on the Ah\ before the Period Maturity. 
vessel then contained no carbonic acid, but a small excess, equal 
to of oxygen gas; during this time the grapes had tripled 
their bulk, and exhaled a considerable quantity of water. The 
leaves also, which adhere to a plant having its root in the soil, 
afford a like result. ^ tn an artificial atmosphere containing j\jth 
of carbonic acid, a detached bunch of grapes, exposed alternate- 
ly to the sun and darkness for four nights and days, decomposed 
almost all the acid gas, and augmented the oxygen. During 
the night, this fruit consumed less oxygen as it approached ma- 
turity, and disengaged also less oxygen in sunshine through the 
day. When confined for four days and nights, and placed al- 
ternately in sunshine and shade, it produced little or no change 
in the air at the period of maturity. To make a comparative 
estimate of the effects produced on the air by sour and ripe 
grapes, two experiments were simultaneously instituted and kept 
up for five nights and days. They gave the following results : 
Atmosphere of 
the green and 
ripe grapes be- 
fore experi- 
ment. 
Atmosphere of 
green grapes 
after ex^iefi- 
ment. 
Atmosphere of 
ripe grapes af- 
ter experi-» 
ment. 
Oxygen gas, 
210 
199.4 
202.6 
Azpte, 
T90 
T95.6 
792.1 
Carbonic acid, 
0 
0.0 
7.3 
1000 
995.0 
1002.0 
These results, obtained three times over, indicate that the 
portion of oxygen removed by the green grapes is not represent- 
ed by a corresponding quantity of carbonic acid ; while the ripe 
grapes, according to M. De Saussure, appear not to act on the 
oxygen, since it is evident that the small portion of carbonic acid 
left in the recipient might have been decomposed in this, as it 
was in a former instance. 
That grapes nearly ripe still retain the power of decomposing 
carbonic acid, M. De Saussure farther satisfied himself by the 
the following experiment. He confined a portion of this fruit 
when nearly ripe, in an artificial atmosphere, which contained 
5’^5th of carbonic acid. The experiment w’as continued for four 
days and nights, at the end of which time, nearly two-thirds of 
the acid gas had disappeared, and a portion of oxygen gas was 
produced. And from this and other experiments, it is inferred, 
