PIANO-FORTE (Ital. piano, soft, and forte, loud) a stringed musical instrument played by keys. developed out of the clavichord and harpsichorX(q.v.), from which the piano forte differs principally in the introduction of hammers, to put the strings in vibration, connected with the keys by a mechanism that enables the player to modify at will the intensity of the sounds; whence the name of the instrument.
The idea of the piano-forte was conceived independently about the same time by three persons in different parts of Europe—a German organist of the name of Sat-Liter; Marius, a French harpsichord-maker; and 'Bartolomeo Cristofali, a harpsichord-maker of Padua. Priority in point of invention (1714) is due to the Italian maker. Schriiter's discovery was followed up in Germany by Silbermann of Strasburg., Spilt of Itatisbon. Stein of Augsburg, and others. The first piano-forte seen in England was made at Home by father Wood, an English monk there. A few German manufacturers and workmen settling in London, gave an impetus to the new instrument. The English piano-forte has been brought to its present state of perfection by Broadwool, Stud:at. Collard, Wornum, Hopkinson, and others. Erard and Petzold nude mans improvements in France; Germany has long been famous for its pianos; American makers have lately become well known. The compass of the early piano-forte was, like that of the harpsi chord, 4 to 5 octaves, and has gradually increased to 6i, or 7 octaves, or occasionally more.
The most natural of the various forms which the instrument assumes is that of the grand piano-forte, derived from the harpsichord, with the strings placed horizontally, and parallel to the keys. The strings are stretched across a compound frame of' wood and metal, composed of bars, rods, and strengtheners of various kinds—appliances necessary to resist the enormous tension. This framework includes a wooden sound 1,0ard. The mechanism by which hammers are connected with the keys is called the action of the instrument. In the earliest piano-fortes, the hammer was raised from below by a button attached to an upright wire fixed on the back-end of the key. The impulse to the hammer caused it to strike the string, after which it immediately fell back on the button, leaving the string free to vibrate. This was called the single action. As
the hammer, when resting on the button with the key pressed down, was thus neces sarily at a little distance from the string, the effectual working of this action required that a certain impetus should be communicated to the hammer to enable it to touch the string. Hence it was impossible to play very piano, and it was found that if the ham mer was as to be too close to the string when resting ou the button, it was apt not to leave the string till after the blow had been given, thereby deadening the sound, This defect was remedied by a jointed upright piece called the hopper, attached to the back end of the key, in place of the wire and button. When the key was pressed down, the hopper, engaging in a notch in the lower side of the hammer, lifted it so close to the hammer, that the lightest possible pressure caused it to strike; and at his moment, when the key was still pressed down, the jointed part of the hopper, coming in contact with a fixed button as it rose, escaped from the notch, and let the hammer fall clear away from the string. To prevent the hammer from rebounding on the string, a projection called the check was fixed on the end of the key, which caught the edge of the hammer as it fell, and held it firmly enough to prevent it from rising. A necessary part of the action is the damper, which limits the duration of each particular note, so as to cause it to cease to sound as soon as the pressure is removed from the key. It consists of a piece of leather resting on the top of the string, and connected with the back part of the key by a vertical wire. When any key is pressed down, its damper is raised off the string, so as to allow the sound produced to be clear and open; bat immediately on the finger being lifted off the key, the damper-wire falls, and the damper again presses on the string, muffling and stopping the vibration. The whole range of dampers may, when required, be raised by the use of the damper pedal, so as to prolong the sound of one note into another.