DescriptionBritannica Pianoforte Modern Pianola.png	English: Modern pianola
Date	published 1911
Source	Encyclopædia Britannica, 11th ed., Vol. 21, p. 573
Author	Unknown authorUnknown author
Permission (Reusing this file)	Public domainPublic domainfalsefalse This image comes from the 13th edition of the Encyclopædia Britannica or earlier. The copyrights for that book have expired in the United States because the book was first published in the US with the publication occurring before January 1, 1929. As such, this image is in the public domain in the United States.

A, Blowing pedals operated by feet of player connected by metal crank to feeder B, which exhausts air from bellows C, which in turn exhausts air from all working valves and bellows in Pianola.

D, is perforated roll passing over tracker bar E winding on to spool F operated by a pneumatic motor and controlled by lever G, which is connected to metrostyle pointer H. This is used in conjunction with a specially marked roll, giving correct interpretation of tempo.

I, is channel leading to primary pneumatic J operating secondary pneumatic K, which exhausts striking motor L, connected to key lever M to depress piano key.

The themodist device consists of two small holes, one at each end of tracker bar E, connecting with pneumatic valve, which increases power of suction instantaneously when melody notes are being played, by means of an extra perforation at each outside edge of music roll D; one hole for bass melody at left, and one at right edge for treble melody.

N, is metal arm or bracket connected to lever in front for purpose of depressing sustaining pedal of piano.

O, is the governing bellows of motor for operating music-roll and prevents pace of roll being accelerated or retarded by hard or soft pedalling, thus allowing great change of expression to be made without interfering with speed of roll.