THE SOURCES OF NITRIC ACID. 



CHAPTER XI. 



NITRIC ACID. ITS COMPOSITION, AND USES IN THE 1 , 

 GROWTH OF CROPS. 



Nitrogen itself is wholly inert and has no positive action- 

 in nature. Its office is wholly negative. But when com- 

 bined with oxygen as nitric acid, or with hydrogen as am- 

 monia, it becomes endowed with the most active properties- 

 and enters into the most interesting and useful combina- 

 tions in the structure of organic matter. Nitrogen forms 

 one-sixth part of the animal tissues and the same propor- 

 tion of the so called nitrogenous, or albuminoid portions of 

 plants. But there is no evidence to prove that the nitro- 

 gen so combined in organic substance is derived directly 

 from this element as it exists in the atmosphere; but on the 

 contrary abundant reason to believe that it enters into thei 

 composition of plants in the form of nitric acid, which is a 

 combination of nitrogen and oxygen. Moreover we are at 

 a loss to know how this nitric acid enters into the compo- 

 sition of plant tissue; the general drift of the evidence gained 

 by the most careful experiments going to show that it is, 

 carried into the plants in solution in the water of the soil,, 

 and is derived from the ammonia which is abundantly 

 evolved from decaying organic matter in the soil and only 

 to a very small extent from the contributions drawn from 

 the atmosphere. 



The sources of nitric acid are threefold; first; from the 

 atmosphere in which it exists as a product of the decompo- 

 sition of organic matter and from which it is washed by the 

 rains which dissolve it; second; from a peculiar fermenta- 

 tion of organic matter, in the soil or in manure; which is 

 produced by the agency of a low form of plant life ; a germ 

 or fungus which grows and spreads through the mass and 

 causes the oxidation of the nitrogenous matter in it; or it 



