E oy 
thofe mifchievous exhalations be- 
ing, very providentially, {pecifically 
lighter than common air, rife at 
the fame time up; and thus the 
lower region, in which we breathe, 
is freed from them: almoft as foon as 
they are produced; whereas the de- . 
phlogitticated air iffuing out of the 
plants in great abundance in the 
day-time is fpecifically heavier than 
common -air, and is therefore in- 
clined to remain longer among us, 
and to afford us all the benefit for 
which the Supreme Wifdom has 
providentially deftined it. 
Sr Co. 
