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 cannot form like potass an insoluble triple salt with the reagent. The acetate of soda is permanent in the air, while the acetate of potass is one of the most deliquescent salts known. In trying this last test, which is very characteristic, care must be taken to avoid an excess of acid in the acetate of soda by expelling it at a temperature of 212°, otherwise the salt is as deliquescent as the acetate of potass.—Another difference is, that the chloride of sodium, being nearly as soluble in temperate as in boiling water, crystallizes with difficulty and but sparingly by cooling a concentrated boiling solution; while the chloride of potassium is much more soluble in hot than in cold water, and crystallizes easily and abundantly when a concentrated boiling solution is cooled down.

Process for Potash and its Carbonate in Organic Mixtures.—The following method has been lately recommended for the detection of potash and its carbonate in complex organic mixtures. Ascertain that the mixture is alkaline in its action on litmus-paper and turmeric-paper, and that it is not ammoniacal in odour. Distil to one-third; ascertain that it has still an alkaline reaction, and evaporate to dryness in a porcelain basin. Agitate the residue, when cold, with absolute alcohol; boil, pour off the liquor, and filter it while hot. Repeat this with the residuum and more alcohol. Distil off most of the alcohol, and evaporate to dryness. Raise the heat to char the residuum, continue the heat as long as vapours come off, remove the charcoaly matter, and incinerate it for forty-five minutes in a silver crucible. Try to separate potash from what remains by means of absolute alcohol; and if this do not succeed, remove carbonate of potash by boiling water. In either case search for potash by litmus-paper, turmeric-paper, chloride of platinum, and perchloric acid.

The conclusiveness of this process depends upon the fact, that absolute alcohol cannot dissolve from solid organic substances such a proportion of lactate, tartrate, acetate, sulphate, or phosphate of potash, or chloride of potassium, as to be acted on by chloride of platinum or perchloric acid. —It is to be observed that carbonate of potash singly is insoluble in absolute alcohol; but it becomes soluble in that fluid, when it is conjoined with various organic matters. Hence it is that this process, intended fundamentally for caustic potash alone, is applicable to carbonate of potash also.

Process for Soda and its Carbonate in Organic Mixtures.—These substances may be separated by the method just described for potash. If the alcoholic solution of the extract of the suspected matter be alkaline in its action on litmus, and be afterwards found to contain soda or its carbonate, the evidence of these substances having been derived from without is satisfactory, because the carbonate of soda contained in many animal matters cannot be so detached. But if no indications of the presence of soda be thus obtained, it is not enough that soda be found in the alcoholic solution of the incinerated alco-*