The Laundry 



1 107 



Fig. 38. — Cotton fibers 



chloric acid (muriatic acid) and sodium hydroxid (lye), both of which if 

 strong can almost instantly eat holes in any fabric and even into flesh itself, 

 are united in certain proportions a harmless salt, common table salt, is 

 formed. The bases chiefly used in the laundry are known as alkalis. The 

 chief household alkalis are lye, washing soda, ammonia, and borax. 



Cotton and linen 



The soft fibrous material covering the seeds of the cotton plant is known 

 as cotton. If a single mature cotton fiber were examined under the 

 microscope, it would show itself to be a long, flattened, twisted tube, 

 thicker at the edges than in the 

 middle. Its hollow, twisted con- 

 dition gives to cotton a character- 

 istic lightness and elasticity, 

 making it suitable for the manu- 

 facture of fine yams. Linen is a 

 product of the flax plant. A linen 

 fiber under the microscope looks 

 like a long, transparent tube with 

 thick, smooth walls and a central canal. Fabric made from linen is 

 stronger and more lustrous than that made from cotton and is a better 

 conductor of heat. Both cotton and linen consist for the most part of a 

 plant substance, cellulose, and they respond similarly to chemical sub- 

 stances or to cleansing agents. 



Action oj acids on cotton and linen. — Strong mineral acids have an eating 

 (corrosive) action on cotton and linen; if they are allowed to eat for 

 any length of time, the fabrics are entirely destroyed. Such eating, or 

 corrosion, is greatly increased by heat. Cold dilute mineral acids affect 



the fabrics but little if 



the acid is thoroughly 

 washed out immedi- 

 ately after its use, but 

 the cloth may be seri- 

 ously injured if the acid 

 is allowed to dry on it. 

 The appearance of the 

 cloth may not undergo 

 any change, but its 

 durability will be 

 affected. The mineral acid having the least effect on vegetable fibers 

 is hydrochloric acid, more commonly known to the housekeeper as muri- 

 atic acid ; but hydrochloric acid also damages fabric if allowed to dry on it. 



Fig. 39. — Linen fibers 



