2 26 Experiments on the Production of Air 



actually retained their vegetative powers for some time 

 after they were separated from their stock, but also that 

 it was in consequence of the exertion of these powers that 

 the air yielded in the experiment was produced. 



But I have found, that though the leaves, exposed in 

 water to the action of light, actually do cease to furnish 

 air after a certain time, yet that they regain this power 

 after a short interval, when they furnish (or rather cause 

 the water to furnish) more and better air than at first, 

 which can hardly be accounted for upon the supposition 

 that the air is elaborated in the vessels of the plant. 



Experiment No. ig. 



A globe containing 46 cubic inches, filled with fresh 

 spring-water and two peach-leaves, was exposed in the 

 window to the action of the sun's rays 10 days succes- 

 sively (the weather being in general fine), when the fol- 

 lowing appearances took place : — 



The ist and 2d day a certain quantity of air was pro- 

 duced, about as much as in former like experiments. 

 The 3d day very little was produced ; and the 4th day 

 none at all, the globe to all appearance being quite ex- 

 hausted. Continuing the experiment, however, upon 

 the 5th day, the water having acquired a faint greenish 

 hue, air was again produced pretty plentifully, making its 

 appearance upon the surface of tlie leaves in the form of air- 

 bubbles, as at the beginning of the experiment ; at the end 

 of the 6th day the air was removed, and it was found to 

 amount to ^-^g- of a cubic inch, its quality being 232 de- 

 grees, or 1 a -\- 2 n ^= 1.68. 



Upon the 7th day -^^ of a cubic inch of air was pro- 

 duced of 297 degrees, or i ^^ -|- 3 « = 1.03 ; and, 



During the 8th, 9th, and loth days, if cubic inch of 



