CHAPTER XVII 



APPLICATIONS OF ELECTRICITY 



Electricity is one of the greatest servants of mankind. 

 It may be sent far and wide, and is always ready to 

 start work the instant we turn a switch or push a button. 

 It has so utterly changed living conditions that con- 

 veniences now are available that were not even dreamed 

 of a half-century ago. 



Electricity lights our homes, and sometimes heats them. 

 It cooks food, and preserves it in electric refrigerators. 

 Electricity runs our sewing machines, washes our clothes, 

 and cleans dust from our rooms. It makes possible 

 magazines and papers at low rates. It aids us in illness. 

 It transmits our messages, and adds to our pleasure by 

 gathering from the air entertainment for our free mo- 

 ments. The study of how it is applied is bound to be 

 fascinating. 



We have spoken of magnetic effects of electricity. There 

 are also chemical and heating effects of great importance and 

 interest. Among the processes depending on the chemical effects 

 are electrolysis, electroplating and electrotyping. 



Electrolysis. Electrolysis is the process of breaking up a 

 compound into its elements by passing an electric current through 

 it. All compounds capable of conducting electricity when dis- 

 solved in water may be more or less broken up in this way. Water 

 itself may be broken up into its elements, oxygen and hydrogen, 

 by electricity. 



Electroplating. We often hear certain metal articles spoken 

 of as plated ware. This means that some cheaper or stronger 

 metal has been coated with another metal to render it more 

 attractive, or to preserve it from injury by contact with the 

 air. For example, iron spoons may be covered with a silver 

 coating. This is done by passing a current of electricity through 

 a solution of a silver compound. The spoons and a bar of silver 

 are suspended in the solution by wires, the spoons from a rod 

 connected with the negative terminal of the source of the 



229 



