L. TECHNOLOGY. 471 



ZINC WATER-PAINT. 



The unpleasantness of occupying a newly-painted house 

 may, it is said, be avoided by the use of zinc water-paint. 

 Powdered oxide of zinc (which may be heated with a little 

 potato starch if more " body" be wanted) is combined with 

 the desired mineral or vegetable color, and with this an aque- 

 ous solution of chloride of zinc, to which some tartrate of po- 

 tassa has been added, is then mixed, the water-paint thus 

 formed being applied with a brush on the surface to be coat- 

 ed. In half an hour this paint will be perfectly dry, and the 

 object of the alkaline tartrate is to make the drying process 

 less rapid. The advantages of using the water paints are 

 very numerous : they are more durable than oil paints, do 

 not blacken by exposure to sulphurous vapors, are devoid of 

 odor, dry quickly, resist dampness and the action of water, 

 can be cleansed with boiling water and soap like oil paints, 

 and preserve the wood to which they are applied from decay, 

 and render it less combustible. This latter property may be 

 increased by the addition of borax. Both the oxide and the 

 chloride of zinc can be manufactured without danger to the 

 health of the workmen, sold at a low price, and kept for any 

 length of time in any climate. 8 A, April 1, 66. 



PREPARATION OF ZINC PAINT. 



A useful hint in regard to the preparation of paint with 

 oxide of zinc instead of white lead will be found in the fol- 

 lowing instructions, published in a German journal : The 

 ordinary boiled linseed-oil should be replaced in the mixing 

 operation by one prepared by gently boiling two hundred 

 pounds of the raw oil for five or six hours, then adding about 

 twenty-four pounds of coarsely-broken lumps of binoxide of 

 manganese, and continuing the boiling operation for about 

 ten hours longer. In this manner a very quickly drying lin- 

 seed-oil is obtained, which is eminently fit for the purpose of 

 beino: used with zinc-white and other zinc colors. According 

 to the writer of the article, much depends upon the use of old 

 linseed-oil, and also upon the pains taken with the boiled oil, 

 which, unless carefully kept from the contact of the air, be- 

 comes thick in a very short time. The boiled oil so prepared 

 is not to be used alone in painting with zinc-white, but must 



