332 SCIENCE OF HOME AND COMMUNITY 



3. How can the parts of a telegraph system be used to send a 

 message ? 



4. How are messages sent at high speed? 



5. What advantages have the wireless and ordinary telegraph 

 each over the other ? 



REFERENCES 



Baker, Boys' Book of Inventions, Doubleday Page and Co., 



New York City. Chap. 3 (Wireless). 

 Cressey, Discoveries and Inventions of the Twentieth Century, 



E. P. Button Co., New York City. Chap. 17 (Wireless). 

 Darrow, The Boys' Own Book of Great Inventions. Chaps. 2, 5, 6. 



Macmillan Co., New York City. 

 Holland, Historic Inventions, G. W. Jacobs Co., Philadelphia. 



Chaps. 10 and 15. 

 Maule, Boys' Book of New Inventions, Grosset and Dunlap, 



New York City. Chap. 11 (Wireless). 

 Massie and Underbill, Wireless Telegraphy and Telephony, 



D. Van Nostrand Co., New York City. 





