PROPERTIES OP TOTASH.

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Potash was for a long time unknown in its pure state, becauseit was difficult to obtain it. We shall examine its properties inthat state, and then point out the methods of obtaining it.

PROPERTIES OF POTASH.

Potash, in a crystallized form, consists of soft quadrangularcompressed prisms, which are extremely caustic, and deliques-cent. It dissolves all soft animal matters when brought into con-tact with it. It liquefies by a gentle heat, and rises in fumes athigh temperatures. It does not unite in a direct manner withphosphorus. It easily combines with sulphur and metallic oxids.It dissolves alumine in the humid way, and even a small quan-tity of silex; but it does not act on glucine or zircon, nor onmagnesia or lime. It contracts no union with barytes. It ab-sorbs water and carbonic acid rapidly. It fuses into glass withsilex by the aid of fire. It forms salts which in general do notyield their acid unless to barytes. It changes blue vegetable co-lours green, and possesses all the general properties of alcalies.

METHODS OF OBTAINING POTASH.

It has long been a desideratum with chemists to possess amethod of preparing potash in a state of absolute purity; thestrong tendency which it has to combination renders this ex-tremely difficult. The following are the methods now made useof.

1. Bouillon la Grange'sapp aratus* consists of several boxes ofcommon deal. At the bottom put river-sand, which must bewell washed, and over it add another stratum, but of a finerkind, and cover the whole with a cloth, besprinkled with wood-ashes. In the bottom of each box a hole is made, into which is

P 3

La Grange’s Manual of Chemistry, vol. i. p. 172.