The method of boiling such a soap is the same as for any settled soap up to the strengthening change. When this stage is reached, sufficient lye is added to strengthen the kettle strongly. It is then boiled down with closed steam on salt brine or "pickle" until a sample of the lye taken from the bottom stands at 16°-22° B. The soap is then run into barrels and after standing therein for a day is hand crutched until cool to prevent streaking of the soap.
Besides a soap of this type a settled tallow chip soap is used.
WOOL THROWER'S SOAP.
Soaps for wool throwing are sometimes made from olive oil foots but these are often objected to because of the sulphur-like odor conveyed to the cloth due to the method by which this oil is extracted with carbon disulphide. A potash soap hardened somewhat with soda is also used. As a formula for a suitable soap of this type this may be given.
| Olive Oil Foots | 12 parts |
| Corn Oil | 46 " |
| House Grease | 20 " |
| Soda Lye, 36° B. | 3 " |
| Potassium Carbonate (dry) | 5-3/4 " |
| Potassium Hydrate (solid) | 23 " |
This soap is made as a "run" soap by the general directions already given for a soap thus made. The kettle is boiled with open and closed steam, adding water very slowly and aiming to obtain a 220-225 per cent. yield or fatty acid content of the finished soap of 46 per cent. When the soap is finished a sample cooled on a plate of glass should be neither slippery or short, but should string slightly. The finished soap is run directly into barrels.
A soap for wool throwing by the semi-boiled process may be made from olive oil foots in a crutcher thus:
| Olive Oil Foots | 600 lbs. |
| Potash Lye, 20° B. | 660 " |
The oil is heated to 180° F., the lye added and the mass stirred until it bunches, when it is dropped into barrels.