A NEW PRINCIPLE OF MEASURING TIME AND CONSTRUCTING CLOCKS AND CHRONO- METERS
Year: 1808

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CONGREVE, of Garden Court, in the Temple, in the County of Middlesex,
Esquire, send greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-fourth day of
August, in the forty-eighth year of His reign, give and grant unto me, the
said William Congreve, my executors, administrators, and assigns, His especial
licence, full power, sole privilege and authority, that I, the said William Congrevc,
my executors, administrators, 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
"A NEW PRINCIPLE OF MEASURING TIME AND CONSTRUCTING CLOCKS AND CHRONO-
METERS;" in which said Letters Patent there is contained a proviso obliging
me, the said William Congreve, by an instrument in writing under my
hand and seal, to cause a particular description of the nature of my said
Invention, and in what manner the same is to be performed, to be inrolled
in His Majesty's High Court of Chancery within one calendar month after
the date of the said recited Letters Patent, as in and by the same (relation
being thereunto had) may more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
William Congreve, do declare that my said Invention is described in manner
following (that is to say) :-
The new principle or system of measuring time and constructing clocks and

page_text: chronometers, which is the basis of this Patent, is founded on certain modes
herein-after specified, of detaching the time measurer from the first mover for
an extent of duration far beyond anything ever yet effected or proposed, and
which is not confined within the limits of ordinary detachments. Thus the
only detachments hitherto effected have either been limited to a period some-
what less than the smallest portion of time indicated by the vibrations of their
time measurer, and have therefore seldom been extended beyond seconds, or
they have been effected by the intervention of an auxiliary power between the
first mover and the time measurer, which indeed ought scarcely to be con-
sidered as falling within the class of detached movements, as the time measurer,
when discharged from the inaintaining power, is in this case still combined with
another force. But by the system here specified the duration of the detach-
ment of the time measurer from the first mover may, without the intervention
of any intermediate power, be extended to a period comprehending any
number of the smaller portions of time indicated by the time measurer; in
other words, the time measurer shall indicate seconds or any smaller division,
and yet it shall be absolutely detached from the maintaining power for a period
of one or more minutes. This, therefore, gives a most distinct and definable
character to this new mode of measuring. time, the leading property of
which is a new and extremely extended detachment, and which I have
therefore denominated the "mode of extreme detachment."
Before I proceed, however, to the several plans for effecting it, I shall briefly
state its principal advantages. The great difficulty of combining the actions
of the regulating principle of clocks with the maintaining power, so that the
regulating organ shall be operated upon freely and uniformly by the action of
gravity, whether accelerated or retarded by the non-accordance of the first mover,
has long since pointed out that the only true system of effecting this deside-
ratum was by detaching them as much as possible rather than by combination with
the ordinary regulators, that is to say, with the common pendulum or balance
wheel. The extent of this principle of detachment, as already observed, is
extremely limited; for as, with the most perfect detached escapement in use,
the maintaining power is allowed to act on the pendulum for a certain portion
of every oscillation, it follows that with the common pendulum it would be
.extremely inconvenient to detach the first power for an interval much longer
than a second, in so high a law do the lengths of pendulums increase as to
their times, so that to obtain a detachment of 2" would require a pendulum of
-13 feet 0.512 inches in length; to obtain one of a minute would require no
less a length than 11738 feet 4.800 inches. The first, therefore, which would
still be very limited as to any important correction in its effect, would be of a

