





I 







I 



Andhfn of the Air. 239 



X50 fquarc feet, which is equal to 10 times 

 the furfacc 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- 

 sions 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 eftimatcd the fum 

 of the iurface of the vcficles to be 21906 

 fquare inches, which is nearly the fame 

 with my eilimate of the Calvc's lungs. But 

 the bulk of human lungs is much more ca- 

 pacious than 226 cubick inches : For Dr. 

 Jar in, 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 ; and alfo 

 for the fubftance of the lungs. 



Suppofing then, that according to Dr. 

 Juriris eilimate {inMott's Abridgment of 

 theThilofophical Tranfac. Vol. I. p. 415.) 

 we draw in at each common inspiration 40 



cubick 



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