IMPROVEMENTS IN APPARATUS FOR THE TRANSMISSION AND RECEPTION OF SOUNDS."
Year: 1881

page_text: LETTERS PATENT to William Chase Barney, of 53, Bernard Street, in the
County of Middlesex, Gentleman, for an Invention of "IMPROVEMENTS IN
APPARATUS FOR THE TRANSMISSION AND RECEPTION OF SOUNDS."
PROVISIONAL SPECIFICATION left by the said William Chase Barney at
the Office of the Commissioners of Patents on the 9th November 1881.
WILLIAM CHASE BARNEY, of 53, Bernard Street, in the County of Middlesex,
Gentleman. " IMPROVEMENTS IN APPARATUS FOR THE TRANSMISSION AND
RECEPTION OF SOUNDS."
In microphones heretofore constructed, the quantity of electricity passing through
them is extremely weak, and represents an almost infinitesimal part of the electric
power emanating from the source of electricity employed.
The intensity of the current which passes through a microphone and thence
through a coil on a magnet in a telephone should be as great as possible, having
due regard to the sensitiveness of the microphone to the action of sound waves
upon it, because the variations of the intensity of the current produced by the
action of sound waves on the microphone are in proportion to the variations of the
resistance of the microphone.
In order to obtain great intensity of the current it is necessary that the
conductibility of the microphone should be as great as possible, independent
however of the sensitiveness of the latter.
Various forms of microphones have been devised, some in which the contacts of
the several parts of the microphone are made by means of a spring or springs,
others by means of fluids, and others by means of the weight of movable parts of
the microphone on the fixed parts thereof.
This last-named means is that of the microphone invented by Professor
Hughes, F.R.S., and is at the same time the most simple and effective. In a
microphone of this kind the greater the number of points of contact of its parts
the greater will be its conductibility.
I avail myself of these established facts to construct a microphone which will

page_text: present the least possible resistance to the passage of an electric current and at the
same time possess the greatest sensitiveness to the action of sound-waves, whereby
the intensity of the current passing through the microphone is great, and conse-
quently the core of the coil on the receiver is strongly magnetised, and thus the
maximum induction is produced.
In constructing my microphone I use a great number of pencils of carbon or of
other equivalent material, the ends of which are held loosely in blocks of carbon
or of other equivalent material. A block of carbon or of other equivalent material,
about one inch in diameter and half an inch thick, forms the centre of a series of
blocks of similar material about one half an inch in diameter and one half an inch
thick;
this series of blocks are connected together by a ring of copper or other
metal of high conductivity; the centre block has a series of circular holes sunk in
it equal in number to the pencils of carbon or other equivalent material intended
to be used, and each of the blocks surrounding the centre block has a hole sunk in
it opposite to a hole in the centre block. A pencil of carbon or other equivalent
material about one quarter of an inch in diameter, having the diameter of its ends
for the length of about one quarter of an inch reduced to a diameter of about one
sixteenth of an inch, having one end resting loosely in a hole in the centre block,
Each pencil is
its other end resting loosely in the hole of the opposite block.
covered with a metallic sleeve throughout the length of its greatest diameter,
care being taken that this metallic sleeve cannot come in contact with the carbon
blocks.
These multiple contacts being thus disposed for quantity give the maximum
results, and the metal on the pencils and on the series of blocks reduces greatly the
resistance of the microphone.
Each movable pencil acting by its inertia when the fixed blocks are caused to
vibrate should be of greater specific gravity than either of the fixed blocks with
which it is in contact.
In order to confine the movements of the microphone to the action exclusively
of the sound-waves, and to prevent any secondary movements of it, which interfere
materially with its faithful response to the impact of the sound waves, and thereby
cause indistinct articulation, I prefer to attach the microphone to the top of a box
made of a non-resonant, non-vibratory, and sound-absorbent material, such as
In this manner the motion is commu-
cork or felt, or some equivalent thereof.
nicated to the microphone by the molecular action of the material to which it is
attached, caused by the impact of the sound-waves, and thus the tremulous motion
which takes place when the microphone is attached to a resonant vibratory material
is avoided.
