[ xix: ] | 
that.thus the quantity. of dephlo- 
gifticated air neceffary for one mi- 
nute will now ferve for breathing 
during half an hour, and thus the 
expences will be thirty times lefs. 
We confume, in the {pace of 24 
hours, about 21600 cubic-inches of 
air. One pound of nitre yields by 
heat about 12000 cubic-inches of 
.dephlogifticated air, and thus. it 
yields more air than any_ patient 
could confume by breathing this 
ee air the whole day (for 
of or fears and Receflary occu- 
pations), becaufe this quantity will 
ferve thirty times longer by the 
method explained, than in ee or- 
dinary way. It follows by this 
that the expences required fac 
breathing a whole day Foe 
d 
