IMPROVEMENTS IN METERS OR REGISTERING APPARATUS FOR THE ELECTRIC LIGHT
Year: 1882

page_text: LETTERS PATENT to Alexander Melville Clark of the firm of A. M and
W. Clark of 53, Chancery Lane, in the County of Middlesex, Patent Agents,
for an Invention of IMPROVEMENTS IN METERS OR REGISTERING APPARATUS
FOR THE ELECTRIC LIGHT Communicated to him from abroad by Lucien
Hours-Humbert and Josserand de Brancion de Liman both of Besançon,
France
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 10th August 1882.
ALEXANDER MELVILLE CLARK of the firm of A M and W Clark of
53, Chancery Lane, in the County of Middlesex Patent Agent IMPROVEMENTS
IN METERS OR REGISTERING APPARATUS FOR THE ELECTRIC LIGHT [Communi-
cated to him from abroad by Lucien Hours-Humbert and Josserand de Brancion
do Liman both of Besançon, France]
In electric lighting the electric tension should be automatically kept constant by
the generator but the consumer cannot (save in systems altogether exceptional)
regulate the supply of electricity to each lamp. An electric lamp, therefore, burns
from the moment the circuit is established always at the maximum intensity, and
is only under the consumer's control so far as regards the time during which it may
be kept in action.
A ineter registering accurately the sum of the periods during which each lamp
has burned would therefore answer all the requirements of this system of lighting.
Such an apparatus would be a time meter but as the consumption of electricity is
directly as the time it will thus be indirectly a meter of consumption
This is the principle of the chronometric register of the present Invention. To
explain its application take the simplest case, that of a consumer using a single
lamp controlled as usual by a key which is turned in one direction to close and
in the other to break the circuit. Alongside this key I arrange a clock movement
which is kept going and furnished with a counter whose operation is intermittent,
being put into action by the act of turning the key to light the lamp and put out
of operation by turning the key in the reverse direction.

page_text: The index of this counter will therefore register the sum of the periods of time
during which the lamp has been lighted which is what is required.
The counter may be put in and out of action electrically instead of mechanically,
by an electro magnet in the circuit of the lamp. In the case of a single lamp the
key is the most simple means, but there are cases when the current could be usefully
employed. In practice however the consumer usually uses a large number of
lamps as in hotels, cafés, theatres and other establishinents and in such cases it
would be obviously impracticable for many reasons to provide each lamp with a
separate meter and what is required is a single meter capable whatever may be the
number of lamps in an establishment, of registering the total duration or sum of
the periods of time during which each and all of the lamps have been in operation
notwithstanding that they may have been lighted and extinguished indiscrimi-
nately and used for unequal periods.
Before proceeding to a detailed description it is necessary to distinguish between
two very different cases. In certain public establishments it is necessary that all
the lamps or series of lamps should be under the control of a central authority,
thus in a theatre the different series of lights on the stage and in the auditorium
are required to be under the control of a single officer, whereas in an hotel for
instance the lamps must necessarily be under the individual control of many
persons.
A complete system of measuring the supply of electricity must therefore provide
for these different requirements.
In the accompanying drawings Figure 1 illustrates the principle of the Invention
of which various modifications will be described hereafter.
A
Suppose the building to be lighted by 20 lamps all under one central control. It
is first necessary to select a unit of time other than the minute which is too
small and the hour which is too long. I therefore adopt as this unit six minutes
which being a decimal fraction of an hour presents appreciable advantages.
