CHAPTER IX 



DISCOVERIES IN MAGNETISM AND ELECTRICITY 



He snatched the lightning from the heaven and scepters from tyrants. 

 Inscription on Franklin's Bust. 



In these days when streets and houses are lighted by electric 

 lamps, when the telephone is a necessity and the telegraph a 

 commonplace, when the electric motor furnishes power, not only 

 for the shop, but for the washing machine and sewing machine 

 in the home, when old and young alike are amusing themselves 

 with radio concerts and lectures, it is hard to realize that all 

 these electrical contrivances are recent inventions which people 

 not yet old saw introduced. To most of us they are still mysteri- 

 ous. What child has not wondered how they make the electric 

 current that produces the light as he presses the button, or how the 

 telephone can reproduce so clearly the voice of his chum, or how 

 that very modern marvel, the radio, can send messages without 

 even the semblance of connecting wires? What boy has not 

 stood lost in wonder at the window of the telegraph office and 

 watched with fascination the messages sent and received, or 

 envied the electrician at the power-house who seemed to know 

 all about the great dynamo whose smooth, whirring speed sends 

 out the current ? Even our playthings now are electrical, and it 

 is not difficult for the child to repeat experiments that once were 

 great discoveries, and gain from them in his play a knowledge of 

 the principles that underlie these magnetic and electrical appli- 

 ances that have so largely helped to revolutionize the modern 

 commercial world. 



Very ancient peoples knew there was a kind of a stone to be 

 found that attracts bits of iron. It was called the lodestone, or 

 magnet, because it was found quite commonly near Magnesia, 



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