[ 42 ] 
ticular circumftances, to which it is 
not eafy to be fufliciently attentive. 
It feems, however, to be a. general 
rule, that the leayes of all plants, 
growing in a place where they are 
* mot much fhaded by other plants, 
buildings, &c. yield, in a clear day,. 
dephlogifticated air; and that this 
: air is yielded in greater abundance, 
and of a greater purity, when they 
prow in open places unincumbered 
by other plants higher than they are 
themielves, | | : 
I got in general a large quantity 
of air of a very good quality from_ 
fome water plants, as from the per/i- 
urens and willow. The fir 
yielded alfo very fine air, and 
| in abundance. 
“The nafturtium Indicum farpafled 
them all in general,"in regard as 
well to the pa sig 2! as to. the qua- 
= ~ lity, 
