CERTAIN NEW METHODS OF CON-- STRUCTING HARPS, HARPSICHORDS, PIANO FORTES, VIOLINS, AND GUITARS, AND OTHER STRINGED MUSICAL INSTRUMENTS
Year: 1802

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
WOODS, of Barbican, in the City of London, Gentleman, send greeting...
WHEREAS His most Excellent Majesty King George the Third, by His
Letters Patent under the Great Seal of the United Kingdom of Great Britain
and Ireland, bearing date at Westminster, the Twenty-eighth day of June, in the
forty-third year of His reign, did give and grant unto me, the said George Woods,
my executors, administrators, and assigns, His special licence, full power, sole
privilege and authority, that I, the said George Woods, my executors, adminis-
trators, and assigns, during the term of years therein expressed, should and law-
fully might make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, my Invention of "CERTAIN NEW METHODS OF CON--
STRUCTING HARPS, HARPSICHORDS, PIANO FORTES, VIOLINS, AND GUITARS, AND OTHER
STRINGED MUSICAL INSTRUMENTS;" in which Letters Patent there is contained a
proviso obliging me, the said George Woods, under my hand and seal, to
cause a particular description of the nature of my said Invention, and the
the manner in which the same is to be performed, to be enrolled in His Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said in part recited Letters Patent, as in and by the same,
relation being thereunto had, may more fully and at large appear.
-13
NOW KNOW YE, that in compliance with the said proviso, I, the said
George Woods, do hereby declare, that my said Invention consists in fixing to
the strings at one or both ends pullies, beams, levers, or other mechanical
powers, in such a manner that one movement shall effect the whole or a
considerable number of the strings, altering the tension of the same; and that'
these tensions, as far as the friction and imperfection of-niachinery will allow;

page_text: shall be increased or decreased either equally or in geometrical proportions;
but it will generally happen that equal tensions for the whole instrument will
answer the purpose, and that such machinery will be much more easily made.
Before I proceed to describe the construction of any one instrument, I will
briefly explain the principle upon which my Invention is founded, and after-
wards the manner of adapting it. I do not know of any piece of mechanism
with so little friction, or so likely to answer the present purpose, as the beam,
or steelyard made as the scale beam, or in any way so that the three
knife edges, one at each end and the other generally in the centre, may touch
the same straight line and be parallel, that is, at right angles with the sides of
the beam. Should the edges be in the least out of line, there will be only one
situation in which the tensions at each end will be equal, and consequently the
machinery could not answer the required purpose, viz, that of preserving to all
the strings as nearly as possible a certain tension. I may here premise, that
when an instrument is in tune there are only three circumstances which can
possibly make it discordant, namely, alteration of length, of diameter, of
tension, and, independently of the last, I believe it will rarely or never happen
that the two first will occasion any difference of tone perceptible to the car.
The grand object, therefore, is to preserve exact equality of tension; and so long
as this can be preserved, the instrument will be in tune. It is, then, obvious,
that if the contrivances hereafter mentioned succeed in preserving or restoring
this exact equality of tension, an instrument when once properly in tune will
continue so without the necessity of continual recourse to a tuner.
:.
One of the simplest instruments on the new construction will be the
Eolian harp. Let the box or sounding board be made in the usual manner,
but rather wider and longer; and let there be, as usual, twelve or eight pegs
on which to wind the catgut at one end; at the other end is to be fixed the
machinery; and as short levers require much greater exactness of workman-
ship than long levers, it may be better not to make the whole length of the
beam, from knife edge to knife edge, less than three quarters of an inch.
Figure 1-is-a-plan-of-the-machinery-on-the-proposed scale. In the first course
are six beams pulling the twelve strings, all the knife edges being at equal
distances on their respective beams. In the next course are three beams, each
end of these pulling each middle of those in the former row, and all the knife
edges being at equal distances as before. In the next course is only one beau,
each end pulling the middle of a beam in the row before. In the last row is
only one beam, one end pulling the middle of that in the former row, and the
other end pulling the middle of the remaining beam (a) in the second row.
This last beam, having eight strings to pull at one end and only four at the