page_text: most inconvenient, and the latter of an impossible, length. By adopting the
mode of this Patent, however, it will be found that such, or even a greater,
extension of detachment than a minute is practicable without any difficulty or
inconvenience whatever, and even in a smaller space than is required for the
5 common seconds clock. The next general advantage is, that a clock made on
the principle of 'extreme detachment requires a much less first power than a
common clock, for the power of the former may be organized so as to rest
altogether for intervals of minutes, and to be limited when in action to less
than half seconds between those intervals, while that of the latter is constantly
exerted every second; nevertheless the maintaining power of the former need
not have more to perform every minute than the other has every second. It
follows, therefore, that a clock may be constructed on this principle to require
only one sixtieth of the weight or power of a common clock, or, that with the
same power it will go sixty times as long. Again, the mode of extreme
detachment, by diminishing the quantity of the first force to so great a degree,
and by the constant state of repose which it preserves in the train of the clock,
removes almost entirely the strain and friction to which the works of a common
clock are subject, so that the wear of the patent clock becomes next to nothing,
and it can therefore scarcely ever require the application of oil, or get out of
order. So also this system of detachment, will be found greatly to simplify the
train; in fact, the greater the extent of the detachment the more simple will it
be by working from 'minutes or other longer times instead of seconds; notwith-
standing which, however, the second, or any less division of time, may be
indicated with as much accuracy as in the more complicated train of the
common timepiece. Such then are the general advantages of this Patent, and
whether they be viewed with reference to the extent of the detachment or the
diminution of the maintaining power required, the increase of time, the
reduction of friction and wear in the works, or the simplification of the train,'
I conceive that no further discussion of the principle is necessary with those
who are at all conversant with the principles of timekeeping, to convince them
that the attainment of these points is of the utmost importance to the final
perfection of a true measure of time.
I shall therefore now proceed to the Specification of the plan which I havo
practised for their accomplishment. And here I have introduced a new modi-
fication of the action of gravity as applied to timekeeping, by taking, as the
time measurer, <<
a perfectly detached body descending freely down an inclined
plane;" which modification, although it has never yet been applied to the
measurement of time, is as immutable in its operations as the oscillations of a
pendulum, and is, in fact, governed by the same law; the extreme detachment

page_text: of which it is capable, and certain specific advantages which the pendulum
does not possess, have pointed it out to me as an important agent in the
measurement of time. The following are several different modes in which I -
have applied this new regulating organ for the accomplishment of this
Patent-
Fig. 1 and 2 shew the dial and frame plate of an eight-day spring clock,
having a small tube a, b, six inches long, containing a steel ball. This tube
and ball serve the purpose of a pendulum 7 feet 4.038 inches in length;
making exactly forty beats in a minute. The tube is connected with the train
merely by an arbor and pinion, and being a little inclined, the ball runs from
a to b, where it discharges by striking against it a small spring detent d that
holds the tube in the position a, b, when, being so discharged, the tube makes
a half revolution from 6 to d, and is caught again by the same detent, the ball
being thus brought back to the upper end, runs down again, and striking the
detent, repeats its half revolution as before. This tube may be in part con-
sidered as a revolving pendulum, where the centre of gravity oscillates but the
system revolves, and where the time is measured, partly by an oscillation,
The clock is at
and partly by the descent of the ball down the plane.
rest while the ball runs from a to b, that is, two thirds of the whole
time; and a tube of six inches, thus producing beats as slow as a
common pendulum 7 feet 4-038 inches in length, is consequently in that pro-
portion so much less liable to the expansions or contractions of temperature.
All the escapement work also is here avoided, a common steel pinion being
substituted for it, the effect of the escapement being produced by the descent
of the ball. This property, peculiar to the new regulating organ here specified,
is undoubtedly a very important one, from the great nicety required in the
construction of escapements, and the comparative simplicity of making a
common pinion, which here answers all the purpose. The time is regulated
by the small hand at C, Fig. 1 and 2, which, by moving the detent d higher
or lower, diminishes or increases the inclination of the tube, and with it the
time of descent. Fig. 3 is the face of a clock similar to Fig. 1, but having a
small wheel a, b, instead of the tube connected with the train by an axis and
pinion as before; this wheel contains a series of inclined planes a, x, y, z, u, b,
which, being held in a given position by a small spring detent d, as in the
former case, the ball unlocks the wheel, and the time is regulated as above.
In this application six seconds are consumed in the running of the ball from a
to b, and in the shifting of the wheel half round for a fresh run of the ball
This index, therefore, makes ten beats in a minute, or five whole revolutions
and, the wheel not occupying more than half a second in shifting, the first

