AIR AND WATER AS SERVANTS OF MAN 127 



the mountain states from which they may develop immense 

 power for factory purposes. Vermont is already using its water 

 power nearly to the limit; Illinois is using about 50 per cent of 

 that which is available; Washington, about 5 per cent. 



One of our great national problems is the careful develop- 

 ment of this power so that the rights to its use may not fall into 

 the hands of private interests without ample compensation to 

 the people of the states and nation for its use. Timber lands, 

 coal lands, and mineral lands belonging to the people as a whole 

 have been sold to private concerns and to individuals for a mere 

 pittance, and these lands have yielded millions of dollars to such 

 private interests with no return to state or nation other 

 than the meager purchase price. Thus the iron and copper 

 lands of northern Michigan were sold in many cases for 

 $1.25 an acre. One mine, the Calumet and Hecla, yielded 

 over $13,000,000 worth of copper to enrich its owners. Thou- 

 sands of acres of government land on which stand the great 

 western forests, the finest in the world, have similarly been sold 

 when the lumber from a single tree will pay the purchase price 

 many times over. One of the great redwoods yields enough 

 lumber to build several bungalows. It remains to be seen 

 whether we as a people will part with our water power in the 

 same careless manner. 



Another device that has been of inestimable value to man is 

 the pump. It, too, depends on these principles of fluid pressure, 

 although it was in use long before the principle of its operation 

 was understood. Both lift pump and force pump may be readily 

 constructed and the method of operation will be better under- 

 stood after they have been made and operated. 



The lift pump is made readily as follows: Take a length of 

 good-sized glass tubing 12 inches long, a paraffined mailing- 

 tube, or a piece of bamboo. Cut a piece of wood 15 inches long 

 and about as large around as a lead pencil, for the plunger 

 handle. At one end of this fit a slice of cork for a plunger and 

 fasten it securely. The cork should fit the tube snugly. Punch 