page_text: other, must not have its knife edge, in the centre, as in this case each of the
four strings would be stretched with double the tension of each of the eight;
but the distance between the edges at each end must be divided into three
equal parts, and the edge (6) placed at the distance of one part from the
edge (c). By this means, supposing the power at (d), the tension will be
equally distributed through the twelve strings; while all the tensions remain
dépendant on each other and detached from anything else, any laxity of one
string will be communicated to the rest. Suppose, for instance, the string at
(e) was to relax one fourth of an inch, the end of the beam at (f) would move
back nearly one eighth of an inch, the end of the beam at (9) would back
nearly one sixteenth of an inch, and the end of the beam at (c) would move
back nearly one thirty-second of an inch, an equal tension being still preserved
through all the strings. In order to make as little friction as possible, it will
be better to keep all the beams nearly at right angles with the strings; and
this situation, if lost, may be easily recovered by turning the pins at the
further end of the strings. The beams may be made of two thin pieces of
brass, with the knife edges between; and these may also answer the purpose
of rivets by fixing the sides parallel to one another; or the beams may be
one solid piece of brass, with the knife edges projecting on each side. The
steel of which the edges are made must be hard, and those of different beams
may be connected by a piece of steel wire; as at Figure 2, or a flat piece with
two holes, Figure 3. The first will be best for the connection between the
steel edges and the strings. The end (d), in Figure 1, may casily be fixed by
a bolt or screw, and the harp may be strengthened underneath. In making
choice of the catguts, care should be taken to get them as nearly as possible of
one thickness, and their diameters should be measured by a sector of the same
kind as those made use of to measure wires, but of greater length and accuracy,
and steel edges are to be preferred. By the sector which I make use of, I can
measure wires, if not very thick, to the bow part of an inch.
If catgut
twisted with wire be thought desirable, the proper size will be easily found by
a few trials of those of different thicknesses. The bridges may be variously
constructed, and perhaps the following method may be best :-Just before the
machinery fix one bridge of hard wood, or any suitable substance long enough
to support all the strings. This must be exactly on a level with the strings,
so that they may pass it with very little friction. From each end and from the
middle of this bridge must project one firmly fixed pin, with a screw at the top
passing through a piece of wood above, similar to the bridge below, the edges
meeting as in Figure 4. The edges must be so formed, that when pressed
together they may touch every string, and a thin smooth piece of leather glued

page_text: to one side may be found an advantage. On the screw of each pin must be a
nut, in order to press the two bridges together, and the manner of using
which will be presently explained. At the other end of the instrument
each string must have a bridge, with a notch at the middle to keep it
steady, hollowed a little underneath and made rough to prevent its slipping-;
brass may be the best material. Having given a proper tension. to..the
.whole, the strings must be brought into unison by varying their lengths,
moying each bridge separately by the fingers or a forceps; for, however
nice: the measurement of the diameter may be, it is not likely to be perfect.
During the operation of tuning, the upper bridge must not be screwed,
but only pressed with the hand against the other whenever the vibration
Jof. the string shall be tried. The instrument being tuned, screw the
bridges firmly together, and it. is ready for use. Whenever it shall be
out of tune separate the two bridges to .let. the strings and machinery play
freely again, fix the bridge, and the instrument, if accurately made, and if the
relaxation is not exceedingly great, will be again in tune.
Iu making a square piano forte, the chief object is to get the beams into a small
compass; and to accomplish this, I make use of four rows of beams, which I
will call one course, one above another, as represented in the elevation Figure 5,
being a Drawing on the exact scale. Figure 6, an elevation, shews the same
course again, being of the darkest tint, and their manner of communication with
the next course, being of the middle tint; and also the communication of this
latter course with the one still further from the strings, being the third course,
and.. of the lightest tint. The pieces of steel uniting the different courses
must be twisted to the required angle. The direction of the beams in the
different courses, as shewn in Figure 6, will readily shew what this angle
should be. After the twisted pieces of steel joining the third to the fourth
.course they will all be flat, and the beams will be placed in one plane, -as
represented in the plan, Figure 7, on the exact scale. The wires are to com-
municate with the first course by hooks,-Figure 2, as in the Æolian harp. The
machinery here represented is for a piano forte without the additional keys.
For one with the additional keys, the following-alterations-must-be-made-In
the first course must be eight more beams (suppose them put anywhere in
the middle, as the form of the ends will continue as they are, the regularity of
situation being still preserved throughout. In the second course will be four
more beans, the same situation as at present, both in the middle and at the
end, being kept! In the third course will be two beams more, and in the fourth
one, still keeping the present order. This beam we will now suppose to be
the right-hand beam, as at (a) Figure 8, which is to communicate with the

