HISTORY OF GEINE. 83 



The difference, it has been suggested, is owing 

 "to the difficulty of procuring" geine, " pure, from 

 soil." But the analyses of mould or geine, taken 

 from decayed trees, show also, great differences. 

 The process of decay, when air is freely admitted, 

 combines a portion of the oxygen of air, with the 

 hydrogen of the geine ; the whole of the hydrogen 

 is thus removed as water, while the oxygen of the 

 geine, combining with the carbon, escapes as car- 

 bonic acid. There is not enough oxygen to convert 

 all the carbon ; hence, a portion remains. But if 

 water, be present, during decay, and the air partially 

 excluded, then, a portion of water yields oxygen to 

 the carbon. In order to make correct comparative 

 analyses, the substances should each have proceeded 

 to the same point of decay, and who may determine 

 that ? The geine of soil appears to have been fa- 

 vorably situated for the abstraction of its hydrogen, 

 or in other words, it has formed water faster than 

 carbonic acid. Still the proportions are so near 

 those of the artificial, that it seems difficult to be- 



