Take a bottle holding one or two pints, fit a cork to it, through which pass a glass or metallic tube, the end of which is drawn out so as to leave a small aperture at the top. Place in the bottle a few pieces of zinc, and some sulphuric acid, diluted with water, in the proportions of one part of acid to six of water, then insert the cork. You will immediately see bubbles of H rising. The explanation of this is as follows: The zinc takes O from the water, thus liberating H; the O forms an oxide on the surface of the metal, which would prevent further action, did not the acid dissolve the oxide, thus leaving a fresh surface to take the O, and continue liberating H until the metal disappears. After the H has been forming for two or three minutes, hold over the tube an inverted tumbler for a moment, remove the tumbler and then apply a match to the contents of tumbler. When the bottle has become _filled_ with H you can light the gas at the top of the tube, and thus have a steady flame. Be careful not to attempt to ignite the gas until all of the air has been forced out of the bottle, as air mixed with H produces an explosive mixture. In the intense heat of the faint flame you can melt metals or glass. By placing a larger glass tube, open at both ends, over the flame, you may be able to produce the celebrated acoustic tones, varying in pitch and intensity with the size and length of the tube used. A hydrogen gun can easily be made by taking a tin tube five or six inches long (closed at one end), from one half inch to an inch in diameter; make a small aperture near the closed end; then invert the tube for a moment over the escaping H, keeping the small hole closed with the finger, place a cork in the open end, and apply a match to the hole. The cork will be forced out with a loud explosion. What compound is always produced when H is burned? Let us see. Invert a cold, dry tumbler over a burning jet, and you will always observe moisture gathering on its surface. Another pretty experiment may be performed with H by inserting the stem of a common clay pipe in a piece of rubber tubing, slip the other end of the tubing over the gas jet, prepare some strong soap suds, and with a little care you can blow beautiful soap bubbles with your pipe, which, by a skillful movement may be detached, and they will rise in the air like miniature balloons; by placing a burning match under them they will explode. Strike a bell in a large jar filled with H, and it has a squeaky sound. Our whole art and science of music would be changed if H should be mixed with the air to any great extent. Nicely balance a flask or jar containing air; fill the same flask with H, and the beam will at once be seen to rise.