I've posted a pdf of that "Speech Acoustics and the Keyboard Telephone"
article from 2007 in the "Publications and Research" section of
phonozoic.net for anyone who'd like to take a look at the whole thing, but
to summarize the argument I made:
- On May 26, 1877, Edison jotted down ideas for two inventions: (1) a
spectrographic speech recorder based on the principle of the harmonic
telegraph and (2) a "keyboard talking telegraph" that would synthesize
speech sounds over a phone line using combinations of simple electrical
- On July 11, 1877, his notes show that he'd concluded combinations of
simple breakwheels wouldn't do, and that he now envisioned a separate wheel
for each speech sound, containing variously spaced teeth of different
- On July 17-18, 1877, he apparently tried to figure out what patterns of
teeth he'd need to create individual speech sounds by recording the actual
vibrations of a telephone diaphragm, studying the records, and playing them
back to verify what they represented. The results were inconclusive as far
as visually recognizable patterns went, but he'd just discovered the
principle of the phonograph.
- Edison made technical mistakes and missteps throughout this period that he
shouldn't have made if he'd known about the phonautograph -- so he probably
didn't know about it during 1877, or at least didn't understand it.
On Wed, Jun 3, 2009 at 4:16 PM, <[log in to unmask]> wrote:
> TAE certainly had many opportunities, then and later, to
> correct the "record" and preserve for posterity the 'true' story. But he
> did this (apparently). Is there thus some "secret" (or unknown) version?
Well, this isn't exactly the Da Vinci Code -- Edison did try to tell the
"keyboard telephone" version of the story in an interview of April 1878
(quoted on p. 28), so he wasn't treating this as a deep, dark secret. But
the various lines of thought that converged in July 1877 were complicated
and might have been hard for Edison himself to recount clearly. In the long
run, he settled on a couple good anecdotes that were also part of the story,
and that he probably found more gratifying to tell.
> I do not know what year Edison first went to Washington DC, where
> Scott's Phonoautograph (Koenig model) was on Display.... As
> far as I recall, Edison never mentions, in real time, his view of it
> or in abstract thought), before 1877. I think he did see it during his
> trip in April of 1878, where he must have been surprised at how close
> others (Scott & Koenig) had come to his "baby".
You're right -- reporters quoted Edison's remarks upon seeing the
phonautograph during his April 1878 visit to DC, to the effect that he
was astonished anyone could have known about it and not also conceived of a
"playback" phonograph. Those remarks wouldn't have made much sense if he'd
already known about the phonautograph himself in 1877.
> Patrick says: "We do not possess any document in which Edison explains
> the circumstances under which he thought his keyboard telephone might be
> used, or what its practical benefits might be." And yet also: "Edison's
> notebook entries of 26 May 1877 show that he was then already eager to
> both a speech recorder and a speech generator," So I am confused. Is there
> reason why this May 26th document was not quoted (in the article),
> such a 'recorder'? And what was the actual imagined method of "recording"?
Spectrographic, oddly enough -- I summarize the proposed method on pages 18
and 19, and the full text is given in the print edition of the Edison
Papers, 3:361. What we don't have is any statement of the circumstances
under which Edison expected people to use either the keyboard telephone or
the automatic (spectrographic) speech printer. We know the "what" and the
"how," but we can only make educated guesses about the "why."