TELEPHONIC APPARATUS, PARTS OF WHICH APPARATUS ARE APPLICABLE FOR TELEGRAPHIC AND OTHER LIKE PURPOSES
Year: 1883

page_text: "
LETTERS PATENT to Walker Moseley of Queens Road, St Johns Wood, in the
IMPROVEMENTS IN
County of Middlesex, Electrician, for an Invention of
TELEPHONIC APPARATUS, PARTS OF WHICH APPARATUS ARE APPLICABLE FOR
TELEGRAPHIC AND OTHER LIKE PURPOSES
"
PROVISIONAL SPECIFICATION left by the said Walker Moseley at the Office
of the Commissioners of Patents on the 16th March 1883.
WALKER MOSELEY of Queens Road, St., Johns Wood, in the County of
Middlesex, Electrician, "IMPROVEMENTS IN TELEPHONIC APPARATUS, PARTS OF
AND
APPARATUS
APPLICABLE
WHICH
PURPOSES "
ARE
FOR
TELEGRAPHIC
OTHER
LIKE
The main object of this invention is to provide for transmitting the human voice
by means of apparatus that will effect all the objects desired with greater economy
and in less time than is practicable with any existing apparatus or system and
at the same time will be less liable to wear and tear and accident than any
heretofore used.
This improved apparatus is particularly applicable for public exchanges whereby
any subscriber to a system may be put into communication with any other
subscriber attached to the same system as himself, or to any other exchange in
alliance therewith.
. The said invention relates to improvements in the apparatus known as the
"Blake transmitter" also to an adaptation of a carbon transmitter to serve as a
receiver, also to a transmitting instrument which transmits a varying continuous
current but not such as is generally known as an undulatory current or
line" which instrument is adaptable for use either for long or short distances and
either with or without an induction coil.
" wave
The said invention also comprises various improvements in receivers as herein-
after described. It also comprises an indicator or annunciator to call attention to
the telephone in which indicator the exposed surface presents a large front in
proportion to the bulk of the apparatus, the main feature in its construction being
that a light circular disc is pivotted at the two sides of its circumference-by means
Din 0.17

page_text: .
of a pinion which is revolved by a small rack at the end of a movable core
traversing a hollow electro-magnet. Also an indicator or annunciator intended to
be operated by any subscriber to an exchange system putting a continuous current
in action by which the indicator remains in view beyond control of the exchange
operator until attended to. The main features of this indicator are an adaptation
of a horizontal galvanometer the dial of the horizontal instrument being reflected
in a mirror at such an angle as will render the movable dial as readable by its
reflection in the mirror as if placed vertically. It also relates to a shunt indicator
by which the preceding or any other form of indicator may be supplemented by an
additional indicator to shew how the line is being operated upon. And to an
adaptation of a time taker on the principle of the ordinary hour glass.
It also comprises a multiple switch board by which I provide for the connection
with every subscriber on each board so that one operator can attend to a number of
subscribers and put them in communication with any other subscriber connected
with the same exchange or any other exchange through a trunk line provided for
the purpose to be connected with the required number without any communication
with any other operator in the same .exchange. Also a spring winding flexible
cord.
The said invention also relates to a constant battery of a compact and portable
form in which plates of thin zinc and tin foil form the positive and negative plates
and sulphate of lead is the active electrolytic agent. This battery is designed
solely and especially for use in connection with the apparatus herein described and
will not be claimed apart from such other apparatus
It also relates to a method of uniting or joining up the wires for telephonic or
other purposes in order to secure better continuity and durability by inserting the
two ends of the wire to be joined together into a small tubular socket into which
is dropped a sufficient portion of metal composition known as fusible metal.
The said invention further comprises the employment of a photographic detecting
apparatus hereinafter described.
"
It is found in practice that the instrument known as the "Blake transmitter
requires adjusting from time to time to compensate for wear or for variation of
temperature etc, the necessity for such compensation is chiefly due to the fact that
the complete breaks which frequently occur in speaking loudly into the instrument
cause comparatively rapid consumption of the platinum tip and the opposite point
of contact in the particles of the carbon button. I obviate this difficulty. by inter-
posing a fixed resistance consisting of fine wire to represent the same resistance as
the lightest possible contact between the platinum and the carbon so that no
ordinary or accidental break between the points of contact can deteriorate them as
above described and at the same time the reflex current is prevented from causing
the hissing or snappish sounds that are so frequent and troublesome in these
instruments.
I provide for accomplishing all the purposes of the induction coil and electric
bell by the following combination viz; I make the induction coil on the same
electro magnet as that used to ring the bell the primary wire being used both to
ring the bell by a local battery and to induce the secondary current by means of
my improved "Blake transmitter or other transmitter, the secondary coil is used
to operate a relay from the distant station in order to send the local current
through the primary wire to ring the aforesaid bell.
