In regard to Jim Katz' skepticism (131122 MMD) of the information cited
in Joyce Brite's 131120 MMD posting on the Viola Organista, I found the
information very questionable, particularly in the claim that this is
the first example of such an instrument since Da Vinci's time.  I have
been building and playing the manual style hurdy-gurdy or vielle a rou,
which this instrument is based on, for over thirty-five years, and I
have researched the subject quite intensely.  When this article came
out, so many of my friends on Facebook sent me links, with a bit of
skepticism.

This instrument, also known as a Geigenwerk, although not very common,
was made in different variations throughout Europe.  It is also
described in detail in Michael Praetorius' "Syntagma Musicum" (1614)
    http://www.lib.rochester.edu/index.cfm?PAGE=2470
Most of those that I have seen operate by a crank at the opposite end
or by a foot-treadle.  I have also seen over a half-dozen instruments
made in the past fifty years.  In my late 20s I designed one but never
got around to building it.

The mechanism is simple.  The heart of the instrument is several
laminated wooden wheels for each octave, which are geared to turn
slightly faster as you go up the scale.  Each octave of strings is
stretched between three bridges.  The front two bridges are semi-
circular, the first one being slightly larger, and the second having a
slightly smaller diameter than the bow wheel.  Between these bridges
are little hooks which connect to the keyboard.  When the key is
depressed, it pulls the string down the second bridge, where it makes
contact with the bow wheel, very much like the Violino Virtuoso.

The third bridge, being a series of ellipses, transfers the vibration
to the soundboard in a conventional manner.  By quivering the keys you
can also create a vibrato effect.  It has a conventional keyboard which
is the only thing *piano* about the Viola Organista.  It is a bowed
instrument.

Whoever produced the article cited should have done his homework.
Just Google "Geigenwerk" to see more information and pictures.

Brian Thornton