THE TELEGRAPH 331 



DEMONSTRATION 25 



Purpose. To show how the wireless telegraph works. 



Apparatus. A small demonstration form of wireless outfit. 



Directions. Set up the outfit following the directions that 

 accompany it. Study carefully the working of the various 

 parts. Make a drawing showing the parts and their connec- 

 tions. See how far apart the sender and receiver can be placed 

 and still send and receive messages. 



Comparison of wireless and ordinary telegraph. When 

 we come to compare the wireless and ordinary telegraph, 

 the first thing we note is the fact that wireless is much 

 cheaper to construct, because no connecting wires are neces- 

 sary. This is especially evident when we consider how much 

 it cost to lay the Atlantic cable in order that we might 

 telegraph across the ocean. And on land after the lines of 

 wires are set up there is the expense of maintaining the poles 

 and wires, which are often broken down by storms, and of 

 replacing the poles as they decay. 



For communication on water between boats or between 

 boats and land, of course, only the wireless can be used. In 

 certain mountainous countries, or in countries where heavy 

 snowstorms are common as in Alaska, the wireless is much 

 easier to install and operate. For regular service between 

 points where the telegraph is already established, this is 

 largely used in preference to the wireless. Whether the 

 wireless will ever be a serious competitor for this trade it 

 is difficult to say. But for long distance telegraphy over the 

 ocean, there are a number of commercial stations of wireless 

 running in competition with the cable service. 



SUPPLEMENTARY QUESTIONS FOR CLASS DISCUSSION 



1. What part does the telegraph play in our daily life? 



2. What has been the history of the development of the 

 telegraph ? 



