IN- PROVEMENTS IN CLOCKS AND OTHER INSTRUMENTS FOR MEASURING TIME
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by Leo Meurin at the Office of the
Commissioners of Patents, with his Petition, on the 23rd October
1869.
I, LEO MEURIN, Roman Catholic Bishop of Bombay, at present
residing at No. 111, Mount Street, Berkley Square, in the County of
Middlesex, do hereby declare the nature of the said Invention for "IN-
PROVEMENTS IN CLOCKS AND OTHER INSTRUMENTS FOR MEASURING TIME," to be as
follows:-
This Invention has for its object improvements in clocks and other
instruments for measuring time, and consists in the use of two pieces
of metal which expand in the same proportion. One is used as the
pendulum, and the other as compensator to govern the position of the
point of suspension of the pendulum. The expansion of the one is used'
to compensate the expansion of the other.
According to one arrangement a spring C is fixed on a plate A, B,.
(Figure 1). To the end E of the spring C are attached both the
pendulum and the compensator, the latter between the pendulum and
the plate in order to allow of the swinging of the pendulum. The other

page_text: end of the compensator F is fixed to the plate; the spring C should be
strong enough to keep the compensator always tight. The pendulum L, J,
is made of the same metal as the compensator, of the same length,
breadth, and thickness; the change of temperature acts in consequence
equally on both the pendulum and the compensator. At H is the fork,
through which pass both the compensator and the pendulum, and which
fixes the point of swinging for the pendulum; it is also attached to the
plate A, B. In order that the pendulum may be of the required length
either the fork H or the end F of the compensator should be moveable.
Suppose first the plate A, B, not to suffer any alteration from change of
temperature, it is evident that the distance from F to H will also remain
unaltered, both points F and II. being fixed to the plate. Any expansion
or contraction of the compensator E, F, will in consequence make itself
perceptible above the fork H. In case of increase of heat the spring C
will draw the point E upwards towards D, and in case of increase of
cold the contracted compensator will force the point E down towards H.
The spring C must be of such a power as to keep the compensator tight
and allow of its contraction from cold. Instead of the spring C a weight
suspended from a chain passing over a wheel may be employed. Now
as the part of the compensator between H and F remains always of the
same length any alteration in it affecting only the point of suspension E
the same must necessarily be the case with the pendulum L, J, since it
is in every way equal to the compensator. Whatever may be the fall or
rise of its point of suspension L its length from H to J, that is to say,
that part of it which swings, will remain always the same. However
as the previous supposition is contrary to fact and the plate A, B, will
necessarily be affected by changes of temperature compensation for the
changes of the plate must also be provided. If we take for pendulum
and compensator a metal whose expansibility is greater than that of the
metal employed for the plate it will be very easy to make the com-
pensator as much longer as is required by the expansibility of the plato
from the fork H down to the point where the compensator is fixed. The
expansibility of the compensator from G to F must be equal to that of
the plate from G to H. The point G can easily be found scientifically,
the expansibility of the different metals being known, or by experiment.
The whole length of the compensator E, G, will then compensate for the
pendulum L, J, plus the plate from G to H, and consequently the swing-
iag pendulum H, J, will under all circumstances remain unaltered. To
this pendulum is attached the usual clock machinery.

page_text: In order to avoid the effect of the expansion of the plate A, B, the
compensator may be coiled up on a small pin at the point from which
the pendulum swings. If the pendulum and the compensator are both
made of platina or of a common steel spring the compensator is wound
up on a
pin A (Figure II.); its other end B is attached to a spring (as
in Figure I.) or to the weight C which keeps the coil tight. Any
alteration in this compensator will show itself at the point of suspension
B, which will be forced up o down according to the increase of heat or
cold. The pendulum though flexible at the fork should not be so below
it. For this purpose it may be bent a little below the fork in M, so as
to swing with its sharp edge. The effect of the expansion of the plate
is thus avoided, and the compensator will always remain of the same
length from the joint where it is fixed to the pin A to the point D from
which it rises in a straight line. The power of expansion and con-
traction will overcome the friction of the coils. The pendulum L, J,
suspended like the compensator at B, and of the same metal and equal
length, will consequently always remain the same length from D to J.
Any alteration in consequence of change of temperature will shew itself
only in the change of distance from D to L. It must be observed,
however, that the coiled compensator expands not only in length (thus
producing a variation in the point of suspension B) and in breadth
(which is productive of no consequence), but also in thickness. This to
secure perfect accuracy must be compensated. The cylinder A, D,
formed by the pin and the coiled compensator will expand with heat,
and consequently require a greater length of the coiled metal. The
compensator must therefore be lengthened in proportion to the expansion
of the cylinder A, D; this proportion may be ascertained either by
calculation or more casily by experiment. The compensator may be
fastened with a screw at B, which would admit an additional piece above
B being added at convenience to its length. The required length of the
compensator once found it may be easily and cheaply applied to all
clocks of the same construction. In order to regulate the pendulum the
pin A should admit of being wound in either direction, so that the
point B may be drawn up or down, and the pendulum thus shortened or
lengthened.
In the case of watches a similar arrangement is also applicable, as
shewn at Figure 3. In this Figure O represents a spring which keeps the
hair spring A, B, tightly coiled around a pin A. At C is fixed the hair
spring E, F, G, C, which is moveable only from the point D. As the

page_text: length of the former hair spring from A to D remains always the same,
so does the length of the latter from E to D. All changes occur above
D and affect only the points of suspension B and C. It will be easy to
compensate any inaccuracy in the construction of the springs, or any
effect arising from the expansion of the little cylinder A, D, by shortening
or lengthening the compensator at B.
As all metals expand in a steady progression the compensator and the
pendulum or hair spring may be made of different metals. Whatever
metals may be used a few experiments only will be required to shorten
or lengthen the compensator by means of a screw in such manner that
its alterations will perfectly counteract the alterations of the pendulum
or hair spring or any other influencing cause whatever.