Hold a tumbler sideways, and sprinkle a little dust, of powder of any sort, on it; then strike the glass, and make it sound: - the dust keeps dancing about whilst the sound continues; stop the sound, and the dust is at rest.

The sound of a watch laid upon a long table, or upon a plank of wood, will be heard much farther than it otherwise would.

When a vessel on the fire begins to boil, let a communica-tion be made between it and the ear, by means of the poker, and the sound is more distinctly heard.

Tie a string round the end of a poker, and then, winding one end of the string round the fore-finger of the one hand, and the other end of the string round the fore-finger of the other; put the fingers into the ears, and make the poker strike against a table, or any other object, and it will sound like the bell of a church.

Tie a string round the end of a poker, as before, and hold the string with your teeth; when the poker is made to strike against any object, as in the last experiment, the same kind of sound will be transmitted through the teeth.

Make a watch touch your teeth, and you will hear its beat-ing more distinctly.

When a pitchfork is struck, in order to pitch a tune, its end is put on the table, and a greater sound is produced. If the pitchfork, after being struck, be held to the teeth, its sound is still more distinct.

Having shut up both ears with cotton very closely, put your fingers on the teeth of a person who speaks to you, and you will hear his voice.