Just a few thoughts fired off by Dan's comprehensive Themodist article
and the earlier discussions.  Themodist was formally launched in the UK
in November 1907 (just a bit earlier than Dan said), so must be found in
instruments of that date.  It's not obvious from the tracker bar that a
65-note player is themed, because the theme holes are exactly the same
size and shape as the note holes.

Only the gap from the edge of the roll, or the number of holes, gives it
away.  Otherwise the pair of subduing levers are the clue, not to be
confused with earlier non-themed single-lever subduing systems.
Regarding what Richard Vance said, every Pianola pushup I've seen has or
had the Metrostyle pointer - it predates Themodist by several years
(introduced by 1902 ?).

Given the relative timing of the introduction of the Themodist and
the 88-note systems (88n early 1909 in the UK from Aeolian), it is very
probable that the Themodist system was designed for 65-note machines,
using additional tracker bar ports the same size as note ports.  65-note
perforations are large, so a theme accent using a perforation that big
would be fairly crude, and would overlap into adjacent punch rows.

Using two small holes to span the width of a standard 65-note tracker bar
hole then seems a fairly logical move, allowing accents to be restricted
to one punch row.  When the Themodist system was ported to the 88-note
scale, the same theme perforation and tracker bar port sizes were used.
This seems a credible explanation of the system's final form.

Using two small holes give much greater timing accuracy improvement on a
65-note system than on an 88-note system which uses smaller punches
throughout.  Not all manufacturers used smaller perforations for theme
holes - Hupfeld didn't.  Duo-Art rolls recut by Custom Music Rolls get by
fairly well without them.

Paddy Handscombe tells me the Themodist patent was awarded to a Mr. Crook
of the Aeolian-Skinner organ company.  There was some infringement fight
with Hupfeld after which the patents were shared, so Hupfeld and Aeolian
were the only two to make continuously-variable accompaniment systems.
Others are on/off fixed accompaniment or fixed accompaniment/theme ratio.
Interestingly, the 'snakebite' coding must have been shared, even if the
expression box technologies weren't.

Aeolian actually perforated the Angelus rolls with snakebites, so they
clearly had no problem with their use, but the Angelus Melodant boxes are
quite different to Aeolian's so the technology wasn't licensed.  I'll see
if I can dig out more about these stories when we have more time to talk.

Julian Dyer

 [ Very interesting!  Thanks, Julian.  I'd like to know more about the
 [ system where the accompaniment is a fixed ratio of the theme.
 [ To me, this should help the pianolist when he is pumping a Themodist/
 [ Solodant roll.  -- Robbie