Atmospheric Air and Oxygen Gas by Respiration. 2 6% 
carbonic acid gas required exactly a cubic inch of oxygen 
for its formation ; the ten parts of carbonic acid may therefore 
be reckoned as oxygen, which would make the constitution of 
, r t, ■ , f ox yg el b 
the gas after the experiment j g^ azote 
whereas before the experiment it was) 21 ox yg en > 
[ 79 azote. 
Now we did not suppose the residuum of 8b to be all azote, 
though 79 might be ; therefore seven parts appeared to have 
been added by this unnatural mode of respiring, and we con- 
jectured the addition might be gaseous oxide of carbon. 
To ascertain this, we put 4 o parts into a flint stopper bottle, 
and nearly filled it with about 100 parts hyperoxygenised 
muriatic acid, procured as before, and recently prepared ; the 
stopper being put in, over distilled water, we plunged it in 
quicksilver, and filled a second bottle in the same way, as a 
comparative experiment. 
We next procured some pure azote, by absorbing the 
oxygen from a portion of atmospheric air by the saturated 
green sulphate and simple green sulphate as usual ; 40 parts 
of this azote were mixed with the same proportion of the acid 
gas as in the other experiment, and the whole suffered to stand 
for forty-eight hours ; at the end of this time the azote was ex- 
amined, by washing it first in distilled water, and afterwards 
in the eudiometer with the tests for oxygen ; and there were 
still exactly 40 parts left ; proving that the hyperoxygenised 
muriatic acid gas has no action upon azote. 
We then examined the bottles containing the residuum from 
the air that had been so often respired, and found that it had 
not experienced the slightest change ; it was therefore plainly 
