1 86 OUR FEDERAL LANDS 



ment yet supplementing each other to give the most 

 perfect and cheapest service when combined in ex- 

 tensive systems. Where water powers are abundant 

 and can be economically developed, fuel as a source 

 of power is held as a reserve, supplying peak loads 

 and supplementing steam shortage in low-water sea- 

 son. In other areas, where fuels are abundant, fuel 

 power dominates the field, water powers, if devel- 

 oped at all, being used as feeders to the power stream 

 but not being relied upon for base load." 



Considering our possession of more than half 

 the world supply of coal, our power situation is in- 

 deed fortunate. With only eight per cent of the 

 world's population, wrote Secretary of the Interior 

 Lane in 1920, we produce annually 46 per cent of 

 all the coal taken from the ground. In less than a 

 hundred years, our annual production has increased 

 from a hundred thousand tons to seven hundred mil- 

 lion tons. Steinmetz has estimated that the coal 

 mined in the United States in 1926 would surround 

 the boundary and coast lines of the entire country 

 with a wall as big as the Great Wall of China, and 

 that this same coal contains the latent power to lift 

 that same wall two hundred miles in the air. 



Water power's contribution to so fortunate a 

 balance in power is an interesting chapter in the de- 

 velopment of national enterprise. 



Water power began in America with the 

 stream-turned wheel of the first grist mill, which is 

 believed to have been built in Dorchester in 1638. 



