This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
Often the ice box is placed in a dark closet or some out-of-the-way place, and it is almost impossible to locate articles already in the box or put others away without considerable inconvenience on account of the lack of proper light. This difficulty can be easily overcome by mounting a small electric lamp in each of the different compartments of the box, which will be automatically lighted when the lid of the box is raised or the door opened. The circuit through the lamp is controlled by a special switch mounted in such a way that its contacts are open when the doors and lid of the box are closed. A diagram of the circuit is given in Fig. 1, which shows three lamps, each controlled by a separate switch, connected in parallel to a battery of several dry cells. The lamps should be of low voltage and need not be very high in candlepower. The number of cells needed in the battery will depend upon the voltage of the lamps. The voltage of the battery and the rated voltage of the lamps should be approximately the same.
Ill: Fig. I Fig 2 The Lamps will be Automatically Lighted When the Door of the Ice Box is Opened
A special switch that will serve the above purpose is shown in Fig. 2. It consists of two pieces of spring brass, A and B, about % in. wide, bent into the forms shown. These pieces are mounted in a recess cut in the jamb of the door or lid in such a way that the free end of the piece A is held away from the piece B when the door or lid is closed. When the lid of the box or the door is open the two springs come in contact and the lamp lights; upon closing the lid or door the contact is broken and the lamp goes out.
A good quality of rubber-insulated copper wire should be used in making the connections, and all parts should be as well protected from moisture and the possibilities of mechanical abuse as possible. It would be best to tape the lamps in the sockets with a piece of friction tape so as to prevent moisture getting into the socket and, perhaps, shortening the lamp. A short piece of brass tubing can be mounted around the lamp to protect it mechanically. Be sure to place the batteries where they will be kept dry.