FORMATION OF NITRATES. 88 



Where then there is abundance of organic matter without 

 alkaline bases, there is also fully evolved ammonia and 

 apocrenic acid, and apocrenates result. Where, on the con- 

 trary, little organic matter and abundance of alkaline bases 

 are present, there the ammonia, both of the air and of the 

 decaying body, is converted to nitric acid, and nitrates re- 

 sult. If the nitric acid which is produced, meets with humate 

 of ammonia, the acid is decomposed into apocrenic and 

 ammonia, while the ammonia of the humate is transferred 

 to other portions of geine acid, always forming in the soil. 



The crenic and apocrenic acid are mutually convertible, 

 but with very different results. Freely exposed to air, oxy- 

 gen is absorbed by crenic acid ; apocrenic acid and water 

 result. While apocrenic acid by nitric acid is changed to 

 crenic and carbonic acid. 



All these changes are worthy of study. The ultimate re- 

 sults of all are the formation of water and carbonic acid. 

 The intermediate products are ammonia and nitrates, and 

 soluble salts of the bases in soil, essential to the growth of 

 plants. 



Here then is at once opened to view the necessity of the 

 presence of geine in soil. No practical farmer ever had 

 other opinion than this, that decaying vegetable matter in 

 soil, matter in an active state of decay, is essential to a 

 good crop. It is the experience of ages, the result of observ- 

 ation and experiment from the remotest times. Though, in 

 the conflict of opinion, attempts have been made to set aside 

 this experience and practice, it may be assumed that science 

 has now shown the specific grounds of this universal belief. 



127. Hitherto the action of geine on soil only, has been 

 considered, and its chemical composition pointed out, suf- 

 ficiently for all practical purposes. The chemical proportion 

 of the elements of geine is unconnected with the practical 



