don : but in other instances, this has, in a small de- 
gree, appeared to happen. Aware, however, of the 
various causes by which the volume of air may, to a 
small extent, be affected, and calling to mind the late 
accurate experiments of Messrs Allen and Pepys*, in 
which no diminution of volume was found to attend 
the conversion of oxygen gas into carbonic acid by 
combustion, as Crawford and others had previously 
supposed, we do not hesitate to express our convic- 
tion, that the bulk of carbonic acid produced in ger- 
mination is, like that in combustion, exactly equal to 
that of the oxygen gas which has disappeared. 
210. In thus stating the volume of carbonic acid, 
produced by seeds, to be equal to that of oxygen 
consumed, it is necessary to bear in mind that we 
speak of its formation in ttye process of germination 
alone. We have before shewn, that moistened seeds 
equally produce carbonic acid when confined in ni- 
trogen (5.), or in tubes filled with mercury (19.) ; 
but no sign of development is then observed, and 
the volume of gas, instead of continuing the same, is 
greatly augmented. These experiments have been 
repeated by Mr Acton, who found the formation of 
carbonic acid by seeds, introduced into a tube of 
mercury, to commence in a few minutes ; and in 
twenty-four hours the air, on analysis, afforded -^V 
of carbonic acid, although no evident sign of putre- 
faction appeared. Hence he contends, that, since 
seeds thus form carbonic acid when no oxygen gas is 
present, it must be difficult, if not impossible, to fix 
* Phil. Transact, J807- 
