PROJECTS 603 



on good enamel ware. Keep an enamel kettle clean by washing 

 it, or boiling it if necessary, frequently with a strong solution of 

 washing soda. Either oxalic acid or nitric acid will remove scale 

 from enamel ware without "eating" through the enamel, but any 

 strong acid will remove the high polish from the surface of enamel. 



PROJECT XXXI. How to Soften Hard Water for Domestic Use, 



page 146 



Water of temporary hardness does not offer a serious problem 

 because it can be softened by boiling. Permanently hard water 

 requires something more to soften it. 



For Laundry Use. Washing soda is the most common softener 

 for laundry purposes. The two mistakes commonly made in its use 

 must be guarded against : do not make too strong a solution ; and 

 be sure that the soda is thoroughly dissolved. A failure to observe 

 these cautions may result in injury to the clothes. 



Dissolve 1 pound of washing soda in a quart of hot water. For 

 most hard waters, 2 tablespoonfuls of this solution will soften a 

 gallon of water. If the water is unusually hard, more of the solution 

 will be required. 



For Delicate Fabrics. Borax is much to be preferred to washing 

 soda as a water softener because it will do no injury either to the 

 hands or to delicate fabrics. It is so expensive, however, that it 

 cannot be used in great abundance. To soften water for washing 

 delicate fabrics, dissolve 1 tablespoonful of borax in a cup of hot 

 water. This will soften a gallon of water. 



For Toilet Purposes. (a) Borax used as suggested in the preced- 

 ing paragraph will soften water satisfactorily for toilet uses. 



(6) The addition of the juice of one or two lemons to a bowl of 

 hard water softens it agreeably for washing or rinsing the hair. 



PROJECT XXXII. How to Read a Water-meter or Gas-meter Dial, 

 pages 200-206 



Water is sometimes sold to the consumer at a flat rate by the 

 month or year. In such cities there is no direct measurement of 



