Page:Popular Science Monthly Volume 58.djvu/391

Rh  , at the expense of the equipped and reputable students of the subject. 4. By reason of a hypercritical but uninformed attitude toward the daily forecasts of the United States Weather Bureau, by which the work of the Bureau is hampered and its value to the public materially reduced.

Such is the situation. If the apprehension of the simple fundamental facts of the weather—taking the first count in the indictment into consideration—were difficult, if the problems were beyond the ability of the man in the street, one would excuse the newspaper and quash the indictment, but the practical questions at issue are as clear as crystal and as simple as A, B, C. There is no dispute among observers as to the fundamental facts, and the surface phenomena themselves are as regular as the progress of the sun from tropic to tropic. The abstract and controversial discussion as to final causes which occupies certain meteorologists is not germane, so far as the treatment of the daily weather goes, and it is the newspaper, not the weather men, who cannot tell a meteorological 'hawk from a hand-saw.'

Because a Dolbear, a Trowbridge and a Lodge may not agree on the ultimate expression for electric energy does not prevent a citizen from distinguishing between arc and incandescent lights, or between a trolley car and a call bell. And so it is with the simple weather facts. The synthesis of American weather, which can be given in two sentences, is within the understanding of any one, for American weather is the resultant of a west to east drift in the general circumpolar circulation of the north temperate zone, which drift is broken up into two great eddies, and only two, the cyclonic and the anti-cyclonic; the former, the cyclonic, the center of general storm phenomena, and the condition and cause of local storm disturbances (tornadoes, squalls, thunderstorms, etc., as local conditions and the seasons determine); the latter, the anti-cyclonic, the center of clear weather phenomena. Into this circumpolar system intrude the tropical anti-cyclone and the tropical cyclone, and play their part in the proper season and region. That is all.

The great circumpolar drift moves in ceaseless round from the Pacific to the Mississippi Valley, from the Mississippi Valley to the Atlantic, from the Atlantic to Europe, to Asia, to the Pacific, and back again. In it appear the two great atmospheric eddies, oftentimes over a thousand miles in diameter, and covering 1,000,000 square miles of the earth's surface. These two type eddies, the cyclonic and the anti-cyclonic, are the real distributers of the weather, as we know it. They can be seen to shift as a whole from west to east, not necessarily along a straight line, however, for they have a way of bellying down, or sidling from the northwest to the southeast, and from the southwest to the northeast, or from all points in the west between