Analyfis of the Air. 165 
fyphon / f, fixing the end of the fyphon 
faft at b into the foflet a b: Then by means 
of narrow hoops I placed four Diaphragms 
of flannel at half an inchdiftance from each 
other, into the broad rim of a fieve, which 
was about 7 inches diameter. The fieve 
was fixed to, and had a free communication 
with both orifices of the fyphon, by means 
of two large bladders iinno. 
Linen would probably be more proper 
to make thefe Diaphragms of than Flannel, 
becaufe oil or greafe is ufed in the making 
of Flannel : And as I have heard, it is whi- 
tened by the fumes of burning Brmftone 5 
which I was not aware of, when I made ufe 
of Flannel in thefe Experiments. 
The inftrument being thus prepared, 
pinching my noftrils clofe, when I drew in 
breath with my mouth at a , the valve / b 
being thereby lifted up, the air pafled free- 
ly through the fyphon from the bladders, 
which then fubfided, and fhrunk confider- 
ably ; But when I breathed air out of my 
lungs, then the valve i b clofing the orifice 
of the fyphon, the air pafled thro* the valve 
r into the bladders, and thereby dilated 
them; by which artifice the air which I ex- 
pired muft neceflarily pafs thro' all the Dia- 
phragms, 