>>
I make use of a microphone in my improved receiver in the following manner
the line current being received through a small electro-magnet relay the armature
of which presses upon a carbon button in exact correspondence with the varying
current that comes from the transmitter at the distant station. This armature and
carbon button are included in, the circuit of a local battery and electro-magnetic
receiver the magnet coil of which will consist of coarse wire.
The production of any note by, the apparatus termed the "Sirène" proves that
it is not variation in the volume of sound that is required so much as variation in
the number of vibrations whilst at the same time variation of extent of each
J

page_text: vibration that is to say faintness or loudness is required to obtain a complete
reproduction of the distinct quality of each voice.
Whatever complexity there may be in the human voice as to its varying volume
and rapidity of vibrations there cannot be any variations of tone in the sounds,
received in the metallic diaphragm of the receiver which cannot be dilated and
contracted like the living vocal organs and varying rapidity of vibration can be
produced without any variation of the strength of the electric current.
jj
Hence waves of varying rapidity of vibration or waves of varying multitude of
vibration are more essential in the reproduction of the human voice than in the
mere variation of the strength of the electric current and the "wave line'” referred
to and delineated in connection with various patented inventions although of
purely hypothetical and arbitrary characters, which if they do not mystify do not
explain the operations, subsequent to the Reiss invention can be found no less
easily in telephonic operations with the 'electric currents of uniform strength than
with electric currents of varying strength the conductors in each case being of
uniforin thickness throughout; the whole section of the conductor is inade use of
whether the current be weak or strong alternately or uniformly therefore the
pulsations of the transmitted current no. more describe a wave line than do the
successive pulsations of the steam hammer. It does not even appear necessary to
lessen much the abruptness of each pulsation for by means of the Sirène it is
demonstrated that by the revolution of various series of holes past a jet of air
issuing with uniform velocity any" note of music can be produced of excellent
quality by causing the jet of air to impinge upon a series of holes of greater or
lesser number thereby producing a greater or lesser number of concussions having
the same effect as the air concussions produced by the vibrations of the
diaphragın.
The reason why the same law may not appear to have held good in the case of
intermittent pulsations of electricity acting through an electro-magnet upon a
metallic diaphragm is that the interruption of the electric current produces a
revulsion of a peculiarly violent reflex character exciting great heat in the form of
an incandescent spark followed by an arc and a confusing snapping sound causing
analogous vexations in the old form of vibrating or trembling bell. In the
specification of my former Letters Patent dated September 10 A.D. 1873 No 2969
I have described an improved action in which the electro magnet was short
circuited with each blow of the bell hammer, there being no break at all the current
was necessarily continuous.
I now propose to apply exactly the same principle in my telephone transmitter
in such a manner that as the transmitting diaphragm is vibrated with the voice
each vibration will make contact in such a manner that a resistance is cut out of
circuit with each vibration thus sending a continuous current of pulsations of any
desired volume in excess of the constant minimum flow.
I also multiply the resistances and cause the vibrating diaphragm to make
contact successively with a series of very small or minute bars or strips (say from
five to ten) placed edgewise; each of these bars or strips as aforesaid causing the
current to bridge over successive loops of resistance.
I have found that when the carbons used in the "Blake transmitter" touch with
the slightest possible degree of contact, the tip of platinum in such a manner as to
complete an electric circuit, the quantity of current passing such point of contact
does not amount to one fifth of the battery current in use at the time when using
a current of an Ampère and if the pressure is exerted to an extent less than the
strength of the vibration of the human voice the full strength of the current passes
the point of contact and the various intermediate degrees of pressure produce
corresponding variations of the current. Hence it may be taken as a demonstration
that to transmit the complete quality of the human voice there must be a variation
in the resistance opposed to the electric current in use. I have therefore adapted
the principle of fixed resistances to be introduced and cut out alternately by the

page_text: vibration of the human voice so that the varying current received at the other end
of the line will be an approximate reproduction of the same.
I obtain better results than can be realized by the use of the "Edison" or
"Blake" transmitter or other transmitters at present in use, by an improved trans-
mitter of the following construction, I make use of a given length of fine platinum
wire of a resistance equal to about the resistance of the telephone circuit. I divide
this length of wire into any convenient. number of parts (say 10) and a small
section of each of these parts is brought together forming a very small grid or
series of graduated steps. This may be easily arranged by a set of ten narrow
strips, say of silver or platinum, insulated from each other by similar thin strips of
mica the whole thickness being about one sixteenth of an inch; these strips are
connected into as many loops of resistance, forming together the whole resistance
as aforesaid; the centre of the strips in question to be opposed to a small contact
to be operated by a diaphragm which is so adjusted that a slight vibration thereof
causes it to make contact successively with the aforesaid strips thereby diminishing
the resistance of the fine wire by one or more stages. It will necessarily follow
that the loudest sound which will cause the greatest deflection of the diaphragm
will bridge over the ten stages thus cutting out all local resistance and transmitting
the full battery current capacity to the instrument at the distant station.
