494 



MAGNETISM AND ELECTRICITY 



The sounder is simply an electromagnet such as was made 

 in Experiment 159, arranged to attract a piece of soft iron 

 held at a short distance from it by a spring. When this 



piece of iron is attracted 

 toward the magnet, it 

 strikes on another piece 

 of iron, making a click, 

 and so remains drawn 

 to the magnet as long 

 as the circuit is kept 

 closed. Thus long and 



FIGURE 166 



short clicks can be made. 



Morse arranged a combination of these long and short 

 clicks to represent the alphabet. Thus he was able to 

 send words from one station to another. 



WIRELESS TELEGRAPH STATION, Los ANGELES 



Many improvements have been made since Morse first 

 sent a dispatch between Washington and Baltimore, but 

 his dot-and-dash alphabet and the electromagnet sounder 

 and the key are still in use. Since 1832, the land has been 



