Chapter V
for discussion of soft and hard water.)
Hard water prevents the soap from lathering, and this must be counteracted for laundering. _Temporary hardness_ is removed by boiling. _Permanent hardness_ is not affected by boiling and can be overcome only by the addition of some substance like ammonia, borax, or soda. Only enough of these should be used to allow the soap to do its work, since they may injure fabric and the skin of the worker.
_Soap_ is the most useful of the cleansing agents added to water. It may have been accidentally made in the first place by some housewife who put a greasy pot to soak with a solution of lye made from the ashes of her hearth fire. Heat and alkali break up the fat into two parts, glycerin and a fatty acid. The fatty acid combines with the alkali, giving soap, and the glycerin remains free. Both animal and vegetable fats are used, and different forms of alkali, usually potash or caustic soda, the former for soft, the latter for hard, soap.
In these days soap is much better made in the factory than it can be at home. In the factory the alkali is proportioned by weight, so that as little free alkali is left as possible. Such a soap is called “neutral.” Resin is added, in yellow laundry soaps, and is supposed to aid in forming suds. When there is an excess of resin, as in some cheap soaps, it is hard to rinse out and colors the clothes. Borax is sometimes added to soap, and is useful when the water is hard, but not necessary in soft water. Naphtha or some other petroleum oil in soap increases the cleansing property of soap, by dissolving fatty or greasy impurities.
A _soap solution_ is essential for use in the boiler and in washing machines and is useful for rubbing on spots before washing.
To make soap solution, cut up the soap and dissolve it in hot water, one pound soap to one gallon of water. It should be strong enough to jelly when cool, and may be kept in jars ready to use. Even more convenient are soap chips which come by the barrel, but may be bought at pound rates.
=Bleaching and bluing agents.=——The sun, as it bleaches white fabrics, may be counted in this group. Chemical bleaches are used to whiten clothes, but should not be resorted to unless clothes are yellow from poor washing, as in the end they weaken the fabric. Commercial laundries sometimes use an excess of acid for this purpose. Cream of tartar is a harmless bleach. Javelle water is another household bleach, chloride of lime being the bleaching substance. This is also a good disinfectant.
_To use cream of tartar._——Dissolve cream of tartar in hot water, 1 teaspoonful to each quart. After the yellowed fabrics have been thoroughly washed and rinsed, lay them overnight in a solution of this strength, rinse, blue, and dry in the morning.
_Javelle water._——1/4 pound chloride of lime, 1 pound sal soda, 2 quarts of cold water. Dissolve the chloride in half the water cold, and the sal soda in the other half boiling. Stir together thoroughly, allow the mixture to stand several hours, pour off the clear water with care, and bottle it. Use a tablespoonful of the solution to a gallon of water, and heat the yellow fabric in this mixture after thorough washing, for half an hour, not allowing the temperature to rise above 100° F. Rinse very thoroughly before bluing and drying.
=Bluing= is used to neutralize the slightly yellowish tint of the fabric, when it cannot be completely bleached.
Ultramarine blue is sold in small balls and cakes.
Aniline blue is a strong color, and in a very dilute solution gives a pleasing pearly tint to the fabric, especially when the violet tint is used. Mix an ounce of the blue with one gallon water, and bottle for use.
Prussian blue is to be avoided, since it is a salt of iron, and often yellows or spots the clothes. It is usually sold in liquid form. To test, mix the liquid blue with a strong solution of washing soda and heat. If the mixture turns red, and there is a reddish precipitate, the blue is this salt of iron.
=Starch= is used to fill the interstices of fabrics and give a smoothness and stiffness to the cloth that prevents the rumpling of garments. Both wheat and cornstarch are used for laundry purposes when only the natural starches are available, the wheat starch being better for home laundering, as the cornstarch gives a quality that is too stiff and crackling. Recently, however, the manufacturers have learned to make “thin boiling” starches from corn and have placed on the market a variety of such modifications of cornstarch for laundry use. Rice starch or “rice water” is used for very thin muslins.
_To make starch._——For method of making, see starch experiments,