page_text: mover and train are at rest eleven-twelfths of the whole time, during which
proportion of time the regulating organ is entirely detached from the main-
taining power, and thus the detachment is carried to as great an extent as, by
means of the best detached escapement hitherto made, it could be made with
a common pendulum of 116 feet 8608 inches in length. Fig. 4 is a clock in
which the detachment is carried to a still greater extent. a, b, Fig. 4, is an
inclined plane fourteen inches long and eight inches wide, having thirty grooves
cut in it, as shewn in plan Fig. 5; along these grooves a small ball runs from
a to b, or from c to d, according as the plane is inclined one way or the other.
Now this plane is calculated at a certain inclination to give exactly one minute
for the time of the ball's motion from one end of it to the other, where, having
arrived at the lowest point, it strikes a lever n connected with the detent e,
and unlocking it the maintaining power is allowed to act for a moment for the
purpose of shifting the plane (which is most accurately balanced on a knife
edge) into the position c, d, that the ball may run back again in another
minute to the opposite extremity of the plane, where it again unlocks the same
detent by a corresponding lever m connected with it. The velocity of the ball
is no greater at the bottom of the plane than at the end of the first groove,
for the acceleration required in each groove is destroyed by the small brass
deflectors,,,, &c., Fig. 5, at the end of each groove, which turn the ball
into the opposite direction of each succeeding groove; neither is the ball
allowed to stop the least instant of time during the shifting of the plane, but
is immediately thrown back on its return by the action of a small crooked arm
so regulated by its form and pressure as instantly upon the ball's striking the
lever to throw it back, and keep it moving on its return until the shifting of
the plane is completed with the mean velocity of its motion on the plane when
so shifted, so that no inequality produced by the first power in the time of the
planes shifting can make any variation in the whole time of the ball's motion
from one end of the plane to the other, for, whether the plane rises faster or
slower, the ball always returns at the same rate without a moment's pause.
This correction is indeed almost superfluous, for in the very short and rare action
of the maintaining power, during the almost instantaneous shifting of the plane
once a minute only, any inequality that can possibly arise with ordinary good
workmanship must be next to nothing, and can hardly produce a sensible
effect in the longest period of going. It shews, however, that the principle of
extreme detachment may in this application be made absolutely perfect, inas-
much as neither the motion of the ball in its progress along the plane, nor at
the moment of its departure on its return, is in the least influenced by the first
nover; the time of shifting the plane is not so much as half a second, there-

page_text: fore the first power of this clock is at rest, and the whole train in a state of
repose more than one hundred and nineteen hundred and twentieths of the
whole minute; that is to say, all connection with the moving power is as long
suspended as could be effected, on the ordinary principles of detachment, with
a pendulum of the enormous and impossible_length of 11,738 feet 4-800
inches, which, if it were practicable, would vibrate minutes; yet, notwith-
standing this extreme detachment in the patent clock, the smallest portion of
the intermediate. time may be indicated by the beats of the ball or time
measurer, which, as stated at the commencement of this Specification, is the
great characteristic of this new mode of detachment. This is effected by a
bridge or bridges, &c. f, f, across the plane, under the arches of which the ball
passes. The figures indicating the division of time, thus shewn, are made to
shift according as the ball runs from right to left or from left to right, so that
they may be read the way the ball runs, thus the time may be read off in
seconds or smaller divisions with the greatest accuracy, as the motion of the
ball is nearly uniform, all acceleration in passing down the plane being
destroyed, as already described, at the end of each groove. To explain the
remaining parts of this clock, the circle M shews the minutes advancing one
every time the plane shifts, and the minutes being driven directly from the
moving power P, the circle H shews the hours which are driven from M.
R is the regulator, being the means of connection between M, the minute
hand, and the plane, which is effected by a crank and rod x, y. Every time,
therefore, the ball unlocks the plane, R is allowed to make half a revolution,
which gives the time to both minute and hour hands; the circle R therefore is
graduated, and has a hand which adjusts the distance of the crank from the
centre of the circle, by which adjustment the inclination of the plane is varied,
and with it the time. Thus, in the space of a moderately-sized table clock,
a timepiece is constructed, the vibrations of the regulating organ of which are
as slow as those of a pendulum 11,738 feet 4800 inches in length, by which the
first power is so reversed that the weight or spring of a common eight-day
clock may be made to carry it four hundred and eighty days; neither is there
any friction or motion in its train for one hundred and nineteen hundred and
twentieths of the whole time of its going, while the train itself is also con-
siderably more simple than that of a common seconds clock.
It is evident there are innumerable varieties of configuration in the applica
tion of this principle, which it is impossible to specify or even to anticipate, but
which must nevertheless be integral parts of this Invention, if they in any shape
accomplish the mode of measuring time by means of the extreme detachment
here specified. To attain this, therefore, it cannot be lawful for any one to make

