Anahjfts of the Air. 239 



150 fquare feet, which is equal to 10 times 

 the furface of a man's body, which at a me- 

 dium is computed at 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. 80. found to be equal to 22601- 

 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 5 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 ; and alfo 

 for the fubftance of the lungs. 



Suppofmg 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 