clock movement capable of going for say a month, placed at M. would rotate the
cylinder C once in six months. This cylinder which I will call the multiplying
cylinder may be considered as composed of twenty discs c all of the same diameter
and fixed side by side on a common axis a and turning together. The periphery
of the first disc has one tooth, the second two, the third three, and so on up to the
last which has twenty A is a spur wheel having an indeterminate number of
teeth keyed on an arbor b parallel with a so that it can move along the arbor and
engage with any one of the twenty discs C. It is evident that the wheel A will be
revolved to the extent of as many of its teeth, at every complete revolution of the
cylinder. (2,e, every six minutes) as the disc c by which it happens to be actuated,
has teeth. B is a toothed wheel on an arbor parallel with those of the cylinder
and wheel A and provided with twenty teeth and concentrically around this
wheel are twenty keys d corresponding to the twenty lamps of the establishment
(see Figure 2) each key is so arranged that when any one of them is turned to
establish the electric current it acts at same tine upon a tooth of the wheel B
and turns the wheel from left to right the extent of one tooth and inversely when
the key is turned in the opposite direction to break the circuit. The wheel B will
therefore be advanced to the extent of as many of its. teeth as the number of keys
which have been successively turned to light as many lamps. Similarly the
wheel B receives a retrograde movement equal to one tooth for each lamp extin-
guished so that when all the lamps are extinguished the wheel B will be returned
to its initial position. Thus the position of wheel B will always exactly correspond
to the number of lamps in circuit in whatever order the lamps may have been
lighted or extinguished.
The wheel B is caused to act on A by means of suitable mechanism in such a
way that for each advance of one tooth of wheel B the wheel A is shifted along its
arbor the distance of a disc c and similarly but in the opposite direction for each
retrograde movement of wheel B so that the wheel A shall always be in gear with
that one of the discs c whose number of teeth correspond with the position of

page_text: wheel B i,e, with the number of teeth it has advanced from its initial position.
Supposing all the lamp to be extinguished it follows that B is at its initial position
and that A is opposite the first section or disc which has no teeth so that wheel A
is not actuated. If now any one of the keys be turned to light the corresponding
5 lamp the wheel B will be advanced one tooth and this movement being transmitted
to wheel A the latter will be brought opposite the disc or section of cylinder C
which has one tooth. The wheel A will then be advanced to the extent of one of
its teeth once every six minutes, which movement is communicated to the index of
the meter which will register five units of time if one lamp only has been alight
at a time during half an hour or ten units for an hour. If a second lamp be lighted
at any moment the wheel A is brought opposite the disc or section of the cylinder
which has two teeth and its speed is consequently doubled, and similarly for any
number of lamps so that if the whole of the twenty lamps are lighted wheel A
will be advanced twenty teeth every six minutes and the meter will register
accordingly. Similarly when the lamps are successively extinguished the speed of
the metre will decrease correspondingly and it will cease to register entirely when
the last lamp is extinguished. E is a safety disc covering wheel B so as to prevent
its being acted on by more than one key at a time. It has a semi-circular recess
in the edge just large enough to permit the turning of the bit d of that one of the
keys opposite which is brought by turning the disc E by means of its locking
handle G the other keys being meanwhile prevented from turning by the disc E
so that all fraud is prevented. The teeth of the different sections of the multiplying
cylinder C and of wheel A are such that the latter can only be turned one tooth
by one tooth of the cylinder and so that in the longitudinal movement of wheel A
no hitch can occur. The wheel A actuates the barrel pinion E which is in gear
with a wheel I which in turn actuates the register mechanism contained in
chamber K and which may be of any suitable construction. It will be seen that
the electrical consumption may be registered with exactitude by means which the
consumer can comprehend and the correctness of which he can verify. This it is
impossible to do in the case of meters based on chemical decomposition heretofore
proposed even admitting that the latter can give equally accurate indications which
is more than doubtful. I have so far referred only to the successive lighting of
the lamps but it is required in many cases to light the whole of the lamps or series
in a building simultaneously and to permit by this being done it should be under-
stood that the lamps may first be put in readiness and then be lighted by turning
a single independent key which establishes the general electrical circuit the meter
being only brought into operation by the movement of that key whereupon it
immediately commences to work at a speed commensurate with the number of
lamps in operation. The instrument hereafter described is merely a modification
of the apparatus just described with which it is identical in principle. In this
case the action of the keys is employed in the same manner and the cylinder O
which is the essential and characteristic part of the apparatus is also retained and
fulfils in a different way, it is true, a similar function. The difference consists in
the substitution of electric for mechanical agency for putting the registering
mechanism into action whereby the apparatus is rendered extremely simple and
may be employed as a common type of meter indifferently in cases when the lighting
and extinction of the lamps is effected at a central station, and where these two
operations are effected in distinct places. In this arrangement the keys always act
as commutators as explained hereafter.
