Reported in Scientific American, This Week in World War I: February 20, 1915
The usefulness of scouting from the air had been demonstrated in the early days of the Great War. But gathering information from an airplane is one thing; it is another thing to give that information to people on the ground who could make use of it—for instance those in charge of troop movements or artillery.
Devices for recording information were limited. Cameras could record images but the film needed developing, which took time. “Wireless” (what we now call “radio”) at this stage of the war was limited to Morse code transmissions only, from airplane to ground (there was no wireless transmission from the ground to the airplane). Airborne observers could scribble notes or sketches, which could be stuffed into a bag and dropped over friendly troops for recovery or held until the airplane landed. Cumbersome, to say the least.
One technological boost was suggested by this article. It shows a Dictaphone recorder—usually used in offices for dictation—mounted in an airplane cockpit for the observer’s use. The device had a rotating cylinder coated with a waxy compound. “In certain conditions of flight, it might be difficult to use pencil and paper. In order to remove all obstacles that might hamper the observer's work, a phonograph is now provided, with a speaking tube running to the observer's mouth, so that he may talk into the machine at any time during the flight and thus make a record of his observations, while at the same time his hands are free for the use of field glasses or the sketching pencil. At the end of the flight the phonograph delivers its message.”
The system probably had little value, and I doubt it was ever used. The ferocious noise of an open cockpit a few feet away from a noisy engine would have made any recording difficult to interpret. And the fragile wax cylinder still had to get to the right people on the ground. But the true gold standard of communication was a system that could transmit and receive speech in real time. Such a system was not developed until the end of 1915.