AN INSTRUMENT OR INSTRU- MENTS, MACHINE OR MACHINES, FOR THE IMPROVEMENT OF ALL MUSICAL PER- FORMANCE, WHICH I DENOMINATE A METRONOME OR MUSICAL TIMEKEEPER
Year: 1815

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JoпN
MAELZEL, of Poland Street, in the County of Middlesex, Machinist, do
send greeting.
WHEREAS His most Excellent Majesty King George the Third, by
His Letters Patent under the Great Seal of Great Britain & Ireland,
bearing date at Westminster, the Fifth day of December, in the fifty-sixth
year of His reign, did give and grant unto me, the said John Maelzel,
my exors, admors, and assigns, His special licence, full power, sole privi-
lige and authority, that I, the said John Maelzel, my exors, admors, and
assigns, 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 INSTRUMENT OR INSTRU-
MENTS, MACHINE OR MACHINES, FOR THE IMPROVEMENT OF ALL MUSICAL PER-
FORMANCE, WHICH I DENOMINATE A METRONOME OR MUSICAL TIMEKEEPER;"
in which Letters Patent there is contained a proviso obliging me, the said
John Maelzel, 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
six calendar months next and immediately after the date of the said recited

page_text: 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
John Maelzel, do hereby declare that my said Invention is described. and
ascertained in the manner following, viz*:-
My Instrument or Instruments, Machine or Machines, for the Improve-
ment of all Musical Performance, which I denominate a Metronome or
Musical Timekeeper, is for the purpose of counting or beating time in music
or, in other words, for dividing, indicating, or marking equal portions or
intervals of time, whereby to regulate and determine the degree of quickness
or slowness with which any piece of music shall be performed. These equal
intervals of time are measured by the vibration of a particular kind of pen-
dulum, whereof each vibration is indicated in an audible manner to the
performer by the click or drop of an escapement similar to that used in
a certain description of clocks, and the said escapement, by transmitting the
action of the maintaining power of a weight or spring to the pendulum, keeps
it in continual oscillation as long as the weight or spring continues wound up.
The construction of the pendulum which I employ in my machine is such as
to admit of readily adjusting the period of its vibrations, that any necessary
number of vibrations shall be performed in a minute of time, thereby to adopt
it to beat or keep the time for the performance of all the different kinds of
music, whether the movement of the same be quick or slow. By this means
the performance of music will be improved, because the intervals of time will
be always referred to the same standard, viz, the number of vibrations in
a minute, and the equality of the said intervals will be more perfectly attained
by this means than by the ordinary mode of counting or beating equal intervals
of time by the hand or foot. But be it known that I'do not make any claim
to the Invention of beating or counting the time for musical performance by
means of a machine regulated by a pendulum, but for the, particular manner
and mode which I have invented of applying a pendulum to such a machine
whereby the pendulum can with the greatest facility be made to vibrate a
greater or less number of times in a minute, at the pleasure of the performer;
and this admits of each vibration being marked by the tick or drop of the
escapement without any hammer or other apparatus for that purpose. To
effect this regulation of the vibrations I make the pendulum so short from its
center of motion to the weight or bob that it will vibrate quicker. or perform
its vibrations in less time than ever can be required for beating time in music;
and I continue the rod.or stem of the pendulum above the center of motion,
and upon this upper part of the rod or stem I apply a second weight or bob

page_text: in such manner that it can at pleasure be placed at a greater or less distance
from the center of motion. The action of this second weight placed above the
center is to retard the motion of the pendulum, and the higher it is placed
above the center the slower the vibrations will be, and vice versa. The rod or
stem is divided into notches, and the secondary or sliding weight has a spring
catch to hold it at any required notch, and support the secondary or sliding
weight at any part of the rod; a scale is placed behind the pendulum with
a division opposite each of the notches, and the divisions are figured with
the number of vibrations which the pendulum will make in a minute when
the weight is placed upon the rod opposite to any divisions of the scale.
By this application of a sliding weight to the upper part of the stem or rod of
the pendulum I can render the machine very portable and convenient. A
pendulum that will vibrate forty or fifty times per minute will be found to suit
the performance of the slowest music. A pendulum for this purpose con-
structed according to my Invention can be contained in a machine of only one
foot in height, or even less, but by sliding the secondary weight near to the
center of motion the same pendulum will vibrate one hundred and sixty times
per minute, whereas a common pendulum with a single weight or bob beneath
the center of suspension would require to be of very inconvenient length to
vibrate at so slow a speed as forty per minute. The metronome or musical
timekeeper may be constructed of different forms and dimensions, and may:
be kept in motion either by a spring like a watch or by a weight in the
manner of a clock; and wheelwork may, in either case, be introduced
to keep up the action of the machine for a longer or shorter period of time,'
and also different kinds of escapements may be employed, provided they will
produce a sufficiently audible tick or beat. But to render this my Specifica-
tion more precise I have hereunto annexed Drawings of two different con-
structions of the instrument, one put in motion by a spring and the other
by a weight.
Figure 1 is an elevation, and Figure 2 a section of a metronome, which is
contained within a pyramid or case A, B, C, or any other figure may be
employed, according to the fancy of the maker. D, E, is that part of the.
stem or rod of the pendulum which is above the center of motion E; and F
is the sliding weight fitted upon it. I is the bob or weight at the lower end
of the pendulum.
The same letters of reference are used in Figures 4 and 5, which
represent the mechanism detached from the case, to render the con-
struction of the instrument more clear. I is the axis upon which the pen-
dulum swings, and at the opposite end of it are fixed the two pallets a, b, of

