56 



of the Northern Atlantic Ocean, which I have 

 published, by tracing in it with particular care the 

 direction of this retrograde current, that like a 

 river, the bed of which is gradually enlarged, 

 traverses the vast extent of the sea. I flatter my- 

 self that the navigators, who have studied the 

 charts of Jonathan Williams, of Governor Pow- 

 nall, of Heather, and of Strickland % will find 

 several objects in mine worthy of their attention. 

 Independent of the observations I have made 

 during six voyages, namely, from Spain to Cuma- 

 na, from Cumana to the Havannah, from the Isle 

 of Cuba to Carthagena in America, from Vera 

 Cruz to the Havannah, from this port to Phila- 

 delphia, and from Philadelphia to the coasts of 

 France, I have collected in this map all that my 

 laborious and active exertions could discover in 

 the journals of such authors^ as have been able 

 to make use of astronomical means to determine 

 the effect of the currents. I have indicated also 

 the latitudes, in which the motion of the waters 

 is not constantly perceived ; for in the same man- 

 ner as the northern limit of the current of the tro- 



dip of the magnetic needle, the lines without variation > the in- 

 tensity of the magnetic forces, the stripes of floating seaweeds, 

 and other phenomena which interest physical geography. 



N.B. This chart, not yet engraved, will be published in 

 the succeeding volumes. 



* Amer. Trans, vol. ii, p. 328 j vol. iii, p. 82 and 194 ; 

 vol. v, p. 90; and an interesting essay on the currents, by 

 Mr. Delametherie. Journ. de Phys. 1808, t. 67, p. 91. 



