%66 Analyfis of the Air. 



being found as above 21635 fquare inches 

 only j^g. part of an inch depth, will be 

 evaporated off their inward furface in that 

 time, which is but 3*9 part of the depth of 

 what is perfpired off the furface of a man's 

 body in that time. 



If then life can by this means be fup- 

 ported for 5 minutes with 4 'Diaphragms 

 and a gallon of air, then doubtlefs, with 

 double that quantity of air and 8 Diaphragms 

 wc might well exped to live at leaft 10 

 minutes. It was a confiderable difadvantage 

 that I was obliged to make ufe of bladders, 

 which had been often wetted and dried, fo 

 that the unfavory fumes from them muft 

 needs have contributed much to the unfitting 

 the included air for refpiration : Yet there 

 is a neceffity for making ufe of either blad- 

 der or leather in thefe cafes 5 for we can- 

 not breath to and fro the air of a veffel, 

 whofe fides will not dilate and contrad in 

 conformity with the expirations and in- 

 fpirations, unlefs the veffel be very large, and 

 too big to be conveniently portable. 



Having flopped up the wide fucking orifice ; 

 of a large pair of kitchen bellows, they be- 

 ing firft dilated, I could breathe to and fro 



at 



