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"A.D. 1795, January 12.-No 2028. - STODART,
WILLIAM.- An upright grand piano in the form of a bookcase. The "grand
principle of action" in this invention is stated by the patentee to be that
both the hammers and dampers after "performing are returned by weight. The
drawings represent the movement of a hammer and damper on this principle.
The hammer is raised by a lever, and on being relieved by a button falls
back by a weight attached to the tail end of it. The damper is returned by
the weight of an intermediate joint. [Printed, 10d. Drawings.]"
Specifications Relating to Paints ..., 1871, p. 29
1821
NEW PATENT FOR AN IMPROVEMENT OF THE PIANO FORTE.
The idea is simple and philosophical, and has been long since applied to chronometers, th6ugh its operation in those delicate instruments is the reverse of that to which it has now been turned. — The principle then is to compensate the natural expansion of strings through heat or their contraction through cold, by providing an apparatus possessing the same properties as the strings themselves, upon which they are stretched. To this intent a plate of brass is laid over the belly of the instrument, of about two inches wide, and corresponding in shape with and placed close to the curved side of instrument: to this the strings are fastened in the usual way. The bar which constitutes the front is fixed in its place, about nine inches from the front, by iron clamps, which preclude its moving, and under this bar the strings pass to the pegs, as is customary in other piano fortes. Within this frame and parallel to the strings, but above them, are placed tubes, about three quarters of an inch in diameter, of a similar metal to the string beneath, i.e. brass above the brass and 6teel above the steel. One end of these tubes is placed against the curved side of the frame, the other against the straight bar. They are prevented from rising or curving upwards, through the stress of the tension upon the string, by stout bars of wood laid across. The effect contemplated in this construction is, that as the temperature affects the strings either by expansion or contraction, it will also affect the tubes, which extending or relaxing consentaneously, as it were, with the strings, (It is an opinion commonly receWed that strings will stretch almost indefinitely if the tension be conducted slowly and gradually; but this doctrine is, we beliere, contradicted by facts. Strings baring undergone a certain degrc« are susceptible of no further tension.) will compensate the difference, by allowing the whole frame to coincide with their action. The only conjecture unfavorable to this project which reason suggests, appears to lie in the size of the different masses of metal to be acted upon by heat and cold, but experiment has determined that the expansion and contraction of the larger and the smaller body are so nearly alike as entirely to answer the purpose. A grand piano has been removed from a low to a high temperature, and back again, without undergoing any perceptible difference in the pitch, or going out of tune in the smallest degree.
In addition to this the
main purpose, other benefits are found in the facility it affords in
tuning, and in the superior excellence of the tone, which is improved
both in volume and quality. This circumstance may be traced cither to
four separate causes, or to a combination of them all.
1856
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