230 Experiments on the P production of Air 



Another globe (C), filled with green v/ater alone ^ was 

 exposed at the same time ; but it was broken by an acci- 

 dent before the experiment was completed. 



The two globes (A and B), with their contents, being 

 again exposed from Tuesday noon till Thursday evening, 

 yielded air as follows : — 



Quantity. Quality. 



The globe A, with the peach-leaves 4xVo '^ubic inches 344 degrees. 

 The globe B, with raw silk . . . A^-fj^ " " 350 " 



N. B. The weather on Tuesday and Wednesday was 

 cold, with very little sunshine ; but Thursday was a 

 very fine, warm day, when the greatest part of the air was 

 produced. This air was removed, and proved on Friday 

 morning, the 15th September. 



Perhaps all the appearances above described might be 

 satisfactorily accounted for, by supposing the air pro- 

 duced in the different experiments to have been generated 

 in the mass of water by the green matter, and that the 

 leaves, the silk, &c. did no more than assist it in making 

 its escape by afibrding it a convenient surface, to which it 

 could attach itself, in order to its collecting itself to- 

 gether, and taking upon itself its elastic form. 



The phaenomena might likewise be accounted for, by 

 supposing the green matter to be a vegetable substance 

 agreeable to the hypothesis of Dr. Priestley, and that at- 

 taching itself to the surfaces of the bodies exposed in 

 the water, as a plant is attached to its soilj it grows ; and 

 in consequence of the exertion of its vegetative powers, 

 the air yielded in the experiment is produced. 



I should most readily have adopted this opinion, had 

 not a careful and attentive examination of the green 

 water, under a most excellent microscope, at the time 

 when it appeared to be most disposed to yield pure air 