The efficiency of a microphone composed of pencils resting in wells sunk in
blocks depends in a great measure upon the angle of inclination which the pencils
make with the horizon. When the pencils stand perpendicularly their vis inertice
is almost entirely at the lower end, and when the pencils lie horizontally their vis
inertia is equally divided between the two ends. In this latter case the force
required to overcome the inertia so as to produce a movement of the pencil is the
maximum force, and in the former case the force is the minimum, as this force
would act on the upper end of the pencil where the vis inertia is extremely weak,
and consequently the contact there being very slight the amount of current passing
would be also extremely feeble, in fact two feeble to produce any appreciable effect
on the magnet of the telephone.
It is evident therefore that the best results can be obtained when a microphone
combines great sensitiveness to the action of sound-waves with contacts of its
bearings so arranged as to present the least resistance to the passage of the
current.
By increasing the number of pencils, provided they be arranged for quantity, the
total resistance of the microphones can be greatly reduced. However, a microphone
composed of a very great number of pencils placed perpendicularly will not allow
sufficient current to pass, in consequence of the very slight vis inertia acting on

page_text: its upper end. This vis inertice is increased as the pencils incline from the
perpendicular line. I find that a microphone composed of ten or twelve pencils,
each about two inches long, the pencils inclining at an angle of about 10° from
the perpendicular, gives the best results both in sensitiveness and in quantity of
current. The wells in the blocks sustaining the upper end of each pencil should
be square.
In another part of my Invention I dispense with the use of carbon altogether,
and use a pencil or pencils made of wood or other equivalent material, on each
end of which I fix metallic capsules consisting of tin-foil or other metal. The
capsules at each end of each pencil are connected together by a metallic or other
conductor.
The capsuled ends of each pencil rest loosely in metallic capsules placed in blocks
of wood or other suitable material. The capsules in the blocks are so connected as
to form part of the electrical circuit.
Care is to be taken that the specific gravity of each pencil is greater, bulk for
bulk, than that of the block in which the pencil enters, or on which it rests at each
end.
Another part of my Invention relates to improvements in telephone receivers
in which I use an electro magnet constructed upon any of the following described
forms:-
First Form. A bar of iron or of steel having on one end a shoe of soft iron
equal in weight to about five times that of the core contained within the helix
placed on the other end, to which is attached a short spiral spring of steel wire
about one half an inch long; the other end of this spiral spring is capped with a disc
of steel of the same diameter as that of the core. The whole is then strongly
magnetised.
Second Form.-Around a bar of iron or of steel is wound spirally an iron or
steel wire beginning at the end of the bar, upon which is placed a shoe of soft iron
which encloses the spiral wire and bar. This spiral wire extends about half an inch
above the helix which is placed on the other end outside the spiral wire; the end
of this spiral wire is capped with a disc of steel of the same diameter as that of
the core; the whole is magnetised strongly.
Third Form. Inside a tube of iron or of steel, upon one end of which is fitted
a soft iron shoe, a spiral wire of iron or of steel is placed in close contact with the
soft iron shoe and with the sides of the tube, and projects about half an inch above
the end of the tube, and is capped with a disc of steel. A disc of steel is fastened
inside of this coil even with the top of the bar, on this end of which is placed a
helix as in ordinary electro-magnets. The whole is to be magnetised strongly.
Fourth Form.-A bar of iron or of steel has a spiral spring attached to one end
as described in the first form, with a helix on that end, and from the other end
two or more branches project, and forming curves or angles pass up the sides of the
bar, but not in contact with it, as far as the helix; and the ends of their several
branches are connected together with an iron band. The top of the band is even
with the top of the bar. On this band is screwed a tube of iron expanded at the
other end, upon which a diaphragm or plate of a non-magnetic material is held in
its place by an earpiece of the ordinary kind.
