C 272 3 



SECTION XVIII. 



Experiments Jhewing that the purejl 

 dephlogifiic cited air^ and the great* 

 eft quantity ', is yielded by full-grown 

 leaves. 



121. I PLACED in a jar full 

 of pump-water the extremity of a 

 branch of a vine containing leaves 

 of different ages, from the full- 

 grown to thofe which begin only 

 to unfold themfelves. The bub- 

 bles appeared the firft in the old 

 leaves ; and they- broke out gra- 

 dually upon the next in age ; fo 

 that they appeared the lateft upon 

 the new-formed leaves. The fame 

 proportion takes place alfo in the 

 fize of the bubbles, as well as in 



the 



