Quantity of Carbon in carbonic Acid. 275 
We next tried oxygene gas from the hyperoxygenised 
muriate of potash made over mercury, and which by the eudi- 
ometer left only a residuum of 2 parts in 100. The glass globe 
exhausted as before, and weighed, was screwed on to the 
glass receiver of the mercurial gasometer containing oxygene, 
and 21 cubic inches entered, by which it increased in weight 
7,3 grains. This experiment was repeated with exactly the 
same result. The thermometer and barometer remaining the 
same, we take the volume as before corrected. 
21,58 cubic inches. 
21,58 : 7,3 : : 100 : 33>8s 
Then 100 cubic inches of oxygene gas at mean temperature 
and pressure weigh 33,82 grains. After these experiments, 
we examined Davy’s researches on nitrous oxyde, and had 
the satisfaction to find that his estimate, both of carbonic acid 
and oxygene gases, agreed almost exactly with ours. 
The next point was to ascertain whether lime water would 
take the whole of the carbonic acid gas from a mixture with 
oxygene, or common air; we therefore mixed a known quan- 
tity of carbonic acid gas with a certain quantity of common air, 
and on trying it with our eudiometer and lime water, the whole 
of the carbonic acid gas was in a short time absorbed. We 
also found, that though the solution of green sulphate saturated 
with nitrous gas would not take up the whole of the carbonic 
acid gas, yet the simple green sulphate, merely by its water 
of solution, absorbed it very readily. 
It may be proper to notice here, that though we repeatedly 
tried the oxygene procured from hyperoxygenised muriate of 
potash by the eudiometer and lime water, it never gave the 
least trace of carbonic acid. 
