Contractions. - Arg. Nit. Ag.-n.

Present name. - Argentic Nitrate. AgNo3.

Lunar Caustic. For. names: German, Salpetersaures Silber; French, Argent Nitrate.

The British Pharmacopoeia gives the following directions for preparing this: -

Take of

Purified Silver . . .

3 ounces;

Nitric Acid ....

21/2 fluid ounces;

Distilled Water . . .

5 fluid ounces.

Add the Nitric Acid and the water to the Silver in a flask, and apply a gentle heat till the metal is dissolved. Decant the clear liquor from any black powder which may be present into a porcelain dish, evaporate, and set aside to crystallize; pour off the liquor, and again evaporate and crystallize. Let the crystals drain in a glass funnel, and dry them by exposure to the air, carefully avoiding the contact of all organic substances. Nitrate of Silver must be preserved in bottles carefully stoppered.

Characters and Tests. - In colourless tabular crystals, the primary form of which is the right rhombic prism; soluble in distilled water and in rectified spirit. The solution gives with Hydrochloric Acid a curdy white precipitate, which darkens by exposure to light, and is soluble in solution of Ammonia. A small fragment heated on charcoal with the blow-pipe, first melts, and then deflagrates, leaving behind a dull white metallic coating. 10 grains dissolved in 2 fluid drachms of distilled water give with Hydrochloric Acid a precipitate, which, when washed and thoroughly dried, weighs 8.44 grains. The filtrate when evaporated by a water-bath leaves no residue.

Preparation. - A solution of 1 in 10 in distilled water; and for dilution continue to use distilled water up to 3, then use dilute alcohol for 4, and afterwards rectified spirit. The salt ought not to be prepared as a trituration, on account of its action on organic matter.

Reference to Horn. Proving. - R. A. M. L., iv. (Est. Zeitsch. f. Horn., ii.

Proper forms for dispensing. - Below 4, watery Solution only. 4, dilute Tincture only. 5 and upwards, Tincture, Pilules, or Globules.

N.B. - It is difficult to preserve the watery attenuations unless they are kept in yellow actinic bottles.