Page:Physical Geography of the Sea and its Meteorology.djvu/462

436 817.The waves they get up.—Arrived at this point, another view in the field of conjecture is presented, which it is proper we should pause to consider. The movements of the atmosphere on the polar side of 40° N. are, let it be repeated, by no means so constant from the west, nor is the strength of the westerly winds there nearly so great on the average as it is in the corresponding regions of the south. This fact is well known among mariners. Every one who has sailed in that southern girdle of waters which belt the earth on the polar side of 40°, has been struck with the force and trade-like regularity of the westerly winds which prevail there. The waves driven before these winds assume in their regularity of form, in the magnitude of their proportions, and in the stateliness of their march, an aspect of majestic grandeur that the billows of the sea never attain elsewhere. No such waves are found in the trade-winds; for, though the S.E. trades are quite as constant, yet they have not the force to pile the water in such heaps, nor to arrange the waves so orderly, nor to drive them so rapidly as those "brave" winds do. There the billows, chasing each other like skipping hills, look, with their rounded crests and deep hollows, more like mountains rolling over a plain than the waves which we are accustomed to see. Many days of constant blowing over a wide expanse of ocean are required to get up such waves. It is these winds and waves which, on the voyage to and from Australia, have enabled the modern clipper-ship to attain a speed, and, day after day, to accomplish runs which at first were considered, even by the nautical world, as fabulous, and are yet regarded by all with wonder and admiration.

818. A meteorological corollary.—Seeing, therefore, that we can bring in such a variety of facts and circumstances, all tending to show that the S.E. trade-winds are stronger than the N.E., and that the westerly winds which prevail on the polar side of 40° S. are stronger and more constant than their antœcian fellows of the north, we may consider it as a fact established, independently of the conclusive proof afforded by Plate XIII., that the general system of atmospherical circulation is more active in the southern than it is in the northern hemisphere. And, seeing that it blows with more strength and regularity from the west in the extra-tropical regions of the southern than it does in the extra-tropical regions of the northern hemisphere, we should deduce, by way of corollary, that the counter-trades of the south are not so easily