The Dream Doctor by Arthur B. (Arthur Benjamin) Reeve
page 86 of 388 (22%)
page 86 of 388 (22%)
![]() | ![]() |
|
the arc could be used as a transmitter, too, if a sensitive
receiver replaced the transmitter at the other end. The things needed are an arc-lamp, an impedance coil, or small transformer- coil, a rheostat, and a source of energy. The alternating current is not adapted to reproduce speech, but the ordinary direct current is. Of course, the theory isn't half as simple as the apparatus I have described." He had unscrewed the Osram lamp. The talking ceased immediately. "Two investigators named Ort and Ridger have used a lamp like this as a receiver," he continued. "They found that words spoken were reproduced in the lamp. The telephonic current variations superposed on the current passing through the lamp produce corresponding variations of heat in the filament, which are radiated to the glass of the bulb, causing it to expand and contract proportionately, and thus transmitting vibrations to the exterior air. Of course, in sixteen-and thirty-two-candle-power lamps the glass is too thick, and the heat variations are too feeble." Who was it whose voice Brixton had recognised as familiar over Kennedy's hastily installed detectaphone? Certainly he must have been a scientist of no mean attainment. That did not surprise me, for I realised that from that part of Europe where this mystical Red Brotherhood operated some of the most famous scientists of the world had sprung. A hasty excursion into the basement netted us nothing. The place was deserted. |
|