Chap. III. Alkalies and Alkaline Salts,

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SlJBCARBONAS KALI. Dllb.

Subcarbonate of Kali.

Take of

Potashes, in coarse powder,Cold water, each six pounds.

Mix them by trituration, and macerate them for a week in awide vessel, with occasional agitation. Filter the ley, andevaporate it to dryness in a very clean iron vessel. To-wards the end of the evaporation, stir the saline mass con-stantly with an iron spatula. When thus reduced to coarsepowder, keep it in close vessels.

Before the ashes are dissolved in the water, if they be not suf-ficiently pure, roast them in a crucible till they becomewhite.

Cabbonas potass^, purissimus ; olim, Sal tartabi. Ed.Pure Carbonate of Potash ,- formerly Salt of Tartar.

Take of

Impure super-tartrate of potass, any quantity.

Wrap it up in moist bibulous paper, or put it into a cruci-ble, and burn it into a black mass, by placing it amonglive coals. Having reduced this mass to powder, expose itin an open crucible to the action of a moderate fire, till itbecome white, or at least of an ash-grey colour taking carethat it do not melt. Then dissolve it in warm water ;strain die liquor through a linen cloth, and evaporate it ina clean iron vessel, diligently stirring it, towards the end ofthe process, with an iron spatula, to prevent it from stick-ing to the bottom of the vessel. A very white salt will re-main, which is to be left a little longer on the fire, till thebottom of the vessel becomes almost red. Lastly, when thesalt is grown cold, keep it in glass vessels, well stopped.

Kali e tartaro. Dub.Kali from Tartar.

Take of

Crystals of tartar, any quantity.

Heat them to redness in a silver crucible, loosely covered, un-til they cease to emit fumes. Reduce the mass which re-mains to coarse powder, and roast it for two hours in thecame crucible, uncovered, stirring it frequently. Boil thisin twice its weight of water, for a quarter of an hour, andafter the liquor has become pure, pour it off. Repeat thisthree times.