INPLUENCE OF AIR UPON FRUITS. 85 



yellow and die. In this case it appears that the water has 

 become exhausted of oxygen, without having the power of 

 renewing it, and when that is no longer present for the 

 roots to absorb, they decay ; whilst, if the root were sup- 

 plied with flowing water, it would be constantly receiving 

 fresh supplies of oxygen for the formation of carbonic acid, 

 which furnishes the principal nutrition of* the plant 



The wood, the parenchyma, the petals, and, in general, 

 all those parts of plants which are not green, do not inhale 

 and exhale, alternately during the day and night, the oxy- 

 gen gas which surrounds them ; but they absorb a small 

 quantity, which combines with their carbon, and remains 

 in solution in their juices, till it is conveyed to the leaves, 

 when it is decomposed by the rays of the sun. According 

 to this it appears, that carbon, which forms one of the 

 most abundant principles of the juices and other manures 

 which are furnished to plants to supply them with nourish- 

 ment, cannot be assimilated by them, unless it be com- 

 bined with oxygen, and form carbonic acid. In this state 

 it is thrown into the atmosphere, whence it is gradually 

 absorbed by the leaves, and decomposed by them. One 

 experiment, which seems to establish this opinion, is that 

 of absorbing, by means of lime or the caustic alkalies, the 

 carbonic acid, as fast as it is transpired by the leaves, the 

 consequence of which is the death of the plant 



ARTICLE in. 



The Influence of Air upon Fruits. 



M. Berard, in his experiments on the effect of air upon 

 fruits, placed green fruits of various kinds in well-corked 

 flasks, or under bell-glasses inverted over mercury, and ex- 

 posed them to a strong light. After the fruit had remained 

 within these glasses twenty-four hours, an analysis of the 

 air, of which the volume was from seven to eight times 

 greater than that of the fruit, always presented him with 

 the following results. 



