326 DR. ANGUS SMITH ON PEAT. 



It is a common mode of decomposition of woody fibre 

 to give ont marsh-gas ; but we can hypothetically form the 

 humic acids without this evolution, as Malaguti did by 

 merely adding oxygen and drawing off carbonic acid ; and 

 this I conceive to be mainly the action in bogs in cold cli- 

 mates. The evolution of marsh-gas is found also in peat bogs; 

 but I suppose it to be a non-essential j)art of the process, 

 although sometimes this gas escapes in great abundance. 



Liebig also supposed a decomposition of woody fibre by 

 removal of carbonic acid and water only, not accounting 

 for marsh-gas. In peat bogs we have products of decom- 

 position removed in the form of brown matter ; so far as 

 we see, this brown matter has less oxygen than the 

 woody fibre, judging from all the analyses, and the peat 

 left has less oxygen ; so that oxygen has been removed, but 

 carbon also flows away in the brown matter. The removal 

 of carbon with less oxygen than the original substance 

 would increase the proportion of this latter element, where- 

 as its diminution leads to the conclusion without further 

 observation that a higher oxide of carbon escapes ; this is 

 no doubt the carbonic acid removed finally by the abun- 

 dant water. The apparent deoxidation is really an oxida- 

 tion. But hydrogen does not much change its proportion ; 

 this shows that some of it also is removed, since the dimi- 

 nution of the other two elements would otherwise increase 

 its amount. Possibly the marsh-gas may account for it 

 all, although I am not inclined to grant the formation of 

 so much. 



This reasoning leads us to the conclusion that the effect 

 is due chiefly to oxidation — the splitting-up of bodies into 

 gases, such as in fermentation is effected in warmth ; if by 

 putrefaction, then also at a higher temperature; and in a 

 former paper I showed that it begins very slightly below 

 I2'2°C. (54°Fahr.). I do not know if woody fibre will 

 give off gas at a very low temperature ; it probably ceases 



