| 36·7 | 500 | 38·9 | | 2700 | 35·2 | .. | 600 | 39·2 | | 2720 | .. | 35·4 | 700 | 39·0 | | | | | 800 | 39·1 | | | | | 900 | 38·2 | | | | | 1000 | 36·9 | | | | | 1100 | 37·6 | | | | | 1200 | 36·7 | | | | | 1300 | 35·8 | | | | | 1400 | 36·4 | | | | | 1500 | 36·1 | | | | | Bottom. | 34·7 | +--------+----------------+----------------+---------+------------+ On computing the extent to which the three columns A, B, and C are each expanded by heat according to Muncke’s table of the expansion of sea water for every degree Fahrenheit, I found that column B, in order to be in equilibrium with C (the equatorial column), would require to have its surface standing fully 2 feet 6 inches above the level of column C, and column A fully 3 feet 6 inches above that column. In short, it is evident that there must be a gradual rise from the equator to latitude 38° N. of 3½ feet. Any one can verify the accuracy of these results by making the necessary computations for himself.[99] [Illustration: PLATE III. W. & A. K. Johnston, Edinb^r. and London. SECTION OF THE ATLANTIC nearly North and South, between LAT. 38° N. & LAT. 38° S.] I may observe that, had column C extended to the same depth as columns A and B, the difference of level would be considerably greater, for column C requires to balance only that portion of columns A and B which lies above the level of its base. Suppose a depth of ocean equal to that of column C to extend to the north pole, and the polar water to have a uniform temperature of 32° from the surface to the bottom, then, in order to produce equilibrium, the surface of the ocean at the equator would require to be 4 feet 6 inches above that at the pole. But the surface of the ocean at B would be 7 feet, and at A 8 feet, above the poles. Gravitation never could have caused the ocean to assume this form. It is impossible that this immense mass of warm water, extending to such a depth in the North Atlantic, could have been brought from equatorial regions by means of gravitation. And, even if we suppose this accumulation of warm water can be accounted for by some other means, still its presence precludes the possibility of any such surface-flow as that advocated by Dr. Carpenter. For so long as the North Atlantic stands 3½ feet above the level of the equator, gravitation can never move the equatorial waters polewards.