Anah^fts of the Air> 
150 fquarc feet, which is equal to to times 
the furface of a man’s body, which at a me- 
dium is computed at 1 5 fquarc feet. 
I have not had an opportunity to take 
in the fame manner the capacity and dimen- 
fions of human lungs ; the bulk of which 
Dr. James Keill in his Tentamina Medico- 
phyfica, p. 80. found to be equal to 226 cu- 
bick inches. Whence he eftimated the fum 
of the furface of the veficles to be 21905 
fquare inches, which is nearly the fame 
with my eftimate of the Calve’s lungs. But 
the bulk of human lungs is much more ca- 
pacious than 226 cubick inches : For Dr. 
Jurin, by an accurate Experiment, found 
that he breathed out, at one large expirati- 
on, 220 cubick inches of Air } and I found 
it nearly the fame, when I repeated the like 
Experiment in another manner : So that 
there muft be a large allowance made for 
the bulk of the remaining Air, which could 
not be expired from the lungs j and alfo 
for the fubftance of the lungs. 
Suppofing then, that according to Dr. 
Jurin’s eftimate {in Mott’s Abridgment of 
the Thilofophical Tranfac. Vol. I. p. 415.) 
we draw in at each common infpiration 40 
cubick 
