TURBINE WATER-WHEELS. 



223 



Suction and Forcing-Pump. The accompanying cut (fig. 

 249) represents a suction and forcing-pump combined in one, 

 for the purpose of drawing water from a well or cistern, 

 and forcing it to tanks in upper stories, or throwing water 

 into upper rooms in case of fire. By lengthening the rod, 

 the working parts may be placed at the bottom of a deep 

 well, and the whole used as a deep well pump. 



TURBIXE WATER-WHEELS. 



The large wooden wheels formerly used for the appli- 

 cation of water power to mills and other machinery are 

 rapidly giving place to iron Turbine wheels. Overshot 

 wheels, the best kind formerly employed, were turned by 

 the weight of the water, the whole of which was held in 

 the slowly descending buckets of the wheel. Turbine 

 wheels do not hold the water, but merely receive and im- 

 part the force of the rushing current, the water being 

 held by the flume above. Hence, a turbine wheel of 

 quite small size may impart to machinery nearly the 

 whole force of a powerful current of water. 



Turbine wheels are j)laced in a horizontal position, with 

 ^^-^^- vertical axes. Being 



under water, they never 

 freeze ; and they are not 

 impeded by back-water 

 when a flood occurs. 

 There are two principal 

 kinds amons: those in 



common use. 



those. 



like the Reynolds wheel, 

 which have a single 

 opening at the side, 

 Secmn of Reynolds' wiieei. through which the wa- 



ter is admitted ; and such as the Leflel and Van de Water 

 wheels, into which the water is admitted through several 

 openings around them. 



