EREMACAU3I3 OR DECAY. 



103 



Kuhlmanu coull not succeed in causing | 

 pure nitrogen to combine directly with oxy- 

 gen, even under the most favourable circum- 

 stances ; thus, with the aid of spongy plati- 

 num at different temperatures, no union 

 took place. 



The carbon in the cyanogen gas must, 

 therefore, have given rise to the combustion 

 of the nitrogen by induction. 



On the other hand we find that ammonia 

 (a compound of hydrogen and nitrogen) 

 cannot be exposed to the action of oxygen, 

 without the formation of an oxide of nitro- 

 gen, and in consequence the production of 

 nitric acid. 



It is owing to the great facility with which 

 ammonia is converted into nitric acid, that 

 it is so difficult to obtain a correct determi- 

 nation of the quantity of nitrogen in a com- 

 pound subjected to analysis, in which it is 

 either contained in the form of ammonia, or 

 from which ammonia is formed by an eleva- 

 tion of temperature. For when ammonia is 

 passed over red-hot oxide of copper, it is 

 converted, either completely or partially, 

 into binoxide of nitrogen. 



When ammoniacal gas is conducted over 

 peroxide of manganese or iron heated to 

 redness, a large quantity of nitrate of ammo- 

 nia is obtained, if the ammonia be in excess ; 

 and the same decomposition happens when 

 ammonia and oxygen are together passed 

 over red-hot spongy platinum. 



It appears, therefore, that the combination 

 of oxygen with nitrogen occurs rarely during 

 the combustion of compounds of the latter 

 element with carbon, but that nitric acid is 

 always a product when ammonia is present 

 in the substance exposed to oxidation. 



The cause wherefore the nitrogen in am- 

 monia exhibits such a strong disposition to 

 become converted into nitric acid is un- 

 doubtedly 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 pre- 

 sence 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, dif- 

 fering from the common process of putrefac- 

 tion, 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 azotis.'d bodies their nitrogen as- 

 sumes the form of ammonia, and that in this 



form, nitrogen possesses a much greater dis- 

 position to unite with oxygen than it has in 

 any of its other compounds ; we can with 

 difficulty resist the conclusion, that ammo- 

 nia is the general cause of nitrification on 

 the surface of the earth. 



Azotised animal matter is not, therefore, 

 the immediate cause of nitrification, it con- 

 tributes 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 pre- 

 sent in the atmosphere, so that nitrates 

 might thence be formed in substances which 

 themselves contained no azotised matter. It 

 is known also, that porous substances pos- 

 sess generally the power of condensing am- 

 monia; there are few ferruginous earths 

 which do not evolve ammoniacal products 

 when heated to redness, and ammonia is the 

 cause of the peculiar smell perceived upon 

 moistening aluminous minerals. Thus, am- 

 monia, by being a constituent of the atmo- 

 sphere, is a very widely diffused cause of 

 nitrification, which will come into play 

 whenever the different conditions necessary 

 for the oxidation of ammonia are combined. 

 It is probable that other organic bodies in 

 the state of eremacausis are the means of 

 causing the combustion of ammonia ; at all 

 events, the cases are very rare, in which 

 nitric acid is generated from ammonia, in 

 the absence of all matter capable of erema- 

 causis. 



From the preceding observations on the 

 causes of fermentation, putrefaction, and de- 

 cay, we may now draAV several conclusions 

 calculated to correct the views generally en- 

 tertained respecting the fermentation of wine 

 and beer, and several other important pro- 

 cesses of decomposition which occur in 

 nature. 



CHAPTER IX. 



ON VINOUS FERMENTATION : WINE AND 

 BEER. 



IT has already been mentioned, that fer- 

 mentation is excited in the juice of grapes 

 by the access of air ; alcohol and carbonic 

 acid being formed by the decomposition of 

 | the sugar contained in the fluid. But it was 

 I also stated, that the process once commenced, 

 continues until all the sugar is completely 

 | decomposed, quite independently of any 

 further influence of the air. 



In addition to the alcohol ana* carbonic 

 acid formed by the fermentation of the 

 juice, there is also produced a yellow or 

 gray insoluble substance, containing a large 

 quantity of nitrogen. It is this body which 

 possesses the power of inducing fermenta- 

 tion in a new solution of sugar, and which 

 has in consequence received the name of 

 ferment. 



