TRANSFERENCE OF ENERGY 



expends its force by driving a portion of the water 

 through the other valve and small tube to the hill- 

 top, until the water ceasing to flow in the main tube 

 the large valve again falls open by gravity ; the 

 flow recommences through it, when its full velocity 

 again closes the main valve and so " da capo." By 

 this arrangement, which is known as the hydraulic 

 ram, a small but nearly constant and adequate sup- 

 ply of water is carried up to a reservoir many feet 

 above its source in the bed of the brook. 



In the living plant and in animals a transfer of 

 the surplus energy occurs in some respects analogous 

 to the action of the flowing water in the apparatus 

 described. In the plant life, as well as in that of 

 animals, the energy that is not available immediately 

 or required for its momentary functions is stored up 

 in the vessels until wanted, often in the shape of 

 starch or fat. Partly even in daylight, but especially 

 at night, when the chlorophyll molecules are no 

 longer acting, processes of tissue formation are at 

 work. These processes are essentially oxidizing: a 

 portion of the hydrocarbons formed during the day 

 unite with oxygen, and form again carbon dioxide 

 and water, thus reversing the prior action of the 

 chlorophyll corpuscles. This degradation, or falling 

 down from the higher levels of chemical or organic 

 construction to the lower level of inorganic affinities, 



251 



