PAINT PIGMENTS AND THEIR PROPERTIES 49 



mended for use on iron and steel. Its composition runs approxi- 

 mately as follows: 



Lead sulphate 50% 



Lead oxide 35% 



Lead sulphide 5% 



Lead sulphite 5% 



Zinc oxide 2% 



Carbon 3% 



The color of the pigment is largely due to the carbon and the 

 lead sulphide. Its specific gravity is 6.4, and it grinds in 



Sublimed White Lead 



10% of oil to a stiff paste, 100 Ibs. cf which may be thinned 

 with about 26 Ibs. of oil to working consistency. Paint manu- 



View of largest Zinc Oxide Works in America, at Hazards, Pa. 



facturers use it in mixture with iron oxide and other pigments 

 for the production of paints for metal surfaces. Wood and 

 others have found it of great value for this purpose. It has a 



