THE CONQUEST OF NATURE 



Germany and England were greater producers than 

 America; but by the close of the century the annual 

 output in the United States was above fifteen million 

 tons as against England's ten and Germany's seven; 

 and since 1900 this lead has been greatly increased. 

 The steel industry has become so great, in fact, that 

 it is "a sort of barometer of trade and national progress." 

 The great advances in the quantity of steel pro- 

 duced have been made possible by corresponding ad- 

 vances in methods of winning the iron ore from the earth. 

 Mining machinery has been revolutionized at least 

 twice during the last half century, first by improved 

 machines driven by steam, and again by electricity 

 and compressed air. Ore is still mined to a limited 

 extent by men with picks and shovels, but these im- 

 plements now play so insignificant a part in the process 

 that they cannot be considered as important factors. 

 Steam shovels, automatic loaders and unloaders, dyna- 

 mite and blasting powder, have taken the place of 

 brawn and muscle, which is now mostly expended in 

 directing and guiding mining machinery rather than 

 in actually handling the ore. 



THE LAKE SUPERIOR MINES 



At the present time the greatest iron-ore fields lie 

 in the Lake Superior region, and it is in this region 

 that the greatest progress in mining methods has been 

 made in recent years. There are, of course, extensive 

 mines in other sections of the United States, but at 

 least three-quarters of all the iron produced in America 



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