5S 
green sour grapes, while growing on the vine, and 
exposed to the sun in closed vessels, ameliorated 
common air without producing carbonic acid, and 
ripened in fifteen days ; but when the vessels contain- 
ed lime, they vitiated their atmosphere, in the same 
circumstances, and did not ripen. Grapes, apples, 
and pears, when separated from their respective trees, 
and placed in vessels of common air exposed to the 
sun, have vitiated their atmosphere in twenty-four 
hours, and produced carbonic acid ; and when the 
experiment was made in perfect darkness, the acid 
produced was equal in bulk to the oxygen that had 
disappeared *. 
275. Many experiments on the fresh roots of se- 
' veral plants were made by Dr Ingenhousz, who 
found them, in like manner, to deteriorate the air f ; 
but as the roots were all immersed in vessels filled 
with water, these experiments are not so unexcep- 
tionable as those which he made on flowers. He 
elsewhere observes, however, that if a carrot, or the 
root of any other plant, be drawn fresh from the 
earth, and exposed, with its leaves, in a vessel of 
common air to the sun, the air will soon be manifest- 
ly deteriorated ; but if the root be placed under wa- 
ter, and the foliage only be left in the air, the deterio- 
ration produced by the root will soon be repaired 
by the leaves *. 
w 276. But the most precise information on this 
* Recherches, &c, p. 129. 
f Exper. t. i, p. 274. J Ibid, t. ii. p. 38. 
