Dear Hal and Mike,

Thanks for your replies about the 20-key (or more) scale.  Could you
folks please do me a favor and measure the hole spacing on your
respective tracker bars?  I don't trust my measurement on the old
Jaeger & Brommer roll -- it's punching is _sloppy_!  (I hope the music
sounds better than it looks!)

I used a metric rule, altho English inches would work too, and observed
the "Vernier pattern", so to speak, until an even number of holes lined
up with the rule.  That's how I measured 18 holes in 7.0 cm.  It might
be nearer 23 holes in 9 cm.

I'm slowly compiling a list of tracker bar scales for the various
European organs.  Many dimensions taken from actual tracker bars and
book readers on the big, old organs have noticeable (although not
critical) variations.

Thanks,

Robbie Rhodes