IMPROVEMENTS IN APPARATUS FOR TRANSMITTING AND RECEIVING ARTICULATE AND OTHER SOUNDS
Year: 1879

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
APPARATUS FOR TRANSMITTING AND RECEIVING ARTICULATE AND OTHER
SOUNDS." A communication from abroad by Frédéric Allen Gower and
Cornelius Roosevelt, of Paris, in the Republic of France.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 25th January 1879.
"
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. IMPROVEMENTS IN APPARATUS FOR TRANSMITTING AND RECEIVING
ARTICULATE AND OTHER SOUNDS." A communication from abroad by Frédéric
Allen Gower and Cornelius Roosevelt, of Paris, in the Republic of France.
Articulate and other audible sounds have heretofore been transmitted either by
the employment of galvano-electricity or of magneto-electricity, by mechanically
producing or interrupting a current of electricity so as to obtain what is known as
an intermittent current, or by producing undulations in such currents by various
methods without intercepting then entirely; or again by the employment of
magneto electric currents generated in induction coils arranged upon a magnet. In
the latter case the currents are generated by altering the distance between the pole
or poles of the magnet, and a vibrating plate of soft iron placed in front of the said
pole or poles, but not in contact therewith.
On examination it will be observed as an essential condition to the effectual
transmission of articulate sounds, especially with regard to the latter method, which
is the only one that has hitherto been capable of transmitting words by electro
magnetic currents without employing a battery, that the vibrating plate should
never be in actual contact with the two poles of a magnet when two poles are
employed, or in contact with the pole of the magnet when one pole only is employed.
It is found to be the case that when the vibrating plate strikes the magnet, the
vibrations of the plate are suspended for a period of sufficient duration to per-
ceptibly diminish the volume of the sounds delivered by the instrument, and to
render it almost incapable of transmitting articulate sounds.

page_text: _Now_ according to this Invention as hereinafter described, the transmission of
articulate and other audible sounds is effected by processes in direct contravention
to the results obtained by the best systems heretofore employed, and without
-having-recourse to either of the two well known methods of transmitting speech
hereinbefore-referred to..
In the apparatus constructed according to this Invention, the poles of the-magnet-
are in permanent-and-actual-contact. with an armature of soft iron, and it has been
ascertained that this armature may be attached to a plate of soft iron, or of other-
suitable materials in such a manner that, the said. plate.will. reproduce words or
other sounds produced in the vicinity of the apparatus, and that the apparatus so
constructed may be employed with excellent results, either as a transmitting or as
a receiving instrument without any alteration.
I J
In carrying out this Invention a permanent magnet is employed of a semi
circular shape, with its poles bent inwards, or converging, or of any other
convenient form having pieces of iron of a round or other suitable shape screwed or
otherwise attached to its poles, and forming prolongations or continuations of the
same. These pieces of iron pass through and form the cores of induction coils in
which the electricity is generated, and are united by an armature of soft iron placed
across them; and with which they are in direct and actual contact, thus forming an
armature proper.
A diaphragm or membrane of iron, parchment, wood, or any
other suitable material is firmly soldered or otherwise attached to the centre of the
said armature, and is secured at its edges by one or more copper rings (it being
placed between the rings when two are employed); the object of the said rings is
to attach it firmly to a disc forming the cover of a case of wood or other suitable
This disc or cover which
material containing the magnet herein before referred to.
may be formed of the same materials as the case to which it is secured by screws
or otherwise, is made with a hollow or concavity on the side next to the membrane,
the depth of which may be varied according to the materials of which the
membrane is composed, and a hole is formed in its centre so as to place the said
hollow in communication with a mouth piece or an acoustic tube provided on the
other side of the cover.
The magnet is maintained in position by means of two screws passing through
the disc or cover hereinbefore referred to, and screwed into the magnet itself in
such a manner that by turning the said screws, the distance between the magnet
and the cover may be altered, so as to enable the tension of the membrane which is
attached at its centre to the armature of the magnet, and at its edges to the disc as
herein before described to be adjusted as required.
A hole may be provided in the case in order to enable the apparatus to bo
employed for producing pneumatic signals to call attention, as described in the
Provisional-Specification accompanying the application for Letters Patent filed by
me on the 3rd day of October 1878, No. 3892.
The results obtained by the employment of the apparatus hereinbefore described,
and the chief points of interest which are exhibited by the same are the following,
viz:-
1st. No applicable magnetic power is transmitted to the membrane, even when
the said membrane is made of soft iron, provided that the armature is sufficiently
large to entirely cover the upper and exposed surface of the magnetic cores; formed
by the prolongations of the poles of the magnet.
2nd. A perceptible magnetic power is transmitted to the membrane when the
armature is not sufficiently large to entirely cover the said surface of the magnetic
cores, formed by the prolongations of the poles of the magnet.
The
3rdly. When the armature is too small and allows a perceptible amount of
magnetic power to be transmitted to the membrane, the efficiency of the apparatus
is considerably diminished in transmitting articulate or other audible sounds.
efficiency of the said apparatus increases in proportion to the part of the surface
of the armature in contact with the magnetic cores, which form the prolongation's