Fifth Form. The bar of the magnets of the first, second, and fourth forms,
instead of being placed in a shoe of soft iron, is attached to a soft iron plate larger
than the area of a cross section of the bar; upon this plate is fastened one end of a
soft iron tube enclosing the bar, but not in contact with it, while the other end of
this tube comes up to the helix. Upon this tube is screwed a tube of iron
expanded at the other end, for the purposes described in the fourth plan. The
effect produced by this tube is to confine the magnetic field to the space in front of
the open end of the tube, there being little or no magnetism along the tube; the
open end of the tube having the opposite polarity to that of the end of the magnet
near to it, they act upon each other by induction, as in the case of the horse-shoe
magnet, and the close proximity of the tube to the bar enables the one pole to

page_text: exert greater inductive action on the other than in the case of the horse-shoe
magnet, and it has also a greater sustaining power than the horse-shoe magnet.
The plate or diaphragm must be placed in close contact with the extreme end of
the magnet, and is not necessarily made of iron or steel, or of any material liable to
inductive action; nor is it necessary that the material of which the diaphragm or
plate is made shall possess even a modicum of elasticity, or the property of inten-
sifying or reflecting sound-v
-waves. With a diaphragm or plate of cork, about
one-twelfth of an inch thick, words are reproduced in my telephone in a clear, loud,
and distinct tone, even when spoken to one of my transmitters as rapidly as
possible compatible with distinctness.
The action of this magnet in my telephone is entirely of a different kind to that
in telephones heretofore constructed. In them the inductive action of the magnet
is exerted upon the diamagnetic diaphragm or plate armature; but in my telephone,
from the peculiar form of the magnet, two parts of the same magnet having the
same polarity are brought opposite to each other, and the action between these two
parts is that of repulsion. One of these parts being very much lighter than the
other, and also being the end of a spring, is repelled against the diaphragm with
greater or less force corresponding to the impulses of the force of the current
passing through the helix, and with greater or less frequency corresponding to the
rapidity of changes of the tension of the current. The function of the diaphragm
or plate against which the spring end of the magnet acts, is to confine within a
small space the to-and-fro movement of the spring end of the magnet.
The plate may be only a small strip of wood or other material a very little wider
than the spring end of the magnet.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Chase Barney in the Great Seal Patent Office on the
8th May 1882.
WILLIAM CHASE BARNEY, of 53, Bernard Street, Middlesex.
"IMPROVEMENTS
IN APPARATUS FOR THE TRANSMISSION AND RECEPTION OF SOUNDS."
This Invention relates to improvements in apparatus for the transmission and
reception of sounds by electricity.
In microphones heretofore constructed, the quantity of electricity passing through
them is extremely small, and represents an almost infinitesimal part of the electric
power emanating from the source of electricity employed.
The current which passes through a microphone used for telephonic purposes
should be as great as possible, having due regard to the sensitiveness of the
microphone to the action of sound-waves upon it, because the variations of the
intensity of the current produced by the action of the sound-waves are in proportion
to the variations of the resistance of the microphone.
Various forms of microphones have been devised, some in which the variations
of the contact-points of the several parts of the microphone are caused by means
of a spring or springs, others by means of a tympan.
The microphone invented by Professor Hughes is, simple and effective. In a
microphone constructed on the principle of Professor Hughes, the greater the
number of points of contact, the greater will be its conductability, which is a great
desideratum.
My microphones present the least possible resistance to the passage of an electric
current, and at the same time the greatest sensitiveness to the action of sound-
waves, and consequently the current induced in the secondary wire of the induction
coil, to the primary wire of which the microphone and battery are connected, has
great variations of tension, and its action on the coil on the receiving instrument is
proportionately great.
