54 On the Respiration of Atmospheric Air. 



primitive volume. The same volume, having been respired! 

 three times during 30 seconds, the diminution amounted to 

 12 cubic inches, == ^ of the primitive volume. 



4. Sixty cubic inches were respired three times during 

 25 seconds: the diminution was 6 cubic inches, ^ yV of the 

 primitive volume. 



5. 170 cubic inches were respired four times during one ; 

 minute: the diminution amounted to 20 cubic inches. This 

 experiment was repeated several times. The diminution was 

 almost always the same, 18, 19, 21, or 20 cubic inches, 



6. 1 68 cubic inches being respired during 50 seconds, at 

 four great and four small respirations, were diminished by 

 14, = -yV of their primitive volume. 



7. 430 cubic inches vmderwent, at twelve respirations in 

 00 seconds, a diminution of 24, = y'^. 



These results agree very well with those obtained by Mr. 

 Davy on the diminution of air by respiration. Davy found 

 the diminution by a single respiration = ^V* ^y respira- 

 tion continued for a minute, the diminution was = yL-. 



The greatness of the diminution does not depend alone on 

 the time during which a given volume of air is respired, but 

 principally on the greatness of the volume itself: and this 

 diminution ought to be relatively as much less as the volume 

 of air that is inhaled is greater. There is undoubtedly a very 

 essential error in the conclusions of Abernethv, inasmuch as 

 he assigned to the expired air a greater volume than to that 

 which was inhaled. And the calculations of Goodwyn rest 

 upon very untenable grounds, since he supposes the volumes 

 of both to be equal. 



To determine comparatively the diminution of oxygen gas 

 by respiration, 170 cubic mches of oxvgen gas, drawn from 

 manganese, were respired in the same manner, and under the 

 same circumstances, as the qbove {vide 5.) 170 cubic inches 

 gf atmospheric air. The diminution amounted to 30 cubic 

 inches; in the other experiments to 33, 29, 31 : ihuSj by 

 a mean term, to ■('- of the primitive volume. 



This diminution, being established in a precise manner, 

 served as a basis for determining the absorption of azotic gas. 



8. Eighty cubic inches were respired once, and slowly, 



during 



