PROOFS OF THE PROPERTIES OF HIDROGEN GAS.

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a lighted taper be presented to them, they catch fire and burnwithout noise.

If into a bason of soap-suds a mixture of hidrogen gas and at-mospheric air be blown, by means of a bladder and pipe, so asto form bubbles over a considerable part of the surface of thesuds, and a lighted match be then presented to it, the wholewill explode with a loud report.

The theory of balloons or aerostatic machines is founded onthe levity of hidrogen gas. It is sufficient that the weight of theballoon itself and of the inclosed gas should be lighter than anequal bulk of common air, and it must rise till its weight is inan equilibrium with an equal volume of the surrounding me-dium. The theory of the Mongolfiers is very different from this.

Experiment III.

Hidrogen gas extinguishes turning todies.

Bring an inverted jar filled with hidrogen gas, over the flameof a candle and depress the jar at once, so that the lighted wickmay be wholly surrounded by the gas. The candle will imme-diately be extinguished.

Experiment IV.

Hidrogen gas is unfit for combustion.

Introduce hidrogen gas into a jar filled with mercury; whenthe mercury is displaced pass up into the gas a piece of tinderto which is affixed a little phosphorus, and apply to the latter aheated wire. As soon as the phosphorus is touched with the hotwire it will melt but will not burn ; the gas is therefore unfitfor combustion.