In my first form, Figure 1, of microphone I use a number of pencils "p" of hard
coke-carbon or other equivalent material; the ends of the pencils are held loosely
in blocks "b, b," of carbon. I use the word carbon in its widest sense. A block of
carbon B, to which is connected one terminal of the primary wire of an induction
coil, about one inch in diameter and about half an inch thick, forms the centre of a
series of blocks "b, b," of carbon placed around the centre block at a distance of about
two inches from it; this periphery of blocks is connected together by any good
conductor "c," to which is connected one pole of a battery, the other pole thereof
being connected to the other terminal of the primary wire of an induction coil;
the centre block has a series of holes around its circumference, equal in number to
the blocks surrounding it, and in each of these blocks is a hole in which lies loosely
one end of a carbon pencil, the other end of which lies loosely in a hole in the
centre block; each pencil is covered with a metallic sleeve "8," which must not be
in contact with any of the blocks; this metallic sleeve increases greatly the
conductivity of the pencil, and also increases its specific gravity, both of these
effects being advantageous.
My second form of microphone, Fig. 2, is made with carbon pencils and carbon
bars in the following manner :-Two carbon bars "b, b," about half an inch thick
having a length proportionate to the number of pencils used, placed parallel to
each other about two inches apart, having a series of holes in their sides facing
each other, in which holes lie loosely the ends of carbon pencils "p, p," thus con-
necting electrically the two bars of carbons, one of which is to be connected to one
terminal of the primary wire of an induction coil, and the other bar to one pole of

page_text: the battery, the other pole thereof being connected to the other terminal of the
primary wire; a third carbon bar may be added with carbon pencils connecting
it electrically with one of the other bars; in this arrangement the two outer bars
should be connected together by a good metallic conductor, to which one terminal
of the primary wire should be connected, and the centre bar should be connected
to one pole of the battery.
In my third form, Fig. 3, of microphone, composed of pencils and bars of carbon,
I use pencils "p, p." bevelled at one end, and square at the other end, for the
purpose of obtaining great sensitiveness to the action of sound-waves, combined
with great variations of surface-contacts. In this microphone the pencils stand
upon their bevelled ends, loosely, in holes sunk in a bar "68" of carbon, inclining
at an angle of not more than five degrees from the perpendicular, and the square
ends rest loosely in square holes sunk in the upper bar b of carbon.
The vis inertiae of the loose pencils is almost entirely at their lower ends, and
the changes of surface contacts at these ends, when sound-waves fall upon the
pencils, would be very slight, and consequently very little variation of the current
will be produced by these slight modifications of surface contacts, at the same time
the upper ends of the pencils having large surface contacts with the bar, and their
vis inertiae there being very little they will be excessively sensitive to the action of
sound-waves, and consequently the variations of the current would be propor-
tionately great.
My fourth form, Fig. 4, of microphone I construct without carbon, using
pencils "p,p," of wood, bone, ebonite, or any equivalent suitable material, placing on
each end of the pencil a small capsule "c" of hard tin, or of any hard metal, preferably
of platinum; the capsules on each pencil are connected together by a metallic
conductor, such as fine copper wire or tin foil, the capsule ends rest loosely in
similar capsules placed in holes in blocks or bars "b, b," of wood, ebonite, bone, cork,
or any suitable non-conducting material. The exterior surfaces of the capsules on
the pencils are roughened, and the interior surfaces of the capsules in the holes of
the blocks are also roughened, the connections of this microphone with the
induction coil and battery are made in the same way as above described for carbon
microphones. In order to contine the movements of a microphone to the direct
action exclusively of sound waves, and to avoid any secondary movements of it
which must occur when sound waves act upon a microphone through the medium
of a tympan or of any vibratory plate, which movements interfere materially with
its faithful response to the sound-waves, the blocks or bars are firmly secured to a
flat surface of a non-resonant, non vibratory, sound absorbing material, such as
cork, sponge, felt, husk of the cocoa nut, cuttle fish shell, pumice stone, or their
equivalents; this material may or may not form one side of a box made of the same
material; if enclosed thus in a box, or not enclosed, the material on which the
carbons are fixed must not be fastened to any other material, but should rest
loosely in a narrow frame of wood or other suitable material, or it may be sus-
pended in any convenient manner; when pumice stone is used the bars or blocks
may be clamped between two pieces of pumice stone. The sound waves may fall
directly upon the carbons or other pencils, or upon the obverse side of the material
to which they are fixed. The object of leaving the material to be kept in its
place by its own vis inertia only is to allow the whole mass to be moved by the
impact of sound-waves upon it. The molecular movement in these light, porous
substances being much greater than in dense compact substances, will communicate
to the fixed blocks or bars a much greater movement than denser materials would.
