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NATURAL HISTORY OF POTASH.

POTASH.

PART LXVII.

SECT. I.

NATURAL HISTORY OF POTASH.

J[f wood or vegetables be burnt in the open, air, and the ashesrepeatedly washed with water till it passes tasteless, and if this li-quid be evaporated to dryness, the substance which remains iscalled potash ; far however from being in a state of purity. Inthis state it occurs in commerce.

It is seldom found in an uncombined state, except in wells intowns, as at Douay, &c. It is said to exist in the aluminous oreof La Tolfa. In combination with the sulphuric, nitric, andmuriatic acids, it is found in Spain and in the East Indies.

Potash was formerly denominated die vegetable alcali, butimproperly, because it is met with abundantly in mineral bodies,more especially in volcanic products. Dr. Kennedy has latelydiscovered.it in the pumice stone. Vauquelin has found it in theZeolite from the Ferro islands. Klaproth has likewise discoveredit in the Leuclte, an earth of the siliceous genus.

Vegetable physiologists are not agreed whedier potash be de-rived from the soil in which vegetables grow; whedier it existsuncombined with any acid in plants; whether it be a productof vegetation; or whether it be generated during the process ofburning.