276 



COMMUNICATION 



Within recent years much progress has been made 

 in the advancement of telephone engineering. The 

 dial telephone has made it possible to make a large 

 portion of the switching automatic in the central sta- 

 tions where it is used. Figure 451 shows a picture of 

 a modern dial telephone. The teletypewriter is also 

 a modern device which combines two essentials of 

 any office, the telephone and the typewriter. It is a 

 carrier of written conversation. It is similar to the 

 ordinary typewriter and is operated in the same way. 

 Words typed on a machine in one office are recorded 



Courtesy Bell Telephone Laboratories 



FIG. 451. MODERN DIAL TELEPHONE 



on a machine connected with it in another office or 

 another city. These devices are used by large news 

 agencies, brokers, and police departments. One ma- 

 chine operated in New York may transmit messages 

 at the same time to machines in Boston, San Fran- 

 cisco, New Orleans, and St. Louis. It is now possible 

 to telephone from your home to many parts of Europe 

 and to South America. It is also possible to send 

 photographs over wires. You will learn of these last 

 two achievements later in this unit. 



REFERENCES FOR FURTHER STUDY 

 Texts 



Caldwell and Curtis, Science for Today, Unit 9 



Clement, Collister, and Thurston, Our Surroundings, Chap. 17 

 (part) 



Hunter and Whitman, Science in Our World of Progress, 

 Unit 10 



Lake, Harley, and Welton, Exploring the World of Science, 

 Chap. 25 



Pieper and Beauchamp, Everyday Problems in Science, Unit 

 16 



Powers, Neuner, and Bruner, Man's Control of His Environ- 

 ment, Chap. 23 



Skilling, Tours through the World of Science, Tours 11 and 

 12 



Van Buskirk and Smith, The Science of Everyday Life, Chap. 

 18 



Watkins and Bedell, General Science for Today, Chap. 26 



Webb and Beauchamp, Science by Observation and Experi- 

 ment, Unit 2 



Courtesy Bell Telephone Laboratories 



FIG. 452 



Wood and Carpenter, Our Environment: How We Use and 

 Control It, Topic 12 



Special references 



Meister, Magnetism and Electricity 



Morgan, The Boy Electrician 



Seaver, The American Boy's Book of Electricity 



Pamphlets of American 



Telephone and Tele- 

 graph Company 



Birth and Babyhood of 

 the Telephone 



The Magic of Com- 

 munication 



The Telephone Alma- 

 nac 



Triumphs of Tele- 

 phone Engineering 



The Story of a Great 

 Achievement 



Things Worth Know- 

 ing About the Tele- 

 phone 



How to Use the Dial 

 Phone 



WHAT YOU SHOULD 



AIM TO ACQUIRE FROM 



THIS STUDY 



1. Something of the 

 history of the tele- 

 phone. 



FIG. 453 



