340 Scientific Proceedings, Royal Dubhin Society. 
time, I put up other portions for fermentation, both operations 
being carried out as described in my former Paper. I was, however, 
unable to examine these latter portions for the results of fermenta- 
tive changes until nearly seven months afterwards, viz. the 
following November, owing to pressure upon my time by other 
duties. 
In the following Table the results of analysis, before and after 
keeping, are given :— 
Gases expressed in c.cs. at O° and 760 mm., bar., and other consti- 
tuents as grammes, per 1000 c.cs. of water. 
Date of 
commencement N as N as N 
and of conclusion CO; O, Ne NH, N,O; N,O; 
of Experiment. 
Sample 
No. 1 | April 28, 1894, | 116-05 0°99 15:08 0044 00024 “00992 
55 Noy. 21, 1894,| 123-68 0 lleiiealwd -0050 | 0 “00900 
Differences, | + 7°63 | — 5°99 | + 2:09 |+-0006 |—-00024 | — -00092 
No. 2 | April 28, 1894, | 116-39 7°38 | 15:58 | -0013 | -00018 | -01084 
»» | Dec. 12, 1894,| 119-71 0 15°63 | -0006| -00016 | -01174 
Differences, | + 3°32 | — 7:38 ah —:0007 |—-00002 | + -0009 
The fermentative changes recorded in the preceding Table show 
at a glance the character of the organic matters in the two samples 
of water. 
It is evident, for example, that the organic matter in sample 
No. 1, or a portion of them, bad not undergone fermentation at 
the time the sample was collected. This is shown by the fact that 
not only was the free ammonia increased in quantity by fermenta- 
tion, but that all the nitrous acid and a portion of the nitric acid 
were reduced. Hvidence of the reduction of the then two bodies is 
afforded not only by decreased quantities of nitrogen as nitrous and 
nitric acid shown after fermentation, but also in the increase in 
volume of the dissolved nitrogen. 
It may indeed be stated in the light of the experimental 
evidence given in my former Paper, that the fermentative changes 
recorded for the sample No. 1 was entirely confined to those 
