594 Adeney — Dissolved Oases and Fermentative Changes. 



Again, it will be observed that the proportion of carbon to nitrogen in peaty 

 matters is very similar to that of the carbon and nitrogen found in the fermented 

 matters which result from the complete fermentation of sewage during slow filtra- 

 tion through sand. We find from an experiment recorded by Dr. Frankland 

 (Frankland's "Experimental Researches," p. 751) that this proportion may be from 

 9-6 : 1 to 6-3 : 1. 



The fermented organic matters which are formed during slow filtration of 

 sewage through such substances as sand or pumice, besides showing a similarly 

 high proi^ortion of carbon to nitrogen, as peaty matter, and we may take it, a 

 similar resistance to fermentation, since it must be remembered these matters are 

 obtained in very decided quantities even after a fermentation in a filter, which has 

 been so complete, that little more than traces of the original ammonia in the 

 sewage may be left unfermented, also possess other properties such as colour and 

 optical properties, which are very similar to those of peaty-colouring matters. 

 Thus, on allowing sewage to jDercolate very slowly through a pumice filter, I have 

 obtained effluent waters therefrom, coloured very decidedly with a brown tint, 

 which could not be distinguished from the brown varieties of peaty matter, and 

 which on analysis gave the proportion of carbon to nitrogen as 7'1 : 1. 



Neither could it be distinguished from peaty water coloured to a similar depth 

 of tint when examined by Professor W. N. Hartley's spectroscopic method. 

 A similar series of dilutions of both afforded identical ultra violet absorption 

 spectra. 



The experiments with easily fermentable matters, which have already been 

 quoted, more especially those with the effluent water from the sand filtration 

 recorded in Table V., afford abundant evidence that the organic matters which are 

 formed during the first stage fermentation of animal and vegetable substances may 

 themselves take part in, and suffer a further oxidation during, the subsequent 

 second stage. 



The question naturally suggested itself — Do peaty matters undergo similar 

 fermentative changes under similar conditions ? 



This question apjieared the more interesting because from those of my experi- 

 ments already recorded, and from others, I had come to the conclusion that the 

 presence of small quantities of fermented organic matters, such as peaty-colouring 

 matters, probably are essential to the nitric fermentation of ainmonia, and that the 

 failm-e to obtain a nitric fermentation of this body under conditions which, as the 

 researches of Professor P. F. Frankland and Mrs. G. C. Frankland, of Warrington 

 and of Winogradsky, have abundantly demonstrated, are most favourable to 

 nitrous fermentation, may be ascribed to the complete absence of peaty or 

 humus-like bodies. 



In every experiment which I have made, and in which it has been found that 



