Wiring Diagram for Two or More Bells (Fig. 4, Fig. 5, Fig. 6)
The diagram, Fig. 5, shows the proper connections for operating two bells from two independent push buttons, each push button operating a particular bell. Any number of bells operated from any number of push buttons, all of the bells being rung from any one of the push buttons, are connected as shown in Fig. 6. Such a circuit can be used as a fire alarm or time call in a factory, the operation of the circuit being controlled from any one of a number of different points.
Wiring Diagrams for Return-Call Bells (Fig. 7, Fig. 8, Fig. 9)
The proper connections for what is called a return-call circuit is shown in Fig. 7. The circuit is so arranged that the bell at one end is controlled by the push button at the other end. Such a circuit can be used in transmitting signals in either direction. A ground return-call circuit is shown in Fig. 8. In the circuits shown in Figs. 7 and 8, only one battery is needed.
The connections of a two-wire metallic return-call circuit are shown in Fig. 9. A special push button must be used in this circuit, and in this case two batteries are used instead of one, as in Figs. 7 and 8. This circuit may be changed to a ground return-call circuit by using the earth as a conductor instead of either wire. There are, of course, numerous other methods that may be used in connecting call bells, but the connections shown in the diagrams are perhaps the most common.
Refrigerator for Dry and Warm Climates
Set a bowl containing butter, cream or fruit in a saucer and cover the bowl with a moistened napkin, allowing the edges to hang in a larger saucer filled with water, and place the whole in the air out of the sun's rays. The article to be kept cool may also be placed in a pan with an earthenware crock turned over it and covered with a small towel or cloth, the edges of which extend into another outer pan partly filled with water.
The method can be applied on a larger scale by using a shallow galvanized pan which will contain many articles and more water. This manner of cooling is especially adapted to camping parties and will prevent sloppy butter, sour milk and spoiling fruit. The articles are also kept free from ants and flies.—Contributed by C. B. Hosford, Swansea, Ariz.