Adeney — Dissolved Gases and Fermentative Changes. 607 



Experiments 1 and 1 a show that for the consumption of 6"48, 7*09, and 

 7*07 CCS. of oxygen, 0*00224, 0'0024, and 0*00248 grammes of nitrous nitrogen 

 were formed, respectively. 



If we raise these volumes each to 10 c.cs., for convenience of comparison, then 

 the quantities of nitrous nitrogen formed would be, respectively, 0*00344, 0*0033, 

 and 0*00351. That is for 10 c.cs. ( = 0*1437 grammes) of oxygen consumed, we 

 have, taking the mean of these last three quantities, 0*00342 grammes of nitrous 

 nitrogen formed. In other words, the formation of one part by weight of nitrous 

 nitrogen is accompanied by the consumption of about 4*2 parts by weight of 

 oxygen. 



The volume of oxygen theoretically equivalent to the last-mentioned quantity 

 of nitrous nitrogen, viz. 0*00342 grammes, on the assumption that it is derived 

 from ammonia, is 8*14 c.cs. 



Thus it will be seen, as was only to be anticipated, that, during the fermenta- 

 tion of ammonia in the absence of all organic matter, the volume of oxygen 

 consumed is in excess of that theoretically equivalent to the nitrous acid formed, 

 in the proportion of 10 : 8*14. 



On turning to the result of the experiment with ammonium chloride and peaty 

 matters, the influence of the latter on the former, during fermentation, is shown 

 in a most marked maimer. Thus, not only is the quantity of nitrous and nitric 

 acids greater in the presence than in the absence of these substances, but the 

 product of oxidation is almost entirely nitrie acid and not nitrous acid, as in their 

 absence ; the oxygen consumed being much the same in both cases. 



If we raise the volume of oxygen, viz. 6*72 to 10 c.cs., for convenience of 

 comparison with the results from experiments 1 and 1 1<, and the nitrous and nitric 

 nitrogen in the same proportion, we find that for 10 c.cs. of oxygen consumed, 

 0*00024 grammes nitrous and 0*00408 grammes nitric nitrogen would be formed. 

 These two weights are theoretically equivalent, on the assumption that they 

 were both derived directly from ammonia, to 0*5036 and 13*02 c.cs. of oxygen, 

 respectively. 



We see from these figures that, when peaty matters are present with the 

 ammonium compounds, the volume of oxygen consumed during fermentation, 

 instead of being larger^ is decidedly less than that equivalent to the ammoniacal 

 nitrogen oxidized. These results then confirm those recorded in Table XV. 



To consider now the determinations of the carbon dioxide. These show that, 

 although the peaty matters must have so largely entered into the chemical 

 changes set up during fermentation in this experiment, ko carbon dioxide was formed, 

 and it is extremely doubtful whether any was fixed, the difference recorded in the 

 Table being possibly due to experimental errors. 



