Rensselaer Union, Volume 8, Number 2, Rensselaer, Jasper County, 30 September 1875 — MECHANICAL AND SCIENTIFIC. [ARTICLE]

MECHANICAL AND SCIENTIFIC.

—A cement, impermeable by air and steam, and especially well adapted to use for steam or gas pipes, is made of powdered graphite six parts, slaked lime , three parts, sulphate of lime eight parts and boiled oil seven parts, well kneaded. —lt is thought that M. Jamin’s researches point to an important modification in the construction of magnets. Thus, supposing that a great number of plates, which, after being separately magnetized to saturation, are placed together, the magnetism of tlie combination is seen to increase up to a limit which cannot be passed, and which is reached when the polar surfaces are filled. Supposing that ten plates are required—if the same experiment be recommenced, applying the same plates against two iron armatures of a large surface—the intensities increase much more slowly, because tha sum of tlie magnetism is diffused over a more considerable extent, the limit not being reached till this extent is full. For this it may be needful to superpose twenty, thirty or forty plates, and, generally speaking, a number so much greater as the armatures are larger. The total power of the magnet increases, therefore, with its —The Londoft~Sfew«, speaking of the superior elasticity of steel as compared with iron, gives an illustration of the fact as presented in the course of some recent investigations, as follows: A bar of hardened steel, one inch square, being laid on two supports/ fifty-four inches apart, a load was applied at the center, beginning at fifty pounds and increasing gradually by that amount until it reached 1,400 pounds. Now, under 800 pounds the deflection was one inch; with 1,000 pounds it was one and one-fourth inches, and with 1,200 pounds a little over one and one-half inches, showing the increase of deflection to be nearly as the strain. With a load of 1,200 pounds a slight “set” -was observed, amounting to .016 inch, which was quadrupled by the addition of another fifty pounds. From this point the deflection and set increased more rapidly, being 14.5 inches and .133 inch respectively, under a strain of 1,300 poupjis, and with 1,350 the set was .429 inch—the fact thus appearing that the elasticity remained perfect until the load exceeded 1,200 pounds. According to the New London (Conn.) Telegram, an affair of the Charley Ross sort-is. threatening Niantic. The Episcopal clergyman in that village was visited by burglars recently. They secured but few articles of value, but left a note threatening to abduct his child if SI,OOO were not left beneath a certain tree by a certanT date. —— —’ _ T A Buffalo physician assures the Express that the treatment known as “ moxa,” which was administered to Clara Morris recently, is a painless one, as irons at a white heat cause only a prickling sensation when applied to the flesh. The doctor claims himself to have undergone the treatment. ’