Dr, blagden on the Heat of 
3 j J 
the fea-coaf| may be eftimated at the fame from Monf. godin’s 
obfervations * ; but as the coaft of the continent which bounds 
the gulf to the weftward and fouthward is probably warmer, 
perhaps a degree or two may be allowed for the mean tempera- 
ture of the climate over the whole bay : let it be ftated at 82° 
or 8 3 0 . Now there feems to be great probability in the fuppo- 
iition that the fea, at a certain comparatively fmall diftance be- 
low its furface, agrees in heat pretty nearly with the average 
temperature of the ah during the whole year in that part ; and 
lienee it may be conjectured, that the general heat of the 
water, as it iffues out of the bay to form the ftream, is about 
82° the fmall variations of temperature on the furface not 
being fufficient to affeft materially that of the general mafs. 
At the tropic of Cancer I found the heat to be 77 0 ; the ftream, 
therefore, in its whole courfe from the gulf of Florida, may 
be fuppofed to have been conftantly running through water 
from 4 0 to 6° colder than itfelf, and yet it had loft only 4 0 of 
* Monf. godin’s experiments upon the pendulum were made at the Petit 
Goave. They continued from the 24th of Auguft to the 4th of September, and 
the average heat during that time was fuch as is indicated by 25° of Monf. urn 
reaumur’s thermometer (fee Mem. Acad, Scienc. 1735, p, 517.)* According to 
Monf. de luc’s calculation (fee Modifications de i’Atmoipere, vol. I. p. 37 ^“) 
the 23th degree of IVlonf. de reaumur s true thermometer anfwers to about the 
g -th of Fahrenheit’s; but the average heat in Jamaica during the months of 
Auguft and September is alfo 85°; hence we may conclude, that the mean heat 
for the whole year is nearly the fame on the fea-coafts in both iflands. 
f The lovveft calculation of the mean temperature of the gulf is preferred on 
this occafton, becaufe of the Conftant influx of new water from the Atlantic' 
Ocean produced by the trade-winds ; which water not having been near any land 
muft, I think, be fenfibly cooler than that which has remained fome time inclofed 
in the bay. On this fubjeift the obfervations made by Alexander dalrymple, 
Efq- relative to the heat of the fea near the Coaft of Guinea, ought to be con- 
sulted (fee Phil. Tranf.vol. LXVI 1 I. p. 394, ,&c.). 