I obtain a greatly improved effect in the receiving instrument by forming the
poles of an electro-inagnet of a bundle of fine soft iron wire as in a Rubmkorff coil.
The advantage of this construction is more valuable for telephonic apparatus than
for the purpose of the induction coil, for, as is well known, solid iron, even if only
a quarter of an inch thick, will not part with its magnetism quickly enough to
allow perfect correspondence between the variations of the current in the receiver
and the variations of the vibrating diaphragm in the transmitter. I obtain this
result as follows, I arrange the bundle of fine iron wire (which will be a little
more than double the length of the wire coil) as the core of the electro magnet
and bend them back round the circumference of the said coil. Three or four of
these wires I rivet through the diaphragm thus fixing the diaphragm close to the
ring formed by the outer portion of fine iron wire; the relative proportion of the
outside diameter of the coil should be about one third the diameter of the
diaphragm which leaves a considerable part of the surface of the diaphragm
perfectly free from contact with any other part of the apparatus, thus giving a
greater volume of sound for every impulse acting upon it. I may vary this
arrangement by fixing the diaphragm to the centre of the core and leaving a space
between it and the outer circle of iron wires free.
I obtain a very satisfactory result without the use of a metallic diaphragm by
placing a series of vibrating tongues of iron or steel inside a coil of wire the
fixed end of the same being attached to the case.
My improvements in the receiving instrument with parchment or similar
diaphragm are as follows, any form of electro magnet may be adapted to operate a
movable armature by which the varying pressure upon the said diaphragm fixed in
contact therewith will produce corresponding variations of sound which should be
sufficiently developed for practical purposes by fixing a suitable tip to the end of
the armature to impinge upon the diaphragm, the tip being formed of any
suitable material having an attractive affinity for resin or similar substance; the
shape of the said tip is such that it will be released by the diaphragm in such a
manner as to produce a varying sound as each portion of the tip operates upon the
surface of the diaphragm. The sound partakes of the qualities developed by a
drum, tambourine, violin, or similar instrument.
In some instances the diaphragm, instead of being fixed, is revolving at any
suitable speed to vary the volume or quality of the sound produced by the
preceding arrangement.
My improved indicator with revolving discs pivotted on its axis affords the
following advantages viz, The superficial area of the surface exposed to view is
very neatly as large as the full front of the instrument and it is closed and

page_text: disclosed without encroachment upon the surrounding area, thus obtaining greater
concentration of a series of instruments without diminishing the magnitude of the
signal which catches the eye. It requires a less amount of electric force to operate
it, and may be turned to its normal position either manually or electrically by
reversing the current. It is almost silent in its movement and is subject to less
wear and tear than any other known form of such apparatus.
The annunciator with the small horizontal galvanometer is designed to answer
all the purposes of an annunciator and a galvanometer combined.
In order to operate these annunciators for the purpose of calling the attention'
of the exchange operator. I propose to employ such an arrangement that hanging
the telephonic instrument on a particular hook shall put the current on the line-
and retain the deflection of the needle until the operator replies. In order that
the reply may be conveyed notwithstanding the opposing current on the line,
either the exchange battery may be stronger than the subscribers battery, or the
current may be reversed.
It may be desirable to supplement this arrangement by adding a similar galvano-
metric indicator on a shunt line that would always go to earth at the exchange;
by means of this contrivance when two exchange subscribers are in communication
with each other the shunt indicator will remain fully deflected until the corre-
sponding instruments are replaced on the stationary hooks. I propose to adopt
the principle of the ordinary hour glass for the purpose of indicating to the
exchange operator the length of time two subscribers have been placed in
communication.
I make the switch board on such a scale that about one hundred subscribers
occupy the superficial area of fifteen inches square so that as many subscribers as
can be connected to one exchange may be brought within the range of one operator.
For effecting this object I provide a metal tube or cylinder extending through the
switch board from front to back for each subscriber; at the back of the board a
double contact maker is arranged so that when the plug is pushed through any one
of these metallic tubes the aforesaid contacts are separated and the corresponding
number on every other board will be thereby disconnected. I connect a line
through any number on one board through one of the contact makers to the
corresponding number on each successive board returned along through the other
contact maker connected with the same numbers through a magnetic sounder in a
local battery circuit with a branch connecting it to earth.
