%66 Messrs. Allen and Pepys on the Changes produced in 
and as 100 cubic inches of carbonic acid gas weigh 47.26 
grains, 
100: 47.26 :: 39534 : 18683.76 ; 
the weight of the carbonic acid gas amounts to 18683.76 
grains ; and estimating the carbon in it at 28 parts in 100, 
according to Lavoisier, or 28.60, as calculated in the experi- 
ments on diamond, recorded in the Society’s Transactions. 
100 : 28.60 : : 18683.76 : 5363.55 grains ; 
it will follow that 5363.55 grs. or above 11 oz. troy of solid 
carbon, are emitted by the lungs in the course of twenty-four 
hours ; and that 39534 cubic inches of oxygen gas are con- 
sumed in the same time. But when we consider that in re- 
spiration perfectly natural, a much smaller quantity of air can 
come in contact with those parts of the lungs calculated to act 
upon it, the proportion of carbonic acid gas given offin natural 
respiration, ought probably to stand considerably lower than 
in the above estimate ; but at all events it will be very consi- 
derable. 
Sixteenth Experiment. 
Having made so many experiments upon atmospheric air, 
we now proceeded to ascertain the effects produced upon 
oxygen gas by the process of respiration. The water gaso- 
meter was filled with oxygen gas made from the hyper- 
oxygenised muriate of potash by heat, care having been taken- 
to clear all the tubes, &c. as much as possible of common air, 
by forcing a quantity of oxygen gas through them. 
One hundred parts from the water gasometer being treated 
with the usual tests in the Eudiometer, a residuum of only 
2.5 was left ; so that 97.5 per cent, were pure oxygen, and: 
the rest azote. 
