stay in contact with the string as long as one’s finger is held down. Some device must be
devised to allow the hammer to rebound immediately whether the key is held down or not.
Such a device is called an escapement. It is essentially an upright stick, called a jack,
which is mounted just above the rear of the key. When the front end of the key goes
down, the back end goes up, and the jack pushes the hammer towards the string and then
immediately falls back again even if the key is held down.
Cristofori succeeded in solving the fundamental problem of piano design. The hammers
must strike the string but must not remain in contact with the string (as a tangent remains
in contact with a clavichord string) because this would damp the sound. The hammers
must return to their rest position without bouncing violently and it must be possible to
repeat a note rapidly. Cristofori’s piano action, which was a single escapement, served as
a model for the many different approaches to piano actions that followed.
Double escapement
By the 1820s the centre of innovation had shifted to Paris where the Erard firm
manufactured pianos used by Chopin and Liszt. Sébastien Erard invented the double
escapement action, which permitted a note to be repeated even if the key had not yet risen
to its maximum vertical position. This facilitated the repetition of notes, chords and
octaves and generally facilitated rapid playing.
When the invention became public, as revised by Henri Herz, the double escapement
action gradually became standard in all pianos. Liszt exploited the invention in his piano
works many of which would be difficult to play otherwise.
EVOLUTION
The piano is a musical instrument played by means of a keyboard. The piano produces
sound by striking steel strings with felt hammers that immediately rebound, allowing the
string to continue vibrating. These vibrations are transmitted through the bridges to the
soundboard, which amplifies them.
The piano is widely used in Western music for solo performance, chamber music, voice
accompaniment, composing and rehearsal. Although not portable and often expensive,
the piano’s versatility and ubiquity have made it one of the most familiar musical
instruments. The piano keyboard offers an easy means of melodic and harmonic
interplay and, since a large number of composers were and are proficient pianists, the
piano has often been used as a tool for composition. Pianos were, and still are, popular
instruments for private ownership and use in the concert hall.
The word ‘piano’ is a shortened form of the word ‘pianoforte’, which is seldom used
except in formal language. It is derived from the original Italian name for the instrument,
‘clavicembalo col piano e forte’ or ‘harpsichord with soft and loud’. This refers to the