Mat 7, 1920] 



SCIENCE 



447 



The success of this simple experiment 

 immediately led. to more thorough con- 

 sideration of the entire subject. 



One of the questions to be investigated 

 was the general efficiency of the electron 

 tube when used as a potentially operated 

 instrument. The following experiment 

 was made: 



A strip of wire netting was buried in 

 the snow outgide the office of the Chief 

 Signal Officer in Washtagton and a wire 

 attadhed thereto leading to the second story 

 of the building. The upper end of this 

 wire was connected directly to the grid of 

 an electron tube. The reason for con- 

 necting the grid to the upper end of the 

 antenna is of course obvious if we are to 

 use the tube as a potentially operated 

 device. It was necessary for maximum 

 sensitiveness to connect it to the point of 

 maximum potential of the antenna which 

 in the case of a linear oscillator occurs at 

 the open end. By this arrangement, 

 messages were readily received from dis- 

 tant points in the United States. 



These two simple experiments, above 

 described, demonstrated the po^i'bdlity of 

 transmitting electromagnetic waves along 

 bare wires submerged in water and the use 

 of an electron tube as a potentially 

 operated device for the reception of sig- 

 nals. The technical data ynB. be published 

 later. 



SUMMABT 



For military reasons, if for no other, 

 as stated in the introduction of this paper, 

 the Signal Corps has recently undertaken 

 certain investigations in the phenomena 

 connected with the transmission of high 

 frequency electromagnetic waves over bare 

 wires in earth and in water. 



In carrying out these investigations and 

 in attacking the problems from various 

 angles, the research staff of the Signal 

 Corps laboratory at Camp Alfred Vail, 



Little Silver, New Jersey, was directed to 

 carry out experiments on bare wires laid 

 on the surface of moist ground and also 

 buried in earth. The staff at the Signal 

 Corps research laboratory at the Bureau of 

 Standards was directed to investigate fun- 

 damentally the transmission of electro- 

 magnetic waves over bare wires in fresh 

 water. In addition to this, the engineer- 

 ing staff of the Office of the Chief Signal 

 Officer has carried out from time to time 

 certain experiments of a more or less 

 crucial character which have come up for 

 solution in the prosecution of this work at 

 the other laboratories. 



Certain data from each of these groups 

 of engineers have been presented above. 

 The phenomena associated with the trans- 

 mission of high frequency waves over bare 

 wires in earth or water are obscure and 

 complex, and the writer has formulated no 

 definite theory at the present time. 



RESULTS OBTAINED 



1. Telephone and telegraph communica- 

 tion has been established between Fort 

 "Washington, Maryland, and Fort Hunt, 

 Virginia, across the Potomac River, below 

 the city of "Washington, over a distance of 

 about three quarters of a mile, by the use 

 of a bare No. 12 phosphor bronze wire laid 

 in the water to connect the stations. The 

 transmitter consisted of an electron tube 

 oscUlator which delivered a current of 

 about 270 miUiamperes to the line at a 

 frequency of about 600,000 cycles a second. 

 At the receiving end of the line an elec- 

 tron tube and a 6-stage amplifier were 

 used without any ground connection. 

 "With this arrangement good tuning was 

 obtained at both ends of the line, and 

 telegraphic and telephonic transmission 

 secured over the bare wires immersed in 

 fresh water. 



2. A resonance wave coil has been devel- 



