316 MARITIME OBSERVATIONS. 
that it is always warmer than the fea on each fide of it, 
and that it does not fparkle in the night: I annex hereto 
the obfervations made with the thermometer in two voy- 
ages, and poflibly may add a third. It will appear from 
them, that the thermometer may be an ufeful inftrument 
toa navigator, fince currents coming from the northward 
into fouthern feas, will probably be found colder than the 
water of thofe feas, as the currents from fouthern feas into 
northern are found warmer. And it is not to be wonder- 
ed that fo vaft a body of deep warm water, feveral leagues 
wide, coming from between the tropics and iffuing out of 
the gulph into the northern feas, fhould retain its warmth 
longer than the twenty or thirty days required to its paf- 
fing the banks of Newfoundland. The quantity is too 
great, and it is too deep to be fuddenly cooled by pafling 
under a cooler air. The air immediately over it, how- 
ever, may receive fo much warmth from it as to be rari- 
fied and rife, being rendered lighter than the air on each 
fide of the ftream; hence thofe airs muft flow in to fup- 
ply the place of the rifing warm air, and meeting with 
each other, form thofe tornados and water-fpouts fre- 
quently met with, and feen near and over the ftream; and 
as the vapour from a cup of tea in a warm room, and 
the breath of an animal in the fame room, are hardly vifi- 
ble, but become fenfible immediately when out in the cold 
air, fo the vapour from the gulph ftream, in warm lati- 
tudes is fcarcely vifible, but when it comes into the cool 
air from Newfoundland, it is condenfed into the fogs, for 
which thofe parts are fo remarkable. 
The power of wind to raife water above its common 
level in the fea, is known to us in America, by the high 
tides occafioned in all our fea-ports when a ftrong north- 
eafter blows againft the gulph ftream. 
The conclufion from thefe remarks is, that a veffel from 
Europe to North-America may fhorten her paflage by a- 
voiding to ftem the ftream, in which the thermometer will 
be 
jy 
