Hackers have an extremely old joke about “write-only memory” — just like read-only memory, but the other way around.
It turns out that the first phonograph — a number of years before Edison’s well-known invention — was just such a system. It could record sounds onto a piece of paper, but they couldn’t be played back.
Right around 1.5 centuries later, Édouard-Léon Scott de Martinville’s April 9, 1860 autophonogram of a woman singing “Au Claire de Lune” has finally been rediscovered and played back with the help of some serious image-processing work by scientists at Lawrence Berkeley National Laboratory.
Note that this sound recording is, believe it or not, still subject to state-law copyright protection in the United States until February 15, 2067. 17 U.S.C. 301(c).