Anatyfis of the Air. 26 <p 
time, which is but -V 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 
we might well exped to live at leaft 10 
minutes. It was a considerable difadvantage 
that I was obliged to make ufe of bladders, 
which had been often wetted and dried, fo 
that the unfavoury fumes from them mu ft 
needs have contributed much to the unfitting 
the included air for refpiration : Yet there 
is a necefflty for making ufe of either blad- 
der or leather in thefe cafes 5 for we can- 
not breathe to and fro the air of a veffel, 
whofe fides will not dilate and contrad in 
conformity with the expirations and infpi- 
rations, unlefs the veflel be very large, and 
too big to be conveniently portable. 
Having flopped up the wide fucking ori- 
fice of a large pair of kitchen bellows, they 
being firft dilated, I could breathe too and 
fro at their nofe, the air contained in them 
for more than 3 minutes, without much in- 
convenience, they heaving and falling very 
cafily by the adionof refpiration, Some fuch 
like 
