PROOFS OF THE PROPERTIES OF SODA.

239

SECT. II.

Experimental proofs

OF

THE PROPERTIES OF SODA.

Experiment I.

Method of distinguishing soda from potash.

Let fall into a solution of the alcali to be investigated a fewgrains of oxalic acid ; for this acid forms with potash oxalate ofpotash, which is very soluble, and on the contrary with soda itproduces oxalate of soda, which is of a very difficult solubility.

Experiment II.

Formation of soap.

The combination of soda or potash, with oils, or fat in gene-ral, forms the compound called soap. The union of oil, &c. withpotash, affords those called soft soap ; the combination of sodawith the same substances affords those called hard soap. Itseems to be an established truth that potash combined with anykind of fat can only afford a soap, to which no cooling can give