Page:Physical Geography of the Sea and its Meteorology.djvu/200

174 360. At sea in the southern hemisphere we have the rule, on land in the northern the exceptions, as to the general circulation of the atmosphere.—In the southern hemisphere, we may, by reason of its great aqueous area, suppose the general law of atmospherical moments to be better developed than it is in the northern hemisphere. We accordingly see by the table (§ 353) that the movements north and south between 45° and 50° correspond with the movements south and north between 25° and 30°; that as you go from the latter band towards the equator the winds with southing in them increase, while the winds with northing in them increase as you go from the former towards the pole.

361. The magnetic poles, the poles of the wind and of cold coincident.—This is the law in both hemispheres: thus indicating that there must be in the polar regions, as in the equatorial, a calm place, where these polar-bound winds cease to go forward, rise up, and commence their return (§ 214) as an upper current. So we have theoretically a calm disc, a polygon—not a belt—about each pole. The magnetic poles and the poles of maximum cold (§ 347) are coincident. Do not those calm discs, or "poles of the wind," and the magnetic poles, cover the same spot, the two standing in the relation of cause and effect? This question was first asked several years ago, and I was then moved to propound it by the inductions of theoretical reasoning. Observers, perhaps, may never reach those inhospitable regions with their instruments to shed more light upon this subject; but Parry and Barrow have found reasons to believe in the existence of a perpetual calm about the north pole, and later, Bellot has reported the existence of a calm region within the frigid zone. Professor J. H. Coffin, in an elaborate and valuable paper on the "," arrives by deduction at a like conclusion. In that paper he has discussed the records at no less than five hundred and seventy-nine meteorological stations, embracing a totality of observations for two thousand eight hundred and twenty-nine years. He places his "meteorological pole"—pole of the winds—near latitude 84° north, longitude 105° west. The pole of maximum cold, by another school of philosophers, Sir David Brewster among them, has been placed in latitude 80° north, longitude 100° west; and the magnetic pole, by still another school, in latitude 73° 35' north, longitude