The apparatus thus modified is composed essentially of two cylinders A B. (see
Figure 3) of the same length and diameter placed parallel and in position to make
contact with one another as bereafter described. B is the multiplying cylinder and
A the distributing cylinder. The figures on the cylinder B (the multiplying
cylinder) indicate the number of metallic contacts on each section thereof. Cylinder
B is identical with the cylinder C above described except that in lieu of teeth it
has a like number of metallic contact pieces fixed in an insulating material and all
connected with a central conductor. It rotates once in six minutes as before. The

page_text: distributing cylinder
takes the place of the spur wheel A, the devices which
operate the same, and the wheel B acted on by the keys d. This distributing
cylinder A is actuated by two electro magnets one of which causes it to turn one
division in the direction from right to left when one lamp is lighted, the other
causing it to turn in the reverse direction one division when a lamp is
extinguished, in either case by the intervention of keys as before explained. This
cylinder which is composed of non conducting material is also provide with
inetallic contacts connected to a central conductor. These contacts are bedded on
an elastic surface which allows them to yield under pressure of the contacts on B
and to ensure good contact.
In the typical case of an establishment provided with twenty lamps the
cylinder A would be divided lengthwise into twenty-one equal sections of which
the first would have no contact each of the others being furnished with a single
contact making twenty in all arranged in a helical line It will be readily under-
stood that by the rotation of the distributing cylinder A by the electro magnets
each of its contact pieces may be brought onto the line of contact of the two
cylinders and in this position during an entire revolution of the multiplying
cylinder B a number of contacts will be made equal in number to the number of
contact pieces of the section of the multiplying cylinder B to which a contact piece
of cylinder A is opposite.
These electrical contacts bring into operation a third electro magnet which at
each vibration, causes the escape of one tooth of the first wheel of the register.
This description will suffice for the comprehension of the working of the
apparatus thus modified.
Suppose all the lamps to be extinguished, the multiplying cylinder B performs
its revolution being actuated as in the previous case by a clock movement M; but
the distributing cylinder A is at zero, that is to say it is its division which has no
electrical contact which is now opposite to the cylinder as shown in figure 3 so that
no contact & consequently no electrical vibration is produced.
ર If a lamp be lighted the distributor A is rotated by the action of the electro-
magnet to the extent of one division from left to right and the first contact piece
is presented opposite to the first longitudinal section of the multiplier B, so that at
each revolution of the latter an electrical contact will be made which will cause
the third electromagnet to be excited and advance the register wheel one tooth.
'
If three, four, or ten lamps be lighted, it is the third, fourth, or tenth contact
point which will be brought to the line of contact of the two cylinders, and
consequently opposite to the third, fourth, or tenth section of the multiplier as the
case may be, and during each revolution the latter there will be produced a
corresponding number of electrical vibrations and the register will be advanced a
corresponding number of teeth,
The extinction of one or more lamps produces an analogous result in the inverse
direction and if all be extinguished the distributor is returned to zero.
The above described construction of the two cylinders is the most easily
understood but it is possible to sensibly reduce the number of sections of the
multiplying cylinder B and consequently to diminish the length of the two
cylinders:
L
This result is obtained by providing the distributing cylinder with longitudinal
rows of contact pieces varying in number in each row from one to a number equal
to the number of sections of the multiplier, so that either one or several or all of
these sections may act simultaneously so as to produce at each revolution a number
of electrical vibrations equal to the total number of points of contact of the
multiplier, but in this case in order to avoid the meeting of several contact points
at the same instant which would have the effect of causing but a single electrical
vibration when several should be made, care must be taken to distribute the points
of contact of the multiplier in different and equidistant lines so that these various
contacts shall only come successively and at regular intervals into contact with
the contacts on the distributor which are in the line of contact for the time being.

