CHAPTER XX 



MAN'S CONQUEST OF SUBSTANCES 



201. Chemistry. Man's mechanical inventions have been 

 equaled by his chemical researches and discoveries, and by 

 the application he has made of his new knowledge. 



The plain cotton frock of our grandmothers had its 

 death knell sounded a few years ago, when John Mercer 

 showed that cotton fabrics soaked in caustic soda assumed 

 under certain conditions a silky sheen, and when dyed took 

 on beautiful and varied hues. The demonstration of this 

 simple fact laid the foundation for the manufacture of a vast 

 variety of attractive dress materials known as mercerized 

 cotton. 



Possibly no industry has been more affected by chemical 

 discovery than that of dyeing. Those of us who have seen 

 the old masterpieces in painting, or reproductions of them, 

 know the softness, the mellowness, the richness of tints em- 

 ployed by the old masters. But if we look for the brilliancy 

 and variety of color seen in our owji day, the search will be 

 fruitless, because these were unknown until a half century 

 ago. Up to that time, dyes were few in number and were 

 extracted solely from plants, principally from the indigo and 

 madder plants. But about the year 1856 it was discovered 

 that dyes in much greater variety and in purer form could 

 be obtained from coal tar. This chemical production of dyes 

 has now largely supplanted the original method, and the in- 

 dustry has grown so rapidly that a single firm produced in 



218 



