[ to 7] 
the air inferior to the leaves of trees? | 
Does not this conjecture get fome 
weight, if we confider that dephlo- 
gifticated air is in reality {pecifically 
heavier than common air, and thus 
tends rather to fall downwards? 
If we add to thefe reflexions ano- 
ther of no lefs importance, v7. that 
moft forts of foul air are {fpeci- 
fically lighter than common air, we 
fhall be inclined to believe that the 
difference of the fpecifical gravity of 
that beneficial air.of which I treat, 
and that which is become hurtful 
Sd our geneitation, By corruptdis 
cates « one ae ae fpectal bleffings 
-defigned by the hand of God: for 
by this arrangement we get foon rid, 
in a great meafure, of that air which 
is become hurtful to us, as it rifes 
{oon up out of our reach; whereas 
the 
