CERTAIN IMPROVEMENTS IN CHRONOMETERS AND OTHER TIMEKEEPERS
Year: 1846

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HUTTON, of Commercial Road East, Middlesex, Chronometer Maker, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-second day of
October, in the tenth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said John Hutton, my exors, admors,
and assigns, Her especial licence, full power, sole privilege and authority,
that I, the said John Hutton, my exors, admors, and assigns, or such others
as I, the said John Hutton, my exors, admors, and assigns, should at any
time agree with, and no others, from time to time and at all times 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,
and in all Her Majesty's Colonies and Plantations abroad, and in the
Islands of Jersey, Guernsey, Alderney, Sark, and Man, my Invention of
"CERTAIN IMPROVEMENTS IN CHRONOMETERS AND OTHER TIMEKEEPERS;" in which
Letters Patent is contained a proviso that I, the said. John Hutton, shall
cause a particular description of 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, 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 in

page_text: part recited Letters Patent, as in and by the same, reference being thereunto
had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Hutton, hereby declare that the nature of my said Invention, and in
what manner the same is to be performed, are fully described under the
several heads thereof, in and by the present Specification, reference being had
to the Drawings hereunto annexed, that is to say:―
My Invention has, firstly, for its object, to correct an error common to all
chronometers as ordinarily constructed, which is known by the name of "the
error in extremes," for as chronometers are required in all latitudes, and are
subject consequently to the greatest extremes of temperature, it becomes a
matter of importance to remove or even to lessen in any degree that error.
I employ for this purpose an auxiliary compensation, which may be put on or
taken off without stopping the balance, and is therefore equally applicable to
good old as well as new chronometers. It is constructed on the principle of
diminishing and encreasing the resistance of the atmosphere to the motion of
the balance, in proportion as the temperature either rises or falls, and thereby
maintaining a greater uniformity of rate.
b
In the Drawings, Figures 1, 2, 3, 5, and 6, the black lines represent parts
of a chronometer as usually made, and the red lines the parts belonging to
my auxiliary compensation. Figure 1 is a top plan of the chronometer
(supposing the face to be turned downwards); and Figure 2 a cross section
on the line v, w, of as much of it as is above the upper plate I of the move-
ment. A, A, is a metallic thermometer or compound piece of brass and
steel, or of any other two metals subject to different degrees of expansion
(constructed on the well-known principle of the compensation balances),
which is made fast at one end to the foot of the cock J by means of the two
screws a, a. A plan of this thermometer is given separately in Figure 3.
B is a small cock, with an adjusting screw 6 (shewn separately in plan and
section in Figures 6 and 7), which is attached to the free end of the thermo-
meter A. C is a flat ruby or other hard stone fixed to the free end of the
thermometer. D, D, is a light cap or lid, made of boxwood or other suitable
material, which nearly surrounds the balance, the part of it from n to o being
cut away in order to free the cock and balance spring. The interior of this
cap forms the space of the balance. It is attached by two arms d, d, to a
piece e, fixed on the fast end F, F, of the thermometer A. At the points f,f,
these arms are made much thinner than at any other part, and have also
pieces cut out of them, in order that the cap may have its centre of motion at
those points. G, G, G, is a triple-branched cross piece, fixed to the arms d, d,

page_text: and g is a regulating screw. H is a ruby or other hard stone, fixed in the
extreme end of the centre branch of the cross piece G. A plan and section of
the
cap and its immediate appendages are given separately in Figures 4 and 5.
By reference to the Drawings it will be seen that the cock B, and its regu-
lating screw b, are on one side of the centre of motion (5) of the cap D, while
the part of the cross piece G that carries the regulating screw 9 is on the
other side of it. The action of the apparatus, therefore, is as follows:-At
first the cap rests on the upper plate I, and shuts up (as it were) the balance,
when the temperature rises, and the free end of the thermometer (A) expands
with it; the ruby C coming in contact with the point of the regulating screw g
gradually raises the cap from off the balance, and thus gives more freedom to
the air around it, and consequently diminishes the resistance to the motion of
the balance. When, on the other hand, the temperature falls, and the free
end of the thermometer contracts with it, the point of the regulating screw b
of the cock B comes in contact with the ruby H, and this again raises the
cap, and causes a corresponding diminution of resistance to the motion of the
balance.
Secondly, my Invention has for its object to correct the error in astrono-
mical and other clocks arising from changes in the density of the atmosphere.
I employ for this purpose a barometer, in which the rising and falling of the
mercury is made to serve as a motive power, whereby to enlarge or contract
the air space of the pendulum, according to the increase or diminution of
barometric pressure. When the mercury rises the air space is enlarged, and
when it falls the space is contracted. The manner in which this is effected is
shewn in Figure 8. A, A, A, represents a portion of the interior of the case
of an astronomical clock, the lower part of which may be called the air space
of the pendulum. The barometric tube a, a, is fixed to one side of the case.
B is a piston or float, to which is attached a light rod b, the upper end of
which, E, may be either made sufficiently smooth and hard to bear a slight
degree of friction, or have a friction roller attached to it. F, F, is an air
resister, consisting of a plain surface suspended by spring rods R, R, from a
projecting bracket in the back of the case, as more clearly shewn in the side
view.Figure 9. e is a smooth incline plane, which is fixed in an angular
position to the top of the plate F, and projects over the short end of
the barometer, so that the top point (or roller) E of the piston rod may,
The effect
on rising perpendicularly, catch against the inclined plane.
of the springs attached at f, f, to the hanging rods R, R, is to throw
the plato F, in the first instance, into the position indicated by the dotted
line 9; but as the mercury rises, and the piston rod b rises with it, the

