IMPROVEMENTS IN TELEPHONIC APPARATUS AND CONDUCTORS
Year: 1881

page_text: LETTERS PATENT to John Imray, of No. 28, Southampton Buildings, in the
County of Middlesex, for an Invention of "IMPROVEMENTS IN TELEPHONIC
APPARATUS AND CONDUCTORS." A communication from abroad by Doctor
Cornelius Herz, of Paris, France.
PROVISIONAL SPECIFICATION left by the said John Imray at the Office of
the Commissioners of Patents on the 8th January 1881.
[A communi-
JOHN IMRAY, of No. 28, Southampton Buildings, in the County of Middlesex.
"IMPROVEMENTS IN TELEPHONIC APPARATUS AND CONDUCTORS."
cation from abroad by Doctor Cornelius Herz, of Paris, France.]
This Invention relates to the construction and arrangement of telephonic
instruments and their conductors so as to obtain great distinctness in the articulate
sounds transmitted by them even over considerable distances, and to obviate the
interfering effects of earth currents. In order to secure distinctness the receiving
instrument, according to this Invention, is rendered microphonic by the employ-
ment of discs or blades of conducting ores, such as sulphides of iron, copper, lead,
and other analogous compounds, each of those discs or blades being separately
connected to pairs of voltaic elements, and all being pressed together with adjustable
pressure and subjected to the sound vibrations of a diaphragm. By the use of discs
thus connected and arranged the sounds are magnified, and in order to render them
clear and distinct when transmitted, condensers are introduced in the line con-
ducting from the one station to the other. A condenser may for this purpose be
applied near either station, or it may be introduced into any part of the line, or
several condensers may be introduced along the line. The microphonic appliance
above referred to can be variously modified; for example, between the discs or
blades conducting powders, such as pulverised graphite bronze and other powder's
may be introduced with good effect. The battery to which this appliance is con-
nected is most advantageously arranged with its elements connected for tension,
the junctions of the elements being connected by branch wires to the microphonic
[Price B21

page_text: ->
discs or blades, and the terminal wires being connected respectively to the receiving
diaphragm, and to one of the plates of the condenser from which the line wire is
led. Instead of voltaic cells dynamo-electric or magneto-electric machines may be
employed, their several coils being connected in a manner similar to the connections
of the voltaic cells as above stated. Independently of the use of microphonic
appliances such as those described, the introduction of condensers in the line is of
value for producing distinctness of transmission, whatever be the telephonic instru-
ments employed. In some cases it has been proposed to employ condensers, but
only when the electrical currents are of high tension, and when they are used for
transmission of inarticulate sounds such as musical tones. By the use of condensers
according to this Invention for ordinary telephonic lines, the distinctness of
transmitted articulation is greatly improved; and in consequence of such improve-
ment in distinctness by this means the sounds may be magnified by any known
microphonic appliances, and consequently can be transmitted over great distances.
In order to avoid interference from earth currents the line wire, instead of being
led directly to earth from the receiving instrument, is made to terminate in a
number of fine points extended over a considerable area, and another set of such
points in close proximity to the former set communicate by a wire to earth. Thus
electricity in passing from the one part of the line to the other forms a brush, or
passes by a diffused and silent flow from the one set of points to the other. The
space between the two sets of points may be filled with a medium such as alcohol,
oil, or hydrocarbons, or with gas other than air, or air or gas more or less rarefied,
The diffusing apparatus, instead of being introduced between the receiver and earth,
may be introduced in any convenient part of the line, but the former arrangement
is preferable... -
The diffusing apparatus is applicable to telephonic lines generally, but it is
preferably used in combination with the condensers and microphonic appliances
above described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Imray in the Great Seal Patent Office on the 7th July
1881.
JOHN IMRAY, of No. 28, Southampton Buildings, in the County of Middlesex.
"IMPROVEMENTS IN TELEPHONIC APPARATUS AND CONDUCTORS." A communi-
cation from abroad by Doctor Cornelius Herz, of Paris, France.
This Invention relates to the construction and arrangement of telephonic
instruments and their conductors, so as to obtain great distinctness in the articulate
sounds transmitted by them even over considerable distances, and to obviate the
interfering effects of earth currents. In order to secure distinctness the receiving
instrument, according to this Invention, is rendered microphonic by the employment
of discs or blades of conducting ores, such as sulphides of iron, copper, lead, and
other analogous compounds, each of those discs or blades being separately connected
to pairs of voltaic elements, and all being pressed together with adjustable
pressure, and subjected to the sound vibrations of a diaphragm. By the use of
discs thus connected and arranged the sounds are magnified, and in order to render
them clear and distinct when transmitted, condensers are introduced in the line
conducting from the one station to the other. A condenser may for this purpose
be applied near either station, or it may be introduced into any part of the line, or
several condensers may be introduced along the line. The microphonic appliance
above referred to can be variously modified. For example, between the discs or
blades conducting powders, such as pulverised graphite, bronze, and other powders
may be introduced with good effect. The battery to which this appliance is
connected is most advantageously arranged with its elements connected for tension,
the junctions of the elements being connected by branch wires to the microphonic
discs or blades, and the terminal wires being connected respectively to the receiving
diaphragm, and to one of the plates of the condenser from which the line wire is
led. Instead of voltaic cells, dynamo-electric or magneto-electric machines may
be employed, their several coils being connected in a manner similar to the
connections of the voltaic cells as above stated. Independently of the use of
microphonic appliances, such as those described, the introduction of condensers in
the line is of value for producing_distinctness of transmission whatever be the
telephonic instruments employed. In some cases it has been proposed to employ
condensers, but only when the electrical currents are of high tension, and when they
are used for transmission of inarticulate sounds, such as musical tones. By the use
of condensers according to this Invention, for ordinary telephonic lines, the
distinctness of transmitted articulation is greatly improved; and in consequence of
such improvement in distinctness by this means the sounds may be magnified by
any known microphonic appliances, and consequently can be transmitted over
great distances.
In order to avoid interference from earth currents the line wire, instead of being
led directly to earth from the receiving instrument, is made to terminate in a
number of fine points extended over a considerable area, and another set of such
points in close proximity to the former set communicate by a wire to earth. Thus
electricity in passing from the one part of the line to the other forms a brush, or.
passes by a diffused and silent flow from the one set of points to the other. The
space between the two sets of points may be filled with a medium, such as alcohol,
oil, or hydrocarbons, or with gas other than air, or air or gas more or less
rarefied. The diffusing apparatus instead of being introduced between the receiver
and earth may be introduced in any convenient part of the line, but the former
arrangement is preferable.

