82 SOURCES OF APOCRENATES. 



though in part insoluble, form a compound soluble salt. 

 These double salts are, therefore, those which the plants 

 chiefly abstract from the soil. Hence, that there may be, as 

 there must be in fertile soil, a continued supply of these 

 salts, nature has provided constant sources of their repro- 

 duction. The sources are two-fold. This is a point of too 

 much importance to be passed by without fuller elucidation. 



It has been stated (100) that the union of hydrogen and 

 nitrogen forms ammonia. This alkali, by the action of the 

 oxygen of the air, becomes nitric acid. These are the facts. 

 Ammonia in air, in contact with porous or decaying matters, 

 becomes aqua fortis. Moist decaying substances induce the 

 nitrogen of air inclosed in their pores, to become first ammo- 

 nia, and then an acid. There is then a constant formation 

 more or less, according to circumstances, of nitric acid in 

 the transformation of geine. What now becomes of this 

 nitric acid? It forms either nitrates or apocrenates. 



If abundant alkaline bases are present, as potash, soda, 

 lime, magnesia, the nitric acid unites with these, one or all 

 according to quantity and varieties of saltpetre — that is, 

 nitrates result. If alkaline bases are absent, then nitric acid 

 converts humic acid into apocrenic acid and ammonia, itself 

 furnishing the nitrogen for that alkaline base. The kind of 

 change need not be detailed, or here illustrated. It is enough 

 to state, that nitric acid and humic acid, by their mutual 

 reactions, produce apocrenate of ammonia, water, and car- 

 bonic acid. This is one source of the reproduction of apo- 

 crenate. 



A second source is found in an abundance of decay- 

 ing organic matter in soil. Ammonia is here copiously 

 produced, but not a corresponding proportion of nitric acid, 

 for the oxygen of the air essential to this change, is seized 

 by the carbon and hydrogen of decaying matter. 



