The principles of chemistry : illustrated by simple experiments / by Julius Adolph Stöckhardt ; translated from the 3rd German ed. by C.H. Peirce.

  • Stöckhardt, Julius Adolph, 1809-1886.
Date:
1850
Catalogue details

Licence: Public Domain Mark

Credit: The principles of chemistry : illustrated by simple experiments / by Julius Adolph Stöckhardt ; translated from the 3rd German ed. by C.H. Peirce. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    an inch deep, and then invert the vessel intended for the reception of the gas, with its mouth exactly over the opening, placing the extremity of the glass tube, from which the gas proceeds, directly beneath, so that the gas may enter it as through a funnel. This con- trivance is called a pneumatic trough. In order to col- lect and preserve larger quantities of gas, and to ex- periment with them more conveniently, special contriv- ances, called gasometers, are used in chemical labora- / tories. /C Of -Mtfys, 61. Chlorate of potassa contains for every one hun- dred grains about forty grains of oxygen chemically combined; by the application of heat, these become free and escape. Red oxide of mercury contains only eight per cent, of oxygen; therefore the former will yield five times more oxygen than the latter. If vials of twelve ounces' capacity are selected for receiving the gas, we shall be able to fill five of them, and shall have in each about eight grains, or nearly twenty cubic inches, of oxygen. Chlorate of potassa may, under some circumstances, as when strongly rubbed, or treated with sulphuric acid, occasion very dangerous explosions; but no dan- ger is to be apprehended from the application of it, when made as above directed. 62. Experiment. — Add warm water to the salt re- maining in the test-tube after the expulsion of the oxy- gen, and place the tube in a warm place until the salt is dissolved; evaporate the solution gradually, over a stove, when small cubic crystals (chloride of potas- sium) will be deposited. The chlorate of potassa cry* tallizes m thin tables or plates, the heated massin cubes; this difference in the form of the crystals alone indicates that, by the heating of the former, an entirely