IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. Telegraph sounders convert electrical ...
Telegraph sounders convert electrical pulses into audible sounds and are used to receive Morse code messages. The message travels as a series of electrical pulses through a wire. Short pulses make a ...
Some results have been hidden because they may be inaccessible to you
Show inaccessible results
Feedback