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, Chapter VIII. The starch must be perfectly smooth, and should be stirred while it is boiling for a few minutes, and strained. _Proportions._ 1. For lingerie, 1 teaspoonful of starch to 1 quart water. 2. For medium fabrics, 1-1/2 to 3 tablespoonfuls starch to 1 quart water. 3. For stiff work, 5 tablespoonfuls starch to 1 quart water. =Ironing.=——The ironing process is the most difficult art in laundering, and requires good tools, practice, and patience. In the summer it is an exhausting labor unless an electric or gas iron is available. Much energy may be saved in hot weather by omitting the ironing of certain articles. Dish towels, even toilet towels, and soft underwear may be stretched and folded, and are perfectly comfortable to use. Some women who do their own work even fold sheets and pillow cases without ironing. The smoothing of the fabric is accomplished by heated irons, or by pressing between rollers in a mangle. _To summarize._——The essential steps in laundering are: the forcing of clear water through the fabric; loosening of the soil and stains by soap and appropriate chemicals, sterilization by boiling temperature, drying and sweetening in the air if possible. The less essential are bluing, starching, and in some cases ironing.