Page:Popular Science Monthly Volume 41.djvu/299

Rh water on glass. He found that a cubic centimetre of water dissolved at 20° C. in one hour from one to two millionths of a milligramme from a square centimetre surface of glass; that with temperature rising arithmetically, the growth of solubility is considerably more rapid than that of a geometrical series; that the increase of conductivity of the water for a given kind of glass under like conditions is a characteristic constant; and that later, when a certain quantity of alkali is dissolved, further action involves a dissolving also of silicic acid, and the salts then formed may cause a decrease of conducting power.

of asbestos has been found near Broken Hill, New South Wales, in which there are fibers thirteen inches long, of silky and flexible texture, but less tough than Italian asbestos. It is reddish in color.

sixth annual meeting of the Iowa Academy of Sciences was held at Des Moines, December 29th and 80th. The programme of discussions was full, and besides technical subjects of biology, zoölogy, petrology, etc., included several topics of domestic and other economical importance, such as the determination of the active principles of breadmaking, the bacteria of milk, the effect of feeding on the composition of milk, sugar beets, the coal-bearing strata, brick and other clays, and aluminum in Iowa; the artesian well question, and the report of the committee on State fauna. The President of the Academy, Prof. C. C. Nutting, made an address on Systematic Zoölogy in Colleges, and Mr. J. E. Todd gave some Further Notes on the Great Central Plain of the Mississippi.

statement that the adoption of electric lighting in the English Savings-Bank Department has been followed by a considerable reduction in the amount of sick-leave points to what will probably be one of the chief advantages of this mode of lighting rooms. An electric lamp does not draw on the oxygen of the room, and does not give off irrespirable gases as do gas and oil lights.

to the Minneapolis Tribune, as cited in Garden and Forest, the leading opponents of the proposed forest reservation in northern Minnesota have become supporters of the measure. The Duluth Chamber of Commerce sent its secretary, Mr. Thompson, to the meeting of the State Forestry Association, to protest against the movement, but when he learned that instead of withholding the timber from use it was proposed to secure a constant lumber-supply, and that the forests when protected from fire and larceny would be more productive than they are under the present lack of supervision, Mr. Thompson himself joined the Association and was made a member of the Executive Committee, which is laboring to induce the President to make the proclamation withdrawing the forest lands from sale and entry.

of letters and unedited memoirs by the Swedish chemist, Scheele, is in course of publication, under the direction of Baron Noidenskiold. The question of preparing an English-American edition of the work is under consideration.

the Cambridge Antiquarian Society, November 11, 1891, Prof. Hughes described the results of his examination of some deserted Indian villages in Arizona, one of which consisted of caves excavated in the top of a small hill of lava; and another of dwellings built under the shelter of overhanging ledges in the cliffs of the Walnut Canon, much resembling the cliff dwellings of mediaeval times along the rivers of Dordogne.

of Boussingault, by M. Dalon, and Chevreul, by M. Fagel, are to be erected in Paris, in connection with the Conservatoire des Arts et Métiers. The Chevreul statue is a repetition of one executed by M. Fagel in 1889.

is the name of a new alloy, consisting of copper, nickel, and manganese, which has been brought into the market by a German firm, as a material of great resisting power; it having a specific resistance higher than that of nickeline, which has hitherto passed as the best resisting metal. It is said to be affected in only minute degree by high temperatures, and is therefore adapted for the manufacture of measuring instruments and measuring apparatus in general, which are required to vary in resistance as little as possible under different degrees of heat. While the resistance of other metals is increased by the raising of their temperature, that of manganine is diminished.

is an art in dusting which does not receive the attention it demands. According to the various analyses of different observers, the components of ordinary dust exhibit special characters in almost endless variety. Mineral matters, animal and vegetable debris, morbid germs, and whatever is small and light enough to remain for any time suspended in the air, falls into the category; and among these things are many substances that in the air do mischief. The spread of cholera and exanthematous diseases has, doubtless with truth, been attributed to its influence. Methods of dusting, therefore, which merely remove the dust to another place or fill the air with it, are not sufficient and are not harmless. It should be wiped rather than brushed away, and carried away off, or destroyed. Then let the sunlight in to kill the infection that may remain.

examination of tinned peas, greened, by Drs. M. Charteris and William Snodgrass, of Glasgow, showed, by deposits on the crucible