Therefore if the individual number is disengaged the magnetic sounder will
operate immediately it is touched with a tapper connected with the opposite pole
of the local circuit, and when the plug of the switch board is thrust home the circuit
of every board to the right hand will be broken on one line and every one on the
left hand on the other line.
For connecting one number to another on the same board I make use of a
flexible metallic conductor that is attached at one end to a spring pulley the other
end being simply a plain cylinder plug; by this contrivance all the slack is
tightened up automatically so that the connecting conductors in front of the board
will always form straight lines from one point to another and when disconnected
by the smaller plug it will find its way through any intricacies of adjoining lines
until it is drawn up close home.
The most important feature in the construction of the aforesaid battery is that
when the thin sheets of tin foil are coated with per-oxide of lead the negative
plates having exhausted the active properties of the sulphate of lead rendering
the sulphate useless as an electro-motive generator, they are fully prepared for use
in storage batteries.
The principle of action of this battery is identical with that of the sulphate of
lead battery described in the specification of my former Letters Patent dated
September 29 A.D. 1873 No. 2969.
The part of my invention relating to photographic detectors is designed to be
used in combination with the improvements in the indicating apparatus above

page_text: described or other like apparatus. I apply this photographic detector in order to
check the reports of exchange calls, and by this means to obtain a certain
demonstration as to the exact numbers exposed on the annunciator boards at
certain times and inferentially a fair test of the accuracy with which the calls are
recorded. I fix a photographic camera in such a position that its field will take in
the whole or a portion of the annunciators. A dry sensitized plate is put in the
camera. The shutter is arranged to be operated by a current passing through the
coils of an electro-magnet, which lets the shutter drop by releasing a catch on, or
connected with, the armature. Any line may be used that leads from a central or
main office and may continue in use for other purposes if the armature of the
electro magnet is arranged to require a stronger current than any used for the
other operations.
I sometimes employ clockwork and revolving photographic tissue so as to take
a number of photographic indication's at 'different times.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Walker Moseley in the Great. Seal Patent Office on the
15th September 1883. .
WALKER MOSELEY, of Queen's Road, St John's Wood, in the County of
Middlesex, Electrician. "IMPROVEMENTS IN TELEPHONIC APPARATUS, PARTS OF
WHICH APPARATUS. ARE APPLICABLE FOR TELEGRAPHIC AND OTHER LIKE
PURPOSES.
The main object of my invention is to provide improved apparatus for
transmitting the human voice, which apparatus will act with greater economy and
efficiency and will be less liable to derangement by use or accident than any
apparatus of like nature heretofore employed.
My improved apparatus is particularly applicable for telephone exchanges, and
is designed to enable a subscriber to one exchange to be put into communication
with another subscriber on the same exchange, or with a subscriber on another
Exchange in alliance therewith, by one operator without assistance or information
from any other operator in the same exchange.
"
My said invention relates to an improvement in the apparatus known as the
Blake Transmitter" also an instrument which transmits a varying continuous
current, (but not such as is generally known as an undulatory or "wave line"
current) which instrument may be used either for long or short distances and
either with or without an induction coil.
The said invention, moreover, comprises various improvements in receivers as
hereinafter described.
It also comprises an indicator or annunciator intended to be operated (by any
subscriber to an Exchange system) by causing a continuous current to act upon a
magnetic needle, which needle or a dial attached thereto remains in view beyond
control of the Exchange Operator until the signal thus transmitted by the
subscriber has been attended to. The main feature of this Indicator is an
adaptation of a horizontal Galvanometer, the dial being reflected in a mirror at
such an angle as will render it as readily descernible by its reflection in the
mirror as if placed vertically.
The said invention also comprises a Multiple Switch-Board by which I provide
for the connection of one subscriber with any other subscriber on each Board so
that one operator can attend to a number of subscribers and can put either or any
of them in communication with one or more subscribers connected with the same
Exchange or with another exchange through a line provided for the purpose,
without communication with any other operator in. the saine Exchange.
The said invention further comprises the employment of a photographic tell-tale
apparatus hereinafter described.
It is found in practice that the instrument known as the "Blake Transmitter"
requires adjusting from time to time to compensate for wear or to arrange the
point of contact which, by reason of variations of temperature, is sometimes shifted
from a clean part of the surface of the contacts to a part which does not act
satisfactorily. The necessity for such compensation is chiefly due to the fact that
the complete breaks of the circuit which frequently occur in speaking loudly into
the instrument cause comparatively rapid oxidation and consequent consumption of
the platinum tip and the carbon button,
According to one part of my said invention I obviate this difficulty by introducing
into a shunt off the primary circuit a fixed resistance consisting of fine wire and
equivalent to the resistance corresponding to the lightest possible contact between

page_text: the platinum and the carbon, that is to say, about five times the resistance of the
primary circuit so that no break between the points of contact can deteriorate
them as above described and the reflex current is prevented from causing the
hissing or snapping sounds that are so frequent and troublesome in these
instruments. This fine wire must be arranged so as to bridge over the gap that
occurs when the contact between the platinum tip and the carbon button is
broken.
