SCIENCE IN THE INDUSTRIAL WORLD 



We shall see a little later that within the last half- 

 century a complete revolution in the method of making 

 certain colors has taken place, thanks to the science of 

 chemistry. Yet the basis of most paints is still the time- 

 honored white lead a substance known to the ancients, 

 and used by them practically as it is used to-day. We 

 know that as early as the fourth century B.C., there were 

 written accounts of the process of making this substance, 

 which seemingly differed very little from the process 

 in use in some countries to-day. 



Varnishes seem to have been used at a date almost, 

 if not quite, as early as that of paints. The peculiar 

 coatings of the Egyptian mummy-cases has been ana- 

 lyzed and found to be a solution of resin in an essential 

 oil, such as turpentine or oil of cedar, and therefore 

 practically identical with the ordinary varnishes of 

 to-day. The revolution in the art of paint- and pigment- 

 making, therefore, lies outside the field of the exact 

 knowledge of the chemical nature of such basic sub- 

 stances as resin, pitch, and white lead. There have 

 been revolutionary changes in the methods of obtaining 

 and using these substances, of course, but the great 

 revolution has come in the manufacture of the colored 

 pigments along the lines of synthetic chemistry. The 

 ancient pigment-maker was largely dependent upon the 

 substances furnished him by Nature in a form ready for 

 use. Many of these were rare, costly, and difficult to 

 manipulate. His modern successor, with his knowl- 

 edge of chemical elements and reactions, produces the 

 same material in his laboratory, at a mere fraction of 

 their former cost, and from substances that would 



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