z^z Analyfis of the Air. 
by the fum of all the veficles in the lungs’, 
viz. ioo cubicle inches, will produce 60000 
fquare inches 3 one third Of which muft be 
deduced, to make an allowance for the ab- 
fence of two Tides in each little veficular 
cube, that there might be a free communi- 
cation among them for the air to pafs to 
and fro ; fo there remains 40000 fquare 
inches for the fum of the furface of all the 
veficles. 
And the Bronchi £ containing 41 cubick 
inches, fuppofing them at a medium to be 
cylinders of T V of an inch diameter, their 
furface will be 1635 fquare inches, which 
added to the furface of the veficles makes 
the fum of the furface of the whole lungs 
to be 41635 fquare inches, or 289 fquare 
feet, which is equal to 10 times the furface 
of a man’s body, which at a medium is 
computed to be equal to 1 5 fquare feet. 
I have not had an opportunity to take in 
the fame manner the capacity and dimen- 
fions of human lungs 5 the bulk of which 
Dr. James Keill , in his Tentamina Medico - 
phyfica> p. So. found to be equal to 226 cu- 
bick inches. Whence he eftimated the fum 
of the furface of the veficles to be 21906 
fquare inches. But the bulk of human 
lungs 
