

CONTRIBUTIONS OF PHYSICAL SCIENCE 45 



telephony became for the first time possible through the de- 

 velopment of the De Forest audion into a telephone repeater 

 and amplifier an advance which not only extended enorm- 

 ously the possibilities of communication, but saved at once 

 millions of dollars even in the construction of short telephone 

 lines. With six stage amplifiers of this electronic sort the 

 energy of speech has been multiplied without distortion as much 

 as ten thousand billion fold. Small wonder then that by 1915 

 enormously amplified wave forms produced by speech had been 

 impressed on the ether from the Arlington Towers with such 

 energy as to be picked up and distinctly understood in Paris 

 and Honolulu. But in spite of the success already attained in 

 this field by the physicists of the telephone company, when the 

 United States entered the war the principle of amplification 

 had not been successfully applied either to inter-communica- 

 tion by wireless phone between ships (for example, submarine 

 chasers) or between airplanes, and one of the most pressing 

 problems which General Squier put up in April, 1917, to the 

 Division of Physical Sciences of the Research Council wa<= the 

 problem of wireless communication between planes. This was 

 solved by the mid-summer of 1917 by the group of physicists 

 of the Western Electric Company to whom it was referred 

 and, on Sunday following Thanksgiving 1917, for the first 

 time in history, airplanes in flight were directed in official tests 

 at the Wright field in Dayton, Ohio, in intricate maneuvers, 

 from the ground or by the commander in the leading airplane, 

 and reports and directions were given and received in clear 

 speech. For wire and wireless telephone receiving, sending and 

 amplifying on sea and land three-quarters of a million vacuum 

 tubes were built by the Western Electric Company alone for 

 the purposes of the war, and half as many more by the General 

 Electric Company, so that the amplifying principle was of 

 scarcely less importance in the successful conclusion of the 

 war than were the principles of binaural location and sound- 

 ranging. 

 The fourth tremendously important and altogether new ap- 



