Fig. 294.—A Three-Cell Dry Battery for use in Hand-Lanterns, etc.
Small Batteries consisting of three small dry cells enclosed in cardboard box, as shown in Figure 294, are on the market, and may be bought at prices ranging from thirty to forty cents, depending upon the size and the maker. One of the most convenient and practical sizes of this type of battery has the dimensions shown in the illustration, and with its aid it is possible to construct a number of very useful electrical novelties and household articles in the shape of portable electric lamps, etc. These batteries are quite small and are only intended to operate very small lamps. Only one lamp should be used on each battery at a time, and it should not be allowed to burn long. Some of these batteries will give ten to fourteen hours of intermittent service but if allowed to burn continuously would only light the lamp for about five hours at the most. It is much the better plan to use them only for a few minutes at a time, and then turn the light off and allow the battery to recuperate.
An Electric Hand-Lantern is a very convenient device which is quite simple to make. It consists of a wooden box large enough to receive a three-cell battery, such as that shown in Figure 295. The back of the box should open and close on hinges and be fastened with a hook so that the battery may be easily removed for renewal.
Fig. 295.—An Electric Hand-Lantern.
A three-and-one-half-volt tungsten lamp is mounted on the front of the lantern and connected with the battery and a switch so that the light can be turned on and off at will. The switch may be placed at the top of the box so that the fingers of the same hand used to carry the lantern may be used to turn the light on and off. The lantern is fitted with a leather strap at the top, to be convenient for carrying.
The Ruby Lantern shown in Figure 296 is somewhat similar in arrangement to the lantern just described, which may be used both as a hand-lantern and a ruby light for developing photographs.
Fig. 296.—An Electric Ruby Lantern.