A CERTAIN IMPROVEMENT IN PIANOFORTES
Year: 1820

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JAMES
THOM, of Wells Street, in the Parish of Saint Marylebone, Pianoforte Maker,
and WILLIAM ALLEN, of Castle Street, in the same Parish, Pianoforte Maker,
send greeting.
WHEREAS His late most Excellent King George the Third did, by His
Letters Patent under the Great Seal of that part of the United Kingdom of
Great Britain and'Ireland called England, bearing date at Westminster, the
Fifteenth day of January, in the sixtieth year of His reign; give and grant
unto us, the said James Thom and William Allen, our exors, admors, and
assigns; His special licence, full power, sole privilege and authority, that we,
the said James Thom and William Allen, our exors, admors, and assigns,
should and lawfully might, during the term of years therein mentioned, use,
exercise, and vend, within England, Wales, and the 'Town of Berwick-upon-
Tweed, and also in His said Majesty's Colonies and Plantations abroad, our
Invention of "A CERTAIN IMPROVEMENT IN PIANOFORTES;" in which said Letters
Patent there is contained a proviso obliging us, the said James Thom and
William Allen, by an instrument in writing under our hands and seals, to
cause a particular description of the nature of our said Invention, and in what
manner the same is to be performed, to be inrolled in His Majesty's High
Court of Chancery within two calendar months after the date of the said
recited Letters Patent, as in and by the same, relation being thereunto had,
may more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso; we, the said
James Thom and William Allen, do hereby declare that the nature of our

page_text: said Invention, and the manner in which the same is to be performed, are
particularly described and ascertained in and by the Drawing hereunto
annexed and the following description thereof (that is to say :)-
The object of our said Invention is to lessen the tendency of pianofortes to
get out of tune from the swelling and contracting of the wood, they are com-
posed of, occasioned by the moisture or dryness of the atmosphere or other
causes acting upon the wire strings, as well as from the effects of heat and
cold upon the said strings; and the manner in which we intend to carry this
Invention into effect is, by taking the strain of the wire strings off the wooden
frames of the instruments to which they are affixed at only one end thereof,
and keeping them stretched by means of brass and iron wires, rods, plates,
bars, or tubes properly applied to their other ends, so that the strings will be
but little affected in their tension by moisture or dryness, heat or cold; and
we hereby claim every mode by which this Intention may be carried into
effect. It will, however, be necessary to give an example of at least one of
the methods by which, we propose to accomplish this desirable object, by the
aid of the Drawing annexed as aforesaid to this Specification, in which
Drawing Fig. 1 is a plan of an horizontal grand pianoforte with the cover
taken off, and without the keys and other movements which need not there be
shewn; Fig. 2 is a section and side view of the same, with the side of the
instrument removed, in order to exhibit the different parts; and Fig. 3 is a
section at the dotted line A, A, in Fig. 1, the same letters referring to the
same parts in all the Figures. B, B, is the block to which the strings are
affixed at one of their ends by the wrest pins C, C, as usual; D, D, is an
iron bar resting at each end in gaps made in the two iron plates E, E, which
are firmly secured to the sides of the frame of the instrument, and supported
besides in other gaps made in the iron arches or brackets F, F, &c., which are
firmly secured to the block B, B. One side or edge of the bar D, D, is made
angular to fit into gaps or notches made in one end of each of the brass tubes
G, G, &c. and of the iron tubes H, H, &c., in order to steady and support
those tubes resting or abutting against the said bar. These tubes G, G, &c.
and H, H, &c. pass through holes made in the wooden bars or stays I, I,' &c.,
which are firmly secured at each end to the sides of the frame of the instru-
ment, and thereby support the tubes, and prevent them from being bent from
the strain of the strings upon them. The other ends of the tubes lodge or
rest upon short iron cylindrical studs entering into them, and which studs are
firmly united to the iron brackets or arms J, J, &c., which are likewise
securely fixed upon the iron or other fit and proper metal plates or bars K
and L, which plates or bars are moveable, according to the expansion or con

page_text: traction of the tubes, they merely resting or lying upon the belly or sounding
board M, M, &c. of the instrument. The iron or metal plate K has the other
ends of all the brass wires or strings affixed to it by means of the studs N, N
and the other plate L receives those of the iron wires or strings by means of
similar studs 0, 0, upon it, and thus the brass strings are kept stretched or
extended by the brass tubes G, G, &c., and the iron ones by the iron tubes
H, H, &c., each wire by a tube of similar metal to itself, and thereby are
nearly equally affected with the tubes by any change of temperature from hot
to cold, or the contrary, and are little liable to be affected by moisture or dry-
ness, as they are only connected with the sounding board M, M, &c. by
means of the bridges P, P, and Q, Q, and the studs and pins which are fixed
into or upon them, as usual. The same contrivance is equally applicable to
small horizontal pianofortes, as well as to upright grand and cabinet piano-
fortes, harmonics, &c. under proper modifications thereof and changes in the
construction of the movements of the different instruments.
In witness whercof, we, the said James Thom and William Allen, have
hereunto set our hands and seals, this Fifteenth day of March, One
thousand eight hundred and twenty.