WATER W 'HEELS 



177 



detract from the beauty of this world-known scene, and would 

 rob our country of a natural beauty unequaled elsewhere. 

 172. Water Wheels. 



120 

 small 



In 



Figure 



FIG. 120. A mountain stream turns the wheels of 

 the mill. 



the 



water of a small but 



rapid mountain stream 



is made to rotate a 



large wheel, which in 



turn communicates its 



motion through belts 



to a. distant sawmill 



or grinder. In more 



level regions huge 



dams are built which 



hold back the water 



and keep it at a higher 



level than the wheel ; 



from the dam the water is conveyed in pipes (flumes) to the 



paddle wheel which it 

 turns. Cogwheels or belts 

 connect the paddle wheel 

 with the factory machinery, 

 so that motion of the paddle 

 wheel insures the running 

 of the machinery. 



One of the most efficient 

 forms of water wheels is 

 that shown in Figure 121, 

 and called the Pelton wheel. 

 FIG. i2i. The Peiton water wheel. Water issues in a narrow 



jet similar to that of the 



ordinary garden hose and strikes with great force against the 



lower part of the wheel, thereby causing rotation of the wheel. 



CL. GEN. SCI. 12 



