the Water in the Gulf -fir earn. 337 
we hove-to in order to found, and, finding bottom, we went 
very (lowly all night, and till noon the next day. 
From thefe obfervations, I think, it may be concluded, 
that the Gulf-ftream, about the 33d degree of north latitude, 
and the 76th degree of longitude weft of Greenwich, is, in 
the month of April, at lead fix degrees hotter than the water 
of the fea through which it runs. As the heat of the fea- 
o 
water evidently began to increafe in the evening of the 25th, 
and as the obfervations (hew that we were getting out of the 
current when I firft tried the heat in the morning of the 26th, 
it is 1110ft probable, that the (hip’s run during the night is 
nearly the breadth of the ftream meafured obliquely acrols ; 
that, as it blew a freftr breeze, could not be much lefs than 
twenty-five leagues in fifteen hours, the diftance of time be- 
tween the two obfervations of the heat, and hence the breadth 
of the ftream may be eftimated at twenty leagues. The breadth 
of the Gulf of Florida, which evidently bounds the ftream at 
Its origin, appears by the charts to be two or three miles lefs 
than this, excluding the rocks and fand-banks which furround the 
Bahama Iflands, and the (hallow water that extends to a conii- 
derable diftance from the Coaft of Florida ; and the correfpon- 
dence of thefe meafures is very remarkable, fmce the ftream, from 
well-known principles, of hydraulics, muft gradually become 
wider as it gets to a greater diftance from the channel by which 
it iftiies. 
If the heat of the Gulf of Mexico was known,, many cu- 
rious calculations might be formed by comparing it with that of 
the current. The mean heat of Span i(h- town, and Kingfton in 
Jamaica feems not to exceed 81 0 *; that of St. Domingo on 
* Hiftory of Jamaica, London, 1774, vol. III. p. 652,653. The different 
obfervations of the heat recorded in that work do not agree together ; but thofe 
adopted here are taken from that feries which appeared to the moil cor reft. 
the 
