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Analyfis of the Air. 



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Experiment CXVI. 



I bored a hole in the fide of a large wooden 

 foffct ab, (Fig. 39.) and glewed into it the 

 great end of another fofiet i i, covering the 

 orifice with a bladder valve r : Then I fit- 

 ted a valve b i, to the orifice of the iron 

 fyphon f f, fixing the end of the fyphon 

 faft at b into the foffet a b : Then by means 

 of narrow hoops I placed four ^Diaphragms 

 of flannel at half an inch diftance 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 i i n no. 



The inftrument being thus prepared, pinch- 

 ing my noftrils clofc, when I drew in breath 

 with my mouth at a, the valve i b being 

 thereby lifted up, the air parted freely thro* 

 the fyphon from the bladders, which then 

 fubfided, and (hrunk considerably : But when 

 I breathed air out of my lungs, then the 

 valve i b clofing the orifice of the fyphon, the 

 air pafifed thro* the valve r into the blad- 

 ders, and thereby dilated them -, by which 



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