Special chaining patterns were sometimes used to signify things to the
Player-pianist, especially by the Aeolian company.  Assuming in the
following illustration that adjacent 'o's overlap and a space indicates a
bridge:

•oo oo oo oo oo oo oo 
•= was applied to notes forming the melody line, to aid
in singing, on many 88-note and Duo-Art piano rolls.

•00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
•= the upper manual, or melody;¶
•0000000000 0 0 0 0 0000000000 0 0 0 0
•= the lower manual, on Aeolian 116-note pipe organ music, to aid 
the player in drawing the proper stops by
enabling one to distinguish on which manual a particular passage was
being played.  This convention was retained on the 176-hole Duo-Art pipe
organ rolls, even though these rolls drew the stops automatically.

Earlier recuts, where the original roll was simply used as a 'master' in
the production punch, often show missing or irregular chaining.  This
indicates that the original was 'over-read', that is, many of the holes
and slots on the recut are a punch or two too long.  Modern hole-to-hole
scanning techniques should eliminate this problem.  As long as the first
and last punch in any particular note or dynamic instruction is properly
placed on the recut, and at least three or four holes overlap at the
beginning of the slot, then it doesn't matter what chaining pattern the
recutter's computer places in the remainder of the slot.

Some chaining is necessary on long slots, not to strengthen the paper,
but to prevent the edge of the paper from moving inwards and mis-aligning
other notes.  This is a commonly-seen problem on 58- and 65-note, 6-to-
the-inch rolls, where chaining was impossible due to the vertical
narrowness of the tracker port.

Richard Vance