page_text: use of any body, whether spherical, cylindrical, or conical, moving on any
inclined plane, however the same may be combined with any machinery or
clockwork whatsoever, whether the plane be simple or complex, curvilinear or
rectilinear, whether it vibrate or revolve, whether the body moving down it be
a simple or a compound substance consisting of one or more parts, whether it
be a fluid or a solid, or a combination of both. Various modes also may be
introduced for the compensation of the expansions and contractions of tem-
perature, either in the detent or in the rod x, y, which it is not necessary here
to specify; but it should be observed, that an inherent power of compensation
is combined in the very principle itself, for as the plane expands so also does
the ball, and vice versà; the ball therefore moves quicker as its course is
lengthened, and slower as it is shortened, because the vertical distance of the
points of contact from the centre of gravity of the ball increases with the
expansion and decreases with the contraction of the ball and plane, so as to
accelerate the motion of the ball in the first case and retard it in the second.
It appears, therefore, that this inherent property may be a due proportioning of
the diameter of the ball, and the matter of which it is formed, to the mean
length of the plane, and its component materials be so adjusted as of itself to
produce a perfect compensation. And lastly, with respect to the workmanship
of clocks made on this principle, it appears that less attention to it is required
than in common clocks; for as to the train it has so little comparatively
to perform, and so little of the measure of time has been shewn to depend
upon it, that any want of superior workmanship must be little felt, and for
ordinary purposes, therefore, even less than ordinary accuracy must be sufficient.
And as to the plane, as any inequality in the surface or irregularity in the first
formation of the grooves, must always similarly, reeur to the ball in every
descent, it follows that no such circumstances can destroy its true measure of
time; but should any change in the surface of the plane or in the form of tho
ball take place in a length of time, such change must be for the better, since
the edges of the grooves will become more and more even and polished as the
ball travels, and the ball will wear itself into the most perfect sphericity, as
from its rolling over at the extremity of each groove by means of the deflectors
,, 2, Fig. 5, its axis of motion is constantly varying. It appears, therefore,
that no part of the truth of the action of such a clock depends, as is the case
5 with the present system of good timekeepers, upon the exquisite perfection of
their workmanship, neither does it depend upon any particularly nice adjust-
ment or preservation of position; for although the clock be placed out of the
true level, so that the plane in shifting becomes more inclined one way than
the other, still it will be found that what the ball has gained one way it will:

page_text: exactly lose the other, and that therefore the result of every two librations of
the plane must (in any position in which the ball will continue its motion both
ways) be the true measure of the sum of any two consequent periods of its
course, a principle of self-correction which does not exist in common pendulum
clocks.
The next application of this new modification of the power of gravity for
the measurement of time which I propose to specify is that in which two
balls are used instead of one, as in the cases hitherto explained. A, B, C,
Fig. 6, is a wheel attached to the train of the clock by an axis and pinion
similar to that in Fig. 3, having three tubes A, B, B, C, and C, A, and two
balls. Suppose the two balls at 1 and 2, then will the wheel oscillate slowly
till the balls are brought nearly into the position 2 and 3, by the simple
operation of gravity, and suppose that at this point the first mover is allowed
to act for an instant to throw the wheel a little further round, so that the upper
tube becomes in a small degree inclined, that ball will then run to the other
extremity, so as to restore the first position 1 and 2, which change will imme-
diately produce another slow and detached movement of the wheel nearly one
third round, and this being compleated, as before, the first position will be
again assumed. This variation, therefore, though depending upon the action
of two balls instead of one, must be considered as another integral part of this
Patent, not only because it acts by a similar process, but because it produces
the same effect. It cannot therefore be lawful for any one to construct a clock,
the time measurer or regulating organ of which shall be constructed by means
of this or any similar application of two or any greater number of balls, whether
they act by partial revolution or oscillation, or however they may be connected
with each other or with the train, and it is evident that no possible application
of the descent of any body or bodies fluid or compound down an inclined
plane can be made for the purpose of measuring time or of procuring the
system herein specified of extreme detachment between the regulating organ of
clocks and chronometers and their maintaining power which must not be a
violation of this Patent.
I shall now therefore proceed to specify the mode by which I accomplish
precisely the same system of measuring time by the simple pendulum;
that is to say, where, agreeably to the characteristic distinction which
pervades this Patent, the duration of the detachment shall not, as by the
present system, be limited to the times of vibration, but on the contrary, let a
pendulum vibrate half seconds, quarter seconds, or any smaller portion of time,
still, like the ball on the inclined plane, it shall be absolutely detached from
the first mover for any number of these portions, as a minute or any number

page_text: of minutes, and this also without the intervention of any intermediate or
auxiliary power. Fig. 7. A is a light spring wheel with thirty teeth uncon-
nected with everything but the seconds hand and the small pair of pallets
X, Y, which by an inverted action drive the wheel. B, B, is a large swing
wheel having sixty teeth connected with a single pallet P on the same stock as
those X, Y; P being driven by the wheel B, B. C a wheel of sixty teeth on
the same arbor as B, being the last wheel of the train, or effected, if preferred,
by sixty steel pins on the face of B. E, F, a lever locking the wheels C and B
by the pressure of the spring S, except when discharged by the pin p on the
face of A. D, centre of suspension of the pendulum. Now suppose the wheels
C and B locked by E, F, in such a position that the pallet P works within the
teeth of B, without touching either way, and suppose a seconds pendulum set
in action under these circumstances; then will the force of oscillation given to
it drive the small wheel round by means of the pallets X, Y, with a dead beat
indicating seconds at every vibration, so as to make the seconds hand revolve
once in 60". At the 60th second the pin p will come in contact with the
lever E, F, and unlock B, which has remained in a state. of repose for 59",
during which time the pallet P has had no connection with the swing wheel
B, and the pendulum has vibrated perfectly free and detached from the moving
power. On being unlocked, however, as above described, the wheel B starts
forward by the action of the first mover, and, encountering the pallet P, gives
it an impulse regulated to restore the oscillating power lost by the pendulum
during the 59 vibrations of seconds; at the end of the 60" second, however,
the pin p has escaped the lever E, F, and the wheels C and B are again locked
so as to allow of 59 more free vibrations of the pendulum until the pin p comes
round at the 60" to release them again. Thus then there is obtained by the
common pendulum a perfect and extreme detachment for 59" of the minute,
and it is evident that the principle may be extended by increasing the numbers
to any greater degree within the limits of the inherent and detached oscillating
force of which the pendulum can be made capable without increasing the time
of the oscillation, and also without introducing any auxiliary force between the
first mover and the regulator, contrary, as before stated, to the properties of
every escapement yet applied. I shall now, therefore, compare the advantages
of this mode with the present system of detached escapements.
In the first place the description of its action shews how much more the
detachment is extended, and how much more the pendulum, as the regulating
organ, is in this case left to the pure and unmixed action of gravity. In no es-
capement hitherto constructed has the pendulum a perfect freedom of oscillation,
even for a single second, without having at some given point or other to unlock