page_text: This construction will be understood from figures 4 and 5 which respectively
represent the multiplying cylinder B and the distributing cylinder A, projected on
a plane. These diagrams are arranged for 50 light meter. The whole of the
apparatus is comprised by these two cylinders, the three electromagnets, the clock
movement, and the three external wheels constituting the register or counter.
The form of a cylinder has been adopted for the multiplier and distributor as
being the most practical but this form is not obligatory. Other and quite different
forms may be used according to circumstances; for instance a disc. upon the face
of which contacts would be placed. The essential principle consists in the
combination whereby under the action of the keys and by a mechanical or electrical
process a multiplying operation is performed the result of which is transmitted to
the register.
When the clock has run down the electric current will be interrupted and the
consumer will be obliged to wind it up again in order renew the current,
whereby the fraudulent and unregistered consumption of the current is rendered
impossible.
The arrangement shown in figures 1 and 2 illustrates the kind of meter for
establishments where all the lamps are under central control and in cases which
most frequently occur where the lighting of the lamps is under individual control
at different distant points it is evident that the apparatus would require modifi-
cation and that the agency of the electric current would be indispensable. The
arrangement of distributing and multiplying cylinder represented in figures 3. 4.
and 5 fulfils the necessary conditions of this case. The general arrangement of the
apparatus may remain unaltered but the wheel B instead of being under the direct
action of the keys d is operated by two electromagnets e (as shown in figure 6)
one of which causes it to advance from left to right at each vibration and the
other causes it to move in the inverse direction, by means of an escapement. In
this figure the wheel B has for axis a screw f which causes a loose wheel retained
by a jumper h to advance or recede. The wheels i and k are operated by a clock
movement.
When a key located at any distant point, is turned for the purpose of lighting a
lamp, this key by means of conducting wires, puts an electromagnet into operation
by which the wheel B is moved from left to right. As many lamps lighted, so
many vibrations of the electro-magnet, so many movements of the wheel B from
left to right, and so many times the wheel A is shifted in the direction of the
motion of the register.
If a lamp be extinguished the inverse motion of the key brings into action the
other electro magnet which produces the reverse movement of the wheel B. (this
action of the key upon one or other of the two electromagnets according to the.
direction in which it is turned being produced by very simple mechanical means)
The wheel B now receives a retrograde motion, which is repeated as many times
for as many lamps as may be extinguished, the motion of the register being
correspondingly slackened.
The Electromagnets may be excited either by a local battery or by the current
which produces the light.
The commutator keys & should have their bits so formed as to intersect one
another when placed as close together as represented in the drawing but this form
of bit has not been represented, for the sake of simplicity. Plain key bits may be
used by having only one key for two teeth.
The wheel B moved by the key is provided with a jumper which ensures the
accurate completion of the movement commenced by the action of the key

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Melville Clark in the Great Seal Patent Office on
the 10th February 1883.
ALEXANDER MELVILLE CLARK of the Firm of A, M, and W, Clark of
53 Chancery Lane in the County of Middlesex Patent Agents IMPROVEMENTS
IN METERS OR REGISTERING APPARATUS FOR THE ELECTRIC LIGHT a communication
to me from abroad by Lucien Hours-Humbert and Josserand de Brancion de
Liman, both of Besançon, France
In gas lighting the consumption may vary according to the difference of pressure,
and also at the will of the consumer who is able to control the supply to each
burner, whereas in electric lighting, whilst on the one hand the electric tension may,
and should be automatically kept constant by the generator, the consumer is on
the other hand unable (save in systems altogether exceptional) to regulate the
supply of electricity to each lamp. An electric lamp therefore, burns from the
moment the circuit is established, always at the maximum intensity, and is only
under the consumer's control so far as regards the time during which it may be
kept in action.
A meter registering accurately the sum of the periods during which each lamp
has burned would therefor answer all the requirements of this system of lighting.
Such an apparatus would be a time meter, but as the consumption of electricity is
directly as the time, it will thus be, indirectly, a meter of consumption.
