26 ROYAL SOCIETY OF CANADA 
bed be not stagnant, this is drained away and the fermentation con- 
tinued to the stage where volatile hydrocarbons cannot be retained and 
marsh gas is given off. The point at which fermentation is arrested no 
doubt determines in great measure the chemical composition of the 
ultimate product. The possible history of the process of the chemical 
change may be summed up as follows:— 
During the fermentation stage the loss of CO? is raising the percent- 
age of hydrogen and carbon, then marsh gas is lost and these two per- 
centages decrease. This process may be repeated many times, but can- 
not continue indefinitely, entombment under other deposits evidently 
will check it and the hydrogen percentage of the mass may vary from a 
stable condition with low hydrogen to an unstable one with high hydro- 
gen percentage. 
Experiments on fermentation have been undertaken with the object 
of tracing the origin of natural gas. The composition of the gas given 
off has been carefully noted and in all the published results, the tendency 
has been first toward a production of CO? with N. in small amount and 
toward the end of the experiment the production of CH,. The results 
of several of these experiments may be here cited. 
Substance fermented :— 
Pure cellulose—C* H'°O*. 
Experimenter—T appeiner. ' 
Gas evolved at beginning at end. 
CO, | 
HS f 85 .40 76.98 
Ei, 0.0 0.0 
CH, 11.86 23.01 
Ni. "2418 0.0 
99.99 99.99 
In another experiment given by “ Hoppe-Seyler” the gas expelled : 
from the marsh gas fermentation of cellulose was:— 
CO? 50. 
CH, 45. 
H. 4. 
‘Ber. I. Chem. Geo. 1883 Part 16, pp. 122 & 1734. 


