Fig. 79
Fig. 80
11. Electric Curling Iron ([Fig. 79]).—One who has flat hair needs no curling iron, but those who have round hair may curl it temporarily, if they will unscrew an electric light bulb and screw into its socket the plug of an electric curling iron. The flexible cord contains two wires insulated from each other. One of these wires is attached to the outer shell of the plug, the other wire is attached to the central button of the plug. These make connections with the two separate dynamo wires in the socket. The current comes down one of the wires in the flexible cord, passes through a coil of fine German silver wire inside of the curling iron, and returns by the other wire in the flexible cord. The small wire in the curling iron offers 220 ohms of resistance when hot and passes half an ampere of the 110-volt current.
(110 volts)/(220 ohms) = .5 ampere.
12. Electric Soldering Irons ([Fig. 80]).—Or coppers, as they should be called, are ideal implements for soldering. They remain continually at the proper temperature and are free from corrosion. They require from 55 to 220 watts. On the 110-volt current they take from one half to two amperes.