SECT. VI. MANURES. 87 



appeared above ground nine days sooner than the 

 former, and produced 25 beans ; while the former 

 produced only 15. Now the result of this experi- 

 ment, as well as the preceding facts, is evidently 

 favourable to the presumption of Senebier, and shows 

 that if carbonic acid is not the state in which carbon 

 enters the plant, it is at least a state preparatory to 

 it; and there are other circumstances tending to 

 corroborate the opinion, resulting from the analysis 

 of the ascending sap of plants. The tears of the 

 Vine, when analysed by Senebier, yielded a portion 

 of carbonic acid and earth ;* and as the ascending 

 sap could not be supposed to have yet undergone 

 much alteration, the carbonic acid, like the earth, 

 was probably taken up from the soil. 



.But this opinion, which seems to be so firmly Contro- 

 established upon the basis of experiment, Hassen- Hassen- 7 

 fratz strenuously controverts. According to experi- fratz< 

 ments which he had instituted with an express view 

 to the investigation of this subject, plants which 

 were raised in water impregnated with carbonic acid 

 differed in no respect from such as grew in pure 

 water, and contained no carbon that did not pre- 

 viously exist in the seed. Now if this were the 

 fact, it would be decisive of the point in question. 

 But it is plain from the experiments of Saussure, as 

 related in a preceding section, that Hassenfratz 

 must have been mistaken both with regard to the 

 utility of carbonic acid gas as furnishing a vegetable 

 * Seneb. Phys. Veg. vol. iii. p. 55. 