This is the principle of the chronometric register of the present invention To
explain its application, take the simplest case, that of a consumer using a single
lamp controlled as usual by a key which is turned in one direction to close, and in
the other to break the circuit. Alongside this key I arrange a clock movement
which is kept going, and furnished with a counter whose operation is intermittent,
being put into action by the act of turning the key for the purpose of lighting the
lamp and put out of operation by turning the key in the reverse direction.
The index of this counter will therefor register the sum of the periods of time
during which the lamp has been lighted, which is what is required.
The counter may be put in, and out, of action, electrically, instead of mechanically,
by an electro-magnet in the circuit of the lamp. In the case of a single lamp the
key is the most simple means, but there are cases when the current could be
usefully employed
In practice however the consumer, usually, uses a large number of lamps, as in
Hotels, Cafés, Theatres and other establishments, and in such cases it would be
obviously impracticable, for many reasons, to provide each lamp with a separate
meter, and what is required is a single meter capable, whatever may be the number
of lamps in an establishment, of registering the total duration or sum of the periods
of time during which each, and all, of the lamps have been in operation notwith-
standing that they may have been lighted and extinguished, indiscriminately, and
used for unequal periods...
Before proceeding to a detailed description it is necessary to distinguish between
two very different cases. In certain public establishments it is necessary that all
the lamps or series of lamps should be under one central control; thus in a Theatre.
the different series of lights on the stage, and in the auditorium, are required to be
under the control of a single officer, whereas on the other hand in an Hotel, for
instance, the lamps must necessarily be under the individual control of many
persons.
A complete system of measuring the supply of electricity must therefore provide
for these different requirements.

page_text: In the accompanying Drawings, Figure 1 illustrates the principle of the invention
of which various modifications will be described hereafter.
Suppose the building to be lighted by 20 lamps, all under one central control. It
is first necessary to select a unit of time other than the minute which is too small,
and the hour which is too long. I therefore adopt as this unit six minutes,
which being a decimal fraction of an hour, presents. appreciable advantages. A
clock movement, capable of going say a month, placed at M, would rotate the
cylinder C once in six minutes This cylinder which I will call the multiplying
cylinder, may be considered as composed of twenty discs c, all of the same diametor
and fixed side by side on a common axis a, and turning together. The periphery
of the first disc has one tooth, the second two, the third three, and so on up to the
last which has twenty teeth.
A, is a spur wheel having an indeterminate number of teeth, placed on a square
arbor b, parallel with a, so that it can move along the arbor and engage with
any one of the twenty discs c. It is evident that the wheel A will be revolved to
the extent of as many of its teeth, at every complete revolution of the cylinder,
(i.e. every six minutes) as the particular disc c. by which it happens to be for the
time being actuated, has teeth. B, is a toothed wheel on an arbor parallel with those
of the cylinder and wheel A, and provided with twenty teeth, and concentrically
around this wheel are twenty keys d, corresponding to the twenty lamps of the
establishment, (see Figure 2) Each key is so arranged that when any one of them
is turned to establish the electric current, it acts at same time upon a tooth of the
wheel B, and turns the wheel from left to right to the extent of one tooth, and
inversely when the key is turned in the opposite direction to break the circuit.
The wheel B, will therefore be advanced to the extent of 1. 2. 3. 4 or more of its
teeth, according as 1. 2. 3. 4 or more keys have been successively turned to light as
many lamps. Similarly, the wheel B receives a retrograde movement equal to one
tooth for each lamp extinguished, so that when all the lamps are extinguished the
wheel B will be returned to its initial position. Thus the position of wheel B will
always exactly correspond to the number of lamps in circuit in whatever order the
lamps may have been lighted, or extinguished.
