38 AMERICAN MANURES. 



It does not exist in nature, in the free or un- 

 combined state, nor does it exist so abundantly 

 as oxygen. It forms a part of all animals and 

 plants, and one-ninth of the weight of water. 

 At the same temperature, and under like pressure, 

 it is sixteen times lighter than oxygen, and nearly 

 fourteen and a half times lighter than common air. 



This gas will not support a flame or combus- 

 tion. But although hydrogen does not exist in 

 nature in the free state, it is being continually 

 formed by the decomposition of water, caused by 

 the putrefaction of organic bodies ; this liberated 

 hydrogen uniting with nitrogen, carbon or sul- 

 phur, forming ammonia, carburetted and sul- 

 phuretted hydrogen. It is generally found in 

 plants, in excess of the amount required to form 

 water, showing that water is decomposed in the 

 plant, and that the oxygen is expelled; the 

 hydrogen being possibly retained as an attractive 

 element, should there be a scarcity of moisture, 

 to again combine with more oxygen and form 

 water. 



This element is assimilated by plants in 

 ammonia and water; these sources are sufficient 

 to furnish hydrogen. 



CARBURETTED HYDROGEN. 



Carburetted Hydrogen is found in large 

 quantities during the decay of vegetable matter 



