[ xsi J 
a little elevated.’ In this pofition, 
the fprigs of mint grew very well, 
and in fome of the phials he ob- 
ferved a quantity of air to be col- 
lected, though very flowly 3 but he 
was much difappointed, that fome 
of the moft Vigorous plants © pro= 
duced no air at all. At length, 
however, from about ten plants he 
collected, in the courfe of a-week, 
about half an ounce-meafure of air, 
a he found: ia ee eae ee 
air ae the: {pace of ai one 
meafure. 
This remarkable faé& contributed 
not a little to confirm his faith in 
the hypothefis of the - purification 
of the atmofphere by vegetation; 
but he did not enjoy this fatis- 
faction long; for, as he found -that- 
; other — of the fame -fpecies 
Ez, I produced 
