At  http://www.fmp.com/aq/autohist.html I found an interesting
article on the history of the chorded zither, originally published
in "Autoharp Quarterly", Volume 3, Number 3.

According to the author, Ivan Stiles, Charles F. Zimmermann held
a patent on an unsuccessful chorded zither which he called the
"autoharp", but with great success he produced and sold the
instrument previously developed by violin-maker Karl (Christian)
August Guetter of Markneukirchen, Germany.  Stiles says, "In 1883,
Guetter sold the rights to the chorded zither to Herman Lindemann
from Klingenthal, near Markneukirchen."

Lindemann was granted a German patent and named it the "Volkszither"
(which was actually a common name for the zither name from the early
19th century).  He was very annoyed that Zimmermann was making and
selling the same instrument in the USA as the "Autoharp".  Zimmermann
ignored the complaints from Lindemann.

Stiles concludes:

  What this all really boils down to is that Zimmermann never
  produced what he patented and he never patented what he produced.
  Instead, he manufactured Guetter's instrument and called it an
  "autoharp."  He also put his patent number on the instrument --
  a patent issued for "new and useful Improvements."  Had he, in fact,
  employed his chord bar improvements, then we could give credit to
  Zimmermann for a new way of playing a harp.  However, what we are
  playing today is actually Guetter's chord zither, or "Volkszither,"
  and not Zimmermann's "Autoharp."

The name Autoharp (with a capital 'A') is a registered trademark owned
by the Oscar Schmidt Company (who in turn is owned by guitar maker
Washburn International) and is used as the brand name for the chorded
zither they sell.  Under US trademark law no other firm can make a
chorded zither and call it an "Autoharp".  However, an essentially
identical instrument named "Tennessee Autoharp" is sold by a competitor,
Musik Produktiv of Ibbenbueren, Germany.  One imagines that this would
annoy Washburn and Oscar Schmitt -- will they complain?  ;->

Roger Waring's antique stringed instrument may be called by its generic
name, autoharp with a small 'a', since it clearly was not made by
Oscar Schmidt nor by Musik Produktiv.  If it was made by Lindemann it
might be called eine Volkszither (with a capital "V" only because it's
a German noun).

Robbie Rhodes