CHAP. VIII.] THK QULF-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. 

 Plowing 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, tw^o 

 thousand two hundred feet deep, with an average 

 velocity of four miles an hour, and a temperature of 

 86° Eahr. (30° 0)." ^ The hot water pours from the 

 strait with a decided though slight north-easterly 

 impulse on account of its great initial velocity. Mr. 

 CroU 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 133,816,320,000,000 cubic feet per day. This 

 mass of water has a mean temperature of 18° 0. 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 0. 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 'Enoyclopsedia Britannica.' By 

 Sir Jolin F. W. Herschel, Bart., K.H.P. Edinburgh, 1861, p. 49. 



^ On Ocean Currents. By James Croll, of the Geological Survey of 

 Scotland. Part I. Ocean Currents in relation to the Distribution of 

 Heat over the Globe (Philosophical Magazine. February 1870.) 