In the accompanying drawings
Figure 1 is a front elevation of one form of transmitter constructed according to
'my said invention.
Figure 2 is a vertical central section of the same, the contacts being shown in
elevation.
The remaining Figures are hereinafter described
The production of any musical note by the apparatus termed the "Siren" proves
that it is not variation in the loudness or volume of sound that is required, to
produce the various notes of speech or music so much as variation in the number
or rapidity of the vibrations; whilst at the same time variation of extent of each
vibration, that is to say, faintness or loudness, is required to obtain a complete
reproduction of the characteristics of each voice. Whatever complexity there may
be in the human voice as to its varying volume and rapidity of vibrations when
speaking into a telephone transmitter, there cannot be any variations of tone in
the sounds produced by the diaphragm of the telephone receiver, which cannot be
dilated and contracted like the living vocal organs. Moreover varying rapidity of
vibration can be produced without any variation in the strength of the Electric
current.
Hence varying rapidity of vibration or varying multitude of vibration are more
essential to the reproduction of the human voice than mere variation in the
strength of the Electric current, and the "wave line" referred to and delineated in
connection with various patented inventions, is of a purely hypothetical and
arbitrary character which, if it does not mystify, does not explain the operations of
the transmitting instruments used subsequently to the Reiss inventions. Whether
Electric currents of uniform strength or of varying strength are used, the conductors
in each case being of uniform thickness throughout, the whole section of the
conductor is made use of whether the current be weak and strong alternately or
whether it be of uniform strength; therefore the pulsations of the, transmitted
current no more describe a wave line than do the successive pulsations of a steam
hammer. It does not even appear necessary to lessen to any great extent the
abruptness of each pulsation, for by means of the "Siren" it is demonstrated that,
by the revolution of various series of holes past a jet of air issuing with uniformn
velocity, any note of music can be produced of excellent quality, by causing the
said jet of air to impinge upon a series of holes of greater or less number, thereby
producing a greater or less number of concussions having the same effect as the air
concussions produced by the vibrations of the diaphragm of a telephone.
The reason why the same law may not have appeared to hold good in the case
of intermittent pulsations of electricity acting through an electro-magnet upon a
metallic diaphragm is that the interruption of the Electric current produces a
revulsion of a peculiarly violent reflex character causing great heat in the form of
an incandescent spark, and a confusing snapping sound.
In the specification of my former Letters Patent dated September 10th A.D. 1873.
N° 2969, I have described an apparatus in which an electro-magnet is short-
circuited at each blow of a hammer upon a bell, so that the current employed is
continuous.
I now apply the same principle to a telephone transmitter in such a manner
that, as the diaphragm is vibrated by the voice, one or more resistances are cut
out of, or introduced into, the circuit with each vibration; thus sending con-
tinuously a pulsating or vibratory current of any desired volume in excess of the
constant minimum flow."

page_text: I have found that, when the carbons used in the Blake Transmitter" touch
with the slightest possible degree of contact the tip of platinum in such a manner
as to complete an electric circuit, the quantity of current passing the point of
contact does not amount to one-fifth of the battery current in use at the time,
when using a current of one Ampère. And when a pressure is exerted upon the
contacts less than that caused by the vibrations of the human voice, the full
strength of the current passes the point of contact, the various intermediate degrees
of pressure producing corresponding variations of the current. Therefore it may
be assumed that to transmit the complete quality of the human voice there must,
be a variation in the resistance opposed to the electric current in use. I therefore
employ the principle of fixed resistances alternately introduced into, and cut out
of the circuit by the human voice or by musical sounds, so that the varying
current at the receiving end of the line will approximately reproduce the said.
sounds.
I obtain better results than can be realized by the use of the "Edison,"
" "Blake"
or other transmitters at present in use by my improved transmitter which is
constructed as hereinafter set forth.
In Figures 1 and 2, a is the box or case of the instrument and b is the
diaphragm; c, c, are a series of bobbins each wound with a fine platinum or silver
wire forming a resistance. These wires are each connected to two of a series of
metal strips done on each side of the bobbin, so that all. the said strips are
connected in series, the current entering by the wire e and leaving by the wire e¹.
