206 PROOFS OF THE PROPERTIES-OF HIDROGEN GAS.

copiously at the time of thunder-storms, is owing to a suddenformation of water in the atmosphere, from the rapid combus-tion of the hidrogen and oxigen gases fired by an electric spark,

The diminution of hidrogen and oxigen gases by their basesmay also be shown in the following manner.

Experiment XI.

Fill a tall jar with oxigen gas, and fill also with hidrogen gas,a bladder furnished with a stop-cock, and with a long brass pipelike the letter S, and drawn out to a fine point. On pressing thebladder a stream of gas will issue from the pipe which may beset fire to and brought cautiously under the inverted jar of oxigengas. By this intercourse, the stream of hidrogen gas will beburnt in a confined portion of oxigen gas; by continuing thecombustion a sufficient time, the water will rise gradually with-in the jar. On the first impression of the heat, indeed, a smallquantity of gas will escape from the jar, which will render itdifficult to ascertain what degree of absorption actually takesplace. But this loss may be prevented by using a jar, with aneck at the top, to which a compressed bladder is firmly tied.The expanded air instead of escaping through the water, willnow' enter the bladder at the top; and when the experiment isclosed and the vessels have cooled, it may be ascertained bypressing out the gas from the bladder, -what quantity of oxigengas has been consumed. When this experiment is made withthe substitution of common air for oxigen gas, a diminutiontakes place, but much less considerable, v'n. not amounting toone-sixth of the original bulk of the gases.

Rationale. ..The disappearance of the gases depends on theunion of their bases, which takes place during the state ofignition, and forms water, as has been noticed already.