The Magnet is fastened to the base by a tin strip, C, which is screwed down at both ends. By nailing a strip, like D, along the left side of the base, the magnet may be fastened to this. This strip would take the place of the base of [App. 125].
The piece, F, of two thicknesses of tin, is made longer than it was in [App. 125]; in fact, it projects through L and forms the part N. To the lower end of N is fastened a large bullet. Hold the cutting-edge of a strong knife-blade upon the bullet, and with a few taps of a hammer drive the blade into it to make a gash.
Put the end of N into the cut, then hammer the bullet so that N will be pinched. If you have no bullet, cut a long strip of tin, about ⅜ in. wide, and wind this about the end of N to serve as a ball.
The Bell, E, may be taken from an old alarm-clock. This is not screwed directly to the base, as it would not ring well. After you have the ball, O, properly fixed, hold E, so that O will strike it near its rim; then cut a piece of wood about ⅝ × ⅝, and long enough to put under E, to raise its rim to the right place. This piece must be screwed to the base from the underside, and on to its top is placed the screw which passes through the bell. In other words, E is mounted upon a rod which is fastened to the base.
The Adjustments are made as in [App. 125]. By bending N a little, O can be made to tap E properly.
The Battery for a bell that is to be used much should be an open circuit one, such as the Leclanché, or the ordinary dry batteries. It is cheaper to buy a dry battery than it is to make one suitable for bells. A and B show wires that lead to the bell from the battery. One of the wires should be passed through a push-button.
220. Electric Bell. By arranging the buzzer of [App. 125] with a bell, you can use the same for an electric bell. The part, F, should be made long enough to extend entirely through L, and project beyond L for about 2 in. To the end of this is fastened a large bullet, or a band of tin. ([See App. 126].)