The wheel B is caused to act on A, by means of suitable mechanism in such a
way that each advance of one tooth of wheel B, the wheel A is shifted along its
arbor the distance of a disc c, and, similarly, but in the opposite direction, for each
retrograde movement of wheel B, so that the wheel A shall always be in gear with
that one of the disc c whose number of teeth corresponds with the position of
wheel B i.e. with the number of teeth it has advanced from its initial position, and
consequently with the number of lamps in circuit. Supposing all the lamps to be
extinguished, it follows that B is at its initial position, and that A is opposite the
first section or disc which has no teeth, so that wheel A is not actuated. If now
any one of the keys be turned to light the corresponding lamp, the wheel B will be
advanced one tooth, and this movement being transmitted to wheel A the latter
will be brought opposite the disc or section of cylinder C which has one tooth.
The wheel A will then be advanced to the extent of one of its teeth once every six
minutes, which movement is communicated to the index of the meter which will
register five units of time (if one lamp only has been alight at a time) during half
an hour, or ten units for an hour. If a second lamp be lighted at any moment, the
wheel A is brought opposite the disc or section of the cylinder which has two teeth,
and its speed is consequently doubled, and, similarly, for any number of lamps, so
that if the whole of the twenty lamps are lighted wheel A will be advanced twenty
teeth every six minutes, and the meter will register accordingly. Similarly, when
the lamps are successively extinguished, the speed of the meter will decrease corre-
spondingly, and it will cease to register entirely when the last lamp is extinguished.
E is a safety disc covering wheel B so as to prevent its being acted on by more
than one key at a time. It has a semi-circular recess F in the edge, just large
enough to permit the turning of the bit d. of that one of the keys opposite which it
is brought by turning the disc E by means of its locking handle G, the other keys

page_text: being meanwhile prevented from turning by the disc E, so that all fraud is pre-
vented. The teeth of the different sections of the multiplying cylinder C, and of
wheel A, are such that the latter can only be turned one tooth by one tooth of the
cylinder, and so that in the longitudinal movement of wheel A no hitch can occur.
The wheel A actuates the barrel pinion H which is in gear with a wheel I, which in
turn actuates the registering mechanism contained in chamber K. and which may
be of any suitable construction.
It will thus be seen that the electrical consumption may be registered with
exactitude, by means which the consumer can comprehend, and the correctness of
which he can verify. This is impossible to do in the electric meters based on
chemical decomposition heretofore proposed, even admitting that the latter can give
equally accurate indications, which is more than doubtful.
I have so far referred only to the successive lighting of the lamps, but it is
required in many cases to light the whole of the lamps in a building, simultaneously,
and to permit of this being done, it should be understood that the lamps may first
be put in readiness and then be lighted by turning a single independent key which
establishes the general electrical circuit, the meter being only brought into operation
by the movement of that key whereupon it immediately commences to work at a
speed commensurate with the number of lamps in operation.
The instrument hereafter described, is merely a modification of the apparatus
just described, with which it is identical in principle. In this case the action of the
keys is employed in the same manner, and the multiplying cylinder C, which is the
essential and characteristic part of the apparatus, is also retained and fulfils in a
different way, it is true, a similar function. The difference consists in the substi-
tution of electric, for mechanical agency, for putting the registering mechanisin into
action, whereby the apparatus is rendered extremely simple, and may be employed
as a common type of meter indifferently in cases where the lighting and extinction
of the lamps is effected at a central station, and where these two operations are
effected at different places. In this arrangement the keys always act as commutators
as explained hereafter
The apparatus, thus modified, is composed essentially of two cylinders A B (see
figure 3) of the same length and diameter, placed parallel and in position to make
contact with one another, as hereafter described. B is the multiplying cylinder,
and A the distributing cylinder. The figures on the cylinder B (the multiplying
cylinder) indicate the number of metallic contacts on each section thereof.
Cylinder B is identical with the cylinder C, above described, except that in lieu of
teeth it has a like number of metallic contact pieces, embedded in an insulating
inaterial, and all connected with a central conductor. It rotates once in six minutes
as before. The distributing cylinder A takes the place of the spur wheel A, the
devices which operate the same, and the wheel B acted on by the keys d
The distributing cylinder A is actuated by two electro-magnets, one of which causes
it to turn one division in the direction from right to left when one lamp is lighted,
the other causing it to turn in the reverse direction, one division, when a lamp is
extinguished, in either case by the intervention of keys as before explained. The
cylinder A, which is composed of non-couducting material, is also provided with
metallic contacts connected to a central conductor. These contacts are bedded on
an elastic surface which allows them to yield under pressure of the contacts on B
and to ensure good contact.
