200 



HYDROBYNAMICS. 



serves it in better condition, and prevents stagnation. 

 The friction being very small, it will last a long time 

 without wearing out. 



Fig 170. 



THE WATER-RAM. 



One of the most ingenious and useful machines for 

 elevating water is the Water-ram. It might be em- 

 ployed with great advantage on many farms, were its 

 principle and mode of action more generally understood. 

 By means of a small stream, with only a few feet fall, 

 a current of water may be driven to an elevation of 

 fifty to a hundred feet above, and conveyed on a higher 

 level to pasture-fields for irrigation, or to cattle-yards 

 for supplying drink to domestic animals, or to the kitch- 

 en of dwellings for culinary purposes. 



Its power depends on the momentum of the 

 stream. Its principal 

 parts are the reservoir 

 or air-chamber, A {Fig'. 

 170), the supply-pipe, 

 B, and the discharge 

 pipe, C. The running 

 stream rushes down 

 the supply - pipe, B, 

 Water-ram. and. Striking the waste 



valve, D, closes it. The stream being thus suddenly 

 stopped, its momentum opens the valve, E, upward, 

 and drives the water into the reservoir. A, until the 

 air within, being compressed into a smaller space, 

 by its elasticity bears down upon the water, and again 

 closes the valve, E. The water in the supply-pipe, B, 

 has by this time expended its momentum and stopped 



