An interesting treasure chest type of (dead) list of dead media, the Dead Media Project. Contains notes on over 600 media that, for various reasons, have ended in a cul-de-sac. The project has - unfortunately - ended, too. Love the list, though, fabulous starting point for some more research.

Favourite so far: the pantograph - pantelegraph - telautograph genealogy. Including a "writing device operating by four electromagnets" developed by G. Hasler 1873 in Switzerland (short mention in The Worldwide History of Telecommunications by Anton A. Huurdeman, 2003).