When electronics was young - part 10

In 1888, the American researcher Oberlin Smith (1859–1934) published his thoughts on magnetic recording, which in 1898 led Valdemar Poulsen (1869–1942) to publish a method of recording sound — magnetic recording. Poulsen found that by passing the output current from a microphone through an electromagnet and drawing a piano wire rapidly past it, the wire was magnetized to varying degrees.