Construction
The outwards appearance of the piano in all its varieties of square, upright, grand, concert grand, etc., is too well known to need description. This instrument possesses keys sufficient for a chromatic scale throughout its compass; each note is provided with one, two or three strings in unison (according to the pitch, the medium and high register usually having three), a hammer and a damper (except the two highest octaves, which have no damper), besides a complex system of mechanism called the action. The chief parts of a piano, about which it imports us to know something are:  The case and framing, the strings, the wrest-plank, the soundboard or belly, the bridges, the action and the pedals.

The case, made of solid wood, with a veneering of mahogany or oak, must be so strongly constructed as to resist the enormous tension of the strings, which approaches thirty tons in a modern concert grand. To that end concurs the cast iron or steel frame placed over the soundboard, which has a strong iron or steel bars (the number varying with different makers) extending across the strings, from side to side of the frame but not touching them. Holes of irregular shape are made in the metal frame for the sake of lightness.

The strings are now made of the strongest and, at the same time, the most elastic of metal, tempered cast-steel wire, which is able to meet a tension of at least 200 pounds for each string in recent grands. The pitch of the strings depends on their diameter as well as their length. In order to reduce the latter for the bass strings, the expedient of covering them with copper or white metal wire has been resorted to, as in the G string on the violin, for example. The earliest stringed instruments with keyboards of which we have knowledge, seem to have made their appearance in Europe about the middle of the fourteenth century, contemporaneously with the first manufactures of drawn iron wire at Nuremberg.

The wrest plank, corresponding to the peg-box of violins, will be found in grand pianos at the keyboard end under the music rest. Into it are inserted the wrest or tuning pins. In order to hear the strain of the enormous tension, the wrest plank is made of layers of the hardest woods – oak, beech, etc. – in each of which the grain runs at right angles to that of the others to prevent splitting. The whole is further strengthened with a metal plate, to assist in insuring the rigidity of the tuning pins.

The soundboard consists of lengths of spruce of fir, glued together, like that used for the best violin bellies, chosen on account of its elasticity and resonant power, and to both sides of which several coatings of varnish are applied to prevent cracking or warping. The soundboard, which is slightly convex to the strings, lies under them along the whole length and breadth of the piano nearly as far as the wrest plank. Between the soundboard and the wrest plank there is a narrow space left, through which the hammers rise to strike the strings. Strings, when set in vibration, give but a poor sound of themselves, owing to the small surface they possess wherewith to influence or set vibrating the surrounding strata of air. But when the strings rest of a wooden bridge, the molecular vibration communicated to them by the fingers through the keys and the hammers is transmitted by the bridge to the soundboard in shocks, which are repeated by the surrounding atmosphere. Thus are sounds produced, the intensity and character of which are directly governed by the quality of the blow or pressure brought to bear upon the strings by the performer.

The vibration of the soundboard as a whole being undesirable, it is prevented by gluing thin ribs of wood – the belly bars – under it, of which the grain runs in a different direction to that of the soundboard. These bars give elasticity and help the formation of vibrating centers or nodes. The soundboard has to be tense to take up the vibrations initiated by the strings.

The bridges are two in number in the piano, each corresponding to a similar part of the violin, i.e. the belly bridge to the violin bridge and the wrest plank bridge to the nut of the peg box of the violin. The first of these bridges, by means of which the vibrations of the strings are communicated to the belly, is made of hard wood. The belly bridge is divided in all pianos, straight of overstrung. With the latter the divisions are disposed at differing angles, so that the bass bridge strings cross over the others in the lower part of the scaling. As a matter of fact, overstringing has entirely changed piano construction. The steel strings are stretched over the longer part, and the covered bass strings (lying above the steel ones) rest on the shorter bridge behind the other and nearer the end of the case. The wrest plan bridge, to which the strings are pinned down to prevent their being forced upward by the blow of the hammer, is the point from which the vibrating length of the string is measured.

The action, situated beyond the keys under the wrest plank comprises the complex system of levers, hammers, checks, dampers, etc., which are set working when a key is depressed. To describe minutely this action, which differs in details according to the various makers, is not possible within our limits. The hammers are covered with the finest white felt and resemble in shape a section out of the middle of a pear. The checks are situated just behind the hammers. A damper made of thick felt lies over or under each set of three strings in unison.

Production of Sound
By depressing a key with a finger, a system of levers is set working which raises the hammer and causes it to strike the strings and then rebound. The damper, which is automatically removed from the string as the key is pressed down, likewise returns to its normal position on the string as the key rises, and thus stops further vibrations after the finger leaves the key. Should the performer wish these vibrations to continue he can, by means of the right pedal, remove the dampers and thus call out the sympathetic upper partials or harmonics of the strings, as well as prolonging the tone.

Quality of Tone
This is subject to so many conditions that it is impossible to do more than refer to a few of them. The tone varies according to the different makers, some making brilliancy and clearness, some mellowness, others a sweet, singing tone their specialty, and so on. The various kinds of touches are more influential than anything else in producing tone (by tone, we mane breadth, depth and fullness of sound, which is quite independent of loudness.) Given an instrument of the very best, two performers playing the same composition on it may give a totally different idea of its tone; the one producing plenty of sound in the forte passages but leaving the ear unsatisfied, on account of a certain hardness and want of elasticity and continuity in the sound; the other performer giving the piano a voice, and making it sing our round, deep-chested notes in which there is no suggestion that the keys have been struck, but rather that the sound is being pressed out of the instrument. No satisfactory elucidation of the mystery of this difference of touch has been brought forward. The fact that so many and minute differences of touch and shades of expression – nay, more than this, that the individual feelings of performers can be transmitted to the piano through the keys, will give an idea of the exquisite nicety and complexity of the mechanism which makes this possible.

