CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF WATCHES AND CHRONOMETERS
Year: 1808

page_text: MATHEW'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, DANIEL
DERING MATHEW, of Upper Marylebone Street, in the Parish of Saint Mary-
lebone, in the County of Middlesex, Esquire, sends greeting.
WHEREAS the said Daniel Dering Mathew did, by his Petition, humbly
represent unto His present most Excellent Majesty King George the Third, that
he had, after much study, labour, and expence, found out and invented "CERTAIN
IMPROVEMENTS IN THE CONSTRUCTION OF WATCHES AND CHRONOMETERS;" he there-
fore most humbly prayed His said Majesty that he would be graciously pleased
to grant unto him, his executors, administrators, and assigns, by His Majesty's
Royal Letters Patent under the Great Seal of Great Britain, the sole use,
benefit, and advantage of his said Invention, within that part of Great Britain
called England, His Dominion of Wales, and Town of Berwick-upon-Tweed,
for the term of fourteen years, according to the Statute in that case made and
provided; and His said Majesty, being willing to give encouragement to all
arts and inventions which might be for the public good, was graciously pleased
to condescend to his request, and therefore, by His Royal Letters Patent,
bearing date at Westminster, the Twenty-seventh day of April, in the forty-

page_text: eighth year of His reign, of His special grace, certain knowledge, and meer
motion, for Himself, His heirs, and successors, did give and grant unto the said
Daniel Dering Mathew, his executors, administrators, and assigns, His special
licence, full power, sole privilege and authority, that he, the said Daniel Dering
Mathew, his executors, administrators, and assigns, and every of them, by
himself and themselves, or by his and their deputy or deputies, servants or agents,
or such others as he, the said Daniel Dering Mathew, his executors, administra-
tors, or assigns, shall at any time agree with, and no others, from time to time
and at all times hereafter during the term of years therein expressed, should
and lawfully might make, use, exercise, and vend his said Invention within
that part of His said Majesty's United Kingdom of Great Britain and Ireland
called England, His Dominion of Wales, and Town of Berwick-upon-Tweed,
in such manner as to him, the said Daniel Dering Mathew, his executors,
administrators, and assigns, or any of them, should in his or their discretion
scem meet; and that he, the said Daniel Dering Mathew, his executors,
administrators, and assigns, should and lawfully might have and enjoy the
whole profit, benefit, commodity, and advantage from time to time coming,
growing, accruing, and arising by reason of the said Invention, for and during
the term of years therein mentioned, to have, hold, exercise, and enjoy the said
licence, powers, privileges, and advantages therein-before granted or men-
tioned to be granted unto the said Daniel Dering Mathew, his executors,
administrators, and assigns, for and during and unto the full end and term of
fourteen years from the date of the said Letters Patent next and immediately
ensuing, and fully to be compleat and ended, according to the Statute in such
case made and provided; in which said Letters Patent is contained a proviso
that if the said Daniel Dering Mathew should not particularly describe and
ascertain the nature of his said Invention, and in what manner the same is to
be performed, by an instrument in writing under his hand and seal, and causo
the same to be inrolled in His said Majesty's High Court of Chancery within
one calendar month 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, should utterly cease, determine, and become void,
anything therein-before contained to the contrary thereof in anywise notwith-
standing, as in and by the said Letters Patent, reference being thereunto
had, may more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Daniel Dering Mathew, doth hereby particularly describo and ascertain the
nature of my said Invention, and in what manner the same is to be performed

page_text: (that is to say), I 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 as follows (that is to say):-
In the Drawings hereunto annexed Fig. 1 represents, in the manner of a
plan, those parts of the structure of a chronometer which are more imme-
diately employed in maintaining the vibrations of the balance, and are dis-
tinguished by the name of the scapement or escapement. The letters a, A,
b, B, c, C, d, D, e, E, F, F, indicate the teeth of two wheels, equal and similar
in all respects, which are fixed upon the last arbor of the train, and the dark-
shaded teeth, marked by small letters, belong to one of the said wheels, and
the light-shaded or outlinė teeth, marked by capital letters, belong to the other
of the said wheels, and are so placed that in the order of rotation the points or
extremities of the teeth of one wheel do respectively stand in or near the
middle of the interval between the points or extremities of the teeth of the
other wheel, and the number and figure of the teeth to be made in the said
equal and similar wheels may be such as the constructor shall think proper,
according to the number of beats he may be desirous of producing in any
given portion of time, and the nature of the material out of which he may
think fit to make the wheels; or otherwise a single wheel may be used
instead of two, and the teeth be made to stand contrate, in the form of pins, or
of any other suitable form, as in Fig. 2; or otherwise (but not by preference)
a single wheel may may be used. G and H are the working extremities
of two pallets, of which the lovers or arms terminate in distinct or separate
axes or centers of motion; but the said axes are nevertheless so disposed as
to cause the motion of the said arms to be concentric with each other and
with the balance itself, or, in other words, the pallets and the balance do each
move in different planes upon one and the same imaginary line or vertical
axis. N, N, is the potence or piece by which the pallets and the balance are
supported. K and L represent back springs, which urge the pallets towards
the wheels (the said pallets being so placed in the potence that one pallet shall
apply itself to one wheel and the other pallet to the other wheel respectively,
or to the opposite sides and faces of a single wheel, if adopted in preference
to two wheels, as herein-before described), and to each lever there is opposed a
stop, which prevents the pallet thereunto belonging from advancing so far
as to touch the rim of its correspondent wheel, and the said back springs may
be respectively adjusted, with regard to their strength and action, upon the
said levers, by means of a screw applied to each, or by setting or bending, or
by taking down the thickness thereof, as is well known to artists, and may, by