In the typical case of an establishment provided with twenty lainps, the cylinder A
would be divided lengthwise into twenty one equal sections of which the first
would have no contact, each of the others being furnished with a single contact,
making twenty in all, arranged in a helical line. It will be readily understood that
by the rotation (to or fro according as lamps are lighted or extinguished) of the
distributing cylinder A, by the electro-magnets, any one of its contact pieces may be
brought into the line of contact of the two cylinders and in this position, during an
entire revolution of the multiplying cylinder B, a number of electrical contacts will
be made, equal to the number of contact pieces of the particular section of the

page_text: multiplying cylinder B to which a contact piece of cylinder A is, for the time being,
opposite.
These electrical contacts bring into operation a third electro-magnet which at
each vibration, causes the escape of one tooth of the first wheel of the register.
This description will suffice for the comprehension of the working of the apparatus
thus modified Suppose all the lamps to be extinguished, the multiplying cylinder B
performs its revolution, it being actuated, as in the previous case, by a clock move-
ment M; but the distributing cylinder A is at zero, that is to say, it is its division
which has no electrical contact, that is now immediately opposite to the cylinder B,
as shown in figure 3, so that no contact, and consequently no electrical vibration,
is produced. If a lamp be lighted, the distributor A is rotated, by the action of
its propelling electro-magnet, to the extent of one division from right to left, and
its first contact piece is presented opposite to the first longitudinal section of the
multiplier B, so that at each revolution of the latter, one electrical contact will be
made which will cause the third electro magnet to be excited, and advance the
register wheel one tooth.
If three, four or ten lamps be lighted, it is the third, fourth, or tenth contact
point, of the cylinder A, which will be brought into the line of contact of the
two cylinders, and consequently opposite to the third, fourth, or tenth section of
the multiplier B, as the case may be, and during each revolution of the latter there
will be produced a corresponding number of electrical vibrations, and the register
will be advanced a corresponding number of teeth. The extinction of one or more
lamps, produces an analogous, but opposite, result, the cylinder A being rotated in
the inverse direction, by its reversing electro-magnet, and if all be extinguished the
distributor is returned to zero.
The above described construction of the two cylinders is the most easily under-
stood, but it is possible to sensibly reduce the number of sections of the multiplying
cylinder B, and consequently to diminish the length of the two cylinders
This result is obtained by variously arranging, and combining, the contacts of
the two cylinders, for instance by providing the distributing cylinder with longi-
tudinal rows of contact pieces, varying in number in each row from one to a
number equal to the number of sections of the multiplier, so that either one, or
several, or all of these sections, may act simultaneously so as to produce at each
revolution a number of electrical vibrations equal to the total number of points of
contact of the multiplier; but in this case in order to avoid the meeting of several
contact points at the same instant, which would have the effect of causing but a
single electrical vibration when several should be made, care must be taken to
distribute the points of contact of the multiplier in different, and equidistant lines,
so that these various contacts shall only come successively and at regular intervals
into contact with the contacts on the distributor which are in the line of contact
for the time being. This construction will be understood from the two diagrams
figures 4 and 5, which respectively represent the perimeters of the multiplying
cylinder B and the distributing cylinder A developed upon a plane. These
diagrams are arranged for a 50 light meter. The whole of the apparatus is
comprised by these two cylinders, the three electro-magnets, the clock movement,
and the three external wheels constituting the register or counter. The forin of
a cylinder has been adopted for the multiplier and distributor, as being the most
practical, but this form is not obligatory Other, and quite different forms, may
be used according to circumstances, for instance a disc upon the face of which
contacts would be placed. The essential principle consists in the combination,
whereby under the action of the keys, and by a mechanical or electrical process, a
multiplying operation is performed, the result of which is transmitted to the
register.