These strips may be of silver, platinum or other suitable material and are insulated
from each other by thin strips of mica or films of shellac and by ebonite pieces f
There are ten of these strips, which are connected to the said wires, forming
together a resistance equal to that of the other parts of the circuit. Upon the fifth
and sixth strips bears a small contact maker g fixed to the arm g¹ which is provided
with a button g2 bearing against the diaphragm and is carried by a spring g³.
This contact maker is operated by the diaphragm which is so adjusted that a slight
vibration thereof causes contact to be made successively with the aforesaid strips
thereby connecting two or more of them and diminishing the resistance by short-
circuiting one or more of the fine wire coils. The loudest sound (which will cause
the greatest deflection of the diaphragm) will cause the said contact maker to
bridge over the ten strips thus cutting out all local resistance and transmitting the
full battery current to the Instrument, at any desired station. I provide an
adjusting screw h which can be connected to the contact maker by a silk thread,
so that the same may be adjusted to bear upon a different part of the said
strips.
I obtain a greatly improved effect in the receiving instrument by forming the
poles of an electro-magnet of a bundle of fine soft iron wires as in a Ruhmkorff
coil. This construction is more advantageous for telephonic apparatus than for
the purpose of the induction coil, for (as is well known) an iron rod even if only
a quarter of an inch thick will not part with its magnetism rapidly enough to
permit perfect correspondence between the force of the vibrations of the trans-
mitter and if the receiver. I construct the receiver in the following manner that
is to say:-I arrange a bundle of fine iron wires as the core of the electro-magnet
which wires should be slightly more than double the length of the electro-magnet.
These wires are bent back over the circumference of the said magnet, and three or
four of them are rivetted through the diaphragm thus fixing the same close to the
rings formed by the outer portions of the said wires; the outside diameter of the
coil should be about one third of the diameter of the diaphragm so as to leave
a considerable part of the surface of the diaphragm free from contact with any
other part of the apparatus and thus enable a greater volume of sound to be
produced for every impulse acting upon the said diaphragm. I may vary this
arrangement as shewn in Figure 3 which is a sectional elevation and in which
is the bundle of wires, j is a wire coil and j' is an additional coil outside of the
said wires i, in this case the diaphragm is fixed to the centre of the core formed

page_text: of the bundle of wires and a space is left between the said diaphragm and the
ends of the outer portions of the said wires.
My improved annunicator or indicator is shewn in Figures 4 to 7 and is designed
to answer the purposes. of an annunciator and a galvanometer.
Figure 4 is a front elevation of my improved annunciator and part of the switch-
board to which it is attached.
Figure 5 is a transverse section of the annunciator on the line x, x Figure 4,
drawn to an enlarged scale.
Figure 6 is a front elevation of part of the same drawn to this enlarged scale,
and
Figure 7 is a plan shewing two of the dials, also drawn to the same enlarged
scale.
The annunciators at present in use require an electric current of considerable
strength before the indicator will move in the slightest degree and its action is then
uncertain, even with, a moderately strong current by reason of the frequent changes
that take place in resistance and leakage and the diminution of battery power.
But in my improved indicator or annunciator the condition of the line and the,
battery power are indicated by the amount of deflection of the polarized needle.
The attention of the operator at the exchange is called by the position of the
needle k or a figure card or dial ¹ mounted thereon in a similar manner to that of
a mariner's compass. This needle and the dial are mounted upon a pivot and
half of the said dial is enclosed in a coil of wire m, and the dial is reflected in the
mirror n as shewn at k². The needle is attached to its normal position by the
employment at the back of each instrument of a permanent magnet o of suitable
power. One end of this magnet is placed in proximity to the circle described by
the ends of the said needle as it rotates. The pole of the magnet in proximity to
the needle must be of opposite polarity to that end of the needle beneath the
indicating portion of the dial so as to retain this portion out of sight when no
current is passing. It is obvious that a slight uniform force is thus available to
keep the indicators in their normal position without the necessity for any delicate
or troublesome adjustment.
In order to operate these annunciators for the purpose of calling the attention
of the exchange operator I employ an arrangement whereby the subscriber by
hanging the telephonic instrument on a particular hook will complete the circuit
and cause a current to pass through the line and deflect the needle until the
exchange operator replies and the subscriber removes the telephonic instrument
froin the said hook in order to use it thereby breaking the circuit and indicating to
the exchange operator, that he has the instrument in his hand. In order that the
-reply may be conveyed notwithstanding the opposing current on the line either
the exchange battery may be stronger than the subscribers battery or the current
may be reversed.
It may be desirable to supplement this. arrangement by adding a similar
galvanometric indicator on a shunt line passing to earth at the exchange; by
means of this contrivance when two exchange subscribers are in communication
with each other the shunt indicator will remain deflected until the corresponding
instruments are replaced on the hooks.
