The Laundry. 



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united in certain definite proportions a salt is formed, and the salt in 

 this case is common table salt. The bases chiefly used in the laundry 

 are known as alkalis because they contain the alkali-metals. The chief 

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



I. Cotton and linen. The soft fibrous material covering the seeds of 

 some plants is known as cotton. If a single mature cotton fibre were 

 examined under the microscope it would show itself to be a long, flattened 

 twisted tube, thicker at the edges than in the middle. This hollow, 

 twisted condition gives to cotton 

 its characteristic lightness and 

 elasticity and makes it suitable 

 for the manufacture of fine yarns. 

 Linen is a product of the flax 

 plant. A linen fibre under the 

 microscope looks like a long, 

 transparent tube with thick 

 smooth walls and a central canal. 



Fig. 31. — Cotton fibres. 



Fig. 32. — Linen fi.bres. 



Fabric made from 

 linen is stronger and 

 more lustrous than 

 cotton and is a better 

 conductor of heat. 

 Both cotton and linen 

 consist for the most 

 part of a plant sub- 

 stance, cellulose, and 

 they react similarly to 

 chemical substances. 

 Action of acids on cotton and linen. Strong mineral acids have a 

 corrosive action on cotton and linen and if they are allowed to act 

 for any length of time the fabric is entirely destroyed. This action is 

 greatly increased by heat. Cold dilute mineral acids affect these fabrics 

 but little if the acid is thoroughly washed out afterwards, but the cloth 

 may be seriously injured if the acid is allowed to dry on. The appearance 

 of the cloth may not undergo any change but its durability will be 

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

 fibres is hydrochloric acid, more commonly known to the housekeeper 

 as muriatic acid, but it also damages fabric if allowed to dry on. 



The organic acids, such as acetic acid in vinegar, oxalic acid in 

 tomatoes, tartaric acid in grapes and citric acid in lemons, have no 

 action on cotton and linen unless they are allowed to dry on the fabric 



