Esa3 7] 
few hours, nay even fometimes in an 
hour and an half, they purify fo 
much a body of air quite unfit for 
refpiration, as to be equal in goad- 
nefs to atmofpheric air. They will 
even do it when they are inclofed in 
a glafs veffel, without any water. 
One leaf of a vine, fhut up in-an 
ounce phial, full of air fouled by 
breathing fo that a candle could not 
burn in it, reftored this air to the 
goodnefs of comman air in the 
{pace of an*hour anda half. But 
plants enjoy this privilege only in 
the day-time, and when they grow 
in unfhaded places. | 
his power of plants extends itfelf 
even to the worft of all airs, in 
which an animal finds his deftruc- 
tion in a moment; fuch as is pure 
inflammable and highly phlogifti- ” 
cated air, which is little or fcarcely_at 
D4 all 