page_text: some detent, or perform some similar operation, which immediately brings upon
it a controlling power in a direction contrary to its spontaneous effort, or an acce-
lerating power to urge it forward, and which from the infinite nicety of appli-
cation required must, from its constant interference, continually tend to effect
the isochronism of the pendulum. Here, on the contrary, for 59" the gravity
of the pendulum is the sole and uncontrolled cause of its motion, having its
ares of vibration neither lengthened nor shortened by any urging or opposing
cause, for the mere driving of the light and perfectly free seconds hand, con-
stant, uniform, equally poised, and opposing no limit to the arcs of vibration;
can be considered as nothing but a small increase of friction on the point of
suspension until the 60" second when it has to unlock the detent, and when at
the same instant it receives a fresh supply of force, left, however, to operate as
freely as before in the production of its effect upon 59 out of 60 of the subse-
quent oscillations of the pendulum.
In the second place, it will be found that considerably less first power
is required to keep the same pendulum in action for a given time by
this mode, because one great impulse will be found to be given with much
less absolute friction than the sum of a great number of small forces,
even if they amount to the same impulse; for as many parts (and even more)
of the train are in motion, and in as much motion each to produce the lesser
impulse as the greater one, and therefore in giving the one united impulse there
is no more friction than in giving each of the sixty lesser ones; that is to say.
the friction in applying the requisite maintaining power on this principle is
only one sixtieth of what it is in the ordinary mode. But this is not all, for a
pendulum thus allowed to act freely would maintain the force of vibration
first given it for a much longer time and with much less variation in its
ares of oscillation than when coming constantly in contact with machi-
nery, supposing no such power given; therefore, although that machinery
may constantly impart to the pendulum fresh increments of of force, still,
in so doing it follows that by the very contact of machinery necessary for
imparting this new force, a certain part of the inherent force at the time of
contact is destroyed at every such contact, which were it not so acted upon would
continue with little variation for considerable periods. To withhold this contact
as long as possible is therefore a direct saving of all this force for the time of
such detachment; nor is there more of this inherent force destroyed in the
contact necessary to give the one impulse every minute (or whatever the
period may be) than would be lost in giving the divided impulses of each
second; for the power required to unlock the detent, in one individual action
at the end of the minute, is no more than in the other individual action at the

page_text: end of each second; nor is the friction in the one individual action of the pallet
at the end of the minute more than in the other individual action of the end
of each second. Here then is a saving of the inherent force of the pendulum in
a ratio of 59 to 1, to be added to the saving of friction above stated to be also
in that same ratio. Now these will be found to be the principal causes of
that loss of motion in the vibrations of pendulums, which is to be restored by
the first power, for the remaining causes of its loss of motion are but the
friction on the point of suspension and the resistance of the air; on these two
there certainly will be always an increase of effort required in the impulse of
the maintaining power in the direct proportion of the length of time they are
allowed to accumulate; but as these latter are extremely trifling compared to
the other two causes of the loss of power above mentioned, in which there is an
absolute gain of 59 to 1, it follows, that although the saving of power, on the
whole, will not be exactly as 59 to 1, still it will be nearly so. To calculate it
exactly is not, perhaps, possible, because it is difficult to say what the propor-
tion of the friction of the point of suspension in the pendulum is to that of the
whole work, and indeed it may not be the same in any two clocks, but is
evidently, under any circumstances, an extremely small part of the whole.
In the third place, this application of the system of extreme detachment has
all the advantages of increasing the time of repose, as to the wear of the
works, in common with the inclined plane regulator; but it is of enhanced
importance with reference to the escapement, for as in this case the swing
wheel B, and the pallet P, by which the force is imparted to the pendulum,
are only in contact once in a minute, a relief, is thus afforded to this most
delicate and important part of the works, not accomplished by any escapement
hitherto constructed. So also is the train in like manner simplified, for the two
swing wheels A and B are here the indicators of seconds and minutes, though
both are connected immediately with the pendulum, that is, A revolves once in
a minute, and B once in an hour, without any intermediate train. Hence arises
a great additional saving of friction and work, for an eight-day clock requires
only one pinion with the ordinary numbers, and an extremely small power;
and a year clock may be made with only two pinions with the ordinary
numbers of an eight-day clock, and with very little more power.
It is evident that this mode of escapement is in every respect above specified,
and with similar advantages, as applicable to the vibrations of the balance
wheel of watches and chronometers as to the oscillations of the pendulum, with
the exception only as to the duration of the period of detachment, inasinuch as
the balance wheel cannot be given the same independent power. of vibration
from its spring which the pendulum possesses from its own gravity. The

