AN IMPROVEMENT OR IMPROVEMENTS IN CHRONOMETERS
Year: 1840

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
MOLYNEUX, of Southampton Row, in the County of Middlesex, Chronometer
Maker, send greeting.
WHEREAS Her present Majesty Queen Victoria, by Her Letters Patent
under the Great Seal of the United Kingdom of Great Britain and Ireland,
bearing date at Westminster, the Seventh day of March now last past, did
give and grant unto me, the said Robert Molyneux, Her especial licence, full
power, sole privilege and authority, that I, the said Robert Molyneux, my
executors, administrators, and assigns, or such others as I, the said Robert
Molyneux, my executors, administrators, or assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term of years therein expressed, should and lawfully might make, use, exercise,
and vend, within England, Wales, and the Town of Berwick-upon-Tweed,
my Invention of "AN IMPROVEMENT OR IMPROVEMENTS IN CHRONOMETERS;" in
which said Letters Patent there is contained a proviso obliging me, the said
Robert Molyneux, by an instrument in writing under my hand and seal,
particularly to describe and ascertain the nature of my said Invention, and
in what manner the same is to be performed, and to cause the same to be
inrolled in Her said Majesty's High Court of Chancery, within six calendar
months next and immediately after the date of the said Letters Patent,
as in and by the same, reference 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 Molyneux, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, is particularly described and
ascertained as follows, and by the Drawings hereunto annexed (in all of which
said Drawings or Figures similar parts are marked with similar letters):
My Invention consists of a certain improvement or improvements in that
part of a chronometer usually known by the name of the balance, by means of
which I am enabled to obtain a much more complete compensation for the
expansion and contraction of the balance spring in various changes of tem-
perature than has hitherto been obtained; and the manner in which I can
effect this purpose will more fully appear by the following description and
Drawing annexed:-Figures 1 and 2 represent two views of a compensation
balance, made in the usual manner, to which is attached one modification of
my Invention of a Certain Improvement or Improvements in Chronometers,
in which a, a, are the weights; b, b, the timing screws; c, c, the arm, and
d, d, the rim or lamina, composed in the usual manner of brass and steel, or
other fit and proper metals. To this balance I attach two supplementary com-
pensation pieces e, f, and e, f, each attached (in this my first modification) to
the inner side of the balance rim d, d, by means of a screw at the end f, the
other end e being free and furnished with a regulating screw g. In the
balance rim is screwed an adjusting screw h, the point of which acts against
'each supplementary piece e, f, by which the free ends of such pieces are
brought nearer or further from the centre of the balance, as may be required.
The action of this modification is as follows:-Having in the usual manner
compensated the balance, so that its vibrations shall be equal at the tempera-
ture of 30° degrees and 55° degrees Fahrenheit, it will be found that if it be
raised to higher temperatures, such balance will vibrate so that the chrono-
meter will decrease its rate or lose its time; but, by my Invention, I am
enabled to compensate for this loss in the following way:-In Figure 1
the balance, with its supplementary compensating pieces, is shewn in the
position it assumes at the temperature of 55° degrees, its rim being then
considered circular, and the middle projecting portions of the supplementary
compensating pieces banked in contact with the inside of the balance rim. Now
if the temperature be raised, the balance rim, with the supplementary com-
pensating pieces, will come into the position shewn in Figure 2, in which, from s
the increase of heat, the balance rim has ceased to be circular, its free ends, to
which the adjusting screws h, h, are attached, having approached nearer the
centre of the balance, and with them carried the free ends e, e, of the supple-
mentary compensating pieces, so that their middle projecting portions no longer

page_text: bank, or are in contact with the inner side of the balance rim; and thus by a
proper adjustment of the length, position, and weight, of the supplementary
compensating picces, I am enabled to compensate for temperatures above that
at which the balance has been adjusted, while the adjustment for temperatures
of 30° and 55 degrees, to which the balance had been before adjusted, remains
unimpaired.
My second modification is a supplementary compensation for lower tem-
peratures than that to which the balance has been adjusted in the usual
manner, namely, 55 degrees and 80 degrees, an example thereof being
shewn in the Drawing, Figures 3 and 4, in which the supplementary compen-
sating pieces e, f, and e, f, are attached to the free ends of the balance rim d, d,
and their middle projecting portions banking or being in contact with such
free ends when at or above the temperature of 55 degrees, as represented in
Figure 3; while for temperatures below that heat, the free ends of the balance
rim having receded from the centre, has left the middle and free portions
of the supplementary compensating pieces, which therefore counteract the
decrease of rate or loss of time which otherwise would have taken place,
while the adjustment for temperatures of 55 degrees and 80 degrees, to which
the balance had been before adjusted, remain unimpaired.
A third modification of my Invention is represented in Figure 5, in
which I obtain a supplementary compensation to the balance, independent
of the action of the balance rim as an auxiliary thereto. To the arm C, C, I
attach the outer arcs of metal i, j, and i, j, by the screws K and K; to the ends
i and i of these arcs are attached two compound ares l, m, and l, m (made of
brass and steel, or other fit and proper metals similar to those composing the
balance rim), by the screws 7 and 1, in such a manner that their opposite
extremities m and m shall be free. To these free ends I fit regulating
screws n and n, and in the outer arcs are adjusting screws o and o, the points of
which act against the free ends of the compound arcs. In this modification the
balance is adjusted for high temperatures similar to the modification shewn at
Figures 1 and 2, the action of the free compound arcs being independant of the
rim, and effecting the same purpose as the supplementary compensating pieces
represented in those Figures.
I do not mean or intend to claim as my Invention any of the parts
herein-before described or shewn in the Drawings which are known or in
use, but which it was necessary to introduce and describe for the full and clear
understanding thereof; nor do I limit or confine myself to the particular modi-
fications of my Invention, shewn or described, or the materials of which the
several parts are composed. But I do claim as my Invention of an "Improve-

page_text: ment or an Improvements in Chronometers," a means whereby the compensation
for changes of temperature usually adopted in the balance of a chronometer
may be made more perfect by the addition of a supplementary compensation
thereto, as represented in the several modifications herein-before described or
otherwise.
In witness whereof, I, the said Robert Molyneux, have hereunto set my
hand and seal, this Seventh day of September, in the year of our
Lord One thousand eight hundred and forty.
Inrolled the same Seventh day of September, in the year above
written.