612 BELL SYSTEM TECHNICAL JOURNAL 



Telegraph Company and Western Electric Company immediately, 

 and within a year and a half went through some rapid transformations. 

 A high vacuum and increased electron emission were provided by 

 H. D. Arnold and A. M. Nicolson, while a practical circuital theory 

 was provided by H. J. Van der Bijl. The internal arrangement was 

 engineered and a socket and base developed. This improved vacuum 

 tube was put into use on the commercial telephone lines in the latter 

 half of 1913 as a telephone amplifier and was the first commercial use 

 of the high vacuum tube. This vacuum tube amplifier contributed to 

 the establishment of the original transcontinental wire telephone line 

 which carried its first messages in July 1914, 



The improved vacuum tube, during its period of development, 

 appeared to have possibilities as a generator of sustained oscillations 

 and suggested to telephone engineers that it might be much more 

 useful in radio than it had been up to that time. With this in mind the 

 A. T. & T. Company decided to start work in that direction and as 

 one result a number of new engineers, including the writer, were 

 employed and began work in the Research Depai^ment of the Western 

 Electric Company in the middle of 1914. Developments on the 

 radio telephone moved rapidly. Early in 1915 plans were made 

 and active work was started for field trials. A transmitting station 

 was established at Montauk, L. I., and a receiver located on Hotel 

 DuPont in Wilmington, Delaware. On April 4, 1915, speech was 

 transmitted from Montauk to Wilmington, a distance of 220 miles. 

 Connections were made with telephone lines at both ends to show its 

 possibilities as a link in a telephone circuit. 



There followed tests to Jekyl Island, off the coast of Georgia, about 

 800 miles, and then work was started for a transoceanic test. To 

 transmit across the ocean required more power and a larger antenna. 

 In order to avoid the antenna expense, arrangements were made with 

 the Navy Department to use the Arlington antenna for transmitting, 

 and to use Naval radio stations at San Francisco, San Diego, Panama 

 and Honolulu for receiving locations. Observers with radio receivers 

 were dispatched to these four receiving locations while a fifth expedition 

 was sent to Paris where in spite of the war the French Government 

 kindly allowed listening on the Eiffel Tower antenna. At Arlington 

 the Western Electric Research Department (now part of Bell Tele- 

 phone Laboratories, Inc.) installed a vacuum tube transmitter, and 

 proceeded to make one-way tests. In August 1915 speech was under- 

 stood at Panama, and in September a one-way demonstration was 

 made across the continent, receiving at San Francisco. Within a few 

 days speech was heard in Honolulu and then in Paris. The tests 



