CONDITIONS AFFECTING INDUSTRIAL LIFE 



287 



are the aniline dyes, and long lists of substances handled in 

 the drug trade. 



The oil fields of Indiana were opened in 1897, of Texas in 

 1901, of California in 1903, and of Oklahoma in 1905. The 

 petroleum from the Texas and California fields has extensive 

 use as fuel supply for shipping and for locomotives in rail- 

 way service. So important is an ample supply of petroleum 



FIG. 92. Location of the larger oil fields of the United States. 



for the navies of the world and for shipping generally that all 

 large sources of its supply, including on this continent the 

 rich oil fields of Mexico, are subjects of greatest concern in 

 international relationships. 



From the development of the petroleum industry in the 

 United States has come great added wealth to the nation 

 as a whole. But it has concentrated vast fortunes in the 

 hands of a few individuals, and has given rise to business 

 organizations exercising far-reaching influences in trade and 

 commerce, and in the social and economic conditions affecting 

 the lives of people generally. As in the case of coal with 

 which it is so closely related in chemical nature and geological 



