The Laundry. 68^ 



take is to think that one kind of soap will ansv/er for all purposes, 

 and this is a possible explanation of much dissatisfaction. In the 

 manufacture of soap, when just sufficient alkali is used completely to 

 saponify the fat present, the product is known as a neutral soap. If an 

 excess of alkali is used, either a medium or a strong soap is produced, de- 

 pending on the amount of free alkali left in the soap. The laundry should 

 contain all three grades of soap. A neutral or mild soap should always 

 be used when the presence of even a small amount of free caustic alkali 

 is injurious to fabrics, as in washing flannels or w^oolen goods, or with 

 frail fabrics and delicate colors. A medium soap should be used for the 

 more durable colored goods and a strong soap is best for much of the 

 white goods, both cotton and linen. 



Action of soap. This leads us to consider the way in which soap acts 

 as a detergent. Much of the dirt in clothing is due to the adherence 

 of particles of dust to the fatty impurities which have accumulated on 

 the fabric. While rubbing and water alone w^ll loosen and remove 

 much of the ordinary dirt, the process is greatly facilitated by the use 

 of a soap solution. Soap-suds penetrates the pores of the fabric more 

 completely than water alone, thus acting primarily to aid in softening 

 the dirt. Fats are emulsified by soap-suds, that is, soapy water acts 

 to divide the fatty material into very minute particles which are removed 

 from the clothing by rubbing and pounding. These particles are then 

 held in suspension in the suds. The adherent dirt is caught in this emul- 

 sion and the whole is carried away in the washing process. When free 

 alkali is present it unites with the fatty impurities present to form more 

 soluble soap, and this action removes a part of the fat and aids in remov- 

 ing more by the above process of emulsification. This serves to illustrate 

 the desirability of the use of strong soaps when much grease is present. 



Aside from its use in removing dirt, soap has antiseptic properties. 

 It is not safe to depend upon it as the only disinfectant in cases of con- 

 tagious diseases, but it is a valuable purifier for the ordinary household 

 washing. 



The question often arises as to the advisability of using kitchen waste 

 fats in making homemade soap. While some housekeepers may find 

 this an economy, the fact remains that homemade soaps are generally 

 poorly made, of poor quality and do not give satisfaction in their use. 

 This may be due to several things. The so-called cold process is usually 

 used in making homemade soap and the saponification is rarely complete. 

 The fat used is often filled with impurities and these are not always 

 removed. As the fat in kitchen waste varies greatly in composition, 

 it is impossible to give the exact amount of alkali to use. The sum 