page_text: of the poles of the magnet, and also in proportion to the diminution of the
magnetic power perceptible in the membrane.
The apparatus may be employed as a transmitter only, any other suitable appa-
ratus being used as receiver, or vice versa, or the same apparatus may be utilized
both as a transmitter and as a receiver.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the 15th
July 1879.
$6
"
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. IMPROVEMENTS IN APPARATUS FOR TRANSMITTING AND RECEIVING
ARTICULATE AND OTHER SOUNDS." A communication from abroad by Frédéric
Allen Gower and Cornelius Roosevelt, of Paris, in the Republic of France.
Articulate and other audible sounds have heretofore been transmitted either by
the employment of galvano-electricity or of magneto-electricity, by mechanically
producing or interrupting a current of electricity, so as to obtain what is known as
an intermittent current, or by producing undulations in such currents by various
methods without intercepting them entirely, or again by the employment of
magneto-electric currents generated in induction coils arranged upon a magnet. In
the latter case the currents are generated by altering the distance between the pole
or poles of the magnet, and a vibrating plate of soft iron placed in front of the said
pole or poles, but not in contact therewith.
On examination it will be observed as an essential condition to the effectual
transmission of articulate sounds, especially with regard to the latter method, which
is the only one that has hitherto been capable of transmitting words by electro
magnetic currents without employing a battery, that the vibrating plate should
never be in actual contact with the two poles of a magnet when two poles are
employed, or in contact with the pole of the magnet when one pole only is
employed. It is found that when the vibrating plate strikes the magnet the
vibrations of the plate are suspended for a period of sufficient duration to per-
ceptibly diminish the volume of the sounds delivered by the instrument, and to
render it almost incapable of transmitting articulate sounds.
Now according to this Invention as hereinafter described, the transmission of
articulate and other audible sounds is effected by processes in direct contravention
to the results obtained by the best systems heretofore employed, and without
having recourse to either of the two well known methods of transmitting speech
hereinbefore referred to.
In the apparatus constructed according to the said Invention, which is designated
by my foreign correspondent a magnophone," the poles of the magnet are in
permanent and actual in contact with an armature of soft iron, and it has been
ascertained that this armature may be attached to a plate of soft iron or of other
suitable materials in such a manner, that the said plate will reproduce words or

