CHEMICAL NAMES.

Sulphide of ammonium

Bisulphide of carbon.

.

EQUIVALENTS.

Hydrosulphate of ammonium,-sulphydrate of ammonia.

Sulphuret of carbon,-spirit or liquor

of Lampadius,-carbon di-sulphide.

Pentasulphide of potassium. Polysulphide of potassium, liver of

FROM the preceding list we select a certain number of especially important substances, for detailed description. As for those materials which are found sufficiently pure in the trade, we shall simply point out their principal characteristics, and refer the reader, desirous of more information, to the numerous and excellent works on chemistry.

Acetate of Copper, neutral (highly poisonous).

It is found in the market either in the form of darkgreen crystals, or of a bright-green powder-highly poisonous-soluble in water, which becomes green; very soluble in ammonia, forming a solution of an azure-blue color; forms colorless double salts with cyanide of potassium and sulphite of sodium; powerful acids, like sulphuric acid, combine with the oxide of copper, and the acetic acid set free is recognized by its smell; is used for preparing electro-baths of copper and brass.

Acetate of Copper, basic (poisonous).
Verdigris.

Powder of a fine turquois bluish-green. Imperfectly soluble in water, and difficult to combine with the sulphites and cyanides, unless previously treated with ammonia. It is often used for adulterating the salt above named.

Acetate of Lead (poisonous).

Sugar of lead.

This is ordinarily in the shape of crystalline masses; white; light, although having lead for its base; very soluble; savor, at first sweetish, then metallic; gives on calcination fumes of acetic acid and acetone, and the residue is oxide of lead with a certain proportion of metallic lead. Is not precipitated by carbonic acid, unless there is mixed with it some basic acetate. Obtained by dissolving litharge or massicot (protoxide of lead) in an excess of vinegar, or acetic acid. Its solution forms, with caustic potassa or soda, a white precipitate which is soluble in an excess of alkali, and then constitutes the bath for producing the colored rings of Nobili.

Sub-acetate of Lead

In solid masses, or syrupy. metallic than the preceding.

(poisonous).

Savor, sweet but more Heavy; white precipitate

by carbonic acid; obtained by boiling a solution of acetate with an excess of litharge. Used for the same galvanoplastic processes.

ing carbonic acid.

Renders turbid distilled water contain

Acetic Acid.

(Vinegar. Pyroligneous acid.)

More or less concentrated and pure, according to the mode of manufacture. The most concentrated crystal

lizes at 25° Fah., and often remains solid up to 50° or 54° Fah.

Wood vinegar or pyroligneous acid is employed in large quantities, and is colorless or more or less yellow. It often possesses an empyreumatic odor, and generally marks 8° of the hydrometer.

Wine vinegar is more or less colored, and may be concentrated. Its smell is sufficient to distinguish it.

Glacial or crystallized acetic acid is obtained by the distillation of perfectly dry acetate of sodium, or acetate of lead, with concentrated sulphuric acid. The vapors are condensed in a glass receiver (Fig. 162), which should be surrounded by a mixture of salt and ice.

Arsenious Acid (poisonous).

(White arsenic. Arsenic. Ratsbane.)

Generally in the shape of a white powder, and sometimes in vitreous-like lumps, resembling porcelain. Slightly soluble in water; savor, scarcely sensible at first, but hot and sharp afterwards, with constriction of the throat. When thrown upon incandescent charcoal it emits abundant white fumes, with a characteristic smell of garlic. Introduced into Marsh's apparatus it furnishes mirrorlike arsenical rings and spots. It is employed in certain silver whitening baths, and also in the electro-baths for brass.