I adapt the principle of the ordinary hour glass for the purpose of indicating to
the exchange operator the length of time two subscribers have been placed in
communication.
I make the switch board on such a scale that a superficial area of fifteen inches
square is sufficient for one hundred subscribers so that as many subscribers as it is
practicable to connect to one exchange may be brought within the range of one
operator. For putting one subscriber in communication with another I provide a
metal tube or cylinder extending through the switch board from front to back for
each subscriber. At the back of the said board a double contact maker is arranged
so that when the plug is pushed through any one of these metal tubes the contacts
are separated and the corresponding number in every other board will be thereby

page_text: disconnected. I connect the corresponding numbers on the different switch boards
through one set of contacts on each successive board, the return circuit forming a
loop at the end board and being connected with the other set of contacts and then
to a magnetic sounder or a silent annunciator in a local battery circuit. Therefore
if any individual number is disengaged the magnetic sounder or silent annunciator
will operate immediately it is touched with a tapper connected with the opposite
pole of the local circuit and when the plug of the switch-board is thrust home the
circuit of every board to the right hand will be broken on one line and every one
on the left hand on the other line.
•
This arrangement will be understood by reference to Figures 8 to 12.
Figure 8 is a central longitudinal section of one form of my.double contact
maker.
Figure 9 is a plan of the same
Figure 10 is a plug for fitting into the tube thereof
Figure 11 is an end view of the said plug, and
Figure 12 is a diagram shewing the connections between one switch-board and
another
p is a block of ebonite or other suitable material having two recesses or holes p'.
closed at the bottom by brass pieces p² p³ and containing mercury.
These blocks
are each secured by screws to a plate q carried by the tube q passing through the
switch-board. Two plugs or floats are secured to a plate of a non-conducting.
material, so that they can be inserted in the said recesses.
Sufficient mercury is
placed in the latter to cause the said plugs to float and hold the plate slight
distance above the top of the block. But the said plugs are normally held down
by a spring o fixed in the tube q' so that the mercury is forced upward and flows
into the recesses or holes t, t¹ which are fitted with brass pieces t² 3 connected with
the terminals u u. The plate q is electrically connected to the plug p²,. q2 is the
plug for fitting into the tube q' in the ordinary manner. The plug shown in
Figures 10 and 11 is made with wires q* which make contact with the tube in a'
very advantageous manner
In Figure 12 v, v, v represent three of these double contact makers corresponding
to the same number, but each pertaining to a different switch-board. The brass
piece p² of one contact maker is connected to the piece t³ of the adjacent contact
maker on the right hand side and the piece 23 with the piece t2 on the left hand
side. It will therefore be seen that when the plug is inserted in one of the
tubes q (Figure 8) and the spring is raised the mercury will descend in tho
recesses p and will break contact between the pieces p², p³ and t², t³.
Another form of double contact maker is shown in Figures 13, 14 and 15.
Figure 13 is a longitudinal central section of this device
Figure 14 is a plan of the same, and
Figure 15 is an end view thereof. This device has a tube q¹ passing through
the switch-board and having a slot q3 formed in its end. A plunger w is fitted*
loosely in this tube and is surrounded by a spiral spring w¹ which bears against a
head won the said plunger and against a collar q* fixed in or forming part of the
said tube. The said plunger is made of ebonite or other insulating material and
has fixed in it two small rods y carrying the wedge-shaped blocks y'.
These blocks in their normal position are held between the brushes or contact
strips and ' by the spring w¹. The said strips are secured to the posts A by
Screws A¹.
When the plug q2 is inserted a sufficient distance into the tube q¹ it.
presses the plunger inward against the force of the spring and breaks the circuits.
For connecting one number to another on the same board I make use of any
ordinary flexible metallic conductor.
The part of my invention relating to photographic tell-tale apparatus is designed
to be used in combination with the improved indicating apparatus above described
or similar apparatus. I apply this photographic tell-tale apparatus in order to
check the reports of exchange calls, and by this means to obtain a record of the,
exact numbers exposed on the annunciator boards at certain times and inferentially.

page_text: .
a-fair test of the accuracy with which the calls are recorded. I fix a photographic
camera in such a position that its field will take in the whole or a portion of the
dials of the annunciator. A roll consisting of a long length of sensitized tissue or
paper is put in the camera, the roller being operated by clock-work; and the shutter
is arranged to be operated by passing a current through the coils of an electro-
magnet B as shewn in Figure 16, which magnet attracts the armature C and
thereby disengages the catch C on or connected therewith from a notched wheel D
connected with the clockwork so that the shutter is operated and the sensitized.
tissue is then moved by the clockwork until the wheel D is again arrested by the
catch C¹. Any line may be used that leads from a central or main office and may
continue in use for other purposes if the armature of the electro magnet is arranged
to require a stronger current than is used for the other operations.
