ON THE FOOD OF PLANTS. 105 



" periment, 5760grs. of that water contain only 

 " one- third of a grain of earth. But, thirdly, it 

 " also follows, that water contributes still more to 

 " the nourishment of plants, besides the service it 

 *' renders them in distributing the nutritive parts 

 •* throughout the whole structure, forming itself 

 " a constituent part of all of them, as may be un- 

 *' derstood from modern experiments. Dr. Injen- 

 ** houz, and M. Senebier have shown, that the 

 " leaves of plants exposed to the sun, produced 

 " pure air: now water has of late been proved to 

 " contain about 87 per cent, of pure air, the re- 

 " mainder being inflammable air. Water is then 

 *' decomposed by the assistance of light within the 

 " vegetable; its iiiflammable part is employed in the 

 ^^Jbrmation of oils, resins, gums, ^x. Its pure 

 " air is partly applied to the production of vege- 

 " table acids, and partly expelled as excremejitJ* 

 He further says, " To M. Hazenfrez we owe 

 " the discovery that coal is an essential ingre- 

 " dient in the food of all vegetables. Though 

 " hitherto little attended to, it appears to be 

 *' one of the primeval principles, as ancient as 

 " the present constitution of our globe ; for it is 

 *' formed in fixed air, of which it constitutes 

 " above one-fourth part, and fixed air exists in 

 " lime-stones, and other substances, which date 

 *' from the first origin of things. 



