Democratic Sentinel, Volume 17, Number 30, Rensselaer, Jasper County, 11 August 1893 — POPULAR SCIENCE NOTES. [ARTICLE]

POPULAR SCIENCE NOTES.

Why Cak Wheels Wear Out.—A car wheel wears out beoause the metal of which it is composed comes away in thin scales. A microscopic examination shows that the continual jarring has a tendency to destroy the coherence of the particles, and thus gradually disintegrates the whole. Car wheels long in use become so brittle that a stout blow with a heavy hammer will sometimes cause them to fly into fragments as though they wore made of glass. Electricity Under Paris. The projected underground electric railway to unite the Bois de Boulogne and the Bois de Vincennes, in Paris, is to consist of a circular cast-iron tube twenty feet in diameter and seven miles long, in which will be laid a double track. Trains of four cars will be run on each track at intervals of two minutes. Stoppages will be made at seventeen stations, and the whole distance from one terminus to the other will be traversed jp about forty-five minutes. Steam engines of 4,000 horse power will generate electricity for running the cars and lighting the subways.

Aletauzino Cloth. —An interesting announcement is made in the French papers of the discovery of a process for metalizing textile fabrics, by which, it is claimed, the latter are rendered proof against the attacks of insects. The materials, such as wool, flannel, calico, etc., are for this purpose immersed in a boiliftg’bath composed of two and onehalf pounds sulpknte of oopper, one pound of sulphuric acid, and sixtytwo gallons of water, the fabric-being calendered and dried after its removal from the fluid. The finish obtained by this process will, it is said, bear two or three washings before it is again necessary to subject the cloth to a repetition of the operation. Smoke Consumers. —Notwithstanding the many and ingenious methods which engineering skill has proposed for consuming smoke, especially in the case of bituminous coal, the simple steam-jet device is proving a most satisfactory contrivance. piece of two-inch pipe runs horizontally along the front wall of a furnace, just under the boiler; at one end it is capped, and at the other it turns outward through the front wall, then passing downward and through the front again into the ash pit. The lower end of this pipe is placed well to one side of the ash pit, so that it may not be in the way of the fireman, and opens under the grate so that it may receive air that has been warmed by the downward radiation from the furnace inside of the upper horizontal part of this pipe, a piece of half-inch steam pipe is secured which comes out through the setting at the side opposite to that on whioh the air pipe makes its exit, aud then passes upward aud enters the boiler at its highest part, so that the steam drawn through it may be dry as possible. Small nozzles, with holes one-sixteenth of an inch in diameter, and six inches or so apart, are attached to that portion of the steam pipe enclosed in the air pipe in the furnace, and these come opposite similar but larger nozzles fitted to the air pipe itself. On the valve being opened, steam blovys out through the nozzle, drawing air along with it by a kind of ejector-like action, and the nozzles are so placed that the discharge of mixed air and steam is directed toward the angle formed by the bridge wall ar.d the grates.