PROOFS OF THE PROPERTIES OF CARBONIC ACID OAS. 23g

denly extinguished, but the glowing wick will be re-lighted in thetube containing oxigen gas, and burn with a dazzling splendor.

Rationale. ..This experiment confirms a fact already esta-blished ; namely, that oxigen gas is much fitter for combustionthan atmospheric air; and is also a most complete proof that car-bonic acid gas extinguishes light.

Remark. ..This property of carbonic acid gas may be advanta-geously made use of to learn whether the air in a newly sunkwell, in subterraneous caverns, pits, mines, vaults, cellars, andthe like, may be approached without danger.

Experiment III.

Carbonic acid gas is fatal to animal life.

Put a mouse or other small animal into a vessel filled with thisgas, and cover the vessel to prevent the contact of atmosphericair. The animal will die in a minute or two.

Remark. ..It is this gas which has produced so many fatal ac-cidents, at the opening of cellars or vaults, in which wine, cyder,or beer has been suffered to ferment.

The famous lake of Averno, where Virgil placed the entranceof Hell, yields so large a quantity of carbonic acid gas, that birdscannot fly close over it with impunity.

Experiment IV.

Carbonic acid gas is heavier than atmospheric air.

Let a long glass tube proceeding from a gas-bottle in whichcarbonic acid gas is disengaged, be twuce bent at right angles.Let the open end of the longest leg reach to the bottom of a jar,perfectly dry within, and standing with its mouth uppermost.The carbonic acid disengaged will expel the atmospheric air fromthe jar, on account of its greater specific gravity. When the