1S4 



11th experi- 

 ment. 



CHANGES ?RODUCED IN AIR BY RESPIRATION. 



Now, although this gasometer was counterpoised by weights 

 in the scale attached to it, yet we can easily conceive, that 

 more resistance might be afforded to thecomplete evaluation 

 in the latter case than in the for mer,and consequently the lungs 

 might contain a few inches more after the experiment than 

 before it, which might in some measure account for the de- 

 ficiency. 



In the eleventh experiment, portions of gas were taken 

 off from each of the mercurial gasometers as they were fil- 

 led, and these portions being afterward mixed were care- 

 fully examined. 



Eleventh Experiment. 



Thermom. 

 Bstroin. Faht. 



304 50* 



Cubic inches 



of common air Cub. in. 



Time, inspired. expired. 



11 rain. 3460 3437 



Defici- 

 ency. 



23 



All the expe- 

 riments made 

 with great 

 care. 



Component 

 parts of the 

 expired gas, 



To prevent repetition, we shall here state, that all the trials 

 were made in the same manner, and with the same appara- 

 tus, namely, the eudiometer, described in the Society's 

 Transactions for 1807, in which one cubic inch is divided 

 into one hundred parls*; and that in almost every instance 

 we made two, and sometimes three experiments on the same 

 gas, and derived fresh confidence from the remarkable co- 

 incidence and uniformity of the results. No precaution was 

 at any time omitted which appeared to us necessary to insure 

 accuracy. 



One hundred parts of the expired gas being agitated with 

 limewater in the eudiometer, the limewater became turbid, 

 and 8*5 parts of the gas were absorbed, which were conse- 

 quently carbonic acid ; the remaining 91*5 parts were treat- 

 ed with the green sulphate of iron, saturated with nitrous 

 gas, as recommended by professor Davy, and afterward 

 with the simple solution of the green sulphate, when 12*5 

 parts were absorbed, which were consequently oxigen, and 

 the remaining 79 azote. 



♦ See our Journal, vol. XIX, p. 80. 



JO0 