page_text: their action upon the balance, altogether supply the place and office of the
spring usually called the pendulum spring. And for the better obtaining and
effecting this and other desirable purposes, a compensation for heat and cold
may be applied in any of the usual methods unto the said springs, in case the
same shall bo preferred to a compensation on the balance itself, and the
strength and action of the said springs may be regulated and rendered more
equable in the several angular positions of the levers by the interposition or
use of a part or piece equivalent to the tumbler in a gun lock, or to the
jointed connection between the main spring and a lever from the axis of the
cock, as is sometimes done in the same instrument, both which, as is well
known, do alter the action of the said main spring, and might, by a due pro-
portion of the parts, be applied (if needful) to equalize the same; and I do so
proportion and apply the said contrivances in some of my said improvements.
And I do make the face of each of my pallets to consist of an inclined plane,
as seen in Fig. 1, or more distinctly at r, t, in Fig. 5, ending at t in a claw
or detent, against which in the detent H, Fig. 1, the tooth d is seen to rest,
and to prevent the wheel from running down. And the said inclined planes are
made to proceed inwards from the levers towards the wheels or wheel in the
same direction as the said wheels or wheel when at liberty do move; and in
order to insure the locking of the teeth upon the claw or detent, so as to pre-
vent the possibility of any trip or disengagement of the wheel at any improper
time, I do, when thought needful, make use of a banking pin, fixed to the
arm of the inclined pallet, as seen in Fig. 6, at 9, which keeps the pallet from
going farther back than is necessary, to allow the tooth to raise up the pallet
to its detent, by means of the catch p, the end or joint of which is a very.
slender spring, And I do make or form a circular part, standing out from
the level of the said catch, against which part the crank of the balance first
acts, so as to remove the said catch out of the way of the banking pin, until
it has knocked out the detent, and set the wheel at liberty. And, lastly, I
do make the verge or axis of my balance in the form of a crank, as in Fig. 4,
in order that the vibration upon its pivots, concentric with the axes of the
levers of the pallets, may be performed without any other interruption or
action than is intended to be produced by the pallets themselves; and I do so
place my balance that the arm or extreme branch of the said crank shall lie
or be disposed between the levers of the said pallets, as at M. And the
action of the said escapement, as, delineated in Fig. 1, is as follows:-The
wheels being urged by the maintaining power to move in the direction marked
by the small arrow at V, are prevented from revolving by the detent of one of

page_text: the pallets, (for example H,) which holds against one of the teeth, (for example
d.) but as soon as the balance is by external motion made to vibrate, and its
crank M comes to drive back and displace the lever and pallet (H), the wheels
become disengaged, and move together, in consequence of which the tooth (E),
nearest the opposite pallet (G), runs along the inclined plane of that pallet, and
raises the same until its detent, being. opposed to the tooth, again stops the
rotation. But during this process the balance will have carried the other
pallet H along with it in its semi-vibration on the opposite side, and will be
followed by the same pallet in its return through a longer are than was
employed in the divergence of the said pallet from the line of quiescence,
because the said pallet will not in its said return be stopped upon the extre-
mity of a tooth, but will proceed into the space between the teeth (d and c)
until it nearly touches the rim of the wheel (being prevented from actual con-
tact by its stop), and as soon as the balance returns to perform its semi-vibra-
tion on the side of the pallet (G) last raised up by its wheel, it will carry
away the pallet, and in like manner disengage the wheels, by the rotation of
which the other pallet (H) will be again raised and the alternations will be
repeated without limit so long as the motion of the wheels is kept up, because
the reaction of the back springs K and L will be greater in the return of the
balance to its first position than in the other parts of cach vibration. And
I do further declare that my said improvements are capable of being
varied, disposed, and applied in and to the construction of watches and chro-
nometers in several different manners, which will readily and. without farther
instruction be deduced from the preceding descriptions and Drawings by any
workman of competent skill in works of this or the like nature, and in par-
ticular that the pallets may be both placed on the same side of the wheels
or wheel, and the balance may raise them and receive their maintaining
reaction by means of pallets proceeding from a straight verge, as is shewn in
Fig. 3, where the same letters denote the same things as in Fig. 1, excepting
that the letter M shews the pallets of the verge, which in this case is not con-
centric with the axes of the levers, and upon that and other accounts I do
not consider it as being intitled to preference. And farther, that the same
materials, workmanship, compensations for temperature in the balance or else-
where, and other expedients and contrivances for insuring the durability and
truth of performance, as are well known and used and applied in the best
chronometers of other constructions, may be also be used and applied with and
to chronometers in which my said improvements herein-before set forth and
explained shall or may be adopted and introduced, provided that attention be
paid to the nature and intention thereof. And I do further declare, that I do

page_text: improve watches and chronometers by stopping the holes with platina instead
of using hard brass or jewelling in movements, or the parts thereof wherein
my said improvement of stopping with platina may be preferred or required.
In witness whereof, I, the said Daniel Dering Mathew, have hereunto
set my hand and scal, this Seventeenth day of May, in the forty-eighth
year of the reign of our Sovereign Lord George the Third, by the
grace of God of the United Kingdom of Great Britain and Ireland
King, Defender of the Faith, and in the year of our Lord One thousand
eight hundred and eight.
Inrolled the Twenty-first day of May, in the year above written.