Messrs . Allen - and Pepys on Respiration. 405 
Our attention was particularly directed to this point in the 
following experiment. The oxygen, procured as usual from 
hyperoxygenised muriate of potash, was found to contain four 
per cent, of azote ; the experiment was conducted in the same 
manner as the preceding ones, except that the tubes of the 
gasometers were filled with oxygen, and the gas was not 
merely passed once through the lungs, but breathed backwards 
and forwards. In order to prolong the duration of the expe- 
riment, which began and ended with a forcible expiration, 
portions of the respired gas were preserved for examination 
from each of the gasometers, in the following order : 
No. 1. 244 
2. 294 
3. 282 
4. 266 
5* 230 
6. 266 
7- 254 
8, 288 
9 - 252 
10. 168 
2544 
The portion of oxygene remaining in the water gasometer of 
the original quantity, not employed in the experiment, was 
found upon trial to contain four per cent, of azote, as before. 
Summary of the Experiment. 
Cub. Inches 
Cub. Inches 
Defi- 
Bar. Therm, of Oxygen 
of Gas ex- 
ciency. 
Time. 
inspired. 
pired. 
2 9,9 51 2 668 
2 544 
124 
13 minutes ; 
mdcccix. 
3 G 
