Page:Popular Science Monthly Volume 47.djvu/328

316 principle that we must know much more about a climate than what the thermometer can tell us before we know very much about it. I kept a record of the temperature in Martinique, one of the Windward Islands lying in 14º north latitude, and it never went above 86º F., nor so high but two or three times during a residence of three seasons, and once so late as the 1st of July. But no sensible person would dare to expose himself to the midday sun with the same impunity that he could in this latitude and a corresponding temperature. The ever-present humidity, bordering on saturation, in the tropics is an important modifying element to be taken into account.

Again, temperature may depend on latitude or on altitude; but it is not a matter of small moment which the cause may be. Sixty degrees of heat at the level of the sea and on the seashore are very unlike in physiological effect to 60º in the dry and rarefied air of an elevated inland situation. There is no doubt that considerable moisture in the air favors the growth of minute organisms, and decomposition of matter takes place rapidly under the influence of heat and moisture. On the other hand, a dry air retards decomposition, and, if sufficiently dry, prevents it entirely, no matter how hot it may be. The Sacramento Valley is very hot in the summer, but it is also dry, so that friends of mine would kill a beef and elevate the carcass by means of rope and pulley to the top of a tall pole, let it down from time to time to cut from it, and it would keep perfectly sweet until it was all eaten up. A good illustration of conditions retarding or favoring the growth of minute organisms may be seen during the orange harvest in portions of California. The altitude of Redlands, California, averages about fifteen hundred feet above sea level. Fogs seldom reach there, the sun shines clear more than three hundred days of the year, and there is not a speck of mildew on any fruit. But go forty miles nearer the sea and seven or eight hundred feet down nearer the sea level, and at every station you will see many people washing oranges. More fogs, denser air, less sunshine, more humidity favor fungous growths. On the high table lands of the central portions of the continent, at an altitude of six or eight thousand feet, as in Wyoming, where a friend lives, milk does not "sour" or change under a week or ten days, and the carcasses of dead cattle, of which there are many, give no offensive stench, but slowly dry up and waste away, showing that comparatively few organic germs exist there, and that the conditions for their rapid propagation are unfavorable. From the facts just stated—and they are representative facts—it would be too hasty to conclude that the higher and drier locality is essentially more healthy than the lower and moister locality, even for consumptives, until we have mastered and estimated the