*The Wires* used to carry the current in a miniature lighting system may be of the sort known as _annunciator_ or _office_ wire if the wires are to be run entirely indoors. The wire should not be smaller than No. 16 B. & S. gauge. When the wires are run outdoors, on a porch, or in some other place exposed to the weather, the wire used should be rubber-covered. Hanging lights or lights intended to be adjustable should be connected with "flexible conductor." This is made of a number of very fine wires braided together and insulated with silk. The wires used in a lighting system should not in any case be longer than it is necessary to have them. When a battery is connected to a system of wires it is found that the voltage at the end of the wires is much lower than at a point near the battery. This is called voltage "drop," and is much greater as the wires grow longer. A light placed at the end of two very long wires will not burn as brightly as it would if connected to the same battery by means of short wires. *Switches* can be made by following the suggestions given in Chapter VII. Suitable switches can be purchased for a few cents at a most any electrical house and will prove very much neater and efficient. They should preferably be of any of the types shown in Figure 286. *The Batteries* used for miniature lighting may be made up of storage cells, dry cells or carbon cylinder cells. Storage cells will prove the most satisfactory, provided that the experimenter has some convenient means of recharging them or of having them recharged. Storage cells will be found of especial value wherever it is desirable to operate several lights from one battery. Carbon cylinder cells are only suitable where one cell is to be operated at a time. If more than one is used, the battery is liable to become polarized and the lamps will not burn brightly. Carbon cylinder batteries are very inexpensive to renew, and will be found the cheapest method of lighting a small tungsten lamp. [Illustration: Fig. 286.—Types of Battery Switches suitable for Miniature Lighting.] If lamps requiring more than two amperes are to be operated on dry cells, the latter should be connected in series-multiple, as shown in Figure 69. Two sets of dry cells connected in series-multiple will give more than twice the service of a single set. Lamps may be connected either in multiple or in series, provided that the proper voltages of both battery and lamps are used.