Meteorology: The Science of the Atmosphere

by Charles Fitzhugh Talman

THE CENTRAL OFFICE OF THE UNITED STATES WEATHER BUREAU IN WASHINGTON

One interesting result of recent inquiries on this subject is the discovery that the bad effects of crowded, “stuffy” rooms are not generally due to impurities in the air, but to heat, humidity, and especially lack of air movement. It seems to be now demonstrated that there is no such thing as “crowd-poisoning,” and that the bad smells of confined places are no indication that the air is deleterious. Professor Hill, who has done more than anybody else to upset traditional ideas with regard to ventilation, tells us that “the deaths in the Black Hole of Calcutta, the depression, headache, etc., experienced in close rooms are alike due to heat stagnation; the victims of the Black Hole died of heat stroke.” Most recent writers on physiology also discredit the time-honored methods of testing the purity of the air by measuring the percentage of carbon dioxide it contains. The amount of this gas normally present in the free air is about three-hundredths of one per cent, but experiments have shown that thirty times this amount—a percentage higher than is found in the worst ventilated rooms—may be breathed for hours together without detrimental effects. A further departure from old-fashioned views is seen in the assertion of recent authorities that a deficiency of oxygen, unless far more pronounced than ever actually occurs in buildings, mines, etc., where the supply of this gas has been the subject of so much solicitude, has no physiological significance whatever. In support of this assertion it is pointed out that at mountain health resorts the concentration of oxygen out-of-doors is much less than that found in the worst ventilated rooms at sea-level. In mines an ample supply of oxygen may be positively dangerous, as favoring the occurrence of explosions. These were rare before the enactment of laws requiring a high percentage of oxygen in mine air.

HILL’S KATATHERMOMETER

Excessive dryness of the skin, which is a common cause of discomfort, is not very closely related to the humidity of the air. “In winter,” says Hill, “if there be a wind the rate of evaporation is so accelerated that the skin feels dry, because in order to check the loss of body heat the sweat glands are inactive and the blood vessels of the chilled skin are constricted.” There has been a great deal of discussion about the dry air of American buildings in winter, and startling figures have been adduced to show that the air of such buildings is dryer than that of deserts. So far as measurements of relative humidity go, this is perfectly true; but, as Dr. G. T. Palmer, of the New York State Commission on Ventilation, has pointed out, there is an important difference between dryness and “dryingness.” The latter depends upon the movement of the air, as well as the relative humidity. The circulation of the air in a desert is generally much more active than that of the air in a building with the windows shut, and therefore much more conducive to rapid evaporation. There are systems of ventilation in which the air is kept in steady and rapid motion, and it is probably only in such cases that the air of our heated houses can be compared to that of a desert. From the European point of view American buildings are notoriously overheated, but this is probably due to the fact that our hot summers—much hotter than those of Europe—have adapted us to a tropical climate.

It is natural to inquire whether the atmospheric conditions that affect the comfort of man do not also exercise a marked influence upon his muscular efficiency and his mental powers. This question has been answered in the affirmative by a number of ingenious writers, who have sought to establish definite quantitative relations between certain states of the atmosphere and the output of work in factories, the grades attained by school children, etc. Thus, Dr. Ellsworth Huntington, a well-known worker in this field, declares that the most favorable daily mean temperature for mental activity (the temperature being measured out-of-doors) is about 40 degrees F., and for physical activity about 60 degrees F. Contrary to the common opinion, he holds that our general efficiency is at low ebb in midwinter and fairly high in summer. Variability in temperature, within certain limits, he finds to be stimulating; equable temperature the reverse. He has drawn charts showing the distribution of what he calls “climatic energy”—i. e., the combination of certain weather factors supposed to control human efficiency—throughout the world, and other charts showing a more or less similar distribution of “civilization.” He has also made an ambitious attempt to interpret the history of mankind in terms of weather and climate.

Another fruitful worker along similar lines is Dr. Griffith Taylor, of Australia, who has made interesting studies of the control of settlement in his own country and elsewhere by temperature and humidity, and has introduced some novel graphic methods (“climographs”) for comparing climates with respect to their effects on humanity.

There has, in short, arisen a new school of climatologists whose aim is to develop exact mathematical formulæ whereby we shall be able to adjust the economic arrangements of mankind on an intelligent basis as regards climate. The success of their efforts is a question for the future to decide, but there is no doubt that their work is profoundly suggestive. These undertakings, it may be noted, bear a striking analogy to those of the present generation of agricultural meteorologists, who are applying climatic statistics to the problem of selecting crops and to the improvement of agricultural methods.

A certain number of specialists are engaged in studying the physiological effects of sunlight and other special kinds of solar radiation, the distribution of which varies greatly from place to place and from time to time, especially on account of differences in the selective absorption of such rays by the atmosphere. The chemical action of sunshine that causes sunburn—even at very low temperatures, as, for example, on high mountains—may have far-reaching effects on the human organism (as it certainly has on plants), and there is great need of collecting more data of “photochemical climate” than we now possess, in order that this subject may be thoroughly investigated. One of the few institutions in the world at which a large amount of work has been done in this line is the private observatory of Dr. C. Dorno, at Davos, the well-known health resort in the Alps. Dorno’s studies throw a good deal of light upon the therapeutic effects of sunshine in a mountain climate.

Many forms of dust in the atmosphere are capable of producing pronounced physiological and pathological effects. There is a long list of “dusty trades” in which the production of excessive dust has notoriously evil effects upon the health of workmen, leading especially to pulmonary diseases; sometimes to various kinds of poisoning. These harmful dusts are by no means confined to factories, mines, quarries, and the like. The air of the average city street abounds in them. Dr. J. G. Ogden states that 61 per cent of the dust found in the air of the New York subways consists of jagged splinters of steel, resulting from the wearing away of brake shoes, wheels, and rails.