USES OF MAGNETS AND CELLS 407 



Telegraph Instrument. Telegraph instruments consist of electro- 

 magnets which cause a little bar of metal to be drawn to the magnets. 

 Examine a telegraph instrument. What causes the " tick "? 



The key acts as the push button, turning on the current through 

 the magnet. Many of these instruments are connected in series in 

 different towns, and messages are sent by means of dots and dashes. 



FIG. 306. Telegraph instrument. Why is A a soft piece of iron? Why is M 



an electro-magnet? 



WIRELESS CONTINENTAL TELEGRAPH. ALPHABET 



E T Period 



I M ._._._ Comma 



S O Question 



H CH Exclamation 



Break 



A - N Hyphen 



U D Distress 



V B Understand 



R P 



W G Call 



J Finish 



L F Wait 



Abbreviations 



K X QRT Stop Sending 



C Z QST Attention 



Q Y QRM Interference 



1 9 QRN Static 



2 8 QRX Standby 



3 7 QRA What Station ia that? 



4 6 



5 

 Dot Fraction Bar 



