258 Messrs. Allen and Pefys on the Changes produced in 
of the water gasometer, and it was again filled with common 
air to the usual division on the scale. This occupied but a 
very short space of time. The operator, without taking his 
lips from the tube, then filled twelve more of the mercurial 
gasometers, which were registered as before, and he conti- 
nued to breathe in the 12th, until the water gasometer was 
again replenished ; eleven more were then filled, and portions 
saved from each : the experiment was completed by a forcible 
expiration of 166 cubic inches into the 12th ; and this last por- 
tion being left for an hour and a half was not perceptibly 
diminished in volume. 
Barom, 
Therm 
Faht. 
Time. 
Cub. inches 
of common air 
inspired. 
Cub. inches 
expired. 
Deficiency. 
29,85 68° 24'-37" 9 S 9° 9 8 7 2 
The breathing was so nearly natural that the operator was 
scarcely fatigued, and thought that he could have gone on 
for a much longer time. 
The smallness of the deficiency, notwithstanding the ex- 
periments occupied 24-j minutes, is a striking circumstance, 
and leads us to suspect still more strongly, that the deficiency 
principally arises from the impossibility of always bringing 
the lungs to the same state after forcible expiration. 
1 00 parts of the mixture of expired gas gave 
8 carbonic acid, 
13 oxygen, 
79 azote. 
100 
