76 APPLIED SCIENCE 



other light machinery. A common rotary water motor 

 is employed, and is attached to the faucet. The water 

 striking against the cup-shaped fans attached to the axle 

 of the motor causes it to rotate. The axle is attached to a 

 shaft which is connected directly or by belts to the machines. 

 The motor is enclosed in a metal case with an opening 

 in the bottom to allow the water to escape into the sink or 

 outlet. 



75. The Pelton Wheel. The Pelton wheel (Fig. 48), 

 a modified form of undershot wheel, has cup-shaped buck- 

 ets sticking outward at .regular 

 intervals around its circumfer- 

 ence. There is a partition in the 

 center of each bucket. A nozzle 

 is so arranged that it directs water 

 on the buckets as they reach the 

 lowest point of a revolution. The 



water strikes the partition of the 

 FIG. 48. Pelton Wheel. . 



cup and turns right and left in- 

 side of the cup. The change of direction transfers the 

 energy to the wheel. 



76. Wasted Water Power. Very few people realize the 

 vast amount of water energy that goes to waste every year. 

 Every particle of falling or running water represents energy, 

 the amount of which depends upon the quantity and the 

 depth of the fall. This energy can be harnessed in the same 

 way as the energy obtained from the coal we burn. Water 

 that possesses energy, that is, water that falls, is often 

 spoken of as " white coal." Power plants that transform 

 the energy of falling water into electrical energy, oftentimes 