page_text: last beam of all, being one behind the beam (6) in Figure 7. To preserve an
equal tension the lever (b, c;) must be eight times the length of the lever (d, c,)
in Figure 8. It is evident that if the wires from the hooks were all parallel the
hammers could not strike them, they must therefore cross, as in the elevation
Figure 9, and there will be a straight line at (a) throughout the whole of the
strings, and at this place the hammers may strike, being at much the usual
distance from the bridge. Between one wire and it's unison at the machinery
end is one fourth of an inch, but, at the other end the distance must not
exceed one eighth. The right hand of the instrument must be made strong,
as the whole of the tension will be concentrated into.one part, where the piece
of steel communcating with the last beam is to be fixed. The manner of
fixing it is immaterial if it be perfectly firm, perhaps it will be better to have
the iron turn partly round the wood, as in Figure 10. If the addition be
thought worth the expence, this end, instead of being fixed, may communicate
with a mechanical apparatus (joined to the instrument) in such a manner that
by turning a handle this end shall be drawn backwards. The object of this'
addition would be to increase or decrease the tension of the whole instrument
with greater facility. The machinery must be over the sounding board, with-
out touching it, and just beyond is to be the bridge, about an inch wide. At
about the middle of the bridge cach wire is to have fixed to it a round piece
of brass, of the form Figure 11, about one eighth of an inch thick, and one
quarter or three cighths long. A slit must be cut, of a proper size, for inserting
the wire at the centre, and not only the two sides pressed together, but, in:
order to keep the wire firm, the two ends must be bent a little out of the right:
line, as in Figure 12, and this operation may be easily effected by a pair of
pincers cut at the end, as in Figure 13. The bridge consists of one straight
piece of wood fixed to the sounding board, of two end pieces, and of a top, all
firmly united, the space between top and bottom being about an inch and
three eighths. At the side of the bridge farthest from the machinery are:
several oblique bars of wood, where vacancies are made by the wires, in order
to prevent the slipping through of the pieces of wood within. In the inner
part are eight pieces of wood, metal, or other substance, of the length of the
internal part, and one inch wide, being one-tenth of an inch thick at one side,
and tapering to a feather edge at the other. Figure 14 is a transverse section.
The lines represent the strings, and the marks (<) shew those parts where
wedges of the whole length are to be inserted, these wedges will much
resemble the other pieces of wood. On forcing in the wedges the strings will
be firm, and on withdrawing them the strings will again have free play.
These wedges in the piano forte are to be used on the same occasion as the
nuts on the screws of the Eolian harp. The direction in which the wires pass
1

page_text: the bridge, being part of the longitudinal elevation, is represented in
Figure 15, and also in Figure 24. Figure 24 is an elevation of the bridge,
with a section of the wires passing through it, and also shewing the situation
and manner of fixing oblique bars of wood before mentioned. These wires,
in number and situation, are such as will be used for an instrument with the
additional keys, and if the previous description of such instrument should not
be sufficiently clear, this Figure will tend to elucidate it. An instrument with
one hundred and forty-four strings (seventy-two notes) will have the lowest
note on the bass #C, and the highest note in the treble C. At the back
of the instrument are pins, on which to wind the wires in the manner of
those made by Broadwood. By these the tension is to be increased or
decreased, and the beams brought to their proper situation. Before these
pins is a bridge about two inches wide at the bass end, and one inch at the
other; and it may be so formed that the first three octaves, besides the strings
for the additional keys, may be made of wire of one thickness. My calculation
for the thickness of strings will commence at thirty-two inches in length, and
the furthermost string in the bass I propose to be about fifty-six inches. The
above-mentioned bridge is to be grooved in such a manner that the bottom of
every groove is to be parallel to the wires passing over it; hence, there will be
one groove for every two strings (unisons), excepting for two notes at each
end, where there must be a groove for each string. The wires would touch
the bridge the whole distance, were it not for a piece of brass with a hole
through, of any other regular shape than round, one quarter of an inch long,
and one eighth thick at each end. The ends must be made sharp, so that
when once placed they cannot move. Figure 16 is a section, the wire will
touch only at the middle. These pieces of brass had better first of all be
- turned, and afterwards hollowed at one part, as a round form would not keep
them sufficiently steady. One of these being put on each wire over the bridge,
and the thickness of the wires being properly regulated agreeably to the in-
structions presently to be given, the instrument must be tuned; for however
nice the calculations and experiments may be, they probably will not be perfect.
To-effect this operation, the wedges of the bridge on the right hand must be
put in no firmer than to make the vibration stop at the brass sufficiently--to-
ascertain the note. It will, perhaps, be better occasionally to remove them,
in order to let the strings move freely. A tension sufficiently great to render
the notes distinct being given, the strings are to be tuned by lengths, as in
the Eolian harp, by moving backwards or forwards the little brass bridges.
The strings being tuned, their tension may be increased, and a pin, staple, or
screw is to be fixed behind every brass bridge, pressing the wire to the bottom
of the groove, thereby making the angle of the wire in passing over the

