Rain-water is the softest, and in the country, where it is clean, should always be used when procurable; but in towns, when full of smoke and soot, it would make the clothes dirty and discoloured.
Water is made hard by the presence of mineral salts; soft water is free from these.
Well, spring, and mineral waters run through the earth, and as they pass along dissolve more or less the rock or soil they touch, thus acquiring mineral salts and becoming hard. Hard water requires a long time to make a lather, because the mineral salts unite with the fatty acid of the soap, and together form white curdy flakes which are called "lime soap." Until soap enough is used to overcome the salts in the water the soap will not dissolve, and can, therefore, have no cleansing effect before much of it has been wasted. If very hard, water can be softened by (1) being placed in the open air for some hours; (2) boiling; (3) the addition of soap; (4) the addition of dissolved soda or borax.
SOAP is a compound of soda with fat or oil; its cleansing effect is due to the soda; but soda used alone would be so strong that it would prove injurious both to skin and fabric; the mixture of fat prevents this. The best yellow soap should be chosen, as cheap soaps contain either an excess of water, too much soda, or a preponderance of fat forming a greasy scum.
SODA is manufactured from ordinary salt, and has the power of dissolving grease and softening water. The frequent use of it tends to make white clothes grey and old-looking, but for coarse things it is invaluable. It should always be dissolved in boiling water before being brought into contact with the clothes, or it may make yellow marks, which in time become holes. It should never be used for coloured clothes or for flannels. It is advisable to keep it in a covered jar, because if exposed to the air it forms a white powder. (14 lbs. of soda can be had for 6d.)
BORAX is a salt found in California, and also prepared in Italy. It has the same power as soda, but not being so injurious can be used for fine things. It is employed in starch to give a gloss, and also to stiffen fine materials. (Powdered borax 2 1/2d. per lb.)
STARCH is a preparation of rice, pulse, maize, wheat, and potatoes. The best for laundry work is made from rice, as the grains, being smaller, enter more easily into fabrics, and are more quickly burst by heat. Raw starch has no stiffening power. In hot-water starch the water must be actually boiling to cook and burst the grains; and for cold-water starch the iron must be hot enough to cook the grains and so make it stiffen. Starch stiffens, improves the appearance of linen, and makes it remain clean longer.
BLUE is made from an Indian plant named indigo, and also prepared from ultramarine. It is used to keep white clothes a good colour. As the linen is blued the water becomes paler, so that it is necessary to add a little fresh blue.
TURPENTINE is used in cold-water starch to prevent the irons from sticking. Care must be taken not to add too much, or the linen becomes yellow and smells unpleasantly.