page_text: the escapement. These pallets are actuated by the leeth of the swing or
escapement wheel K, which has a pinion upon its axis turned by the tooth
wheel L, to which the spring box M is fixed. . The arbor m, Figure 5, of the
wheel L, and spring box is made square at the end m, and this is turned
round-by a key when the spring of the metronome is to be wound up. The
ratchet n is fixed on the arbor m, and the spring catch o acts in its teeth to
prevent the return of the arbor after winding up the spring, as the arbor must
not revolve when the machine is in motion, although the wheel and the
spring box turn round upon the arbor by the action of spring. The spring is
coiled up into the box M the same as a watch spring, and the outer end of
the coil is fastened to the inside of the box, whilst the inner end of the
coil is attached by a hook to the arbor m; therefore, when the arbor is
turned round by applying the key to the square m, it winds up the spring, and
as the click of the ratchet wheel n prevents the arbor turning backwards, the
natural tendency or action of the spring to unwind itself turns the spring box
and the wheel L round in the direction of the arrow. The teeth of the
wheel L acting in the leaves of the pinion turn the escapement wheel K in
the direction of its arrow, and the teeth of the escapement wheel K are
detained by the pallets a,.b, so as to prevent the wheel turning round, except
one tooth, at every time the pendulum vibrates. The pallets are. two small
sectors of polished steel, fixed on the axis I at a small distance behind each
other, and the adjacent edges are exactly in a line, as shewn in Figs. 6 and 7.
When the top of the pendulum inclines to the left side of the perpendicular
the front pallet a detains the tooth of the escapement, as shewn in Fig. 6;
but when the pendulum returns to the perpendicular the tooth of the wheel.
slips by the edge of the front pallet a and falls upon the second pallet b, as in
Fig. 7; but as the edge of the pallet is inclined or sloped at an angle to the
motion of the wheel, the tooth, when it slips by, gives an impulse to the pallet,
and makes the pendulum swing forwards on the right side of the perpendicular,
which it does until by it gravitation it is brought back, and when it returns to
the perpendicular the tooth which in Fig. 7 was between the two pallets a, b,
and rested against the back pallet b, likewise drops off the sloping edge of
that pallet, and a succeeding tooth of the wheel drops upon the front pallet a
in the manner of Fig. 6. In dropping off the sloping edge of the pallet 6 the
tooth of the wheel inpels the pendulum to the left; and in this manner the
action of the machine continues till the spring is uncoiled, and thus requires
to be again wound up. At every time the tooth of the wheel drops against
either of the pallets it makes a blow, which can be plainly heard; but to
render it more audible and distinct, the end pivot of the axis of the pendulum

page_text: projects through and beyond the cock which supports it, and is made to bear
against a piece of metal plate or thin wood, or other similar substance, which
then receives the blow, and makes a sufficient sound, when the machine is
inclosed in the pyramid A, B, C, Fig. 1 and 2; which may be made of tin or
other metal, and the end pivot of the axis of the pendulum bears against the
sides of the same, as shewn in Fig. 2. The divided scale, which is shewn
behind the pendulum in Fig. 1, is for shewing where to place the sliding
weight F upon the rod D, E, for vibrating any required number of times per
minute, and the maker of the instrument must lay down and adjust the divi-
sions of the scale by experiment. The frame which supports the mechanism
consists of a brass plate P, to which cocks p are screwed to support the pivots
of the wheels. R, Fig. 2, is á small wheel, to prevent the over winding of the
spring; it turns round upon a pin screwed to the centre part of the great
wheel L, and a projecting tooth or pin which is fixed the arbor m of the wheel L
acts in notches, which are cut in the edge of the wheel R, and thereby turns
the wheel round upon its centre pin one notch every time the arbor m makes a
revolution; but there are only as many notches cut in the edge of the wheel R,
as the number of times the arbor m is intended to turn round in order to wind
up the spring; and this number of times being completed, the projecting 1.af
of the arbor m stops against the solid edge of the wheel R, and prevents the
arbor being turned any farther, because there is no notch made in the edge of
the wheel to receive the projecting leaf. The metronome may be moved by a
spring barrel and fusee, the same as are used in an ordinary watch, instead of
the spring box, as is represented in the Drawing, and also the number of
wheels may be increased to make the motion continue longer without winding
up, if the same is thought desirable. The metronome shewn in Fig. 3 is more
simple in its structure, as it is adapted to be put in motion by a weight instead
of a spring, and in this case it does not require any other wheelwork than the
escapement wheel K, when the weight can be made to descend from a suffi-
cient height. This instrument is intended to be suspended in a perpendicular
direction in any convenient place, and the brass cock or frame d, d, which
supports the pivots of the escapement wheel K, is screwed to the wood ruler
or scale R, which has a hook or loop at the upper end, by which the instru-
ment is suspended. The line or cord to which the weight M is connected
passes over a pulley fitted upon the axis m of the escapement wheel, with a
ratchet wheel and click, so that it will admit of winding up the weight by
pulling down the small counterweight T, which is attached to the opposite
end of the line. The escapement and the pendulum, with its divided scale,
are the same in this machine as in the former. At the upper end of the