page_text: balance wheel may, however, in the same way, be as absolutely detached
beyond the ordinary limits of its individual vibration, for five or ten of those
vibrations, or perhaps for a considerably greater number, by increasing the
weight of the balance in proportion to the strength of the spring, and, there-
fore, with proportionate savings of power, friction, and the other advantages
belonging to this system of extreme detachment. With regard to the actual
application, it is in fact so precisely the same as to machinery as well as effect,
that it is needless to recapitulate it in the Specification with the mere substi-
tution of the terms balance wheel for pendulum, &c., &c., and with the
difference in the numbers depending on the different extent of the detachment;
for any further Specification of it would obviously be but a recapitulation of
this kind. It is certain, also, that in this movement, whether applied to clocks
or watches, there may be various configurations by which the same effect may
be produced, still, however, as, to produce the same results, they can only be
constructed after the mode of extreme detachment and with the distinct and
characteristic properties of that detachment as above specified to be the
basis of this Patent, they must be considered as integral parts of it. It
cannot, therefore, be lawful for any one to attempt, by means of the double
pallets and swing wheels here specified, or by any other system of machinery
producing the same effect, to detach any pendulum or balance wheel from the
first mover of the clock for any greater period than that limited by the
individual vibrations of the pendulum or balance wheel, for such is the spirit
of the detached escapement here specified and secured; that is to say, that a
detachment is here effected with a common seconds pendulum, or with the
common balance wheel, which would, on the ordinary construction of escape-
ments, require enormous and impossible lengths of pendulums or diameters of
balance wheels; so that it cannot but be contrary to the spirit of this Patent
to apply any machinery which shall give this power of extreme detachment to
any pendulum of balance wheel of less dimensions than would give such detach-
ment according to the ordinary principles. It remains only to be added, that
this system of detachment as relating to the construction of clocks is to be
somewhat extended by the use of a compound instead of a simple pendulum;
and although this cannot in practice be extended to any great degree, because
to increase the times of vibration materially, and at the same time to maintain
sufficient vigour of oscillation to produce any long continuance of vibration, this
compound must as well as well as the simple pendulum, though not in an equal
degree, be made of very inconvenient dimensions, still it may be applied so as
to double some of the effects herein set forth. Such application of the com-
pound pendulum, therefore, as being a mode here specified of extending the

page_text: system of extreme detachment, which is the basis of this Patent, must
be considered an integral part thereof; so that it cannot, therefore, be lawful
for any one to make use of a compound pendulum consisting of two or
more bobs, by the means of any machinery whatsoever for any combination
or assimilation with the system of extreme detachment herein specified and
declared.
In witness whereof, I, the said William Congreve, have hereunto set
my hand and seal, the Twenty-third day of September, in the year of
our Lord One thousand eight hundred and eight.
AND BE IT REMEMBERED, that on the Twenty-third day of September,
in the forty-eighth year of the reign of His Majesty King George the Third,
the said William Congreve came before our said Lord the King in His
Chancery, and acknowledged the Instrument aforesaid, and all and every
And also the
thing therein contained and specified, in form above written.
Instrument aforesaid was stamped according to the tenor of the Statute
made in the forty-fourth year of His said Majesty's reign.
Inrolled the Twenty-fourth day of September, One thousand eight hundred