Cupric Sulphate

CuSO 4 .5Aq. Syn. Sulphate of copper , Blue cop′per as , B. vit′riol ; Cu′pri sul′phas , L.; Sulfate de cuivre , Fr.; Kupfer vitriol , Ger.; Neela tootia , Hind. Prep. (Commercial.) The sulphate of copper of commerce is obtained by the oxidation of native sulphide of copper ( COPPER PYRITES ); by the joint action of air, heat, and moisture, the copper is converted into an oxide, and the sulphur into sulphuric acid. The resulting salt is washed out, and the solution evaporated and crystallised. The water found in and i uing from copper mines often furnishes such a solution ready to the hands of the manufacturers. A large quantity of sulphate of copper is also obtained as a secondary product in the refining of silver, and is occasionally prepared by di olving in sulphuric acid an oxy chloride of copper, made for the purpose by exposing sheets of copper to the joint action of air and hydrochloric acid. (Pure.) By the direct solution of the metal, or preferably, of its oxide or carbonate in sulphuric acid, or by purifying the commercial salt by recrystallisation, . Prop., Uses, . Fine blue crystals, slightly efflorescent, having an intensely styptic and metallic taste. By heat the blue salt loses its water of crystallisation, and becomes a white, anhydrous powder. It di olves in 4 parts of water at 60° Fahr., and in 2 parts at 212°; is insoluble in alcohol and ether; and is decomposed at an intense heat into protoxide of copper, sulphurous acid, and oxygen. It has been used to prevent the dry rot in timber and in dyeing. It is largely employed as a source of metallic copper in the ELECTROTYPE . Grain is steeped in a weak solution of it by the farmer, to prevent the ‘smut,’ As a medicine, it is employed chiefly as a styptic (in solution) and caustic (in substance) to destroy ‘proud flesh,’ and, le frequently, as an astringent or tonic (from 1 ⁄ 4 gr. to 2 gr.), and an emetic (3 or 4 gr. to 10 or 12 gr). It is exceedingly poisonous.