Thanks, Ed.  Here is some added information on the Gulbransen tie-in
with me.

When "Hard Times" came to the Gulbransens in the Depression, and they
had to sell the factory, one of the family, "Cape", had to leave the
piano business.  He went to work in 1936 for Lester Perry of Perry Graf.
My father joined that company in 1940, and sometime around then, Cape
started his own company making identical products, named "Graphic
Calculator", down on printers row in Chicago.  Perry Graf was in
Maywood, Illinois.

Ultimately Cape and the company moved to Barrington, Illinois, and his
son, Cape Gulbransen Jr., took over.  Cape, the younger, died just a
few years ago, and since I knew him and had a business relationship
with him, I attended his funeral.  Graphic Calculator ceased doing
slide chart business then, and I bought the customer lists, equipment,
etc., which became part of American Slide Chart / Perrygraf.

I also had succeeded my father as owner of American Slide Chart when he
died 22 years ago, and at that time had bought the Perrygraf operation.
My father had left Perrygraf in the late 1960s and started American
Slide Chart.

One of the things I saw at the time of Cape's death was a great 1920s
era photo of him sitting on his mother's knee at a Gulbransen upright
player, rolls stacked on the top.

So, to some extent, my business has a succession link to one of the
principals of the Gulbransens.

Julie Johnson
Carol Stream, Illinois

 [ Several vintage Perrygraf slide rules are pictured at
 [ http://www.gizmology.net/sliderules_perrygrafs.htm  -- Robbie