PAINT PIGMENTS AND THEIR PROPERTIES 



47 



Possessed of extreme stability, it finds wide use as a constituent 

 of paints and as a base for tinting colors. The photomicrograph 

 of this pigment shows its extremely fine, amorphous nature 

 with complete absence of crystals. In fineness it closely 

 approaches zinc oxide. On account of its non-poisonous 

 properties it is replacing corroded lead in many places. Unified 

 paints containing sublimed white lead are of great value, show- 

 ing upon long exposure very little decay. 



View of Furnace for Making Sublimed White Lead 



Sublimed Blue Lead. Sublimed blue lead is made by burning 

 coarsely broken lumps of galena, admixed with bituminous coal, 

 in a special form of furnace. The fumes which are volatilized 

 from this mixture are very complex in their chemical make-up, 

 and in color are white, blue, and black. After being drawn 

 through the cooling pipes by the suction of huge fans, whereby 

 the fumes are cooled, the pigment is deposited in bags. This 

 pigment is bluish black in color, and has been highly recom- 



