When they are to be connected in multiple, the voltage of the lamps should be the same as that of the battery. When they are to be used in series, the voltage of the lamps multiplied by the number used should equal the voltage of the battery. For example, suppose that you wish to use a number of six-volt lamps on a six-volt storage battery. In that case they must be connected in multiple. But if it should be that the lamps are only two-volt lamps and you wish to operate three of them on a six-volt battery you will have to place them in series. [Illustration: Fig. 287.—How Lamps are Connected in Multiple.] [Illustration: Fig. 288.—How Lamps are Connected in Series.] It is sometimes desirable to arrange a lamp and two switches so that it can be turned off or on from either switch independently of the other. This is called "three-way wiring," and is a very convenient method of arranging a light in a hallway. If one switch is placed at the top of a stairway and the other switch at the bottom, a person can pass upstairs or downstairs, light the lamp ahead, and turn it out as he passes the last switch, no matter in which direction the previous user of the light may have gone. The switches are two-point switches, and the circuit should be arranged as in Figure 289. The switch-levers should always rest on one of the contacts and never be left between, as shown in the drawing. [Illustration: Fig. 289.—Three-way Wiring Diagram. The Light may be turned off or on from either Switch.] They are represented that way in the illustration in order not to conceal the contacts. Small brackets made of brass and similar to that shown in Figure 290 are for sale at many electrical supply houses, and will add a very realistic appearance to a miniature lighting plant. [Illustration: Fig. 290.—A Lamp Bracket for Miniature Lighting.] Brackets may be constructed after the plan shown in Figure 291. A wooden socket or a pin-socket is mounted on the end of a small piece of brass tubing which has been bent into the shape shown in the illustration. The other end of the tube is set into a wooden block so that the bracket may be mounted on the wall. The wires from the socket lead through the brass tube and through the back or top of the block. [Illustration: Fig. 291.—A Home-made Bracket.]