EXPLANATION OF THE PLATES. xlii^ 



proceeds to the South- Weft, along the coafts of Brafil, up 

 to Maires-Strait inchjfively. This cfFedl is the refult from 

 a law in Hydraulics, the operation of which is generally 

 known : it is this, that as often as a current pafles from a 

 wider channel into a narrower, it forms on the fides two 

 counter-currents. The truth of this may be afcertained, 

 by obferving the current of a brook, to the palfage of the 

 water of a river under the arches near the abutment of a 

 bridge, &c. Accordingly, the current bears to the Eaft, 

 along the coafts of Guinea, and to the South- Weft, along 

 the coafts of Brafil, during the Summer of the South-Pole. 

 But in the middle of the Atlantic Ocean, and beyond the 

 ftrait of the two Continents, it pufties on to the North in 

 full force, and advances to the very northern extremities 

 of Europe and of America, bringing us twice every day, 

 along our coafts, the tides of the South, which are the 

 half-daily effufions of the two fides of the South Pole. 



The other branch, which ilfiies from the South Pole, 

 takes a dire(51:ion to the weftward of Cape Horn, rufties 

 into the South Sea, produces in the Indian Ocean the 

 Eaftern monfoon, which takes place in India during our 

 Winter; and having made the tour of the Globe by the 

 Weft, comes to the Eaft, to unite itfelf by the Cape of 

 Good-Hope, to the general Current which enters into the 

 Atlantic Ocean. It is poflible, partly, to trace on the 

 Chart this general Current of the South Pole, with it's two 

 principal branches, it's counter^currents and it's tides, by 

 the arrows which indicate it's diredl, oblique, and retro- 

 grade movements. 



Six months after, that is, in our Summer, commencing 

 toward the end of March, when the Sun, at the Line, 



begins 



