i 3 8 Analyfts of the Air. 



this deduded from the above found cavity 

 of the lungs, there remains ioo cubick inches 

 for the fum of the cavity of the veficles. 



Upon viewing fotne of thefe veficles with 

 a microfcope, a middle fized one feems to 

 be about T ^o part of an inch diameter 5 then 

 the fum of the furfaces in a cubick inch 

 of thefe fmall veficles (fuppofing them to be 

 fo many little cubes, for they are not fphe- 

 rical) will be 300 fquare inches 5 which mul- 

 tiplied by the fum of the cavity of all the 

 veficles in the lungs, viz. 100 cubick inches, 

 will produce 30000 fquare inches, one 

 third of which muft be deducted, to make 

 an allowance for the abfence of two fides 

 in each little veficular cube, that there 

 intent be a free communication amons; 

 them for the Air to pafs to and fro j fo 

 there remains 20000 fquare inches for the 

 fum of the furface of ail the veficles. 



And the Bro r achi& containing 41 cubick 

 inches, fuppofing them at a medium to 

 be cylinders of tV 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 21635 fquare inches, or 



150 



