%68 Messrs. Allen and Pepys on the Changes produced in 
The gas inspired was 3260 cubic inches, and of this 2.5 per 
cent, was azote. 
100 : 2.5 : : 3260 : 81.50. 
The total quantity of azote in the gas inspired, was there- 
fore 81.50 cubic inches. 
The quantity of gas expired was 3193 cubic inches, and of 
this every 100 parts contained six of azote. 
100 : 6 :: 3193 : 191.58. 
The total quantity of azote in the gas expired, was there- 
fore 191.58 cubic inches ; but the total quantity of azote be- 
fore respiration was only 8-1.50. 
191.58 — 81. 50 = 110.08 ; 
therefore 110.08 cubic inches were added by the process of 
respiration, beside what little remained in the lungs after the 
experiment. 
Calculation for Oxygen. 
The 3260 cubic inches of gas inspired contained 81.50 
azote. 
3260 — 81.50 = 3178.50, 
and consequently the pure oxygen was 3178,50 cubic inches. 
The 3193 cubic inches of gas expired, contained 83 per cent, 
of free oxygen, and 11 per cent, in carbonic acid gas, making 
together 94, 
100 : 94 : : 3193 : 3001.42. 
The oxygen gas, found after the experiment, was therefore 
3001.42 cubic inches, and deducting this from the oxygen 
before the experiment, 
3178.50 — 3001.43 = 177,08. 
