19 



ments, (6.), that when seeds are made to grow in 

 oxygen gas, the bulk of carbonic acid produced is 

 equal to that of the oxygen gas which disappears. 

 Even granting, therefore, that a portion of this gas 

 is absorbed by the seed, this equality of proportion in 

 the carbonic acid produced forbids us to consider any 

 part of it to be retained ; and if it be admitted, that 

 the formation of this acid is in part effected without 

 a previous absorption of oxygen, why should we not 

 allow it to proceed to the fullest extent in which 

 it takes place, rather than have recourse to two such 

 opposite suppositions to account for the same pheno- 

 menon ? 



17. To suppose this oxygen gas to be taken up 

 by the seed by the operation of chemical affinity, 

 necessarily implies its previous separation from the 

 nitrogen gas with v hich it was united ; but how 

 could this be done, unless the seed presented some- 

 thing to the air which had a stronger affinity for its 

 oxygen than the nitrogenous portion has ? And what 

 could it offer but moisture and carbon ? Moisture, 

 however, does not decompose air ; and if carbon be 

 the agent, must not carbonic acid be at once formed ? 

 And if this acid be thus formed, exterior to the 

 fceed, and out of the oxygen gas in contact with it, 

 bow can we hold that gas to be first singly taken in 

 by the seed, and expelled afterwards in the form of 

 carbonic acid ? To say that the air is attracted in 

 its undecomposed state, necessarily requires proof of 

 (he existence of certain cavities in the seed where it 

 can be retained ; for as the nitrogen gas neither 

 suffers (5.) nor produces change, it must be com- 

 pletely expelled after the oxygen is abstracted from 

 B2 



