594 



Popular Science Monthly 



Below : On the right is a barrel 

 filled with dry pigment. The 

 barrel on the left contains the 

 same pigment after it has been 

 milled with the requisite 

 amount of linseed oil. Conden- 

 sation reduces the volume 



Menhaden fish are not used for food. They are steamed and 

 pressed to extract their oil, which is used in making paint 



dressed stone. The paint conies from the 

 mill very smooth, and finely ground. It is 

 allowed to flow into large tanks holding 

 sometimes a thousand gallons or more, 

 where it is thinned with oil, turpentine and 

 drier. Tinting colors are added if a 

 colored paint is desired. 



Linseed oil forms the liquid part of most 

 paints. When brushed out, it takes up 

 oxygen from the air and becomes solid, 

 forming a rubber-like substance which is 

 very waterproof. When pigments are 

 added to the oil, the same thing happens, 

 but the dried oil is made stronger and the 

 surface to which it is applied is colored, 

 according to the colors of the pigments 

 used. Oil 



squeezed 

 from menha- 

 den fish is 

 used in some 

 special kinds 

 of paint. Oil 

 from the nuts 

 oftheChinese 

 wood-oil tree 

 is very useful 

 for making 

 highly water- 

 proof paints. 

 It has been 

 used by the 

 Chinese for 

 many centur- 

 ies to smear 

 their junks 

 and river 

 boats. Oils ex- 

 pressed from 



the soya bean, cottonseed and corn germs 

 are used to some minor extent in the paint 

 industry. 



Turpentine is produced by distilling the 

 resin that comes from pine trees and is used 

 in paint to make it spread easily, to aid it in 

 drying and to help it penetrate deeply into 

 the grain of wood, thus securing a good 

 bond. Mineral spirits obtained by distil- 

 ling petroleum is used for the same purpose. 



Varnish Is Made from Prehistoric 

 Tree-Oozings 

 Paints which dry with a 

 gloss are called enamels. 



Filling cans with the prepared varnish and paints from 

 a battery of storage vats in one of the great paint factories 



high luster or 

 These are 

 made from 

 zinc oxide 

 ground in 

 varnish. 

 Varnish is 

 produced 

 from fossil 

 resins such as 

 copal, kauri, 

 etc. These 

 resins, whici 

 origina 11 

 flowed froi 

 trees, hav< 

 been deposit^ 

 ed for centur-^ 

 i e s in t h 

 earth. They' 

 are mined in 

 Africa and 

 NewZealand, 

 and are found 

 in big lumps. 



