264 GEOLOGY OF OHIO 



The vegetable kingdom is the agent of transfer. The all important 

 office of absorbing, appropriating and storing the power of the sun has 

 been assigned to the plant. The plant accomplishes the all important 

 work of storing the sun's power through the agency of the cells of which 

 it is composed. The vegetable cell has the surprising property of being 

 able to live and multiply itself on air alone, through the agency of the 

 sunlight. 



One of the constant constituents of the atmosphere is carbonic acid, 

 a gas that consists of one atom of carbon combined with two atoms of 

 oxygen. The bond that holds these elements united is a powerful one. 

 We are able to break it in our laboratories, it is true, but only by employ- 

 ing the full resources of chemical skill. But in the vegetable cell, under 

 the sun's light, this bond melts away, like a thread of flax in the flame 

 of a furnace. The carbon is fixed in the forming tissues of the plant, 

 while the oxygen is restored to the atmosphere to maintain its vitality. 



To effect this decomposition a certain measure of the sun's force is 

 required. All the force that was employed in breaking this bond, the 

 heat, the light, the chemical power, is now held in these products of 

 growth, in a potential state. But it is readily given back to all appropri : 

 ate demands and the self-same light and heat by which the vegetable 

 substance grew, we obtain again when we burn this substance in furnace 

 or grate. This is the sole source of the power of fuel, and all fuel, or in 

 other words, whatever will burn, has borrowed its power, to burn from 

 the sun. 



Taken within the animal system, the products of plant growth give 

 to it, also, the force that they hold imprisoned. On this account and in 

 this way, they become the food, the support, of animal life, the sole 

 source of its heat, its activity, in a word, of its vital force. All animal 

 movements, muscular or molecular, that we can see or that we are obliged 

 to infer, result alike from, or at least are alike conditioned by, this trans- 

 formed power of the sun. 



The remarkable office of the vegetable cell is thus brought to light. 

 It is a storer of power, a reservoir of force. It mediates between the 

 sun, the great fountain of energy, and the animal life of the world. The 

 animal can use no power that has not been directly or indirectly stored 

 in the vegetable cell. This storage is forever going on. Of the vast 

 floods of energy that stream forth from the great center of our system, 

 an insignificant fraction is catight by the earth as it revolves in its orbit. 

 Of the little -fraction that the earth arrests, an equally insignificant part 

 is used directly in plant growth. But the entire productive force of the 

 living world turns on this insignificant fraction of an insignificant frac- 

 tion. 



Is there any way in which this sun power can be permanently 

 stored on the large scale ? Nature has devised various ways of retaining 

 and preserving the power which the vegetable cell has accumulated in the 



