iii6 The Cornell Reading-Courses 



free lye would be injurious in washing flannels, woolen goods, or fabrics 

 either frail or delicate in color. A mediumi soap should be used for the 

 more durable colored goods. A strong soap is best for most white goods, 

 both cotton and linen. 



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

 as a cleansing agent. Much of the dirt in clothing is due to the adher- 

 ence of particles of dust to the fatty impimties that have acciimulated 

 on the fabric. While rubbing and water alone will loosen and remove 

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

 use of a soap solution. Soapsuds penetrates the pores of a fabric more 

 completely than does water alone; thus, first, it softens dirt; second, it 

 emulsifies the fats, that is, soapy water acts to divide fatty material into 

 very minute particles, which are removed from clothing by rubbing and 

 pounding. The particles are then held in suspension in the suds. The 

 adherent dirt is caught in the emulsion 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; this action removes a part 

 of the fat and aids in removing more in the process of emulsification. These 

 facts serve 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 on it as the only disinfectant in cases of contagious 

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



A question often arises as to the advisability of using kitchen-waste 

 fats in making homemade soap. While some housekeepers may find such 

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

 poorly made and of inferior quality. The inferiority of homemade soaps 

 may be owing to several causes. The so-called cold process is usually 

 followed in making homemade soaps, and rarely is the union of the fat 

 with the lye complete. The fat used in homemade soap is often filled with 

 impurities and they are not always removed before the soap is made. As 

 the fat in kitchen waste varies greatly in composition, it is impossible to 

 give the exact amount of alkali reqiiired for homemade soap. It is evident, 

 then, that homemade soap is likely to be filled with impurities and to be 

 both greasy and excessively caustic, " eating, " because of the presence of 

 free fat and an undue amount of free alkali. For the benefit of those 

 housekeepers who wish to try its manufacture, however, some formulas 

 are given on pages 122 and 123. 



Soap substitutes and accessories 

 Soap is the best all-round cleansing agent to use in the laundr}', but 

 there are other substances with similar cleansing properties that may be 

 used with good results in its place: 



