of the water, I find that it tastes a little acid to the mouth: it is impregnated with carbonic acid; and if I now apply a little lime-water to it, that will give us a test of its presence. This water will make the lime-water turbid and white, which is proof of the presence of carbonic acid.
Then it is a very weighty gas—it is heavier than the atmosphere. I have put their respective weights at the lower part of this table, along with, for comparison, the weights of the other gases we have been examining:—
| Pint. | Cubic Foot. | |
| Hydrogen, | 3/4 grains. | 1/12 ounce. |
| Oxygen, | 11+9/10 " | 1+1/3 " |
| Nitrogen, | 10+4/10 " | 1/16 " |
| Air, | 10+7/10 " | 1+1/5 " |
| Carbonic acid, | 16+1/3 " | 1+19/16 " |
A pint of it weighs 16+1/3 grains, and a cubic foot weighs 1+9/10 ounce, almost two ounces. You can see by many experiments that this is a heavy gas. Suppose I take a glass containing nothing else but air, and from this vessel containing the carbonic acid I attempt to pour a little of this gas into that glass;
