In consideration of these facts, we are compelled to cast aside tables of "relative humidity" as valueless when taken alone, for the purpose of determining the humidity of climates. The physical properties of vapor in the air—the absolute humidity—are essential elements which can not be ignored, and are of exceeding significance in the treatment of disease.
We have given prominence to this topic, inasmuch as the pamphlet of Dr. Kenworthy is widely circulated by the Bureau of Immigration of the State of Florida, and is quoted in a pamphlet on Florida issued by the United States Department of Agriculture, and also in the well known work on Florida by G. H. Barbour, as establishing conclusively the dryness of the climate. It well shows how figures, correct in themselves, may, by misapprehension of their import, become the source of mischievous error.
Given—a peninsular land subjected to the burning rays of a semitropical sun and surrounded by an ocean of warm water, the average temperature of which is 77° Fahr.—then it is not necessary to ask the Signal Service whether the climate be moist or dry. If they supplied us with tables of absolute humidity, they could only add to our information accurate knowledge of the excess of moisture. Every breeze that blows touches the face with the softness of a moist May morning at the North. The atmosphere is delicious, balmy.
In addition to physical sensation and deductions drawn from geographical position, there are other reasons for deciding that the climate is moist. The necessity of frequently emptying closets during the summer season, and drying clothing-apparel; the impossibility of using cellars, because of the quickness with which mold destroys goods there stored; the thick formation of vert-de-gris on articles of brass; the rapid decay of structures made of wood, as compared with Northern localities; the presence almost everywhere of the Southern moss (Tillandsia), swaying in festoons from the trees—these facts tell of excessive atmospheric moisture.
Sunshine, which is so cheering to the invalid, and the absence of which is so depressing even to the well, is abundant in Florida. There it glitters continually on leaf and flower. Five years' observation at Jacksonville shows an average of only seven cloudy days for each winter month, the other twenty-three being arched by a soft Italian-like sky.
What relation electrical potential may have to climate as regards
- The temperature of the surface-water of the Gulf of Mexico, off Key West, in May, was 772° Fahr., as determined by the United States Coast Survey, 1857, p. 102.
The average temperature of the St. John's River, at Jacksonville, to the depth of eighteen feet, determined by daily observations by Sergeant J. W. Smith, United States Signal Service, from September, 1881, to March, 1882, is 70° Fahr.