PAINT OILS AND THINNERS 



11 



floor and deck paints or wherever great hardness is required. 

 These varnishes are also finding application in the manufacture 

 of concrete, steel, and flat wall paints; being especially .suitable 

 for the above purposes when compounded with kauri gum japan. 

 During the boiling of raw tung oil the temperature must not 

 exceed much over 400 degrees Fahrenheit. Otherwise a peculiar 

 " hamming " will take place, the whole mass becoming solid and 

 of no further value as a varnish or paint vehicle. Some peculiar 



Aleurites Cordata 

 Aleurites Fordii Wood Oil tree at Riverside, Cali- 



Flowering specimen bf the Chinese fornia, planted in 1907. Photo- 



Wood Oil tree, thirty feet high graph taken in 1910, when tree 



and three feet in diameter, on had borne fifty fruits 



banks of Yangtse River, Western 

 Szechuan, China. Opium Poppy 

 in the foreground 



internal disturbance or rearrangement of the molecules is evi- 

 dently effected by heat, and although the reaction is not clearly 

 understood, it has been ascribed to auto-polymerization. Scott 

 has stated that the phenomenon of gelatinization is due to the 

 exposure of the surface of the oil to the air, and that boiling in 

 vacuo obviates such results. The lusterless surface produced when 

 tung oil varnishes are dried in vitiated air would tend to confirm 

 the conclusion that the oil is very subject to atmospheric influences. 



