2. Materials. “Mary Had a Little Lamb,
” the first words to be recorded and played back, were spoken by Thomas Edison to a sheet of tinfoil wrapped around a brass drum. (One could make a case for something like “Hello
” as the first word recorded, since Edison had shouted it at a strip of paper pulled along under a diaphragm in an experiment on 18 July 1877, and then “ran the paper back over the steel...