Signor Marconi and his Instrument
Dam, J.W. “The New Telegraphy: An Interview with Signor Marconi.” The Strand 13, no. 75 (March 1897), p.275.
This publicity photo was taken of Guglielmo Marconi for a magazine interview in 1897. On the left is a type of spark-gap transmitter. On the right is a receiver that rang a bell when it received a signal.