AN IMPROVEMENT ON PIANOFORTES AND CERTAIN OTHER STRINGED INSTRUMENTS
Year: 1820

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
WORNUM, of Wigmore Street, Cavendish Square, in the County of Middlesex,
Pianoforte Maker, send greeting.
WHEREAS His most Excellent Majesty King George the Fourth did, by His
Letters Patent under the Great Seal of the United Kingdom of Great Britain
and Ireland called England, bearing date at Westminster, the Thirteenth day
of May, in the first year of His reign, give and grant unto me, the said Robert
Wornum, my exors, admors, and assigns, His especial licence, full power, sole
privilege and authority, that I, the said Robert Wornum, my exors, admors,
and assigns, during the term of years therein mentioned, should and lawfully
might make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, my Invention of "AN IMPROVEMENT ON PIANOFORTES
AND CERTAIN OTHER STRINGED INSTRUMENTS;" in which said Letters Patent
there is contained a proviso that if I, the said Robert Wornum, shall not
particularly describe and ascertain the nature of my said Invention, and in
what manner the same is to be performed, by an instrument in writing under
my hand and seal, and cause the same to be inrolled in His Majesty's High
Court of Chancery within two calendar months next and immediately after
the date of the said Letters Patent, that then the said Letters Patent, and all
liberties and advantages whatsoever thereby granted, shall utterly cease,
determine, and become void, as in and by the same, relation being thereunto
had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Robert Wornum, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed; are particularly described
and ascertained in the following description thereof (that is to say):
As the object of Specifications is to enable others to produce or manufacture
the Invention after the expiration of the term for which a Patent is granted
to the Inventor, I shall here confine myself entirely to that view of their use
or intention; and I do declare that the following directions are fully sufficient
to enable any person warranted in undertaking such an enquiry to produce or
manufacture an instrument upon the above principle. Take, for example, a
cabinet pianoforte, and determine what length you will give to your longest
plain string; then set off that length on a monochord, and after having fixed
what size the string shall be, and the tightness that you wish it to bear (for
these are points only at the discretion, approbation, or experience of the
manufacturer), strain a string accordingly on the monochord, and see what note
it is unison with on a well-tuned pianoforte. This note being determined, you
must sound the next above on the pianoforte, and move the shifting bridge of
the monochord until you have brought it into unison, and so proceed until
you have ascertained and marked all the notes of one octave. You then
transcribe those marks on a rod, and for all the corresponding notes that you
want upwards you must halve the several lengths until you have produced
another octave, and so on for as many octaves as you require, always halfing
from the last octave. For the covered strings you must adopt another
method. First, fix on the length of your longest covered string, and draw a
line from that to your longest plain string, and thus you will have the several
lengths of your covered strings; you must then ascertain what weight will
bring your longest plain string to its proper pitch, and with this weight you
must try all your covered strings (that is), you must increase or decrease the
size of your covering wire until that weight brings each note at its given
length to its proper pitch. A few of the first will necessarily be open spun, but
take up close spinning as soon as possible, which of course will depend entirely
on the fineness of the covering wire. The scale thus produced must be strung
with one size of steel wire throughout; it may be varied in different instru-
ments, but not in the same, as two sizes of wire would instantly destroy the
equality of the tension.
In witness whereof, I, the said Robert Wornum, have hereunto set my
hand and seal, this Eleventh day of July, in the year of our Lord One
thousand eight hundred and twenty.
ROBERT (L.s.) WORNUM..

page_text: AND BE IT REMEMBERED, that on the Eleventh day of July, in the
year of our Lord 1820, the aforesaid Robert Wornum came before our said
Lord the King in His Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained and specified, in form above
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.
Inrolled the Eleventh day of July, in the year of our Lord One thousand
eight hundred and twenty.