193 



KEPOE.T 1875. 



It will not do as an objection to assert that, according to the gTavitation theory, 

 the ocean never attains to a condition of static eqiiilibrium. This is perfectly true, 

 as has been shown on former occasions* ; but then it is the equator that is kept 

 below and the poles above the level of equilibrium ; consequently the disturbance 

 of equilibrium between the equatorial and polar columns would actually tend to 

 make the difterence of level between the equator and the Atlantic greater than 

 85 feet, and not less, as the objection would imply. 



"Another featiue of this section irreconcilable with the gravitation theory is the 

 fact that the warm water is all in the North Atlantic, and little or none in the 

 South, a condition of things the reverse of what ought to be according to that 

 theory. But according to the wind theory of oceanic circulation the explanation 

 of the whole phenomena is simple and obvious. Owing to the fact that the S.E. 

 trades are stronger than the N.E., and blow constantly over upon the northern 

 hemisphere, the warm surface-water of the South Atlantic is drifted across the 

 equator. It is then carried by the equatorial current into the Gulf of Mexico, and 

 afterwards, of coiu-se, forms a part of the Gulf-stream. The North Atlantic, on 

 the other hand, not only does not lose its surface-heat like the equatorial and South 

 Atlantic, but, in addition, receives the enormoiis amount of heat constantly carried 

 into it by the Gulf-stream. And the reason why the warm surface-strata are so 

 much thicker in the North Atlantic than in the equatorial regions is perfectly 

 obvious. The surface-water at the equator is swept into the Gulf of Mexico by 

 the trade-winds and the equatorial current as rapidly as it is heated by the sun, 

 so that it has not time to accumulate to any great depth. But all this warm water 

 is carried by the Gulf-stream into the North Atlantic, where it accumulates. 



North Pacific Ocean. — The temperature-soundings made in the U.S.S. ' Tusca- 



* ' Phil. Mag.' October 1871; 'Climate and Time,' Chapter is. 