page_text: other sounds produced in the vicinity of the apparatus, and that the apparatus so
constructed may be employed with excellent results either as a transmitting or as
a receiving instrument without any-alteration.
_And_in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose-shall refer_to
the several Figures on the annexed Sheet of Drawings, the same letters-of-reference
-indicating-corresponding parts in both the Figures..
Figure 1 of the accompanying Drawings is a sectional elevation (the section
being taken along the line 1-2, Figure 2), and Figure 2 is a sectional plan (the
section being taken along the line 3-4, Figure 1) of an apparatus constructed
according to the said Invention.
In carrying out the said Invention a permanent magnet a is employed of a semi-
circular shape, with its poles bent inwards, or converging, or of any other
convenient form having pieces of iron of a round or other suitable shape screwed
or otherwise attached to its poles, and forming prolongations or continuations of
the same. These pieces of iron pass through and form the cores of induction coils h
in which the electricity is generated, and are united by an armature 7 of soft iron
placed across them, and with which they are in direct and actual contact, thus
forming an armature proper. A diaphragm or membrane 6 of iron, parchment,
wood, or any other suitable material is firmly soldered or otherwise attached to the
centre of the said armature at x, and is secured at its edges by one or more copper
rings (it being placed between the rings when two are employed); the object of
the said rings is to attach it firmly to a disc d forming the cover of a case d¹ of
wood or other suitable material containing the magnet herein before referred to.
This disc or cover which may be formed of the same materials as the case to which
it is secured by screws or otherwise, is made with a hollow or concavity at x' on
the side next to the membrane, the depth of which concavity may be varied
according to the materials of which the membranee is composed, and a hole is
formed in its centre so as to place the said hollow in communication with a mouth
piece, or an acoustic tube e provided on the other side of the cover.
The magnet is maintained in position by means of two screws y passing through
the disc or cover herein before referred to, and screwed into the magnet itself in
such a manner that by the act of turning the said screws, the distance between the
magnet and the cover may be altered so as to enable the tension of the membrane,
which is attached at its centre to the armature of the magnet, and at its edges to
the disc as herein before described to be adjusted as required.
A hole may be provided in the case in order to enable the apparatus to be
employed for producing pneumatic signals to call attention, as described in 'the
Specification to Letters Patent granted to me dated the Third day of October, One
-thousand eight hundred and seventy eight, No. 3892.
The results obtained by the employment of the apparatus herein before-described,
and the chief points of interest which are exhibited by the same are the following,
videlicet:
First. No applicable magnetic power is transmitted to the membrane b, even
when the said membrane is made of soft iron, provided that the armature q is
sufficiently large to entirely cover the upper and exposed surface of the magnetic
cores, formed by the prolongations of the poles of the magnet.
Second. A perceptible magnetic power is transmitted to the membrane b, when
the armature q is not sufficiently large to entirely cover the said surface of the
magnetic cores, formed by the prolongations of the poles of the magnet.
Thirdly. When the armature is too small and allows a perceptible amount of
magnetic power to be transmitted to the membrane b, the efficiency of the appa-
ratus is considerably diminished in transmitting articulate or other audible sounds.
The efficiency of the said apparatus increases in proportion to the part of the
surface of 'the armature q, in contact with the magnetic cores which form the
prolongations of the poles of the magnet; and also in proportion to the diminution
of the magnetic power perceptible in the membrane b..

page_text: The apparatus may be employed as a transmitter only, any other suitable
apparatus being used as receiver, or vice versa, or the same apparatus may be
utilized both as a transmitter and as a receiver.
Having now described and particularly ascertained the nature of the said Inven-
tion, and the manner in which the same is or may be used or carried into effect,
I would observe in conclusion that what I consider novel and original and
therefore claim as the Invention secured to me by the herein before in part recited
Letters Patent is,―
First. The employment in apparatus for transmitting or receiving, or trans-
mitting and receiving articulate and other sounds of a permanent magnet, having
an armature in actual and permanent contact with its poles, or with magnetic cores
forming prolongations or continuations of such poles, and passing through induction
coils, substantially as and for the purposes hereinbefore described.
Second. The combination in apparatus for transmitting or receiving, or trans-
initting and receiving articulate and other sounds of a diaphragm or membrane of
iron, parchment, wood, or any other suitable material, a plate of soft iron attached
thereto, and a permanent magnet, the said soft iron plate forming a permanent
armature to the magnet in actual and permanent contact with the poles of the
same, or with magnetic cores forming prolongations or continuations of such poles,
and passing through induction coils, substantially as and for the purposes herein-
before described.
In witness whereof, I, the said John Henry Johnson, have to this my Specifica-
tion set my hand and seal, the Fifteenth day of July; One thousand eight
hundred and seventy nine.
J. HENRY JOHNSON. (L.S.)