204 



HYDRODYNAMICS. 



Flash or fen wheel/or raising water rapidly short distances. 



it has "been driven by steam-engines ; and in one in- 

 stance, an eighty-horse-power engine, with ten bushels 

 of coal, raised 9840 tons of water six feet and seven 

 inches high in an hour. This is equal to more than 

 29,000 lbs. raised one foot per minute by each horse- 

 power, showing that very little force is lost by friction 

 in the use of the flash- wheel. 



Fig. 174. 



SECTION IV. 



WAVES. 

 NATURE OF WAVES. 



An inverted syphon, or bent tube like 

 that shown in Fig. 174, may be used 

 to exhibit the principle on which de- 

 pends the motion of the waves of the 

 sea. The action of the waves on shores 



