20 



it. Lastly, M. de Saussure has endeavoured to 

 show, that the carbonic acid formed in germination 

 contains in it precisely the quantity of oxygen gas 

 that has disappeared : And although, from the dif- 

 ference of opinion which prevails concerning the ac- 

 tual proportions of the elements which constitute 

 that substance, this cannot be positively assumed ; 

 yet the near proportions which, in our own experi- 

 ments, as well as in those of Saussure and Cruick- 

 shank, the two gases bear to each other at the be- 

 ginning and end of the process, renders it extreme- 

 ly probable. If this opinion be well founded, no 

 part of the oxygen can be retained by the seed ; and 

 we may conclude, therefore, with M. de Saussure, 

 that none of it is either attracted or absorbed *. 



1 8. If indeed oxygen gas were in part retained by 

 seeds, we might expect, since they deteriorate so 

 large a portion of it, that they would acquire weight 

 as well as other substances with which the base of 

 that gas combines. But Mr Gough found, that 

 steeped peas germinating in air, and sprouting to the 

 length even of two inches, did not increase in 

 weight ! We found, that if peas be steeped a suf- 

 ficient time in water, they almost exactly double 

 their weight, which increase of weight rapidly dimi-* 

 nishes if they be afterwards exposed freely to \he* 

 air. Six peas, weighing nineteen grains, were, after 

 forty-eight hours steeping in water, increased in 

 weight to thirty-eight grains, and in this state were 



* Journal de Physique, loc. cit. 



f Manchester Memoirs, vol. iv. p. 316, 