Microphones thus attached to porous substances will be affected by the molecular
movement in these substances, as well as by the movement of the mass, and there
cannot be any compression of the carbon; but the effect of sound-waves upon it
is to vary the surface contacts, by a shaking or jolting, or molecular motion; it
may be possible that there occur rapid makes and breaks of the circuit; but these,
however, are so rapid that an undulatory current flows corresponding faithfully
to the sound-waves, which is not the case when sound waves act on the microphone

page_text: through the medium of a tympan or vibratory plate, because the vibrations of a
tympan or plate produce secondary motions.
In order to protect a microphone from the secondary action of any vibrations
which might occur when the fixed parts of a microphone are attached to the surface
of any material whatever, I attach the series of blocks surrounding the centre
block, as described in my first form, Fig. 1, of microphones, to a narrow flat ring
of copper "m," or other suitable metal, and the centre block is attached to a
narrow strip "e" of wood, ebonite, or any non conducting equivalent material,
lying across the centre of the ring, to which its two ends are secured.
In the microphones described in my second, Fig. 2, third, Fig. 3, and fourth forms
the blocks supporting the loose pencils form two opposite sides of a frame, the other
two sides being of wood "w," ebonite, or other suitable material; the microphone
thus held together may or may not be fixed to any other substance, but I prefer
to suspend it by cords or springs so that sound-waves may fall directly upon the
microphone.
The efficiency of microphones constructed with pencils and blocks or bars depends
in a great measure upon the angle of inclination which the pencils make with the
perpendicular. When the pencils stand perpendicularly their vis inertiae is almost
entirely at their lower ends, and when they lie horizontally their vis inertiae is
equally divided between the two ends. In this latter position the force of the
sound-waves necessary to overcome their vis inertiae is the maximum force, and in
the former position the force required to overcome the vis inertias of their upper
ends is the minimum force, but the contacts there being very slight, the current
passing through these ends will be very feeble, and consequently the variations
of the current passing through the microphone would be very slight, inasmuch
as the current passing through the lower ends of the pencils. would be almost
uniform.
The greater the variations of the quantity of current passing through a micro-
phone used in a telephonic circuit, the greater will be the effect on the coil of the
receiving instrument; hence it is necessary that a microphone should combine great
sensitiveness to sound-waves with the bearings of the contacts of its several parts
so arranged as to present the greatest surfaces of contacts where the variations of
the current are produced.
A microphone composed of from eight to ten pencils connected together for
quantity, inclining at an angle of about twenty degrees from the perpendicular,
gives excellent results. The microphone can be placed in a box of wood, ebonite,
brass, iron, or any suitable material, about one inch from one of its sides, in which there
is the usual hole with a mouthpiece, care being taken to have a hole in each side of
the box between the michrophone and the side of the box to which the mouthpiece
is attached.
I prefer hard coke-carbon, the specific resistance of which cannot possibly be
changed by pressure produced by sound-waves falling upon it to such a degree as
to produce undulations of a current sufficiently great for telephonic purposes.
Another part of my Invention relates to improvements in telephone receivers.
In telephone receivers constructed on the principle of that of Professor Ball it is
necessary that a plate armature of iron or steel, or other material capable of inductive
action, should be firmly held in front of, close to, but not liable to come in contact
with, the pole or poles of a magnet.
