SOME EECENT DEVELOPMENTS IN TELEPHONY AND 



TELEGRAPHY.! 



By Fkank B. Jewett, 

 Assistant Chief Engineer Western Electric Co. {Inc.). 



With an art such as that of telephony and telegraphy which has 

 been either wholly or in large part developed within the last 30 years, 

 it is difficult to cover in an article of a few thousand words all that 

 might be construed under the term " recent developments." It is even 

 difficult to determine what should be classified as recent developments. 



As soon as the researches and discoveries of scientists and inventors 

 along any line show signs of developing into an art which will aid 

 in the every-day life of mankind, a great stimulus is given, not only 

 to a betterment of the physical means for affording the service, but 

 also to the development and exploitation of the commercial possi- 

 bilities made available by the new art and to the production of an 

 operating organization which will render the physical equipment 

 most fully available for the commercial needs. Thus, it happens that 

 in the field of telephony and telegraphy, both wire and radio, great 

 strides have been made during the past few years in perfecting the 

 commercial and operating organizations which have been found nec- 

 essary to make the work of the scientist and engineer fully available 

 to the public. In what follows no attempt has been made to cover 

 any features of these latter developments. This seemed the more 

 necessary since the commercial and traffic needs of no two countries 

 are exactly alike and a full presentation of the subject would require 

 more space and more particularly larger knowledge than the author 

 possesses. In limiting the paper to the physical and engineering 

 aspects of telephony and telegraphy an attempt has been made fur- 

 ther to confine it to those developments which have brought about 

 rather radical changes in the existing state of the art or which bid 

 fair to bring about such changes in the future. 



Before passing on to a consideration of these recent physical and 

 engineering developments, it might be well to point out that, con- 

 trary to a more or less general belief, most of the physical develop- 

 ments have followed as a direct result of commercial or traffic oper- 

 ating requirements rather than as the result of a priori considera- 

 tions on the part of the scientist and the engineer. Although not 



1 Read at the Second Pan American Scientific Congress, at Washington, Dec. 27, 1915- 

 Jan. 8, 1916. Printed by permission of Executive Committee of the Congress. 



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