Pur., &c. Pure nitrate of silver, whether crystallised or fused, is entirely soluble in water, yielding a colourless solution, from which metallic silver is precipitated by a piece of bright copper; both are originally white, but are darkened by exposure to light and contact with organic matter.
Uses, &c. Nitrate of silver is a powerful tonic, antispasmodic, astringent and escharotic.—Dose, 1⁄8 to 1 gr., gradually increased, twice or thrice a day, made into a pill with crum of bread; in cholera, epilepsy, &c., preceded by purgatives. It has been highly extolled by Mr Ross as a remedy in cholera. Its continued use permanently colours the skin. It is also extensively employed externally as a caustic. It is powerfully poisonous. A solution of common salt, emetics, and demulcents, constitute the treatment in such cases. Nitrate of silver is much employed in the manufacture of ‘indelible ink’ for linen, and hair dyes.
Silver, Di′oxide of. Ag2O2. Syn. Argenti suboxydum, L. Prep. From dry citrate of silver heated to 212° Fahr., in a stream of hydrogen gas, until it turns dark brown, when it is dissolved in water; the solution is next treated with potassa, and the precipitate is carefully washed and dried. A black powder, easily decomposed, and soluble in ammonia.
Silver, Oxide of. Ag2O. Syn. Protoxide of silver; ARGENTI OXYDUM, A. PROTOXYDUM, L. Prep. 1. (Lane.) Nitrate of silver, 2 parts; hydrate of potassa, 1 part; dissolve each separately in distilled water, mix the solutions, and, after frequent agitation during an hour, collect and wash the precipitate, and dry it by a gentle heat in the shade. A pale brown powder.
2. Recently precipitated chloride of silver is boiled in a solution of hydrate of potassium of the sp. gr. 1·25, with frequent stirring and trituration, until, on testing a little of it, it is found to be entirely soluble in dilute nitric acid, when it is washed and dried, as before. A black and very dense powder. Chemically pure.
3. Nitrate of silver, 1⁄2 oz.; water, 4 fl. oz., dissolve, and pour the solution into a bottle containing lime water, 2 quarts, or q. s.; agitate the mixture well, collect and wash the sediment, and dry it at a heat not exceeding
212° Fahr. A dark olive-brown powder. Pure.
Prop., &c. Very soluble in solutions of ammonia and of the alkaline hyposulphites; slightly soluble in water; reaction alkaline; decomposed by light.—Dose, 1⁄2 to 2 gr.; in epilepsy, gastralgic irritations, &c. It is much used in France, and has been highly extolled in menorrhagia. By some, however, it is not considered superior to the nitrate.
Silver Pencils, Nitrate of. According to A. Huber, very thin pencils of nitrate of silver, such as are sometimes required for intra-uterine applications may be prepared in the following manner:—Silver nitrate is fused in a capsule, and the liquid drawn up by slow and cautious suction into a glass tube, the calibre of which is a trifle larger than the required diameter of the pencil. Especial care is to be taken that no cavities filled with air-bubbles are produced in the contents of the tube. When entirely cold the tube is warmed by turning over a spirit-lamp until the outer surface of the stick has become soft, when it may be easily pushed out by means of a knitting needle. With a little practice very handsome pencils of considerable length may be obtained in this manner.
Silver, Perox′ide of. Syn. Argenti peroxydum, L. A black crystalline substance which forms on the positive electrode of a voltaic arrangement employed to decompose solution of nitrate of silver.