206 
exposed in it for successive days and nights ; and 
his experiments are the more unexceptionable, as 
the plants, in many of them, grew in their natural 
states ; and shoots, or branches from them, only 
were introduced through water into the confined 
atmosphere. 
I have made some few researches on this sub- 
ject, and I shall describe their results. On the 
12th of July, 1800, I placed a turf four inches 
square, clothed with grass, principally meadow 
fox-tail, and white clover, in a porcelain dish, 
standing in a shallow tray filled with water ; I then 
covered it with a jar of flint glass, containing 380 
cubical inches of common air in its natural state. 
It was exposed in a garden, so as to be liable to the 
same changes with respect to light as in the com- 
mon air. On the 20th of July the results were 
examined. There was an increase of the volume 
of the gas, amounting to fifteen cubical inches ; 
but the temperature had changed from 64° to 71° ; 
and the pressure of the atmosphere, which on the 
12th had been equal to the support of 30.1 inches 
of mercury, was now equal to that of 30.2. Some 
of the leaves of the white clover, and of the fox- 
tail were yellow, and the whole appearance of the 
grass less healthy than when it was first introduced. 
A cubical inch of the gas, agitated in lime-water, 
gave a slight turbidness to the water ; and the 
absorption was not quite of its volume. 100 
parts of the residual gas exposed to a solution of 
green sulphate of iron, impregnated with nitrous 
gas, a substance which rapidly absorbs oxygene 
from air, occasioned a diminution to 80 parts. 