When the clock has run down, the electric current will be interrupted, and the
consumer will be obliged to wind it up again in order to renew the current.
Thus the fraudulent and unregistered consumption of the current is rendered

page_text: impossible, the intervention of the consumer in the working of the apparatus being
limited to the winding up of the clock.
The arrangement shown in figures 1, and 2, illustrates, in principle, the kind of
meter for establishments where all the lamps are under central control, and in cases
which most frequently occur, when the lighting of the lamps is under individual
control at different distant points, it is evident that the apparatus would require
modification, and that the agency of the electric current would be indispensable.
The arrangement of distributing and multiplying cylinder, represented in figures 3,
4, and 5, fulfils the necessary conditions of this case. The general arrangement of
the apparatus may however remain as in figures 1 and 2, except that the wheel B,
instead of being under the direct action of the keys d, is operated by two electro-
magnets e (as shown in figure 6) one of which causes it to advance from left to
right, at each vibration, and the other causes it to move in the inverse direction, by
means of an escapement. In this figure the wheel B has for axis a screw f, which
causes a loose wheel g, retained by a jumper h, to advance or recede. The wheels i
and k, are operated by a clock movement.
When a key, located at any distant point, is turned for the purpose of lighting &
lamp, this key, by means of conducting wires, puts an electro-magnet into operation
by which the wheel B is moved from left to right
According to the number of lamps lighted, so many vibrations will there be of
the electro-magnet, so many movements of the wheel B from left to right, and so
many times the wheel A is shifted accordingly
If a lamp be extinguished, the inverse motion of the key brings into action the
other electro magnet which produces the reverse movement of the wheel B (this
action of the key upon one or other of the two electro magnets, according to the
direction in which it is turned, being produced by very simple mechanical means.)
The wheel B now receives a retrograde motion, which is repeated as many times
for as many lamps as may be extinguished, the motion of the register being
correspondingly slackened.
The electro magnets may be excited either by a local battery or by the current
which produces the light.
The commutator keys d should have their bits so formed as to intersect one
another when placed as close together, as represented in the drawing, but this form
of bit has not been represented, for the sake of simplicity. Plain key bits, may be
used, by having only one key for two teeth. The wheel B, moved by the key, is
provided with a jumper which ensures the accurate completion of the movement
commenced by the action of the key.
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is.
1 In a chronometric register for the electric light, the combination of a
multiplying toothed cylinder C as described, receiving regular motion from a clock
movement, a toothed wheel B adapted to be turned to a definite extent by each
key in the act of lighting and extinguishing each lamp, a shifting wheel A adapted
to be geared with any one of the toothed sections of cylinder C whilst remaining
in gear with the barrel pinion H, a safety disc E and locking handle G, all arranged
and operating as herein described and represented in Figure 1 for the purpose
specified.
2nd. The multiplying cylinder C, composed of 20 sections c having a progressively
increasing number of teeth for rotating the shifting wheel A, intermediate between
it and the registering mechanism, at a speed proportionate to the number of lamps
lighted, as described and illustrated in Figure 1.
3rd The construction, combination, and arrangement of the distributing and
multiplying cylinders A and B respectively provided with electrical contacts, as
herein described, and shown in Figure 3, and respectively combined and actuated,
the one, A, by electrical mechanism brought into action by the lamp-lighting and

page_text: extinguishing keys, and the other by clock mechanism, substantially as and for the
purpose herein specified.
4th The combination and arrangement of the electrical contacts of the multiplying
and distributing cylinders, combined for operation, as described, so as to leave
sufficient interval between successive contacts whatever may be their number, as
herein described and illustrated in Figures 4 and 5.
5th The mechanism for controlling wheel B from a distance, consisting of an
escapement and two electro inagnets e, in combination with wheel B, mounted on a
screw f, loose wheel g, jumper h, and wheels ik operated by a clock movement, all
as described and represented in Figure 6 for the purpose specified.
In Witness whereof I the said Alexander Melville Clark have hereunto set
my hand and seal this tenth day of February, A.D. 1883.
A M CLARK
01