In my telephones a plate, or diaphragm, or tympan must be held in close contact
with the pole or poles of a magnet, and the plate, or diaphragm, or tympan is not
necessarily made of iron or steel or of any material capable of inductive action, but
with a plate, or diaphragm, or tympan of cork, wood, ebonite, glass, brass, or
equivalents thereof. Words spoken in any good transmitting instrument are
reproduced in a clear, loud, and distinct tone in my receiving telephone placed in
the same circuit with the transmitter.
The action of the magnetic force in my telephone seems to be of a totally different
character from that in the Bell telephone, in which the magnetic force acts directly

page_text: by attraction upon the plate armature, whereas in my telephone the magnetic force
cannot possibly have any direct magnetic effect on the plate or diaphragm when
this plate or diaphragm is not made of any material capable of inductive action,
nor with any such material attached to it. The diaphragm, tympan, or plate may
be made of cork, wood, cardboard, ebonite, ivory, glass, brass, iron, steel, mica, or
their equivalents, and must be held by a constant pressure applied upon its edges,
corners, or points, as the plate is made round, oval, square, star shaped, or triangular,
against the spiral end of the magnet.
One function of the diaphragm or plate seems to be to confine within a narrow
range the molecular elongations of the magnet produced by the passage of an
electric current through a helix encircling the magnet, and it doubless serves to
intensify the sounds emitted by the magnet at this time.
When
I have been led to use a spiral wire for an extension of the core in the helix on
an electro-magnet, from the results of numerous experiments inade with a thin strip
of iron having one end firmly secured to a board and the other end slightly bent
over by a weight attached to it, with a helix placed on the strip of iron.
a current of electricity was sent through the helix, the strip of iron instantly made
efforts to resume its normal position, and sounds were emitted during the passage
of the electric current. The theory I advanced in my Provisional Specifications in
regard to the magnetic action between two parts of the same pole placed opposite
to each other may be erroneous, but the results obtained by that arrangement are
highly satisfactory.
In constructing my telephones I use several combinations of a spiral wire with
electro-magnets.
First Form, Fig. 5. A bar "B" of iron or of steel, which may or may not be a
permanent magnet, having one end fastened to a shoe "8" of soft iron equal in weight
to about five times the soft iron elongation "e" of the other end, on which is placed a
helix "h." To the end of this elongation is fastened a short spiral spring "g" of iron
extending about one half an inch above the end of the core of the belix. The end of
this spiral spring may be capped with a disk of iron or steel the same size as the
end of the core or larger; or the terminating convolutions of the spiral spring may
be wound in a plane gradually diminishing to a centre.
Second Form, Fig. 6. The arrangement of the spiral spring differs from that.
described in the first form only in that the spiral spring is not attached to the
end of the core, but its spiral convolutions are continued around the core of the
belix.
Third Form, Fig. 7. The arrangement of the spiral spring differs from those
described in the first and second forms only in that the spiral spring is continued
around the iron bar to the soft iron shoe to which the spring and bar are attached.
Fourth Form, Fig. 8. Inside of a tube "T" of iron or of steel, upon one end of which
is fitted a shoe "8 of soft iron, is placed a spiral wire "g" of iron or steel fastened
to the soft iron shoe, the spirals being in close contact with the inside of the tube
throughout its entire length, and extending above the end of the tube. On the
spiral wire above the top of the tube is placed a helix "h," and a soft iron plug "p"
is placed inside the spirals encircled by the helix; the end of the spiral wire arranged
as in the first form.
Fifth Form, Fig. 9. The arrangement of this magnet is the same as that described
in the fourth form, except that the helix "h" is placed on the tube T, and the
spiral wire "g" extends a short distance above the top of the helix, and there is no
iron core in the helix.
