MESSRS. ALLEN AND PEPYS ON THE RESPIRATION OF BIRDS. 283 



very much, and he opened it every time he breathed; there was more moisture 

 on the glass opposite to his head, than in the experiment with common air. 

 Towards the conclusion of the experiment, which lasted one hour and ten 

 minutes, the film was pretty constantly over his eyes, but on being taken out 

 he was quickly as well as usual. 



The following was the state of the gas before and after the experiment: 



Vol. of 

 gaa before Vol of 



the expt. gas after Carbonic 



cub. inch. Azote. Oxygen. Time. expt. Azote. Oxygen. Acid. 



69 atmos. air =54.51 14.49 



62 oxyg. 1 per cent = .62 61.38 20' 76.5 = 42.33 29.90 4.27 



86 oxyg. = .86 85.14 21 75 = 19.80 48.73 6.47 



84 oxyg. = .84 83.16 29 73.5= 8.56 58.43 6.51 



7 = .71 5.60 .69 



Residuum 69 = 7. 55.20 6.80 



301 56.83 244.17 70 301.0 78.40 197.86 24.74 



Here again the volume of gas appears to be unaltered : the production of car- 

 bonic acid gas is but little more than in the last experiment, 

 24.74 -f- 72 = .35 cubic inch per minute ; 

 but the proportions of azote are altered as in the former experiment : thus 



Azote in the 301 cubic inches of gas. 



Before the experiment 56.83 



Found after the experiment 78.40 



Increase of azote 21.57 



Oxygen in the 301 cubic inches of gas. 



Before the experiment 244.17 



Foimd after the experiment 197.86 



In carbonic acid gas 24.74 



222.60 



Loss of oxygen 21.57 



It is interesting to notice here also the state of the azote at different periods 

 of the experiment. 



2 o2 



