Note 7 — Chapter III
Reading edition
Hydrogen gas may be made thus:—Put some pieces of zinc or iron filings into a glass: pour over them a little sulphuric acid (vitriol), diluted with twice the quantity of water; then cover the glass over for a few minutes, and hydrogen gas will be given off.
Exp. If a flame be put into the glass, an explosion will be made.
If the experiment be tried in a phial, which has a piece of tobacco-pipe run through the cork; and a light held a few moments to the top of the pipe, a flame will be made.
If a balloon be held over the phial, (so that the gas can inflate it,) the balloon will ascend in a very few minutes.