Robbie wondered in MMD 20.03.05 about when the Themodist accenting
system was devised and who held the patent.  The Pianola Institute
website, by Rex Lawson, tells us:

http://www.pianola.org/history/history_inventors.cfm 

The accenting device was patented in December 1900 by J. W. Crooks,
an employee of Skinner organs.  The patent shows the device in what
is quite obviously a Pianola pushup.  Rex muses that it may have been
work done under contract for Aeolian.  At that time, Aeolian were
still reliant on third-party providers; only later did they purchase
their suppliers.  Crooks later joined the Aeolian retail staff.

The patent was for an "accenting device", but did not use the term
Themodist.  It was a few years before Pianolas were being sold with the
evolved Themodist equipment.  The 1905 Aeolian catalog doesn't mention
Themodist, but the July 1906 catalog has a separate Themodist section
with an "Important Notice" on the front cover describing it.  Only
10% of the music was Themodist, but later Aeolian catalogues reach over
90% Themodist.

These were 65-note rolls, and the Theme accents were in the small
margins at the edge of the paper in the 65-note format.  To get the
accents short enough, two tiny holes were used across a single 65-note
tracker bar port.  With a split action stack, this allowed either side
of the stack to be 'Theme' (louder) or 'Accompaniment' (quieter)
according to what accent perforations were added.

Later, when Aeolian created their new 88-note roll scale they left
a space between the playing notes and the sustaining pedal tracks.  The
theme perforations fitted neatly into this space.  When Aeolian's new
design was adopted [by the industry] as the 88-note standard this meant
that theme could be adopted by any maker -- it wasn't explicitly part
of the "Buffalo Convention" standard, inasmuch as theme accents weren't
mentioned, but the space for those perforations is very much part of
the standard.  The use of paired small perforations was continued from
the original 65-note format.

So, who else used it?  In the USA, Aeolian used it across their
various roll brands, such as Universal as well as the most obvious
Themodist-Metrostyle.  The same device appeared as the Angelus
"Melodant".

The Angelus and Aeolian operations were highly intertwined, with
Aeolian's roll factory in Meridan making the rolls for Angelus.
Aeolian and Wilcox & White shared patents in some areas as a result
of their early history.  "Solodant" rolls are simply Themodist with
different printing ("Artistyle" rather than "Metrostyle").  Later both
the Duo-Art and Artrio-Angelus reproducing systems were based entirely
around theme-accompaniment control using Themodist accents, albeit with
wholly separate mechanisms.

In Europe the accenting idea was taken up by Hupfeld, initially in
their 73-note Phonola.  The "Solodant" used single small perforations
for accenting, the bass and treble accent tracks being in the centre
of the roll.  When Hupfeld started making 88-note standard rolls they
naturally placed the twin-punch accents in the place provided by the
88-note roll standard.  And their Triphonola system is yet another
theme-accompaniment reproducing piano design using accenting
perforations.

And why Hupfeld?  I have been told that Aeolian and Hupfeld had some
form of commercial arrangement and cross-owned shares in the other.
Perhaps Hupfeld thought that a theme-accompaniment system would provide
clear distinctions with their rival, Welte's "Mignon", reproducing
piano with its bass-treble control.

In Europe, however, pretty well every roll maker adopted theme accenting
for their 88-note rolls.  Even makers such as Philipps used it for their
88-note versions of their non-theme "Ducartist" reproducing rolls.
Roll-only firms such as SM adopted it for all their rolls, as did makers
such as Victoria in Spain.  Almost no European maker made non-theme
88-note rolls.

The Welte-Mignon system was a bass-treble system and had no need for
theme accenting (and Welte didn't make 88-note versions of their rolls).
However, even Welte succumbed eventually to the accenting standard
with the T98 "Green" system in the early 1920s.  The T98 expression
mechanism functions like other Welte systems but has its tracker bar
rearranged and its lock-and-cancel controls replaced with extended
slots.  And the T98 layout, with its 9-holes-per-inch note spacing,
has its "sforzando-on" (fast crescendo) control at the theme-accent
point.  So, the pedal-electric T98 pianos are designed to play themed
rolls.

I wonder if the usage tells us anything about patent ownership?  In the
USA, Theme accenting was clearly an Aeolian thing.  But, if everybody
in Europe used it, perhaps it had been made freely available to all.
If so, why not in the USA?  Getting back to the Pianola Institute's
page, it's clear that Rex Lawson hasn't found anything about that.

Julian Dyer
Wokingham, Berkshire, UK