51 



reaches the edge of the stream ; for the elevated 

 temperature of the waters ; their strong saltness, 

 indigo-blue colour, and the shoals of sea-weed 

 which cover the surface, as well as the heat of 

 the surrounding atmosphere, sensible even in 

 winter, all indicate the Gulf-stream. It's ra- 

 pidity diminishes towards the north, at the same 

 time that its breadth increases, and the waters 

 cool. Between Cayo Biscaino and the bank of 

 Bahama*, the breadth is only 15 leagues, whilst 

 in the latitude of 28 degrees and a half, it is 17, 

 and in the parallel of Charlestown, opposite 

 Cape Henlopen, from 40 to 50 leagues. The 

 rapidity of the current is from three to five miles 

 an hour, where the stream is the narrowest, and 

 is only one mile as it advances towards the 

 north. The waters of the Mexican Gulf, forcibly 

 drawn to the north-east, preserve their warm 

 temperature to such a point, that at 40 and 41 

 degrees of latitude I found them at 22*5° (18° 

 R.), when, out of the current, the heat of the 

 ocean at it's surface was scarcely 17'5° (14° R.). 

 In the parallel of New York and Oporto, the 



begins, if he obtain a good observation for the latitude. This 

 method is practised by a great number of captains of mer- 

 chant ships who cross from Europe to North America. 



* Journal of Andrew Ellicott, Commissioner of the United 

 States, for determining the boundary on the Ohio and Missisippi, 

 1803, p. 260. Hydraulic and Nautical Observations on the At- 

 lantic Ocean, by Gov. PownalL (Lond. 1787.) 



E 2 