Sixth Form, Fig. 10. A bar "B" of iron or steel, which may or may not be a
permanent magnet, having a soft iron extension "e" on one end, to which is
attached a spiral spring "g," as described in the first form, with a helix "h" placed
on the soft iron extension, the other end of the iron bar having two or more
branches "b, b," forming curves or angles passing up near to the sides of the bar as
far as the bottom of the helix. The ends of these several branches are connected
together by an iron band "d" encircling the helix, and the top of the band to be

page_text: on the same plane with the end of the core.
On this band is screwed a band of
ebonite, brass, or any suitable material, so arranged as to hold a diaphragm or plate
in close contact with the end of the spiral wire, with the usual ear piece to keep the
diaphragm or plate in its place.
Seventh Form, Fig. 11. A wire "B" of iron or steel permanently magnetized made
into a spiral spring, one end attached to a soft iron shoe "8," with a helix "h" on
the other end about half an inch below the end of the spring, with or without a soft
iron core "p" inside that part of the spring encircled by the helix, the convolutions
of the wire above the helix to be contracted to the size of the diameter of the core,
the end of the spring to be arranged as in the first form, the whole to be enclosed
in a suitable case.
Eighth Form, Fig. 12. A straight magnet B or a horseshoe magnet B having a
soft iron elongation "e" on each end, on each of which elongations is placed a
helix "h," the two helices connected together in the usual way; to the end of each
elongation is attached a small spiral spring "g," as described in the first form;
against the end of each spring is held firmly a diaphragm or plate "d" in the usual
manner. These magnets may be placed in the same case with the transmitting
instrument, and flexible tubes with ear pieces at the ends may be fastened over
the diaphragm, thus enabling the listener to apply one tube to each ear; this
instrument should be placed in a metal case when used on railways or in factories
where loud noises occur.
*k
a
"
"
Ninth Form, Fig. 13. A tube T of iron securely fastened at one end in a soft
iron shoe "8," the other end enlarged was to form a circular chamber "o;" this
chamber is lined with wood, ebonite, glass, brass, or other suitable material w" to
within a quarter of an inch of the top of the chamber, having a recess "r
near the
top of the wood upon which is placed a diaphragm or plate "d" of wood, ebonite,
brass, iron, steel, mica, or of any of the materials heretofore named for such
purposes. An iron bar armature “
about one quarter of an inch thick is attached
to the top rim of the chamber across its centre, a helix "h" surrounds the tube just
below the chamber with a spiral wire "g" enclosed in a tube "i" made of any good
non-conducting material; this tube placed inside the iron tube, one end of the
spiral spring is fastened to the soft iron shoe, and the other end thereof presses
against the centre of a diaphragm which is held down by a ring of brass, ebonite,
or any other suitable material upon the recess in the lining of the metallic chamber
with the usual ear piece.
These magnets may be enclosed in any suitable case "A" having an enlarged
chambered end "C" enclosing the helix "H" arranged to support a dish or plate "D"
in close contact with the top of the wire spring "g," the chamber being screwed on
the other part of the case so as to be able to regulate the pressure of the disk on
the end of the spiral wire by screwing or unscrewing it; on the top of the
chamber is fastened the usual ear-piece.
The arrangement of the wires connecting the microphone, induction coil, and
batteries, as also the wires connecting the helix of the receiving instrument with
the line, are similar to those generally used in telephonic circuits, and need not
therefore be particularly described, further than to say that one pole of a battery is
connected to one terminal of the primary wire of an induction coil, the other
terminal to one part of the microphone, the other part of which is connected to the
other pole of the battery. One terminal of the secondary wire is connected to the
line wire, and the other terminal is connected to the earth or to a second line
wire. The receiving instrument may be placed on any part of the circuit in the
line wire.
Having described my said Invention, I wish it known that I claim,-
First. In an instrument for transmitting undulatory currents of electricity by
means of sound, the use of sponge, felt, husk of the cocoa nut, pumice-stone, shell
of the cuttle fish, as suitable materials upon which to attach a microphone or
current-regulator, substantially as and for the purposes set forth.
