to 

 XVefl, and from Weft to Eaft, is determined, in this Ocean, 

 by the very proje6lion of the Continent of Afia. 



The Atlantic Ocean has, in likemanner, two half-yearly 

 and alternate Currents, which have the fame origin, but 

 one natural diredlion from North to South, and from South 

 to North, though with fome deviation from Weft to Eafl> 

 and from Eaft to Weft, by the very projedion of the At- 

 lantic channel. Our Navigators go on the fuppofition that^ 

 in this channel, there is but one perpetual Current, which, 

 in our Hemifphere, always runs from South to North. 

 Into this miftake they have been led by the courfe of the: 

 tides, which, in fa6l, always do fet in to the North along 

 our coafts, and thofe of Bahama ; but efpecially, by our 

 Aftronomical fyftem, which afcribes all the movements of 

 the Ocean to the adlion of the Moon, between the Tropics. 



How many errors may one fingle prejudice introduce 

 into the elements of human knowledge ! It blinds even the 

 moft enlightened of Mankind, to fùch a degree, as to make 



d 7 them 



