30 PHYSICAL G-EOGRAPHY OF THE SEA, AXD ITS METEOHOLOGY. 



Owing to the diumal rotation, tliey are carried around with the 

 earth on its axis toivards the east mth an hourly velocity of one 

 hundred and fifty-seven* miles greater when they enter the Atlan- 

 tic than v;hen they arrive off the Banks of Newfoundland ; for in 

 consequence of the difference of latitude between the parallels of 

 these two places, then' rate of motion around the axis of the earth 

 is reduced fi^om nine hundred and fifteen! to seven hundred and 

 fifty-eight miles the hour. Hence this immense volume of water 

 would, if we suppose it to pass from the Bahamas to the Grand 

 Banks ifi an horn', meet with an opposing force in the shape of 

 resistance sufficient, in the aggregate, to retard it two miles and a 

 half the minute in its eastwardiy rate. If the actual resistance be 

 calculated according to received laws, it will be found equal to 

 several atmospheres. And by analogy, how inadequate must the 

 pressure of the gentle trade- winds be to such resistance, and to the 

 effect assigned them ! 



92. If therefore, in the proposed inquiry, we search for a pro- 

 Thc G uif stream can- pelling powcr nowlicre but in the higher level of the 

 byabigheTievei.*^^ Grulf, or in the "billiard-ball" rebound from its 

 shores, we must ad.mit, in the head of water there, the existence 

 of a force capable of putting in motion, and of driving over a 

 l^lain at the rate of four miles the hour, aU the waters, as fast as 

 they can be brought down by three thousand (§ 75) such streams 

 as the Mississippi Eiver — a power, at least sufficient to overcome 

 the resistance requu"ed to reduce from two miles and a haK to a 

 few feet per minute the velocity of a stream that keeps in perpe- 

 tual motion one fourth of all the waters in the Atlantic Ocean. Not 

 only so, we must admit the existence of an engine in the Gulf of 

 Mexico, which, being played upon by the gentle forces of the trade- 

 v\'inds, is capable of sending a stream of water from the shores o 

 the New World to the shores of the Old. 



93. The advocates of the trade-wind theory, whether, with 

 Nor by the trada- Franklin (§ 77), they make the propelling power to 

 wii.d {heory. j^g dcrlvcd from a '' head of ivater " in the Gulf, or, 

 with Herschel (§ 79), from the rebound, a la billiard-balls, against 



* In this calculation tlic earth is treated as a perfect sphere, -with a diameter 

 of 7925. 56 miles. 



t Or, 915.26 to 758.60. On the latter parallel the current 'has an east set of 

 about one and a half mile the hour, making the true velocity to the east, and on 

 the axis of the eartli, about seven hundred and sixty miles an hour at the Grand 

 Banks. 



