On the Respiration of Atmospheric Air. 37 



14. 170 cubic inches were respired from a bladder eight 

 times in a minute. The lime water absorbed -f-o%-. 



This quantity of carbonic acid produced by respiration 

 gave a term of comparison to determine the quantity of de- 

 composition of oxygen gas in the respiration of the same 

 quantities of atmospheric air and of pure oxygen. The pre- 

 ceding experiment (7.) had denoted that the diminution of 

 oxygen gas was more considerable than that of atmospheric 

 air. According to this, one might expect, with the appear- 

 ance of probability, that the production of carbonic acid gas 

 should be also more considerable ; which was confirmed by 

 direct experiments. 



15. 170 cubic Inches of oxygen gas obtained from man- 

 ganese were respired four times during 50 seconds : the di- 

 minution was 30 cubic inches. The quantity of carbonic 

 acid which was produced amounted to -^. The atmo- 

 spheric air, respired in the same manner, and under the same 

 circumstances (13.), contained only -^^ of carbonic acid. 



16. Seventy cubic inches, respired from a bladder in the 

 ?pace of 50 seconds, even gave -j-J-j of carbonic acid. 



Bxperiments, on the Respiration of Gaseous Oxide rf 

 Azote. 



The gaseous oxide of azote was obtained, according to the 

 process of Davy, from crystallized nitrate of ammonia. This 

 pitrate of ammonia gives products very different in different 

 temperatures. I undertook on this subject an important 

 pperation, which I submitted to the inspection of the Na-- 

 tional Institute. I haye only to remark, by the way, that 

 we obtain at the commencement oxygenated muriatic gas, 

 if the nitrate of ammpnia is not entirely free from muriatic 

 ^cid : that at a temperature which does not go beyond the 

 220th decree of the centigrade thermometer we obtain the 

 gaseous oxide of azote in very great quantity, and very pure, 

 and without a mixture of those white vapours which have 

 the taste of mustard ; but at higher temperatures, and above 

 all at a red heat, the gaseous oxide of azote is not disen- 

 gaged, but there are formed nitrous gas and white vapours, 



quite 