Second. In an instrument for transmitting undulatory currents of electricity by

page_text: means of sound, the combination of a microphone composed of pencils and blocks
or bars made of carbon or other suitable material with a light frame holding the
parts together, substantially as and for the purposes set forth.
Third. In an instrument for transmitting undulatory currents of electricity by
means of sound, the combination of pencils of carbon bevelled at one end and
square at the other end with bars of carbon; in one of the said bars are wells in
which stand loosely upon their bevelled ends the pencils; the square ends of these
pencils rest loosely in square holes in the other bar. The bars with the holes in
them may be fixed parallel with each other to the flat surface of pumice-stone,
wood, or any suitable non conducting materials, substantially as and for the
purposes set forth.
Fourth. In an instrument for transmitting undulatory currents of electricity by
means of sound, a combination of pencils of wood, ebonite, bone, or other suitable
materials with a small capsule of hard tin or of any hard metal fixed on each end
of the pencils, the exterior surfaces of the capsules being roughened, and the
capsules on each pencil connected together by any good conductor, in combination
with blocks or bars of wood, bone, ebonite, or other suitable non-conducting
material with holes sunk in them, in which are fitted capsules of hard tin or other
hard metal, the inside surfaces of these capsules to be roughened, substantially as
and for the purposes set forth.
Fifth. In an instrument for reproducing sounds by means of electricity, the
combination with an electro-magnet of a short spiral spring of iron or steel
fastened to the end of the core of the helix, substantially as and for the purposes
Bet forth.
Sixth. In an instrument for reproducing sounds by means of electricity, the
combination with an electro magnet of a spiral spring of iron or steel fitting
closely around the core of the helix and extending a short distance above the top
of the core, substantially as and for the purposes set forth.
Seventh. In an instrument for reproducing sounds by means of electricity, the
combination with an electro-magnet of a spiral spring of iron or steel fitting closely
around the entire length of the bar of the magnet and the core of the helix, and
extending a short distance above the top of the core, substantially as and for the
purposes set forth.
Eighth. In an instrument for reproducing sounds by means of electricity, a
tubular electro-magnet in combination with a spiral spring of iron or steel placed
inside of the tube in close contact with the sides thereof, and attached to a soft
iron shoe fitted on one end of the tube, the spiral wire extending above the top of
a helix placed around the spirals at the top of the tube with a soft iron plug
inside the spirals encircled by the helix, substantially as and for the purposes set
forth.
Ninth. In an instrument for reproducing sounds by means of electricity, a
tubular magnet in combination with a spiral spring of iron or steel placed inside
the tube in close contact with the sides thereof and attached to a soft iron shoe
fitted on one end of the tube, on the other end of which is placed a helix, the
spiral spring extending a short distance above the helix, substantially as and for
the purposes set forth.
Tenth. In an instrument for reproducing sounds by means of electricity, the
combination of a wire of iron or steel permanently magnetized made into a spiral
spring, one end of which is attached to a soft iron shoe, with a helix on the other
end encircling the spirals, inside of which is placed a soft iron core, the spiral wire
extending a short distance above the end of the core.
Eleventh. In an instrument for reproducing sounds by means of electricity, a
straight magnet or a horse-shoe magnet having a soft iron elongation of each end,
on each of which elongations is placed a helix in combination with a spiral spring
attached to the end of each soft iron core.
Twelfth. In an instrument for reproducing sounds by means of electricity, a
tubular magnet having one end enclosed in a soft iron shoe, and the other end

page_text: enlarged so as to form a circular chamber in combination with a spiral spring
encased in any good non-conducting material placed inside the tube of the magnet,
and an armature placed on the top of the chambered end of the magnet with a
helix placed on the tube below the enlarged chamber.
In witness whereof, I, the said William Chase Barney, have hereunto set my
hand and seal, this Eighth day of May, One thousand eight hundred and
eighty two.
WILLIAM CHASE BARNEY. (L.S.)
May 8th, 1882.