Action of acids on silk.— Silk is readily attacked and disintegrated by a concentrated acid solution. Dilute acid solutions weaken the fabric, but not so seriously as they weaken cotton. Action of alkalis on silk.- Concentrated alkali solutions act on silk vigorously, but a little less vigorously than on wool. Dilute alkali solutions weaken silk and destroy its luster. As laundering concerns itself continually with the action of alkalis and acids on fabrics, the preceding outline should aid one in grasping some of the reasons for the several laundry processes. WATER A bountiful supply of water good for laundry purposes is an important factor in successful laundering. Water is the natural solvent for much of the dirt that accumulates on clothing; moreover, it acts as a carrier to rid the clothing of all forms of dirt, both soluble and insoluble. Unfortunately, good drinking water is not necessarily equally good for laundry purposes, as water may hold in solution substances not hurtful to health but very detrimental to cleaning processes. A water good for the laundry should be clean, soft, clear, odorless, free from discoloration, free from iron, free from organic matter. Hard and soft water The very characteristic (its solvent power) that renders water valuable as a cleansing agent (detergent) is the cause of its greatest shortcomings; for on its way to us water may pass over, or through, soils that contain soluble substances of an undesirable nature. The characteristic known as hardness, possessed by some waters, is due to the presence of lime salts gathered in the way described. Hard water is not the best for laundry purposes, as lime salts decompose the soap used and form in its place an insoluble lime soap, which collects as a curd on the surface of the water. Such soap decomposition takes place as long as any lime remains in the water and the cleansing (detergent) properties of soap are not in operation until every bit of lime has combined with soap to form lime soap. By leaving minute particles of lime soap in its pores, hard water is said to weaken a fabric. If the available supply of water is hard, then, the problem of the housekeeper is to find some means of removing lime or of reducing its ill effects. Temporary and permanent hardness.- According to the nature of the lime salts present, water is said to be either temporarily or permanently hard. Temporary hardness is caused by the presence of carbonate of lime, and such water may be softened by boiling. If the boiled water is allowed to stand, the lime settles at the bottom of the receptacle and the softened water may be drawn from the top of it. Permanent hardness is due to the presence of sulfate of lime. Boiling has no softening effect on permanently hard water. Another salt often very obnoxious in laundry water is iron. Its presence, even in very small amounts, may give a yellow tinge to clothing, owing to the deposit of minute particles of iron rust in the pores of the fabric. Organic matter may be present in the water used for laundry purposes, which causes clothing washed in it to become dangerous to the wearer. It is very desirable in all the cited cases to eliminate mischievous substances. A number of materials for softening water are on the market. The cheapest and best of them are alkalis, known as washing soda, lye, borax, and ammonia. In softening water the objection to the use of any chemical is the injury it may do to the fabric. Materials for softening water Washing soda (sodium carbonate).- Washing soda is the best alkali to soften water for general household use, for, while effective in its action, it is not so corrosive as to render its handling difficult or its use unduly harmful, nor is it expensive. It should never be used in its dry form, however, for it is an alkali sufficiently strong to eat holes in a fabric if it is used in full strength, and wherever a particle of the dry substance falls a strong solution is formed. Carelessness causes many of the complaints against present-day laundry methods. Lye (sodium hydroxid or caustic soda).- Lye is an alkali of far greater strength than washing soda; one pound of lye being equal to about twelve pounds of washing soda, it should be used with just so much the greater caution. It should never be used save in solution and, as the solution deteriorates very rapidly on exposure to air, if any quantity is made it should be kept in bottles or jars tightly stoppered with rubber stoppers. The compound formed by exposing lye to the action of air and water, is washing soda, so there is no advantage in using it after all. Lye is much more difficult to handle, and its action is so much more corrosive than is that of other alkalis that it is not advisable to use it in the home laundry. Borax (sodium biborate).- One of the mildest alkalis to use in the laundry is borax. This alkali is more expensive than either lye or washing soda and is not so vigorous in its action; but in some instances it is greatly to be preferred to either lye or washing soda. Washing soda and lye, unless they are thoroughly rinsed from clothing, have a tendency to cause yellowing, particularly when starch is used afterward. Borax, on the other hand, has a tendency to whiten fabrics and is added directly to starch, in order to give it good color and to increase its clearness. When colored fabrics or wools are to be washed in hard water, borax is one of the best alkalis to use for softening the water; therefore it should be on the laundry shelf for that purpose if for no other. Ammonia (ammonium hydroxid).