Chap. III. Alkalies and Alkaline Salts.

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acid liquor, and the acid they contain is easily obtained byevaporation and crystallization. The acid may afterwards bepurified by solution in boiling water and crystallization, ac-cording to the directions of the colleges.

But even after repeated solutions and crystallizations, aportion of empyreumatic oil still adheres to the acid, and ren-ders it impure. Other methods of purifying it have beentherefore attempted. Demachy saturated it with lime, sepa-rated the lime by sulphuric acid, and sublimed the succinicacid : Richter saturated succinic acid with potass, decomposedthe salt formed with acetate of lead, and disengaged the suc-cinic acid from the lead by means of diluted sulphuric acid :lastly, MorVeau asserts that he obtained it in a state of perfectpurity, by treating it with nitrous acid. It is often adulte-rated with muriate of ammonia, sulphuric acid, sulphate ofpotass, sugar, &c. When pure it is entirely volatile, givesout no ammoniacal fumes when triturated with potass, is notprecipitated by solutions of baryta, and is soluble in alcohol.Succinic acid, although retained in the Edinburgh andDublin Pharmacopoeias, is never used in medicine. It hasbeen rejected from the London.

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Chap. III.

-ALKALIES, and ALKALINESALTS.

Aqua potass^e : vulgo Lixivium causticum. Ed.Solution of Potass, commonly called Caustic Ley.

Take of

Newly prepared lime, eight ounces;Carbonate of potass, six ounces.

Put the lime into an iron or earthen vessel, with twenty-eightounces of warm water. After the ebullition is finished,instantly add the salt; and having thoroughly mixed them,cover the vessel till they cool. When the mixture hascooled, agitate it well, and pour it into a glass funnel, thethroat of which is obstructed with a piece of clean linen.Cover the upper orifice of the funnel, and insert its tubeinto another glass vessel, so that the Solution of Potass maygradually drop through the rag into the lower vessel. Assoon as it ceases to drop, pour into the funnel some ouncesof water, but cautiously, so that it may swim above thematter in the funnel. The Solution of Potass will again

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