Page:Popular Science Monthly Volume 29.djvu/880

860 that those of 1867 and 1868 were much less than those of 1860 and 1861, on the one hand, and of 1871 and 1872 on the other; and that the number and duration of the cyclones of 1879 and 1880 were much less than those of the cyclones of 1871, 1872, and 1884; but it appears that in 1884 there was less cyclone activity than in 1861 and 1872.

Antiseptics and Disinfectants.—The Committee on Disinfectants of the American Public Health Association calls attention in its report to a distinction which is not always accurately enough observed between disinfectants—substances which destroy germs—and simple antiseptics—which prevent their development. Many of the preparations put on the market as disinfectants are in reality only antiseptics. While practically the words disinfectant, in its strict sense, and germicide, are considered to mean the same thing, so long as it is not proved that all infections are developed from germs, we must regard "disinfectant" as a word of more general significance than germicide. But, as a matter of fact, those agents which by laboratory experiments have been proved to be the most potent germicides have also been shown to be the most reliable disinfectants. While antiseptic agents may fail to fulfill the stronger purpose of disinfectants, they are known to exercise a restraining influence on the development of disease-germs, and their use during epidemics is recommended, when masses of organic material in the vicinity of human habitations can not be completely destroyed or removed, or disinfected. A substance of this kind is sulphate of iron, or copperas, which, while it does not destroy the vitality cf disease-germs or the infecting power of material containing them, is a very valuable antiseptic, the low price of which makes it one of the most available agents for the arrest of putrefactive decomposition. While an antiseptic agent is not necessarily a disinfectant, all disinfectants are antiseptics; for putrefactive decomposition is due to the development of germs of the same class as that to which disease-germs belong, and the agents which destroy the latter also destroy the bacteria of putrefaction when brought in contact with them in sufficient quantity, or restrain their development when present in smaller amounts. Antiseptics are a poor substitute for cleanliness.

Wind-Carving in Maine.—Mr. George H. Stone discusses, in the "American Journal of Science," some instances of wind action on till and bowlders which he has observed in Maine. One of the features of the surface geology of this State is the large areas of sand which were deposited by most of the rivers along the lower part of their courses during the Champlain epoch. The valley of the Androscoggin is particularly distinguished by its sand-dunes. Not rarely spots bare of vegetation can be found on hill-sides exposed to high winds, where, during dry days, the wind removes the finer parts of the till and drives the gravel back and forth just as happens in Colorado during the dry winter weather. The effects of this process are, however, usually obliterated or obscured by the frequent rains and abundant snows; but the wearing marks of the action are plainly observable in many cases, as on the top of a hill near Wayne village. At Bethel are found bowlders which exhibit on one or more of their surfaces grooves, scratches, striæ, and polishings, the origin of which was for a long time problematical; and similarly marked stones have been noticed at Gilead and in Gorham, New Hampshire, all near the Androscoggin River. Mr. Stone believes that he solved the mystery of these marks during his investigation of the glacial gravels of the region in the summer of 1885. In numerous places, at Bethel and elsewhere, he found "bowlders and even small stones which are now being sand-carved by the wind as plainly and incontestably as in Colorado. The drifting dunes of fine sand do not produce this effect to any great extent, probably because the stones are covered and uncovered too rapidly. But there are bare spots not protected by grass where coarse sand and gravel are driven back and forth by the wind, and here the carved bowlders can be seen in considerable numbers and in all stages of the process. In some cases it appeared probable that these bare places were where drifting sand had swept over the surface and the till had been partially denuded by