IMPROVEMENTS IN PIANOFORTES; ORGANS, HARMONIUMS, AND OTHER INSTRUMENTS HAVING KEYBOARDS
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by John George Thompson at the
Office of the Commissioners of Patents, with his Petition, on the 20th
March 1862.
I, JOHN GEORGE THOMPSON, of Madras, in the East Indies, now residing at
Porchester Place, in the County of Middlesex; Gentleman, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN PIANOFORTES; ORGANS,
HARMONIUMS, AND OTHER INSTRUMENTS HAVING KEYBOARDS," to be as follows:-
And it consists in the application to such instruments of an enharmonic
scale, that is, a series of 41 sounds in each octave or settine, which will give
in just intonation every major and minor scale in a series progressing upwards
by fifths from C flat through C natural to C sharp (or from 7 flats through C
natural to 7 sharps to adopt the signatures generally used in music) with the
chromatic and enharmonic of each.
Also in the application to such instruments of a keyboard shifted by pedals,
by which one is enabled to perform in any of the above scales at will (by
shifting the board to the proper position) while one is using the fingering of
the easiest of the scales, namely, C natural major, and A natural minor.
There are peculiarities in the way in which the keys are jointed and kept in
their places.
For the above purpose alone a single keyboard would be sufficient, but I
prefer two keyboards, one behind the other, that before playing music which
modulates from scale to scale, the player may shift one board to the position
required for the first scale, and the other to the position required for the

page_text: second scale. In single music no further shifting will be required, as the
music will return into the original scale to which the first keyboard is already
adjusted. In more complicated music there will be ample time to shift
the first keyboard to the position needed for the third scale during the per-
formance of the part which is written in the second scale. There will thus be
hand to the second
no break in the performance. The player will pass one
board while the other hand is playing on the first board, and so on in a
manner familiar to organists.
A person who cannot follow transition except where it is marked by
change of signature, may adjust the keyboard to the key of C natural, and
play in the same way as on a tempered instrument, striking a sharp key where
a sharp is written, and a flat key where a flat is written. But as composers
sometimes write A sharp instead of B flat, or B flat instead of A sharp, and
so on, the intonation may not always be correct.
My Invention likewise consists in increasing the power of a piano by
inclining the plane of the vibrating part of the strings with reference to the
plane of the sounding board, as the strings of a violin are inclined with
reférence to its sounding board. As this would tend to injure or destroy the
sounding board by excessive pressure if a common bridge were used, I use a
bridge in which the string or strings of one note shall be strained over the
bridge down towards the sounding board, the string or strings of another note
being held to the bridge, so as to be strained from the bridge upwards to
each end of sounding board, the wrest pins being arranged in accordance
therewith.