OF BODIES CONTAINING NITROGEN. 337 



exhibits such a strong disposition to become con- 

 verted into nitric acid is, undoubtedly, that the two 

 products, which are the result of the oxidation of 

 the constituents of ammonia, possess the power of 

 uniting with one another. Now this is not the case 

 in the combustion of compounds of carbon and 

 nitrogen; here one of the products is carbonic acid, 

 which, on account of its gaseous form, must oppose 

 the combination of the oxygen and nitrogen, by 

 preventing their mutual contact, while the superior 

 affinity of its carbon for the oxygen during the act 

 of its formation will aid this effect. 



When sufficient access of air is admitted during 

 the combustion of ammonia, water is formed as well 

 as nitric acid, and both of these bodies combine 

 together. The presence of water may, indeed, be 

 considered as one of the conditions essential to 

 nitrification, since nitric acid cannot exist without it. 



Eremacausis is a kind of putrefaction, differing 

 from the common process of putrefaction, only in 

 the part which the oxygen of the air plays in the 

 transformations of the body in decay. When this is 

 remembered, and when it is considered that in the 

 transposition of the elements of azotized bodies 

 their nitrogen assumes the form of ammonia, and 

 that in this form, nitrogen possesses a much greater 

 disposition to unite with oxygen than it has in any of 

 its other compounds ; we can with difficulty resist the 

 conclusion, that ammonia is the general cause of 

 nitrification on the surface of the earth. 



Azotized animal matter is not, therefore, the im- 

 mediate cause of nitrification ; it contributes to the 

 production of nitric acid only in so far as it is a 

 slow and continued source of ammonia. 



Now it has been shown in the former part of this 

 work, that ammonia is always present in the atmo- 

 sphere, so that nitrates might thence be formed in 

 substances which themselves contained no azotized 

 matter. It is known, also, that porous substances 

 possess generally the power of condensing ammonia;, 



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