CHAP. VIII. ] THE GULF-STREAM. 381 
with it of the waters of the river Amazon, it rises to 
one hundred miles (6:5 feet in a second), but it soon 
falls off again when it gets into the Caribbean sea. 
Flowing slowly through the whole length of this sea, 
it reaches the Gulf of Mexico through the Strait of 
Yucatan, when a part of it sweeps immediately round 
Cuba; but the main stream ‘‘ having made the circuit 
of the Gulf of Mexico, passes through the Strait of 
Florida; thence it issues as the ‘Gulf-stream’ in a 
majestic current upwards of thirty miles broad, two 
thousand two hundred feet deep, with an average 
velocity of four miles an hour, and a temperature of 
86° Fahr. (30° C.).”1 The hot water pours from the 
strait with a decided though slight north-easterly 
impulse on account of its great initial velocity. Mr. 
Croll calculates the Gulf-stream as equal to a stream 
of water fifty miles broad and a thousand feet deep 
flowing at a rate of four miles an hour; consequently 
conveying 5,575,680,000,000 cubic feet of water per 
hour, or 183,816,320,000,000 cubic feet per day. This 
mass of water has a mean temperature of 18° C. as it 
passes out of the gulf, and on its northern journey it 
is cooled down to 4°°5, thus losing heat to the amount 
of 13°°5 C. The total quantity of heat therefore trans- 
ferred from the equatorial regions per day amounts 
to something like 154,959,300,000,000,000,000 foot- 
pounds.” , 
This is nearly equal to the whole of the heat 
1 Physical Geography. From the ‘Encyclopedia Britannica.’ By 
Sir John F. W. Herschel, Bart., K.H.P. Edinburgh, 1861, p. 49. 
2 On Ocean Currents. By James Croll, of the Geological Survey o 
Scotland. Part I. Ocean Currents in relation to the Distribution of 
Heat over the Globe. (Philosophical Magazine. February 1870.) 
