Page:Popular Science Monthly Volume 12.djvu/785

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nished by the experience of the farmers settled on the west side of the San Joaquin River. For years they have tried in vain to raise crops without artificial irrigation. That section of the State of California is an exemplification of the law thus expressed by Guyot, that "when a mountain-chain opposes an horizontal wind the air is forced up along the slopes, its vapors are condensed, and water the side exposed to the wind, while on the opposite slope the same wind descends into the valley dry and cloudless." The author considers very fully the operation of the chief laws of meteorology as applied to California in general, and to special localities in particular. Among the subjects discussed by him, we would mention the conflict between polar and equatorial winds; the influences of the Gulf of California; the comparative rainlessness of the Colorado and Mohave Deserts and the Tulare Valley; the rainfall in the great valleys and on' the mountain-sides; the influence of the great deserts on temperature and rainfall; why the summer temperature of San Francisco is so low as it is, the mean temperature of summer at the Golden Gate being only 56°.


Purification of Illuminating Gas.—The method in common use for separating from coal-gas foreign suspended matter is founded on the principle of condensation by reduction of temperature on contact with water-cooled surfaces, or with water itself. But the liquid globules held in suspension in the gas may be condensed by causing a jet of gas to impinge upon any resisting surface, as a leaf of paper, or a plate of metal, and an apparatus for purifying gas according to this method has been constructed by Messrs. Pelouze & Audouin. The condenser of this apparatus consists mainly of an outer casing with a gas inlet at the lower part, and an outlet at the upper. Suspended within the casing is an annular water-tank, in which is balanced a miniature gas-holder, or bell, formed with four circumference-plates, two of which are perforated in rows with small holes, and two with large holes, the latter being opposite the blank spaces between the rows of the former. The gas from the inlet passes through the central space within the annular lank, and through the four perforated plates of the bell; the tar, etc., which condense on the non-perforated portions of the surface trickle down the plates into the water-tank. It has been found that if the perforated bell has a capacity of 35,317 cubic feet, it will suffice for works producing 3,531, 700 cubic feet per twenty-four hours, or in the proportion of 1 to 100,000.


Properties and Production of Honey.—There was lately held in New York a convention of bee-masters from all parts of the United States, for the purpose of advancing the interests of the important industry with which they are identified. Among the papers read at this convention was one by Mr. F. B. Thurber, in which the commercial history of honey was given with considerable detail. The use of honey antedates that of sugar, going back many centuries before the Christian era, while the general use of sugar is of comparatively recent date. There are evidences of the high antiquity of sugar in China and India, but it appears to have been only vaguely known to the Greeks and Romans. The art of refining sugar was discovered by the Venetians in the sixteenth century. It is hard to say why the production of honey should have fallen so far behind the production of sugar. It is in the highest degree healthful and palatable, and its sources are as plentiful and as sure as those of sugar. In America, within the last few years, a wonderful advance has been made in the production of honey, as regards both quality and quantity.

Honey differs greatly in color and consistence. In the recent state it is fluid, but on being kept it is apt to form a crystalline deposit, and to be converted into a soft, granular mass; its color varies, being sometimes white, but usually yellowish, and occasionally of a brown or reddish tinge. When the bees are very young the honey undergoes less change, and remains nearly white: in this state it is called virgin honey. Ordinary honey is obtained both by pressure and by heat. Recently, however, a process has been invented by which honey is forced from the cells of the comb by centrifugal force, and the combs are then restored to the hives, to be again used by the bees for storing their honey. When honey is extracted from poisonous plants, it partakes