In a thrift store the other day I was a 4th pedal on the left of the
usual 3.  I looked closely at the pedal and it was labeled "Aeoline" in
the nickel plated frame surrounding the pedal.  I looked inside the
piano (the keycover was locked) and it moved something(?) near the
whippen.  BTW, I've heard the muffler pedal (middle) referred to as the
"prayer pedal".  Also, my 1920 Steck grand has an odd muffler instead of
the hammer rail lift.  It is wedge of felt that seems to be pushed to
the string by the striking hammer.  Its position of quite critical.  I
don't think Duo-Art made that kind of soft pedal for long.