3. Sulphate of Copper.

Officinal. Cupri Sulphas, Lond. Edin. Dub. Sulphate of Copper.

Syn. Sulphate de cuivre (F.), Schwefelsaures Kupfer, Kupfervitriol (G.), Kopper vitriol (Belg.), Blaae vitriol (Danish), Vitriuolo di rarne (I.), Caparosa (S.), Vitriolo de Cobre (Portug.), Zungbar (Arab.), Tuteya (H.), Tutt'ha (San.), Toorushoo (Tarn.), Neelatota (Duk.), Palmanicum (Cyng.).

1 Vide Traite des Poisons, etc. par P. M. Orfila, tome ii p. 289.

A considerable part of this salt, which is the blue vitriol of commerce, is obtained by evaporation from the water of some copper mines. Its origin is derived from the natural sul-phurets of copper, which, suffering a chymical change from exposure to a moist atmosphere, are converted into the sulphate, and washed down by the rain and other water of the mines.1 It is also obtained by roasting copper pyrites, and exposing it to the action of air and moisture; in which case, as well as in the former, the compound is oxidized by attracting the oxygen of the surrounding atmosphere, at the same time that it changes the sulphur into sulphuric acid; so that by the gradual combination of these the sulphate is produced, and is then extracted by solution, and crystallized. It is also, in France, made by sprinkling wet sheets of copper with sulphur, then heating them to redness, and plunging them in water. The surfaces of the sheets are thus covered with the sulphuret, which on exposure to the air gradually passes into the sulphate, which is dissolved and crystallized.

Qualities.-Sulphate of copper is inodorous, and has a very harsh, acrid, styptic taste. It always reddens vegetable blues. It is in semitransparent crystals, which undergo a slight degree of efflorescence when exposed to the air: their form is that of a rhomboidal prism; and their colour a deep rich blue. Its specific gravity is 2.1943.

Sulphate of copper is soluble in four parts of water at 60°, and less than two at 212°. It is insoluble in alcohol. The solution reddens litmus paper. It consists of 1 eq. of protoxide of copper = 39.6 + 1 of sulphuric acid =. 40.1 : = 79.7. It is decomposed by the alkalies and alkaline carbonates, the biborate and phosphate of soda, acetate of ammonia, the acetate and sub-acetate of lead, and acetate of iron, nitrate of silver, bichloride of mercury, tartrate of potassa, muriate of lime; and is precipitated by all the astringent vegetable infusions and tinctures; all which substances are therefore incompatible in prescriptions with this salt.

Medical properties and uses.- Sulphate of copper is emetic, astringent, and tonic, when taken internally. With a view to its emetic effect, it has been given in the early stage of phthisis, in croup2, and where laudanum has been taken as a poison; and as an astringent and tonic, in chronic diarrhoea, alvine haemorrhages, intermittent fever, epilepsy, and some other spasmodic affections : but as the list of Materia Medica l From this water at the Parys mine, a large supply of copper is obtained, by decomposing the sulphate, by throwing into the water old iron hoops.

2 Drs. Serle and Malin used it with success. Vide Hufeland's Journ. Jan. 1834.

contains equally powerful and less hazardous remedies, its internal exhibition ought to be altogether discontinued. Externally it may be employed to give a healthy stimulus to indolent foul ulcers, in which I have found it extremely beneficial; and as an escharotic, to consume fungus. Pledgets dipped in a weak solution of it are also sometimes used as a styptic in epistaxis, and other external haemorrhages; and a still weaker solution is a useful collyrium in some kinds of ophthalmia. It forms the basis of a very unchymical preparation, Bate's aqua camphorata 1 which the late Mr. Ware recommended, diluted with sixteen parts of water, in the purulent ophthalmia of infants.

As an emetic, the dose is from grs. ij. to xv., in f ij. of water; but as a tonic it should be given in the form of pill, beginning with gr. 1/6, and gradually increasing the dose to grs. ij.

Officinal preparations.-Solutio Cupri Sulphatis composita, E. Cupri Ammonio Sulphas, L. Cuprum Ammoniatum, E. D.