page_text: bridge less obtuse. The wedges are now to be driven tight, and the instru
ment is ready for use. The angle which the wires make with the back of
the instrument may be much the same as usual. In case I should make any
mistake in the following calculation, I refer to "Emmerson's Miscellanies,
London, 1776, page 361, where d being the diameter, the length, t the
tension, v the relative number of vibrations Av, and d being the letter
wanted, I reduce the equation thus v=1; '=vd; 'v=d. The vibrations
decrease geometrically towards the bass, see page 383, Emmerson. We may
denominate C in treble, at which note by calculation begins, 100,000, this
wire and all above being of one size; and we call it's length thirty-two
inches, the strings of each note increasing three quarters of an inch in
length. The requisite vibrations will therefore be as follows:-100,000 C,
in treble; 94,387 B; 89,090 #A; 84,090 A; 79,370 G; 74,915 G;
70,711 F; 66,742 F; 62,996 E; 59,460 #D; 56,123 D; 52,973 #C;
50,000 C, lowest in treble. These numbers ascertain the quantity of
vibrations in each note, and the questions are solved by the aforesaid equation.
In stringing the treble of the instrument the length of the strings will be
exactly in an inverse proportion, that is, supposing the length of the wire
sounding the lowest C in treble 100,000, the length of the octave above must
be 50,000, C will take the place of .B, as mentioned above 94,387, and
D, the place of A, 89,090, proceeding in the same manner through the
gamut. In all instruments where the strings have the same length and
tension, as in the violin, guitar, and some others, the diameters will increase
exactly in the same proportion as the lengths did in the former instance when
the diameters and the tensions were the same. The proportionate diameters
of the wires will therefore be, for the piano forte, as follows:-
11 0150

page_text: By repeated experiments with the sector of wire of different numbers and
of different manufacturers, all these sizes will probably be found sufficiently
accurate, but should this not be the case, wire must be made accordingly.
Whenever a wire breaks, care should be taken to put on another of a similar
size. The wire here mentioned is all plain, and the requisite size of twisted
wire when used must be ascertained by experiments. The whole of it also
is supposed to be steel. In order to find the relative vibration between strings
of steel and of brass, make this experiment:-Take one wire of each of similar
diameters, and extend them with equal tensions; render them unisons, by
regulating the length; call the length as before; then say, as of steel wire
1 of brass wired of steel wire, as by preceding calculation; d of brass wire
sought. In the same manner may be tried the relative vibrations of strings of
any different. materials. In harpsichords and grand piano fortes the wires
must not any of them be vertical to each other, as in Figure (15), but may be
arranged as in Figure 17. The machinery will be between the keys and the
wires, consequently the wires cannot make one straight line where the
hammers strike as in the square piano forte. Great strength is always requisite
in that part where all the tensions are concentrated. In harpsichords the
jacks must be of different lengths, proportionate to the distance of the wire
from that part of the keys in the inside of the instrument; and in grand
piano fortes it will be better to have four unisons instead of three, and the
hammers will be in the shape of (a), Figure 17. The general construction
will be very similar to that of the square piano forte; should the beams occupy
too much room they may be a little shortened. In the. harpsichords with
additional keys, must be 224 strings, pulled in the first case as described in the
square piano forte, but afterwards in three united, as in Figure 18, all the
tensions being equal. In the grand piano forte with additional keys, will be
228 strings with beams arranged as in Figure 19, all the tensions being equal.
I scarcely know the best construction for the pedal harp, and none that
can be used without diminishing the elegance of it's form. The following
will answer the purpose: The upper part of the instrument may be made as
usual, but the-sounding-board-or box, instead of projecting at the bottom,
must project at one side, and the strings must pass over it in a parallel
direction, as represented in Figure (20). a, b, c, d, e, represents the sounding
board, and the place where the strings are united to the board may be on the
line f, g, the calculations and experiments being made with greatest accuracy,
and the machinery being behind, as in other cases, the strings may be all in one
plane, the levers being short and accurately made. In order to take up less
room the levers may be placed as in Figure 20. The machinery may have a