page_text: point E of the latter presses against and throws out the inclined plane, which
causes the plate to approximate gradually to the piston of the second dotted
line, and thereby to diminish the air space of the pendulum. As the
mercury falls a reverse operation of course take place.
Thirdly, my Invention consists of a compensation spring stud for watches
and other timekeepers, in which a balance and balance spring are employed.
In this improvement I use two or more compound pieces in conjunction with
two or more springs, in such manner that the compound pieces shall act in
opposition to one another, and so maintain the balance spring in one position
and at the same time strengthen or weaken the stud spring or springs according
as more or less strength is required by variations of temperature. A, A,
Figure 10, are two compound arms fixed to the upper plate of the movement
at a. These arms close under the influence of heat, and thereby bring toge-
ther the two springs B, B, to which the balance spring is attached, while with
cold they open, and allow the springs to expand towards the positions indicated
by dotted lines. The effect, therefore, of this alternate action is to increase
the force of the stud spring or springs as the temperature rises, and to diminish
it as the temperature falls.
.
Fourthly, my Invention consists of an improvement in the "two-pin lever
escapement" for watches. This consists of inserting a solid piece of ruby or
other hard stone in the roller, and in placing the impulse notch in this
ruby, and forming the lower part of the ruby so as to receive the fork of the
lever.
Fifthly, my Invention consists in a compensating pendulum of an improved
description, which is represented in the sectional elevation, Figure 11, of the
Drawings hereunto annexed. It is made of three rods A, a, a. The centre
one A is made of a less expansive metal than the two side rods a, a; the
former may, for example, be of steel, and the two latter of brass. B is a
tubular piece, which is made to fit and slide upon the centre rod A, and termi-
nates at bottom in a screwed spindle with nute by means of a cheek; it is
adjustable to any required height. D, D, are two spring levers, a plan of
which is shown separately in Figure 12, which are attached at right angles to
the piece B, and are weighted towards their other ends by the balls C, C. At
e, e, they are filed down to such thinness as may be necessary to establish at
these points their centres of motion. The two side rods a, a, are connected
at bottom to pieces d, d, which are attached to the spring levers D, D, these
cocks being on one side of the centres of motion while the balls C, C, are on
the other. The natural tendency of the spring in these levers is to throw the
balls upwards, but this tendency is counteracted by the downward pressure of

page_text: the side rods a, a. Supposing, however, the pendulum to be adjusted (by
the screw nut c), to mean time, and a change of temperature to occur, the
following action takes place. If the change is to a rise of temperature, the
rods a, a, expand more than the centre rod A, and as the direction in which
they expand coincides with the natural tendency of the levers D, D, the
balls are thrown upwards, and the difference in the length of the main rod A
is thus compensated for, and if the change is to a fall the contrary effect
is produced.
Figure 18 shows a modification of the preceding plan of construction. A
is a hollow tube of glass, which contains the two compensating rods a, a,
which may be of steel or any other metal bearing similar relations to glass
in respect of expansibility. B is segment of a hollow sphere, in which
weighted spring levers similar to those employed in the preceding case are
inclosed, and E is a piece to which these levers are attached.
Sixthly, my Invention consists of a compensation collet to be attached to
the balances of chronometers.
A', A², Figure 14, are the arms of the collet which rest on the top of the
balance, and is slipped on to the same spindle. B, the boss. D¹, D³, are
two compound pieces of metal formed each of a piece of steel E, and a piece
of brass F, which pieces D¹, D³, are each securely fixed at one end to the
arms A', A, leaving their free ends at liberty to expand outwardly from or
contract towards the boss B, according as they may be acted upon by any
variation of temperatures. G¹, G, are two frames, situated in close proximity
to the fixed ends of D¹, D. H', H', are valves placed within the frames
G2, G3, which, in the first instance, present their flat surfaces at right angles
to the line of rotation or vibration of the spring collet, as represented in
Fig. 14, and in that position the pin a, Fig. 15, of a small crank formed on
the lower end of the separate spindles upon which they vibrate within the
frames G, G³, takes into a slot formed in the free ends of the pieces D¹, D³.
The crank of H' takes into the slot in D, and the crank of H³ takes into
the slot in D'. As D¹ and D' bend either outwardly or inwardly from the
boss B, the valves are correspondingly turned round, and in either direction
they present less resisting surface to the air with which they are surrounded,
and thereby effect an uniform rate. Instead of attaching the parts just
described to a spring collet they might be attached to the balance itself.
Seventhly, my Invention consists of a compensation collet or attachment
applicable to timekeepers, in which a balance and balance spring are used.
Figure 15 is an elevation of this collet and attachment, and of several
of the parts connected therewith.

