This useful article should be bought in quantities; say, half cwt. or cwt. at a time, if the family be large; if small, it should be bought by the four bars at once. A bar contains about three pounds of soap. The reason for buying a quantity at once is that it hardens by keeping, and therefore does its work of cleansing without so much waste in the water. The bars should be cut into moderate sized pieces for use with a fine twine, they will harden better than if it be left in the bar. Scented soap should also be kept for use. If shape is not an object, pieces of scented soap of the best kind may be purchased very cheaply of any of the great manufacturers. These are the bits cut off in forming the pats, which, of course, they quite equal, except in shape. They are sold by the pound. Soap is made of fat, exposed to the action of a caustic alkali, which produces on it a peculiar change called saponification.
Almost every kind of fat or oil has been used, at different times, for soap. Of oils, those of hemp-seed, rape-seed, cocoa nut, beech-seed, poppy-seed, palms, almonds and nuts. Fat of any kind (such as tallow, etc.) is also used for soaps. The alkalies used to make soap are potash or soda. Yellow soap is made of whale oil, soda and resin; soft soap, of oil and potash; hard soap of oil and soda. Soda-made soap consists of about 61 parts of fat or oil, 8 1/2 of soda, and 30 1/2 of water. Some portion of the water will evaporate if it be kept in a dry place. In common yellow soap, whale oil, or palm oil and resin, are used with the soda. Soap made of tallow and potash consists of about 28 parts of fat, 12 of potash, and 29 of water. This, as we have said, is soft-soap. Mottled soap is made by mixing a solution of the sulphate of iron with common hard white soap while it is still in a melting state. The alkali in the soap decomposes the sulphate, and black oxide of iron is deposited in streaks through the soap.
Brown Windsor is hard white soap coloured with burnt umber and scented.
Glycerine soap is made with hog's lard, oil of almonds, nut-oil, palm-oil, or suet and soda, with glycerine added to it.
Honey soap has no honey in it; it is simply the same compound as glycerine, with the essential oil of citronella added to it.
Marseilles white soap consists of soda and olive oil, with water. Castile soap of the same materials, with more olive oil and soda, and less water. It has also colouring matter in it. These soaps are expensive.
Common soft-soap is made with coarse fish oil; white soft-soap with potash and tallow, as we have before said. Green soap is made with vegetable oils, such as rape- and poppy-seed oil; soft-soap can be made hard by the addition of common salt when it is in process of making.
The best soap for the skin is the very best yellow soap; it softens it excessively, and when rubbed in instead of being washed off, it is useful as an external remedy for rheumatism, and used to be prescribed by Sir William Fergusson.
Soap is sold - yellow, at about 4 1/2d. per lb.; mottled, about 4d. per lb.; scented soap is sold by the pat, or bar, 1s. per bar, 3d. or 4d. per pat.
Carbolic soap is a valuable preparation, as it has great disinfecting powers, and should always be used in washing the linen of fever patients. It possesses also great cleansing power without injuring the material on which it is used. Its use is fatal also to house insects. There is also a carbolic toilette soap which is excellent in hot weather for the skin. The Kalydor soap is also very good for the skin.
The following process for making soap is practised by emigrants: - Two or three gallons of clean water are poured upon about a bushel of wood ashes, thoroughly stirred, and the ash is allowed to subside. The liquid, which is now a lye, is drawn off and boiled for two or three hours with fat of any description. At the end of that time the fat will have assumed the consistency of soap. It is allowed to settle, and the liquor is then drawn off, being no longer of any use. The residue, although soft, will answer every purpose for which soap is used.