Possibilities
There is no instrument which has greater possibilities than the piano. The rapid development of its technique and the wonderful improvements that have followed in such quick succession during its comparatively short existence, all point to a more and more glorious future for it. The fact that from this instrument one performer can by himself produce the richest and most complete harmonies, and that he requires to devote so much intelligence and care to the study, in order to follow out simultaneously the many parts of these harmonies, instead of each part being taken by a different instrument – all this adds to its dignity and importance.

History
The piano, being a truly complex mechanism has many so-called prototypes in antiquity. The two chief classes of keyed predecessors are the clavichord and the harpsichord with its smaller varieties, the spinet and the virginal. The clavichord was a small instrument in which the strings were struck from below by metal tongues called tangents. While a key was held down, its tangent was pressed against the string near one extremity, thus forming one end of the vibrating part of the string. Swells or subsidences could be caused by increasing or diminishing the pressure on the key while it was held down. These changes were called the Bebung. The tone of the clavichord was infinitely sweet and delicate and it is no wonder that Bach and others clung to it even after the invention of the piano. In the harpsichord the strings, two or three for each note, were plucked by quills carried on jacks that were pushed up when the keys were depressed. The harpsichord often had two manuals or keyboards, and as many as six pedals. The harpsichord included also some couplers, which could unite the two manuals or make a note sound its octave as well as itself. The damper pedal operated by moving some of the jacks until their quills could no longer plug the strings. The spinet was a very light harpsichord with one keyboard. A virginal was merely a box with a keyboard on it which could be laid on a table. The mechanism of these two instruments is similar to that of a harpsichord.

These instruments in turn were evolved from the psaltery, an instrument having strings stretched horizontally  over a soundboard and plucked by plectra or quills. The harp supplied the idea of having a separate string for each note and the harplike shape of the scale supplied the idea of the bridges being divided the length of the strings, which the dulcimer and cembalo of the Arabs and Hungarians supplied the idea of the hammer action.

The earliest mention of the name “pianoforte” applied to a keyed instrument seems to be in 1598 in the letters of a musical instrument maker named Paliarino, addressed to Alfonso II, Duke of Modena. It would seem however that the name was applied to some instrument of the clavichord or cembalo kind, for there is no mention of how the tone was produced, nor do we hear of the “piano e forte” again until 1711, in an account by Scipione Maffei speaking of Cristofori’s “gravecembalo col piano e forte.” Bartolommeo Cristofori was a harpsichord maker of Padua. Invited to Florence by Ferdinando de Medici and encouraged by him, Cristofori produced the first pianoforte, in which the two unison strings for each note were struck by hammers, and damped by pieces of cloth or felt. The check action was added afterward. Others living at the same period claimed to be the real inventors, and it is possible that the same idea occurred to more than one person quite independently. Cristofori was probably not the first who had attempted an instrument of this description; his invention was the result of years of study in his own lifetime and that of preceding generations. It is now proved beyond contention, however, that Cristofori alone was the actual inventor.

The first real damper pedals and soft pedals were adapted in 1783 by John Broadwood to the piano; they had been invented for the harpsichord instead of hand stops by John Hayward about 1670. At first the piano was looked upon as a variety of the harpsichord; it emancipation took place between 1770 and 1780 when it became an independent instrument, chiefly through the exertions of Muzio Clementi, who understood its capabilities. It was Beethoven who first turned the tide from harpsichord, spinet and clavichord to the acceptance of the piano.

In 1778 John Broadwood made a new scale grand, dividing the soundboard bridge. Stein of Augsburg invented the soft pedal with shifting action in 1789. Tension bars were first applied to a grand by James Broadwood tentatively in 1808 and in 1827 he patented a grand in which tension bars and string plate were combined. In 1837 Jonas Chickering patented the first practical casting of a full iron frame to resist the tremendous tension of the instrument. Other important improvements of this were patented by him in 1843 and 1845. Meanwhile the invention of Sebastian Erard in 1080 of the double escapement action had been perfected and was patented in 1821 by his nephew Pierre Erard. The hammer touch ultimately brought about a double improvement in playing and construction. In using the wrist to soften the blow which the indifferent and thin wire strings were too weak to bear and by giving the idea of using an iron frame to which to fasten the strings, as the wooden frame would not bear the increased tension of stronger and thicker strings.

A flute maker was the first to have the idea in 1831 of overstringing pianos, but the invention as applied to grand pianos was patented by Steinway & Sons in connection with a cast frame in 1859.

In 1838 the harmonic bar was introduced by Pierre Erard. By making the treble part of the instrument almost immovable, it favored the production of the higher harmonics in the treble. The firm of Broadwood have since made use of a similar bar across the whole length of the wrest plan. In 1847 Henry Broadwood invented a grand having an entire upper iron framing with only two tension bars. Pursuing this rejection of metal bars, Henry J. Tschudi Broadwood patented in 1888 a barless grand, which is now proved to stand the modern tension satisfactorily. It is in the reduction of weight that this invention will be valued in the future.

Innumerable other improvements have since been patented by Steinway & Sons, Mason & Hamlin and many other firms of piano manufacturers including the sostenuto pedal, the agraffe and the supported soundboard.