- Ammonia is another good alkali for softening water when it is not advisable to use stronger alkalis. Ammonia is a very volatile substance, consequently it should be used only when the laundry process is to be conducted quickly. It is better and cheaper to purchase the full-strength ammonia from a druggist and then dilute it, than to buy the article known as household ammonia, which is of unknown strength. To soften water.- Both permanently and temporarily hard water may be softened by distillation, but that method involves apparatus not practicable for the average home. If water is temporarily hard, however, it may be softened by being boiled, then allowed to stand until the lime settles. The top water is afterward drawn off. The method of boiling water to soften it is without doubt the best if it softens the water sufficiently, as no harmful chemicals are left in the water to injure fabrics. Either temporarily or permanently hard water may be softened by adding lime or washing soda to the water, then allowing it to stand in open kegs for several days before its use. The water should then be drawn from the top. If the water is boiled after the addition of the softening agent, the time for standing may be considerably lessened. Neither of the two processes just described is much in use in the household, as the time consumed by them is often considered unwarranted. The more common method is to add washing soda, lye, borax, or ammonia at the time of washing. The addition of one of those substances at that time prevents the action of the lime on the soap. A good suds may thus quickly be procured, but it does not rid the water of the lime-soap curd which forms and which, in part at least, becomes entangled in the pores of the cloth. entangled curd has a weakening action on the fabric and gives it a close, filled-in appearance. The The only satisfactory method of getting rid of iron is to add washing soda to the water, then let the water settle for five or six days before using it. The top water is afterward drawn off. Water may be softened by any of the following methods: 1. For each gallon of water, use two tablespoons of a solution made by dissolving one pound of washing soda in one quart of boiling water. The solution should be bottled and kept on hand, as it is a useful cleansing agent (detergent). 2. For each gallon of water use one fourth tablespoon of lye dissolved in one cup of water. 3. For each gallon of water use one tablespoon of borax dissolved in one cup of water. If water is very hard, increase the amount of alkali used. Organic matter Organic material may be precipitated by the use of alum in the form of an alum-borax mixture. The sediment should be allowed to settle and the water may then be drawn from the top. To remove organic matter.— For each gallon of water use one tablespoon of a mixture made up of two thirds borax and one third alum. If the water is rich in organic matter, use more than one tablespoon of the mixture. When water is very scarce, alum is sometimes used to separate the dirt from the water and the water is then filtered and used again. SOAP In the "good old days" when the home was the center of larger industrial activities, soap-making was conducted as a household process. In the spring it was a familiar sight to see the winter supply of wood ashes pounded down into a barrel and set on a platform ready for “leaching.” A hole was made in the compacted ashes and water was poured into it. The water leached down through the ashes into little troughs in the platform. Then it was collected in kettles, ready to be used for making soap. The resulting liquid was the homemade lye of the housekeeper of old. A kettle of melted fat hung near the barrel on a big iron tripod, and to the contents of the kettle the housewife added the lye, boiled the two together, and tested the mixture now with an egg, now with a feather, in order to see if it was of the proper strength. After two or three days of anxious effort her task was completed, and the resulting mixture, called soft soap, was put away in barrels for winter use. Alkalis. Among the alkalis familiar to the housekeeper is that known as lye. Lye is a term that is used loosely to describe two substances similar in properties but different in composition. Caustic soda and caustic potash are names that better describe what we commonly call lye. Both kinds of lye have a strong eating (corrosive) action, caustic potash being stronger than caustic soda; both have the power of uniting with fats to form soaps soluble in water. Soap is a convenient and effective form in which to use the caustic lye in either of its two forms, as the corrosive nature of lye is so modified as to render it useful without being unduly injurious to fabrics. There is much difference of opinion as to which kind of lye produces the better soap. That question is settled "practically" in favor of the |