In the Digest of April 6th Christopher Proudfoot wrote:

" -- if an Autotone is an automatic piano?  (I've never heard of it,
and it doesn't feature in the index of the Bowers' Encyclopedia, for
example)."

I used Google and I found this:

  "Hardman, Peck & Company was a large contributor to the piano
  industry at large in the late 19th and early 20th Centuries.
  Hardman Peck produced the Autotone player piano line from about
  1905-1930, and they were built as higher grade instruments of very
  good quality. In addition, Autotone pianos were also sold under the
  'Playotone' brand."

The source is http://www.antiquepianoshop.com/online-museum/autotone 

YouTube is also a good source; you can find there videos of these player
pianos, and Wikipedia also gives some clues, and when searching Google
with "Autotone player piano" (with the surrounding quotes) much more
information is to be found.

Jan Kijlstra
Netherlands