The piano, while similar in some of its features too many other kinds of musical instruments, differs materially in several important points from all other kinds. It resembles the Violin, Harp, Guitar, Zither, Dulcimer, in its being stringed. It resembles the Drum, Triangle, Cymbals, Tambourine, Dulcimer, in its being dependent on percussion for the production of its tone; and it resembles the Organ, Clarinet, Concertina, in its being keyed.

But it differs from all of these instruments in the following important points. Firstly, in its being dependent on the player's method of finger push on the key for its quality of tone. Secondly, in its being dependent on rapidity of finger push for its quantity of tone and thirdly, in its being dependent on keys for the means of producing percussion. The actual mechanism of percussion, namely, the hammers, being reachable only through the pressing of the keys.

It is probably from a want of appreciation of this last fact, that the piano has come to be considered rather as a keyed instrument than as a stringed one.

The distinctive feature of the piano is, then, the system of its key mechanism.

As the seat of tone, the wire, is made to sound only by a series of communication, starting with the key, it is therefore necessary to understand the method by which this communication is conducted and kept open.

The piano key is, basically, a lever that's lifts the hammer that strikes the string. It is a lever of the first class, its fulcrum, or prop, lying between the power and the weight. In the case of the piano, this fulcrum, or centre on which the lever works, is placed about halfway between its two ends, the hammer (with some small intermediate mechanism) being the weight, and the finger the power acting on it. The very limited area should be noticed within which the action of the key is confined.

The immediate factor of tone is the hammer. The hammer, by means of intermediate mechanism, being in direct and close contact with the far end of the key, is raised when the near end is depressed by the finger or any weight; and the force with which the hammer is made to strike the wire is in proportion to the rapidity brought to bear on the ivory by the finger at the moment of the push. Quantity of tone is thus the result of the amount of speed used in pushing the key down.

When the string has been struck by the hammer, the hammer falls back immediately, to allow the string to vibrate freely. This fallback of the hammer is, however, not a return to the position occupied by it before the stroke; it does not fall completely back until the key is allowed to rise. When the piano key rises, the hammer returns to its original position, and is ready for the next key push.

It is of great importance for the student to remember that the hammer is always at some distance from the wire. Except during the very short period of time spent in striking; that after having struck the wire it leaves it instantaneously to assume the half position described above; and that it is powerless to do any more work until after the key has been allowed to rise.