page_text: These calculations are
give nic
the relative (Hameters.
The
catguts of a proper size are to be sought after in the same manner as the wires
before mentioned, having previously been stretched with a tension greater
than the instrument requires. Each string must have a bridge somewhat
similar that of the Eolian harp; this bridge must be so contrived at the
bottom that by pressure it may firmly fix into the sounding board by means of
one or more points or edges. Each bridge must have a top; this top may be
attached to the lower part by a pin on which to move up and down as at
Figure 22. Between these two parts will pass the string, and for the larger
ones the bridges may be notched. The strings are to pass over without
pressure, and are to be tuned by the placing of the bridges, as in other
instruments. These bridges, however, must never be moved so much out of
the straight line as to make any perceptible discordance of sound when the
pedal shall be used; and whenever a string cannot be tuned without so doing,
another of a proper size must be placed in its stead. If strings of a proper
_size_cannot be easily procured, they must be made on purpose. Above these
bridges is to be one piece of wood of sufficient length and breadth to cover the
whole number. Several pins from the sounding board, with screws at the top,
are to pass through, and the instrument being tuned, this board is to be firmly
screwed down by means of nuts at the top. Great care must be taken to let
it press equally against all the bridges, and this being the case all the strings
will be firm and the instrument ready for use. The upper board is to be
loosened when any of the strings are out of tune, and, if necessary, the upper

page_text: part of each bridge slightly raised, and, the strings having had free play, it is
to be again pressed down.
In making violins, violencellos, guitars, and other instruments where the
notes are produced by stopping the strings at certain lengths, the greatest
nicety of workmanship and accuracy of measurement are requisite. In
other cases we calculated by diameters and tuned by lengths, but in the
present instances, the lengths and tensions are invariable; we must there-
fore ascertain the diameters with the greatest accuracy, the strings being
previously stretched with a greater tension than the instrument requires, and
by repeated experiments we shall find that strings which, with a given length
and tension, will produce a certain note. The calculations respecting their
relative thickness may be made as before directed. The diameters of the
strings of the violin and violencello will be in the following proportions:-
18,729, 28,061, 42,045, 62,986; and the proper size of silver-wired catgut, if
used, must be ascertained by experiments. In the common guitar of ten
strings, we will suppose the wires of the same material; and if tuned to the
following notes, the numbers against each will show their relative diameters:-

page_text: In order to fix the same more easily, the end may turn up a little instead of
down. The manner of fixing that part in which the tensions are united is not
material, but friction is always to be avoided as much as possible. Before the
beams is to be placed a bridge similar to that in the Eolian harp. At the
other end of the instrument, the strings, having passed the bridge as usual, are
to be wound upon pins, or pegs. The end of the instrument being made strong,
they may be fixed near that place where in the violin there is generally a
nob to support the conjoined tensions. These are used to increase the
tension of the strings, and to regulate the position of the beams. It may be
adviseable to have the machinery moveable, by means of a string communi-
cating to that piece of steel on which the last beam is suspended, to be wound
on an axis in a similar manner to that of altering the tensions of the strings
on the double bass on the present construction. The object is to vary the
tensions with greater facility than could be done by turning the pegs at the
other end. Figure 23 represents the plan of the beams for 2; 3, 4; 8 and 10
strings respectively.
I have thus endeavoured to shew as clearly as possible the methods of
adapting my principle to various instruments. The application is so perfectly
new and in some few parts apparently so complex-(though in itself simple)
that I am afraid it will occasion .considerable time- and trouble even to one
conversant in the business before he will be able -in every respect to com-
prehend my description. The science of mathematics is one of which so
many are ignorant that I would gladly have excluded every part of it from
this Specification, but I found the introduction unavoidable. Many of the
calculations will be troublesome, but I have explained them as well as I could,
and have also made references, by attending to which the reader, if inclined,
may easily learn more upon the subject. In most questions respecting

page_text: vibrations, and particularly where the tensions varies, logarithms will be found
of great assistance.-Note. Such parts of instruments as are to be made upon
the usual construction, I have generally passed over in silence.
In witness whereof, the said George Woods, have hereunto set my
hand and seal, this Twenty-eighth day of December, in the year of
Our Lord One thousand eight hundred and three