and Oxygen Gas by Respiration. 247 



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 parts ; 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 

 lime-water in the eudiometer, the lime-water became turbid, 

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

 quently carbonic acid; the remaining 91*5 parts were treated 

 with the green sulphate of iron, saturated with nitrous gas, 

 as recommended by professor Davy, and afterwards with the 

 simple solution of the green sulphate, when 12*5 parts were 

 absorbed, which were consequently oxygen, and the remain- 

 ing 79 azote. 



100 parts of the expired gas therefore consisted of 

 8*5 carbonic acid. 



12' 5 oxygen. 



79* azote. 



100 



The air contained in the water gasometer, previous to the 

 experiment, being examined by the same tests, consisted, in 

 100 parts, of 



21 oxygen. 



79 azote. 



100 

 In trying common atmospheric air with lime-water, we 

 could never find any quantity of carbonic acid perceptible in 

 the eudiometer of 100 parts. 



Calculation for Carbonic Acid. 



100 : 8-5 : : 3437 : 292-145. 



So that 292*14 cubic inches of carbonic acid gas were given 



off in eleven minutes, or 26*55 cubic inches per minute, which 



is almost exactly the estimate of professor Davy. 



O-l In 



