Title: Telautograph and Delaney systems for prevention of tapping of telegraph and telephone wires. Letter from the Secretary of War, transmitting, in response to a Senate resolution of March 28, 1918, a report on the method and efficiency of the telautograph and Delaney systems of preventing tapping of telegraph and telephone wires, and submitting copy of a communication from F. R. Curtis, Colonel, Signal Corps, by authority of the Chief Signal Officer, in relation thereto
Subjects: Telegraph, Espionage