Dr. blagden on the Heat , &:c T 335 
far to the fouthward. In this fituation, the greateff heat of the 
water which I ohferved was fuch as raifed the qnickfiiver ill 
Fahrenheit’s thermometer to This happened twice; 
the frff time on the ioth of April, in latitude 2 1° io 7 N. and 
longitude, by our reckoning, 52° W ; and the fecond time, 
three days afterwards, in latitude 2 2° 7' and longitude 55 0 ; but 
in general the heat of the fea near the tropic of Cancer about 
the middle of April was from 76° to 77 0 . 
The rendezvous appointed for the fleet being off Cape Fear, 
our courfe, on approaching the American coaff, became north- 
weffward. On the 23d * of April the heat of the fea was 74 0 , 
our latitude at noon 28° 7' N. Next day the heat was only 
71 0 ; we were then in latitude 29 0 12 ' ; the heat of the water, 
therefore, was now leffening very faff in proportion to the 
change of latitude. The 25th our latitude was 3C f ; but 
though we had thus gone almoft 2® farther to the northward, 
the heat of the fea was this day rather mcreafed, it being 7 2 0 
in the morning, and 7 2°f in the evening. Next day, the 26th 
of April, at half after eight in the morning, I again plunged 
the thermometer into fea-water, and was greatly furprifed to 
fee the quickfilver rife to 78°, higher than I had ever ohferved 
it, even within the tropic. As the difference was too great to 
be imputed to any accidental variation, I immediately conceived 
that we muff have come into the Gulf-ftream, the water of 
which ftill retained great part of the heat that it had acquired 
in the torrid zone. This idea was confirmed by the fubfequent 
regular and quick diminution of the heat ; the ffiip’s run 
for a quarter of an hour had leffened it 2 0 } the thermometer, 
* From the difference between civil and nautical time, it becomes neceffary to 
obferve, that the former is always meant in this paper. 
Y y % at 
