I 248 ] 



^ an ; f only burned in it with fuch a de^r 

 a?rscS-g ree Qf brightnefs that it dazzled 

 ju-oyed. m y e y es? b u t it excited a crackling 



hifiing which accompanies the flame 

 when plunged in pure dephlogifhV 

 cated air. Among the plants which 

 yielded the pureft airs were feme 

 aquatic plants and the turpentine- 

 tree?, from which I always got air 

 of an eminent degree of purity, fo 

 that fometimes lix meafures of ni- 

 trous air were required before the 

 fatuiatlon of the two meafures of 

 the dephlogifiicated air could be ob- 

 tained, and that above |^| of the 

 bulk of the two airs were deilroyed. 

 ioo» In September I got from 

 young leaves of a vine fuch pure 

 air that its tefc gave the following 

 reiult: 1.97; 1.87^; 1.78; 1.68; 



£70 2 -331 3-3°* 



101. And 