page_text: Figure 15 is a plan of the balance and collet. A, A, is one or other of
the plates forming the framework of the clock. B is the cock or bracket for
supporting the upper end of the balance spindle C, which passes at bottom
through the plate A, upon the lower side of which it has its connection with
the other parts of the movement. D is the spring collet balance. E, E, two
compensating pieces of metal compounded of steel and brass in the usual way.
These pieces E, E, are fixed securely into the arms F, F, at one end, with
their steeled sides on the outsides that is furthest from the spindle C, and
their brass edges on the inside, or that nearest to the same spindle. G, G,
are two upright wires connecting the cross piece H with the free ends of E, E.
I is the balance spring, and K, K, two timeing screws. According as the
temperature varies the free ends of the compound compensating pieces E, E,
are curved either outward from or inward to the spindle C. Every incre-
ment of temperature causes them to bend in an outward direction, and
thereby increases the leverage at which the spring acts upon the balance,
while every decrease of temperature causes a reverse action, by which means
the same cause (namely, the variation in temperature), which renders the
action of the spring variable, produces a corresponding corrective variation in
the balance.
And, lastly, my Invention consists in a method of compensating in clocks
for variations in the density of the atmosphere the converse of that secondly
herein-before described. Instead of effecting that object by diminishing and
enlarging as aforesaid the air space of the pendulum, I leave that space un-
changed, but diminish and encrease the sectional area of the pendulum, and
thereby cause it to meet with a greater or less atmospheric resistance,
according as the temperature may rise or fall.
vibrates.
A, A, Figure 16, represents the bob or weight of a pendulum, and Ban
open passage cut through it in a line parallel with the plane in which it
The longer
limb C¹ is carried up behind and attached to the arm of the pendulum near
to its upper end, and the shorter limb C³ is filled to the height a, b, with
mercury. E is a door or valve which slides within the opening B, and is
attached to one end of a lever F, from the other end of which there is
suspended a metal float G, which rests upon the surface of the mercury in
the tube C. The weight of the float is adjusted so as to rather more than
counterbalance the weight of the door or flap E. Supposing a change to take
place in the barometrical state of the atmosphere, and that the mercury falls
in the longer arm of the tube, that will produce a corresponding rise in the
shorter arm C3, which will cause the float G to ascend, and consequently the
C, C, is a barometer tube filled with mercury.

page_text: door or flap E to fall and stop up a greater or less portion of the open
passage B, and so cause the pendulum to meet a greater resistance from the
atmosphere than it did before. But as the barometer by its fall indicates that
the atmospheric medium in which the pendulum is vibrating is thinner, and
therefore calculated to give less resistance, it follows that when the rate of
encrease of the sectional area of the pendulum is nicely proportioned to the
rate of decrease of atmospheric resistance, the necessary correction of the error
arising from the barometric difference in the state of the atmosphere will be
accomplished. When instead of rising the barometer falls the course of
operations is reversed, but with an equally corrective effect on the rate of
the clock.
Another arrangement for the same purpose is shewn in Fig. 17. A is the
pendulum bob. B¹, the longer limb of the barometer, and B' the shorter.
C, a float, and D a flap, which answers the same purpose as the door E in
Fig. 16, which is protruded more or less from the short limb B³, according to
the state of the atmosphere.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, in the several parts of which the samė
consists, I declare that the improvements which I claim as constituting my
said Invention are as follows,―
First, I claim the employment in chronometers of auxiliary compensations,
which act by diminishing and encreasing the resistance of the atmosphere to
the motion of the balance, as herein-before described.
Second, I claim the employment in astronomical and other clocks of a
mercurial column in combination with air space, diminishing and enlarging
surfaces, for the purpose of correcting the errors ordinarily arising from changes
in the density of the atmosphere, as herein-before described.
Third, I claim the compensating spring stud for watches and other time-
keepers, as herein-before described.
.
Fourth, I claim the improvement in the two-pin lever escapement herein-
before described.
Fifth, I claim the employment of compensating pendulums of either of
the forms described under the fifth head of this Specification.
Sixth, I claim the application to timekeepers in which a balance and
balance spring are used, of the compensation collets or attachments described
under the sixth and seventh heads of this Specification.
And, seventh, I claim the employment in clocks of auxiliary compensations
acting by encreasing and diminishing the amount of sectional area exposed by

page_text: the pendulum to the resistance of the atmosphere, as lastly herein-before
described.
In witness whereof, I, the said John Hutton, have hereunto set my
hand and seal this Twenty-second day of April, in the year of our
Lord One thousand eight hundred and forty-seven.
AND BE IT REMEMBERED, that on the Twenty-second day of April,
in the year of our Lord 1847, the aforesaid John Hutton came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, 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.
Enrolled the Twenty-second day of April, in the year of our Lord One