I am surprised that Dan Wilson states that he roll tracking system with
16 pairs of narrow vertical slots above the 88 note holes is a Philipps
system.  I have certainly never heard it called that, and it is in fact
an Aeolian system covered by two British patents.

The first patent, 14,251 dated 13 June 1914, was awarded to Mr A J
Mason, Orchestrelle/Aeolian Co Managing Director.  The right and left
slots (which overall occupy the same width as the note hole below) are
respectively connected to two passages in a bar which connect with a
pair of coupled bellows that operate a cam to move the top right roll
chuck.  The bellows are evacuated through two bleeds, like the Duo-Art
ears system.  No mention is made about cutting off and centring the
system on re-roll, but this was necessarily done in practice.

The pairs of slots are evenly but cleverly disposed to maximise the
probability of tracking music in any key with notes in the centre of
the keyboard compass, which is very common.

The system works reasonably well if the bleeds have not been enlarged
and the cam and return spring are set up well. The bleeds seem often
to have been enlarged in an effort to make the system work faster (for
badly warped or re-rolled rolls?) but this makes it too sensitive and
to centre too fast if several pairs of slots come into operation.

The second patent, 139,257 dated 17 January 1919, obviously cured this
problem somewhat by making the grouped signals operate two conventional
tracking valves which are connected to the tracking bellows.  The slots
are connected by flexible tracker bar tubing to two manifolds and the
tracker bar itself is moved by the bellows, a British Aeolian invention
and preference.  Somewhat superfluously the tracking is cut off during
re-roll.  I think I'm right in saying that Malcom Cole's late 'teens
Steinway O Pianola grand has this system, which works fine.

This patent was awarded to the Aeolian Co and E G Nicholson.  The late
Ernie Nicholson, a terrific chap whom I once met, was one of Aeolian's
top technicians.  He was later given a reward by Aeolian for inventing
the excellent British four hole/moving tracker bar tracking system,
commonly found on Duo-Arts here, which is very kind to rolls and does
not work like other four hole systems but uses negative logic to cope
with damaged roll edges: it tracks on two edges if possible, one edge
if necessary, or where both edges are torn lets the bar remain uncentred
at its last signalled position until a good edge comes along.

I am sending copies of the patent abridgements and drawings to Julian
Dyer who can post them if anyone's interested and will probably do a
piece in the Player Piano Group Bulletin.

Patrick Handscombe
Wivenhoe, Essex, UK

 [ The description of the control logic of Mr. Nicholson's four-hole
 [ tracking system sounds remarkably alike the four-hole tracking
 [ system of the Standard Pneumatic player action in USA.  I wonder
 [ how the systems differ.  -- Robbie