Page:Popular Science Monthly Volume 86.djvu/135

Rh to the psychologist, and it remains for the meteorologist simply to prove that the notions have no basis in fact. When one plots the seasonal or the annual temperatures or snowfalls, or any other elements of climate, using reliable records as far back as they are available, it is apparent that the curves show no appreciable change of climate within the life of any man now living. The explanation for fallacies of this nature must be given in terms of psychology. Present winters do not seem to be as severe as "old-fashioned winters" because of better housing and heating conditions, more efficient clothing, improved methods of transportation, with multiplied comforts and conveniences. The retired farmer living in a steam-heated city apartment building in which there are double windows is apt to exaggerate the severity of past winters when he may possibly have seen the snow drift through cracks in a log house. Moreover, a snowfall of three feet looks considerably deeper to a boy four feet tall than it does to him when he becomes a man six feet in height.

There is no known relation between the weather of one season or year with that of the following season or year, various opinions to the contrary, notwithstanding. The records of the Weather Bureau do not show that a relatively dry spring is followed by an unusually hot summer, or that an abnormally cool autumn is followed by a severely cold winter. Neither can it be shown that cold years or warm years occur in groups of two or three, as is sometimes maintained. While well-marked cycles are recognized in various solar disturbances, particularly sunspots, there is no similar cycle apparent in the weather of seasons or of years. If there are cycles in the weather they must be measured in terms of tenths of units, and they are therefore of no practical importance.

Neither is there any indisputable connection between the weather of one day and that of subsequent weeks or of seasons. Tradition has it that the presence or absence of sunshine on Groundhog Day, February 2, determines whether or not winter conditions shall continue during the following six weeks; that a showery Easter Sunday is followed by seven showery Sundays; and that a rainy St. Swithin's Day, July 15, portends forty consecutive days of rainfall. No basis can be found for these traditions in available records. True it is that springlike conditions come considerably earlier some years than during other years, but such conditions are not related to the weather of February 2. Moreover, spring and summer are the seasons of greatest and most frequent rainfall over the central portion of the United States, but the frequency of rain is not related to the conditions prevailing on Easter Sunday or on July 15.

In the use of the terms cyclone and tornado there is considerable confusion, and the terms are used indiscriminately. As used by the Weather Bureau the term cyclone refers to an area of low barometric pressure with winds blowing counter-clockwise and spirally inward