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exposed on a table in a room at temperature 66* : 

 they gradually decreased in weight, and by the fifth 

 day had fallen back to their original weight and ap- 

 pearance. If, however, the direct effects of evapo- 

 ration be prevented, by inclosing them in a jar, they 

 still exhale moisture and diminish in weight, but 

 much more slowly ; for the peas in the foregoing 

 experiment (8.) were by their germination much di- 

 minished in bulk, and lost rather more than seven 

 grains in weight ; from all which it follows, that 

 no supposed absorption of oxygen adds, during their 

 growth, to the weight of seeds. 



1 9. If then there be no proof that the oxygen gas 

 which disappears in germination enters, either by 

 absorption or by chemical affinity, into the seed, so as 

 to combine with it, it follows, that this gas must be 

 at once converted into the carbonic acid produced in 

 that process, without such previous combination ; and 

 the formation of the acid proceeding always in pro- 

 portion (7. 8.) to the disappearance of the oxygen gas, 

 sufficiently shows that it is derived from that source 

 alone. If the acid were formed independent of the 

 oxygen gas employed, the whole bulk of air ought 

 to be increased by germination : and accordingly, 

 Mr Cruickshank found, that when carbonic acid was 

 produced by steeped seeds, confined either in nitro- 

 gen (5.) or hydrogen gas, the bulk of air was in- 

 creased one-fifth, but nothing like germination then 

 took place. He even found that seeds, after being 

 soaked in water, and passed up into a tube of mer- 

 cury, formed carbonic acid in large quantity but 

 without undergoing any sensible change in their ap- 



B3 



