230 CHEMISTRY OF FARM PRACTICE 



keep the barrel covered and stir occasionally. Beat up 

 separately 2| pounds of rye flour in % gallon of cold water, 

 then add 2 gallons of boiling water. Then dissolve 1\ 

 pounds of rock salt in 2| gallons of hot water. Pour the 

 last two preparations into the first. 



Waterproof Whitewash. Slake 1 bushel of quicklime 

 with 12 gallons of hot water. Then dissolve separately 

 2 pounds of common table salt and 1 pound of zinc sulphate 

 in 2 gallons of boiling water. Pour the last preparation into 

 the first and add 2 gallons of skimmed milk. 



177. Special Ingredients for Whitewash. An ounce of 

 alum added to each gallon of lime whitewash increases its 

 sticking properties. A pint of molasses to 5 gallons of white- 

 wash renders the lime more soluble and increases its pene- 

 tration. Silicate of soda solutions aid in fireproofing, 

 while 1 pound of bar soap dissolved and added to 5 gal- 

 lons of whitewash gives it a gloss. 



178. Calcimine. The basis of calcimine is whiting, or 

 carbonate of lime. This material is carried in water as a 

 vehicle and is made to adhere by the use of glue. Damp- 

 proof calcimine is prepared by thoroughly mixing 16 pounds 

 of Paris white or extra gilders' whiting with 1 gallon of boil- 

 ing water. Soak separately pound of white sizing glue 

 for four hours in | gallon of cold water, then dissolve by 

 heating on a water bath. Also, dissolve 4 ounces of sodium 

 phosphate in 1 pint of boiling water. Mix the last with the 

 first and add the second. For tinting use yellow ochres, 

 sienna, umbers, Venetian red, para-red, maroon, oxid, 

 ultramarine blue, ultramarine green, chromium oxide, or 

 bone black, none of which is affected by lime. 



If lampblack is used for tinting, it must be stirred in hot 

 water containing a little soap or in cold water containing 

 a little borax, the alkali serving to overcome the greasy 

 nature of the lampblack. 



179. Varnishes. A varnish is a dissolved resin, or a 

 drying oil, which, when exposed to the air, becomes hard 



