126 Modern Business Geography 
United States Bureau of Mines 
Fig. 100. The coal tipple is an instance of the way in which machinery works for man. The 
smaller building is the weighing house ; the larger one is the breaker. Trace the route which the 
mine cars take. What two processes take place in the breaker? Where does the coal go next? 
How are all the cars propelled? Where are the empty cars going? Compare the amounts of 
man labor and machine labor emvloved in the work illustrated in this pieture. 
has extensive iron industries, is surrounded by the anthracite mines 
of eastern Pennsylvania. The growth of Birmingham, in Alabama, 
has been encouraged by both coal and iron deposits. 
. In Europe, ‘ coal cities” are more numerous than in our country. 
The best known are Birmingham, Manchester, Newcastle, and 
Glasgow, in Great Britain; Essen in Germany; and Liége in 
Belgium. 
PETROTI.FITM 
Petroleum has been much used for only about sixty years, yet in 
this short time the United States has consumed nearly half of its own 
supply. Petroleum has become so essential to modern man for lighting 
his home, lubricating his machinery, and feeding his motors that a 
French general is quoted as saying that the Allies’ battles in the World 
War * could not have been won without that other blood of the earth 
which is called oil.” 
Perhaps the general who called petroleum ¢ the blood of the earth” 
would think the name even more appropriate if he could look a few feet 
beneath the surface in some parts of the United States and see the net-