PAINTS, DYES, AND VARNISHES 



never have been dreamed of in earlier times. An ex- 

 ample of this is the manufacture of ultramarine. 

 The early painters made this substance by grinding 

 to powder the gem "lapis lazuli," and the pigment so 

 produced was worth many times its weight in gold. The 

 pigment-maker of to-day produces a deeper and better 

 color by a chemical process in which sulphur, soda, 

 silica, and clay are the important factors, and makes a 

 handsome profit if his product brings him fifty cents 

 per pound. This is but one example of how a product of 

 man's puny laboratories has supplanted that of Nature's 

 great one. We shall see presently how many such ex- 

 amples there are in this particular field. 



BLACK PIGMENTS 



The element carbon, in one or another of its varied 

 forms, is the basis of practically all black pigments. It 

 is one of the most universal elements, and being found 

 in abundance in the mineral, vegetable, and animal 

 worlds, pigments are made of it from all three of these 

 sources. Although all forms of carbon, such as dia- 

 mond, coal, charcoal, and lampblack, are identical chem- 

 ically, it is obvious that only certain of these forms are 

 available for making black pigments. Thus diamond 

 dust is white and coal dust black; yet both are pure 

 carbon. The chemist would explain, however, that 

 both their substances are crystalline, and that only the 

 non-crystalline forms of carbon give the desired pure- 

 black color. Of much greater importance to the pig- 

 ment-maker are such plebeian substances as wood, 



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