MOTTLED SOAP FRAMES.
Soft soap is made in the same way, using potash instead of soda, and, generally, a large quantity of train-oil. Castile soap is pure soda soap, and the blueish or red mottled appearance is produced by stirring in some sulphate of iron (green vitriol); when new it is of a blueish color, but gets red by exposure to the air.
Oils and fats combine with the oxides of several of the metals, and a combination of oxide of lead with olive oil forms a firm solid substance, or plaister, which, with the addition of a little resin, is used in surgery, and when spread upon linen or calico, forms the common adhesive plaister.
Oils and fats all consist of a combination of organic acids, (stearic, oleic, and margaric), with glycerine. When these fats are boiled with soda, potash, or metallic oxides, a combination of the oxide and fatty acid takes place, and this constitutes soap. The glycerine is then set free, and, when purified, forms a sweet, oily, colorless fluid, very similar to syrup, but not so sweet; it has lately been used for several purposes, especially as a remedy for chapped hands; a soap called “glycerine soap,” has lately been used for the same purpose; it is a soap made without separating the glycerine.
MACHINE FOR CUTTING SOAP IN BARS.
The above illustration represents an ingenious contrivance for the purpose of cutting soap.