218. The important experiments of Messrs Allen 
and Pepys, to which we have already referred, en- 
able us to make another correction in our conclusions 
concerning the carbonic acid formed in germination. 
We before followed the opinion of M. Guy ton, that 
this acid contains only one-fifth of its weight of car- 
bon ; but these gentlemen have found that the pro- 
portion of carbon comes much nearer to the deter- 
mination of Priestley and Lavoisier, the former of 
whom made it one-fourth, and the latter T.TT of the 
compound. The average result of their experiments 
afforded V^ = y.^ of carbon. They ascertained 
also, with great precision, the specific gravities of 
oxygen and carbonic acid gases ; finding a cubic 
inch of the former to weigh O.3382, and a cubic inch 
of the latter 0.4726 of a grain, which weights, they 
observe, correspond almost exactly with those pre- 
viously assigned by Mr Davy. 
219. If, therefore, the quantity of carbon, given out 
by the seeds in our experiments (8. 9.), be recalcu- 
lated on the suppositions that no change of bulk at- 
tends the conversion of oxygen gas into carbonic 
acid, and that the relative specific gravities of these 
two gases are such as is above stated, it will be found, 
that the quantity of carbon, existing in the acid form- 
ed by germination, is greater than we before assigned 
when proceeding on different data, being T .4~g- instead 
of T-TTJ as before stated (13.) : and, consequently, its 
proportion approaches nearer to the determination of 
Allen and Pepys, who, as we have seen, make it to 
constitute T -i? of the compound. 
220. But now that the specific gravities of oxygen 
