ON THE FOOD OF PLANTS. Ill 



" gas. And in the sunshine, vegetables decom- 

 " pose the carbonic acid gas of the atmosphere ; 

 " the carbon of which is absorbed, and becomes 

 " a part of their organised matter. And the 

 " oxygene gas, the other constituent, is given 

 " off: and, in consequence of a variety of agen- 

 ** cies, the economy of vegetation is made sub- 

 " servient to the general order of the system of 

 " nature. 



" It is shown, by various researches, that the 

 " constitution of the atmosphere has been al- 

 " ways the same, since the time that it was 

 " first accurately analysed : and this must, in a 

 " great measure, depend upon the powers of 

 " plants to absorb, or decompose, the putrefying 

 " or decaying remains of animals and vegeta- 

 *' bles, and the gaseous effluvia which they are 

 " constantly emitting. Carbonic acid gas is 

 " formed in a variety of processes of fermenta- 

 *< tion and combustion, and in the respiration 

 " of animals, and as yet no other process is 

 " known in nature by which it can be consumed, 

 " except vegetation." 



Thus it appears to be a general opinion, 

 among the chemical philosophers, that carbonic 

 acid gas forms a preponderating ingredient in 

 the constitution of the food of plants. And the 

 means of its formation and production are alike 



