PROOFS OF THE PROPERTIES OF SODA. 241

Mottled soap is made in a similar manner as the last, die mot-tled appearance is given towards the end of the operation of boil-ing, by dispersing the ley through the soap, or by adding to it aquantity of a solution of sulphate of iron, which by its decompo-sition, deposits its oxid through the soap, and gives it an appear-ance of blue marble. In some manufactures the black oxid ofmahganese is made use of for the same purpose.

Yellow soap is made with tallow and resin j and these arereckoned good, if 10 cwt. of tallow, and 3|cwt. of resin withdie proper quantity of soda afford a ton of soap.*

Soap of wool may be made by boiling shreds of woollen clothof any kind, with ley, till the whole has acquired a certain con-sistence. This kind of soap has been made and applied withsuccess,f in several manufactures in France.

An ammoniacal soap may be produced, by pouring a concen-trated solution of muriate of ammonia into a solution of commonsoap.

A soap of lime, larytcs , andslronlia, may be formed, by pour-ing solutions of these alcalies into that of common soap. These,together with the following terrene soaps, are insoluble, and pos-sess no detergent properties.

Amongst the earthy soaps those of magnesia and alumine arethe principal. Soap of magnesia is produced by mingling a so-lution of common soap with a solution of sulphate of magnesia.Soap of alumine is obtained by adding to a solution of soap a so-lution of alum of commerce.

V,

Q

Nicholson's Journal, 4to edition, 1779, No. xxviii, p. IOt.t Ann. de Chirnie. ixi, 37.