Copy 1, Volume 1

Hand-book of chemistry / Translated by Henry Watts.

  • Gmelin, Leopold, 1788-1853
Date:
1848-1872
Catalogue details

Licence: Public Domain Mark

Credit: Hand-book of chemistry / Translated by Henry Watts. Source: Wellcome Collection.

    447/562 (page 423)
    _ = GROVE’S BATTERY. — 423. inches, liberates 6 cubic inches of detonating gas per minute, when the con- . necting wires are made to dip into water acidulated with sulphuric acid,— brings a platinum of 7 inches long and #5 of an inch thick to a state of bright ignition—and causes steel needles to burn with brilliancy. (Grove.) A five-pair battery of this description haying in each earthenware cell a platinum plate, 8 inches long and 2 inches wide, immersed in nitric acid of 1:35 sp. gr.,—and in each porcelain cell a zine plate of double the size bent round at the bottom and immersed in hydrochloric acid—yields 15 cubic inches of detonating gas per minute, fuses platinum wire of the thickness of a knitting needle in a few seconds, causes charcoal to emit a light of intolerable brilliancy, and will produce a magnet capable of bearing 31 cwt. Its physiological effects however are but slight [on account of the feeble tension of five pairs]. The current is likewise of constant strength. (Schonbein, Pogg. 49, 511.) Porcelain cylinders, closed at bottom and covered on the outside with a layer of platinum burnt in, may be placed in cylinders of porous earthenware filled with nitric acid, and these again in vessels containing cylindrically bent zinc plates with dilute sulphuric acid, or still better, sulphate of zinc. (Pfaff, Pogg. 53, 303.) Instead of platinum, an iron rod may also be immersed in strong nitric acid contained in a tube of gypsum, and the tube placed in a vessel containing dilute sulphuric acid, in which is immersed a zinc plate bent into the form of a cylinder. After this battery has acted for some time, the acid becomes so much weakened that it dissolves the iron suddenly. (Hawkins, Phil. Mag. J. 16, 115.—Poggendorfi’s Arrangement, Pogg. 54, 425.) | When the following carbonaceous substances are used instead of platinum in Grove’s battery, the quantity of detonating gas evolved ina given time is found to diminish as follows :—Platinum: 3°52;-—graphite: 3°4;—gas-coke, such as is deposited in the form of a hard crust in the retorts in which illuminating gas is generated: 3°27;—well burnt char- coal: 3:17. The action of all these substances is therefore nearly the same as that of platinum. (Cooper, Phil. Mag. J. 16, 35,)—Schénbein (Pogg. 49, 589) found the same result with gas-coke.—Charcoal having a surface of 8 square inches liberates as much gas as platinum 7 square inches in surface. (Smee.) | Bunsen (Ann. Pharm. 88, 811; Pogg. 54, 417) forms cells of car- bonaceous substance prepared in the manner already described (p. 392), fills these cells with a mixture of sand and nitric acid, which is renewed from time to time as it is used up,—and places them in dilute sulphuric acid, also containing the zinc plates. A battery of three such pairs with zine plates 3 inches wide and 4 inches long, liberates from 38 to 45 cubic centimetres of detonating gas per minute,—while, for every atom of water decomposed, not much more than one atom of zine is dissolved in each cell. Platinum wires of some thickness are made red-hot, and charcoal brought to a state of dazzling incandescence. (Vid. Poggendorff, Pogg. 54, 419.) Wohler & Weber (Ann. Pharm. 38, 307) form two cylinders, open above and below, out of a piece of polished iron plate: one of the cylin- ders is made wider than the other, and the two are connected by a bent piece of metal. The wider cylinder is placed in a glass vessel containing dilute sulphuric acid,—-in this is mmersed an earthenware cylinder filled with strong nitric acid,——and in this, the narrower cylinder of the following pair. The iron in the sulphuric acid acts like zinc, that in the nitric acid