Volume 2

The elements of experimental chemistry / [William Henry].

  • Henry, William, 1774-1836
Date:
1818
Catalogue details

Licence: Public Domain Mark

Credit: The elements of experimental chemistry / [William Henry]. Source: Wellcome Collection.

    38/636 (page 18)
    drogen. Sulphur occasions the formation of sulphuretted hydrogen, equal in volume to twice the original gas. Three parts of it in volume condense more than five of oxygen; and one in volume absorbs four of chlorine. It appears to be con¬ stituted of two atoms of hydrogen and one of phosphorus; and the hydrogen in it is condensed into half its bulk. In that case the weight of its atom will be 13. Its formation appears to be owing to the decomposition of water, the oxygen of which, with part of the phosphorous acid, forms phosphoric acid, while the hydrogen dissolving the ex¬ cess of phosphorus existing in another portion of phospho¬ rous acid, composes the peculiar gas. Art. 4-.—Bi-phosphuretted Hydrogen Gas. I. This gas may be procured, by boiling, in a retort, a little phosphorus with a solution of pure potash. The water is decomposed; its oxygen, uniting with the phosphorus, forms phosphoric acid, which combines with the alkali, while the hydrogen dissolves another portion of phosphorus, constituting bi-phosphuretted hydrogen gas.—-This gas may also be obtained, by putting into five parts of water half a part of phosphorus, cut into very small pieces, with one of finely granulated zinc, and adding three parts of strong sul¬ phuric acid. This affords an amusing experiment. The gas is disengaged in small bubbles, which cover the whole surface of the fluid, and take fire on reaching the air; these are suc¬ ceeded by others, and a well of fire is produced. (Davy.) In preparing this gas from phosphorus and solution of potash, both the body and neck of the retort should be en¬ tirely filled with the solution, which Dr. Coxe, of Philadel¬ phia, recommends to be almost boiling hot. He employs a retort holding from half a pint to a pint; and after intro¬ ducing both the phosphorus and the solution, fixes its neck on an inclined plane formed of a block of wood, the upper extremity of which is overhung by the body of the retort, while its mouth projects over the lower end, and is 'dipped Into a small bowl filled with a hot solution of potash. The gas, extricated by the flame of a lamp, accumulates; and, forcing the alkaline solution down the neck, at length escapes,