228 Common Science 



FIG. 129. How the lamp and wire are held to ground the circuit. 



Application 54. Explain why only one wire is needed 

 to telegraph between two stations; why you should not 

 turn an electric light on or off while standing in a tub of 

 water. 



Application 55. In a house in the country, the electric 

 wires passed through a double wall. They were separated 

 from each other and well covered with insulation, but they 

 were not within an iron pipe, as is now required in many 

 cities. The current was alternating. One night when the 

 lights were out a rat in the wall gnawed through the in- 

 sulation of the wire and also gnawed clear through one of 

 the wires. Did he get a shock? The next morning, the 

 woman of the house wanted to use the electric iron in the 

 kitchen and it would not work. The kitchen had in it a 

 gas stove, a sink with running water, a table, a couple of 

 chairs, and the usual kitchen utensils. There was also a 

 piece of wire about long enough to reach across the kitchen. 

 The electrician could not come out for several hours, and 

 the woman wanted very much to do her ironing. Figure 130 

 is a diagram of the wires and the kitchen. Show what the 

 woman might have done in order to use her iron until the 

 electrician arrived. 



