the Water in the Gulf fir earn. 337 
we hove-to in order to found, and, finding bottom, we went 
very flowly ail night, and till noon the next day. 
From thefe obfervations, I think, it may be concluded, 
that the Gulf-flream, about the 33d degree of north latitude, 
and the 76th degree of longitude weft of Greenwich, is, in 
the month of April, at leaft-fix degrees hotter . than, the water 
of the fea through which it runs. As the heat of, the, fea- 
water evidently began to increafe in the evening of the 25 th, 
and as the obfervations fhew that we were getting out , of the 
current when I firft tried the heat in the morning of the 26th, 
it is moft probable, that the fhip’s run during the night is 
nearly the breadth of the ftream meafured obliquely: acrofs ; 
that, as it blew a frefh 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 efti mated 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 dels 
than this, excluding the rocks and fand-banks which furround; the 
Bahamalflands, and the fhalkw water that extends to a confi- 
derable diftance from the Coaft of Florida ; and the correlpon- 
dence of thefe meafures is very remarkable, fince 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 i flues. 
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 Spanifli-town and Kingfton in 
Jamaica feems not to exceed 8T*; that of St. Domingo on 
* Hiftory of Jamaica, . London, 1774, yol. . III. p, 6^2, 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 moft correct. 
the 
