o64

Acids. — Acidiim Aceticum.

PART III.

odour than common vinegar ,• a grateful, not strong, acid taste:is limpid and colourless; and of a specific gravity varying from1*007 to 1*0095. One fluid ounce of spec. grav. 1*007 shoulddissolve 13'8 grains of marble. It dissolves the gum resinsand the active principles of plants, such as those of the squilland the meadow saffron; and forms acetates with the alkaliesand several of the metallic oxides. Darracq' ascertained that itdiffers from acetic acid in containing some uncombined mucilageand extractive matter, but that the acids are otherwise thesame. It is owing to this extractive that, when distilled vinegaris boiled with potass, the solution has a deep reddish browncolour, and during evaporation carbonaceous matter is de-posited. It is sometimes adulterated. Sulphuric acid is de-tected by a precipitate being produced on the addition of asolution of acetate of barytes; lead and tin, by a solution ofsulphuretted hydrogen, forming a dark-coloured precipitate;and copper, by the acid assuming a blue colour, when super-saturated with ammonia.

Medical properties and uses. — The same as those of commonvinegar; but, as it is purer, and not liable to spontaneous de-composition, it is fitter for pharmaceutical purposes.

Officinal preparations. Liquor Ammonite Acetatis, L. E. D. Po-tasscc Acetas, L. E. D. Acetas Ferri, D. Liquor Plumbi Sub-acetatis, L. D. Plumbi Superacetas, L. E. D. Acetum ColcJtici, L.Acetum Scillce, L. E. D. Oxymel, L. D. Emplastrum Ammo-niaci, L. Oxymel Colchici, D.

ACIDUM ACETICUM, Bub. Acetic Acid.

" Take of acetate of kali, (potash), six ounces,- sulphuricacid, three ounces by weight. Pour the acid into a tubulatedretort: 'then add to it in small portions and at different times,the acetate of potass, allowing the mixture to cool after eachaddition; finally, with a moderate heat, distil the acid untilthe residue be dry.

" The specific gravity of this acid is to that of distilledwater, as 1070 to 1000."

Acidum aceticum forte, Edin. Strong Acetic Acid.

" Take of dried sulphate of iron, one pound ; acetate [super-acetate) of lead, ten ounces. Rub them together; then putthem into a retort, and distil in a sand bath with a moderateheat, as long as any acid comes over."

Syn. A i('e Acetirjue (F.), Essigsiiurc ( G.), Acido acetico (7.).

These processes furnish the same acid as that which is con-tained in distilled vinegar, but completely free from extractiveand mucilage, and much stronger. In the process of theDublin College, the sulphuric acid, by reason of its superioraffinity for potass, decomposes the acetate of potass, and sets

Annates de Ctiimie, xli. 261.