Since the introduction of cast-iron frames for piano-fortes, considerable expense has been incurred in drilling the holes for, and fitting in the pins, so as to give them the properties mentioned in Mr. Schwieso 's patent. To remedy these inconveniences, Mr. W. Allen, of Catherine-street, Strand, casts two dove tailed grooves along that end of the frame where the tightening pins are to be inserted, into which he drives pieces of wood of a corresponding shape, to fill up the dovetailed grooves, and to receive the tuning pins. It is evident, that by this ingenious and simple contrivance, the expense of manufacture will be diminished, and the instruments will be improved.
Self-acting Piano-fortes have of late years been introduced they combine the most rapid and brilliant execution with distinctness and neatness. Their her mony is necessarily more full than can be produced by eight fingers, the elements of chords having no other limit than the extent of its scale; the time cannot be otherwise than perfectly equable throughout, yet where pathos is to be expressed, the time can be accelerated or retarded in any degree.
The mechanism of a self-acting piano-forte usually or principally consists of • cylinder turning horizontally on its axis, acted upon by a coiled spring, and regulated by a fiy-wheel. On the surface of the cylinder, a determined arrange ment of brass pins is formed, each of which, in passing under a rank of levers, elevates one end of the required lever, and depresses the other. The depressed end pulls down with it a slender rod, which is connected by a slide withlthe tail of a bent lever, on the further end of which is the hammer which strikes the string. The slide can be shifted further from, or nearer to the axis, on which the hammer lever turns, and thus the stroke of the hammer is Made feeble or strong to any required degree. When wound up, the instrument will continue to play for a considerable time ; and it is provided with a bench of keys like the ordi nary piano-forte, so that a person may accompany the instrument, or play a duet with it.
A very beautifid instrument of this kind we have seen, that was manufac tured by Clementi and Co. ; it had two barrels, each of which played nine tunes. The velocity was regulated by two revolving balls, similar to the governor of a steam-engine.
Messrs. Rolfe and Sons, of Cheapside, have distinguished themselves in this branch of art by several improvements, which were the subject of a recent patent. These improvements they divide into three sections ; and their self-acting piano fortes are constructed either with the first section only, or with the first and second section combined, or with the three sections united. The first section consists of a new apparatus for effecting the transitions of forts and piano, by which means the difficulty of producing those desirable changes is removed, by transferring the mechanical action from the weakest and most uncertain part of the arrangement, viz. the cylinder, to the more powerful and certain action of the engine, by which
transfer the liability to derangement in instruments intended for exportation is avoided. To this branch of their patent, Messrs. Rolfe and Sons have annexed a hand movement, or register, by which the existing arrangement, or distribu tion of forte and piano, may at any time be changed, or altered to suitpcular views, or may at any moment be removed from the government of the self acting apparatus which produces the effect, and be operated upon by the hand, and again be restored to the control of the machine, at pleasure.
The second section consists of a new barrel movement for changing the tunes, which is effected by the introduction of an inclined plane, which forms an abutment for the Dail of the cylinder. This plane is divided into eight portions, and is moved by a radial lever upon a pinion, which by its rotation one revolu tion moves upon a second dial an index to the extent of one eighth of its cir cumference, moving the inclined plane to a proportionate extent. By this simple arrangement the motions are rendered very steady and accurate, and eight distinct airs may thus be performed.
The third section consists in the application of a set of dampers to the self performing action, which are altogether independent of the dampers ; so that each note of the self-acting or mechanical part of the instrument, in common with each particular note of the finger action, possesses its appropriate damper, connected with and identified by its kindred note, hammers, or keys, and acting simultaneously therewith. In conjunction with the application of the mecha nical dampers, suitable staples are introduced into the cylinders, which, acting upon each particular damper as occasion may require, suspends its operation, and enables them to retain the vibration of any given note, or the root and relative intervals of harmonious combinations, in the same manner as the finger of a performer sustains the vibration of chords, whose existence is to be prolonged by continued pressure of the keys, according to the duration expressed by the determined value given to them by the author in the composition performed. In addition to this, the whole set of mechanical dampers are occasionally raised by the cylinder, according to circumstances, in order to produce the effect, or MI of the open pedal when moved by the foot of the performer.