I provide the following means for enabling me to utilize the secondary current
from one station to put the local battery at another station into action for ringing
the bell, and thereby reduce the battery power required to one fourth of that
usually employed with telephonic apparatus.
This part of my invention is illustrated in Figure 17, which is a diagram shewing
the telephonic apparatus which 1 employ at each station, E is the bell, F the
transmitter and G the receiver. I arrange the induction coil H on the electro-
magnet I that is used to ring the bell. The primary wire is connected to the local
battery K through the contact springs L but the circuit is broken at the contact
point M. The primary wire is used both to ring the bell by acting upon the
armature N and to induce a current in the secondary coil at the other station,
which current is used to operate a relay in order to send the local current at that
station through the primary wire to ring the bell.
The said relay operates as follows, that is to say:-assuming a current from a
distant station to be passing through the secondary coil H; the armature O will
be attracted until it makes contact with the point M and thus completes the circuit
of the primary wire. The current from the battery then causes the bell to be
sounded. When the receiver G is lifted off the hook, the lever P is moved by a
spring so that the circuit is broken at the spring L and the current from the
battery then passes through the transmitter.
When it is desired to ring the bell at the distant station, the push-knob Qis
pressed inward thereby completing the circuit of the primary coil.
According to another part of my invention I use a microphone in combination
with a receiver as shewn in Figure 18, that is to say-the line current passes
through a small electro-magnet R the armature S of which presses upon a carbon
button T in exact correspondence with the varying current that comes from the
transmitter at the distant station. This armature and carbon button and the
receiver U are included in the circuit of a local battery V. The coil of the electro-
magnet of the receiver should consist of coarse wire of about the same length and
thickness as the primary wire of the induction coil in the transmitter.
By these means when a current is passed through the magnet R and contact is
made at T the current from the local battery will act upon the receiver and the
variations in the strength of the current through the line will produce variations
in the current from the local battery corresponding with those in the current
through the line but acting with greater effect upon the receiver than the line
current would have if it were passed around the coil of the receiver
Having thus fully described my said invention and the manner of performing
the same I wish it understood that I Claim.
First. The improvement in the Blake Transmitter consisting in introducing into
the primary circuit a fixed resistance, as and for the purpose, specified.
Second. The improved telephone transmitter wherein I employ a series of
resistances arranged to be cut out of, or put into, the circuit by the vibrations of a
diaphragm acting upon a spring or similar device adapted to make contact with
the edges of one or more of a series of metal strips, substantially as, and for the
purpose, set forth

page_text: Third. The improvements in the receiving instrument consisting essentially in
the employment of a bundle of soft iron wires forming the core of the electro-
magnet, and bent over the coil thereof, (with or without the exterior coil) substan-
tially as, and for the purpose, set forth.
Fourth. The improved annunciator or indicating apparatus wherein I employ a
series of devices each consisting of a polarized needle within a coil of wire as in
a horizontal Galvanometer, the said devices being so arranged in combination with a
mirror or mirrors that one end of the needle or one half of a dial attached thereto will
be reflected in the said mirror or mirrors, substantially as and for the purposes
specified.
Fifth. An improved contact device which closes and breaks the circuit in two
places as and for the purposes above specified.
Sixth. A contact device in which mercury is employed in such a manner that
the contact is made or interrupted between two bodies or portions thereof by the
flow of the mercury instead of by the movement of a piece of brass or similar
metal.
Seventh. The modifications of my improved contact device substantially as
described with reference to Figures 13, 14 and 15 of the drawings for the purpose
specified.
Eighth. The photographic tell-tale apparatus wherein I employ an electro-
magnet to release a train of clockwork for opening and closing the shutter of
a camera and revolving a roll of sensitized material, as and for the purpose
specified.
Ninth. The improvements in telephonic apparatus consisting essentially in the
employment of a secondary, coil around the electro-magnet for operating the bell
arranged in combination with the other parts of the apparatus substantially as
described, for the purposes specified.
Tenth. The combination, with a receiver of a microphonic contact regulated or
controlled by the armature of an electro-magnet in the manner or on the principle
of a relay for the purpose above specified.
Eleventh. The improved plug constructed substantially as described with
reference to Figures 10 and 11 for the purposes specified:
In Witness whereof I the said Walker Moseley have hereunto set my hand
and seal this Fourteenth day of September in the year of Our Lord one thousand
eight hundred and eighty three.
WALKER
MOSTLY
WALKER MOSELEY