476

Alkalies and Neutral Salts.

part in.

a greater pressure wiJl be requisite. The fluid must be pre-served in well-corked bottles.

This preparation is milder and pleasanter than the waterprepared with subcarbonate of potash. It is manufactured inlarge quantities on a great scale, of a much superior qualityto any which the apothecary can prepare; and is in very ge-neral use as a cooling beverage. Haifa pint of it poured overtwo table-spoonfuls of lemon-juice, sweetened with a little sugar,forms an excellent and very agreeable effervescing draught,-and the same quantity poured upon two ounces of boiling milkforms an excellent substitute for asses' milk.

SO'D^ SUL'PHAS. Lond. 1 Sulphate of Soda.

" Take of the salt which remains after the distillation ofmuriatic acid, two pounds; boiling water, two pints and a half.Dissolve the salt in the water; then add gradually as muchsubcarbonate of soda as will saturate the acid. Boil the solu-tion until a pellicle appears, and after having filtered it set itapart to crystallize. Pour the water from off'the crystals, anddry them on bibulous paper."

Sulphas Sodj;. Edin. Sulphate of Soda.

" Dissolve in water the acidulous salt which remains afterthe distillation of muriatic acid, and having mixed with it car-bonate of lime {chalk) in powder to remove the superfluousacid, set it apart until the impurities subside; then, havingpoured off the liquor, filter it through paper, and reduce it byevaporation, that crystals may be formed."

Dublin.

u Dissolve the salt which remains after the distillation ofmuriatic acid in a sufficient quantity of boiling water. Evapo-rate the filtered solution to a proper point, and set it apart,that, as it slowly cools, crystals may form.

The theory of the London process for preparing this salt isanalogous to that of the process for preparing the sulphate oipotash ; but, from the low price of the salt, manufactured on agreat scale (see Part ii.) it is preferable to saturate the super-abundant acid with chalk, and reject the sulphate of Jime. Thesalt obtained by the Dublin process has a slight acidulous taste,and contains a quantity of sulphuric acid, but so loosely com-bined as scarcely to entitle it to be regarded as a supersalt;nor do its crystals differ in form from those produced by theother two formulae/

dualities. —The taste of this salt is at first simply saline, but

« Natron Vitriolatum, P. L. 1787. Sulphate de Soude (F) Krystalisirtes Natrum(G.) Solfato di Soda (/.)

2- The crystals of the 6upersulphate formed by dissolving the sulphate in sulphur'*!acid, and crystallizing, are rliomboidal.