Progress of Foreign Science. 153 



ascertain if the green herbaceous substance of fruits, con- 

 sidered in itself, disengages oxygen gas, we ought to consider 

 that those in which this colour is very feeble, and which are 

 formed of a very thick, yellow or white, parenchyma, cannot 

 lead to any very determinate result ; for it is admitted, (with 

 very rare exceptions,) that the vegetable matters, which are not 

 green, corrupt the air, both in the sun and the shade, in what- 

 ever part they are found, and that their effect may overbalance 

 that of the green portions. We regret that our bounds will 

 not permit us to follow the Genevese philosopher through the 

 details of his masterly and decisive researcher. The following 

 is his recapitulation of results, on which, we conceive, perfect 

 reliance may be placed. 



1. Green fruits have the same influence on the air, in sun- 

 shine and obscurity, as the leaves ; the action differs only in being 

 less intense than that of the latter. 



2. They cause the disappearance, during the night, of the 

 oxygen gas of their atmosphere, and they replace it by car- 

 bonic acid gas, which they partially absorb ; this absorption is 

 visually less in the open air than under a receiver. 



3. In equal volume, they consume more oxygen in the dark, 

 when they are distant from, than when they are near to, their 

 maturity. 



4. During their exposure to the sun, they disengage, in 

 whole or in part, the oxygen of the carbonic acid which they 

 have imbibed during the night, and leave no trace of this acid 

 in their atmosphere. Several fruits detached from the plant, 

 add also oxygen gas to air which contained no carbonic acid. 

 When their vegetation is very feeble or languishing, they corrupt 

 the air in every circumstance, butless in the sun thanin theshade. 



5. Green fruits detached from the plant, and exposed to the 

 successive action of the night and of the sun, change the air 

 little or nothing in purity and volume; the slight variations, 

 which we observe in this respect, depend either on their greater 

 or less faculty of elaborating carbonic acid, or on their compo- 

 sition, which is modified according to their degree of maturity. 



6. Green fruits decompose, in whole or in part, not only the 

 carbonic acid which they have produced during the night, but 

 also that which we add artificially to their atmosphere. When 

 we make the latter experiment, with fruits which are aqueous, 

 and which, such as apples and grapes, elaborate but slowly the 

 carbonic acid gas, we perceive that they absorb in the sun, a 

 portion of gas much greater than a like volume of water could 

 do in a similar mixture. Thereafter they disengage the oxygen 

 of the absorbed acid, and appear thus to elaborate it in their 

 interior. 



7. Their faculty of decomposing carbonic acid, becomes 

 feebler, as they ripen. 



