Page:Popular Science Monthly Volume 40.djvu/593

 carries it hanging down, because in that position it is less conspicuous and better eludes detection. A family of wolves playing together undisturbed occasionally carry their tails curled upward. By degrees the tail acquires naturally the upright position as a result of coincident evolution of the mind of the wolf by domestication and of the slow adaptation of the appendage as an organ of expression. The cessation of natural selection in the domestic dog would give the tail greater freedom of motion without detriment to life; and artificial selection modifies it into various shapes.

Sulphur in Sicily.—According to the report of the United States consul at Palermo, there are now about three hundred sulphur mines in Sicily. The deposits are estimated to amount to about 30,000,000 tons, and the annual production to 400,000 tons. The royalties vary from twelve to forty-five per cent, according to the quality of the ore and the facilities for producing the sulphur, and average about twenty-five per cent. The external indications of the presence of sulphur are the appearance of gypsum and sulphurous springs. When the miners detach the ore from the surrounding material, vast cavities are often left which have to be supported on pillars of rock, and frequently give way with disastrous results. Seven different qualities are recognized, and determined by color. The mines have declined in prosperity since the extraction of sulphur from iron pyrites has come into use, and two thirds of them are represented to be at the point of suspension.

Cause of Chinese Emigration.—The main cause of the emigration from China, which is filling all other countries with apprehension, is traced by a Dutch colonial officer in the East Indies, not to the excess of population, but to the poverty of the soil in the provinces whence the emigrants come. The mass of the emigration is from the bare mountainous valleys of the eastern part of China, where the soil yields but little and the rainfall is slight. Disafforestation, making wood scarce and dear, is another factor in the matter. The author believes that as soon as China earnestly sets itself to the task of constructing railways and other great works the stream of emigration will be stopped; for the people will find in the interior of their own country the work and means of livelihood which they now seek for elsewhere,

University-extension Lectures on Science.—Arrangements have been made, in connection with the English university-extension movement, for one month's residence during the long vacation of extension students within the university precincts, where lectures will be given them on the subjects of their studies. The lectures for 1891 included a discussion of the criticism of Weismann's theory of heredity, by Mr. Poult on; the functions of the heart, by Mr. Gotch; the benzene ring, by Prof. Odling; a course of practical chemistry, under the supervision of Mr. Marsh; practical instruction in geology, by Prof. Green and Mr. Badger, with excursions; practical astronomy; four lectures on the application of science to the art of agriculture; the management of poultry; and manures.



paper on Some Means of Health in School-houses is contributed to the 1890 Report of the Wisconsin Board of Health by Hon. W. D. Parker. One of the arrangements that Mr. Parker strongly commends is the "dry-air closet," so called because a current of dry air, coming from the ventilating flues of the building, is passed through the vault and carries off all the moisture from it, leaving only a small quantity of dry, inoffensive solid matter, which can be shoveled out. This result, he says, is almost incredible, but has been established by sufficient tests.

fact that the science relating to electricity has no name of its own is noted by the editor of Our Language, who proposes that it be called "electrics." The pair of words, "electrics" and electrician, would be in analogy with optics and optician, mechanics and mechanician, mathematics and mathematician, and many others. At present the word electricity performs two functions similar to those which are separated in the case of light and optics, heat and thermotics, sound and acoustics.

instance of a spider catching a small mouse, very similar to one published in the Monthly for May, 1890, comes to us from Columbus, Ohio. The mouse was found by Mr. W. J. Dawson suspended by a cable 