to ON HYDROGEN. 



gen and hydrogen in the proportion of nearly 

 89 parts of the former to 1 1 parts of the latter. 

 It may be produced at any time artificially, 

 by a mixture of these gases in their relative 

 proportions, and then passing an electric shock 

 through the mixture. This effects the chemi- 

 cal union of the two gases, and the product is 

 water of the utmost purity, and of the exact 

 weight of the two gases employed. 



Part of. the water when absorbed by plants, 

 remains as a fluid in the substance of the 

 plant, and is evaporated from the leaves after 

 having deposited the salts it may contain, and 

 yielded up all the carbonic acid gas it may 

 have held in solution for the nutriment of the 

 plant. Another part undergoes chemical de- 

 composition, and is resolved into' its elements 

 oxygen and hydrogen ; the former passes off 

 through the leaves, and tends to supply the 

 place previously occupied by the carbon ab- 

 sorbed by the plant; the latter, hydrogen, en- 

 ters into composition with the carbon, and 

 tends to form the resinous and oleaginous mat- 

 ter of the plant, and under other circumstances 

 combines with nitrogen to form ammonia, — 

 after carbon the nutriment the most necessary 

 to the growth and development of vegetable 

 life. 



The most positive proof exists, that plants 

 do decompose the water absorbed by their 

 roots, and assimilate the hydrogen, from the 

 fact that caoutchouc or Indian-rubber, the vo- 

 latile oils, wax, and other matters, the products 

 of vegetalDles, consist almost wholly of hydro- 



