[ 8 7 ] 



the leaves increafe fafter becanfe 

 they are puflied out of the leaves by 

 a vital motion in the leaf. It is alfo 

 true, that leaves thus placed in wa- 

 ter impregnated with fixed air, do 

 not yield that fine dephiogiflicated 

 air which they yield when placed 

 in common pump-water ; which 

 may be owing perhaps to the great 

 abundance of fixed air penetrating 

 the leaves, by being ablbrbed, and 

 oozing out as it were, in a kind of 

 tumultuary way, together with the 

 air already contained in the leaves. 

 Thus the air ifTuing out of the 

 leaves may not have undergone 

 that degree of elaboration required 

 to change it into dephiogiflicated 

 air : for the leaft circumftance may 

 diiturb nature in this work ; the 

 fhade of a building;, or of another 

 plant, may change this wonderful 

 G 4 opera^ 