page_text: The diffusing apparatus is applicable to telephonic lines generally, but it is
preferably used in combination with the condensers and microphonic appliances
above described.
.
The accompanying Drawings illustrate diagrammatically general arrangements
of telephonic instruments according to this Invention, and shew the construction
of the novel parts introduced in those arrangements. Referring to the diagram,
Fig. 1, if in the line connecting two bell telephones A, A', there be interposed one, or
preferably two, condensers C, C', near the telephones, the articulate sounds trans-
mitted acquire great distinctness, become cleared of interfering tones, and can be
transmitted to a greater distance. The condensers of which there may be a greater
number, may be introduced in any part of the line between the two telephones, or
between each telephone and earth T, but they are best placed, as shewn in Fig. 1,
between the telephones and near them. Referring to the diagram, Fig. 2, if in the
circuit of a battery P and microphonic speaker M be introduced a singing
condenser it remains silent except when an induction coil is used, but if the
speaker M be placed in a branch X to earth at the transmitting station the distant
condenser C will act, giving sounds, and even, under certain conditions, articulate.
The arrangement of the instruments may be varied in many ways. One servicable
arrangement is illustrated diagrammatically by Fig. 3. M is a microphonic
transmitter, one convenient form of which is shewn in section at Fig. 6, and in plan
(with front cover removed) at Fig. 7. On the vibrating diaphragm x are fixed a
number of plates p of iron pyrites or analogous material. Against each of these
plates is pressed a piece a of carbon or pyrites on a lever 1, the pressure of which is
regulated by the strain of a spring r. Each alternate contact piece is connected by
a wire to the positive pole of a battery cell, the other alternate contact pieces being
connected to one terminal plate of a large surface condenser C, Fig. 3, the other
terminal plate of which is connected to the line wire. The negative poles of the
battery cells are connected to earth T. At the receiving station a bell telephone A
may be employed alone, but it is better to apply a second condenser C', having one
of its terminal plates connected to the line wire, and the other to earth T¹. The
receiving telephone may then be placed on either side of the condenser, as indicated
at A' or A". According to another arrangement, illustrated diagrammatically by
Fig. 4, the one pole of the tension battery P is connected to earth, the other to the
base of the microphone, and thence to the line wire, and the contacts to the
diaphragm are separately connected to the battery cells. Several inductors I, I¹, |
are introduced as well as the condenser C, so as to strengthen its static charges.
These inductors are closed electro magnets, having in each core one coil of large
wire which excites the magnet, and the other coil of small wire which becomes
the induction coil. The receiving instrument in this arrangement may be a
telephone or a condenser. When a condenser is used it should be adapted to be
applied to the ear, as shewn by the transverse section, Fig. 9, and plan, Fig. 10.
The microphonic transmitter M may be modified, as shewn by the transverse
section, Fig. 5, in which construction discs of sulphide d are pressed by the levers e
against the diaphragm x, the pressure in each case being regulated by tightening
screws and springs r. Instead of employing the discs d grains of platinum or
other metal or conducting material may be placed on the ends g of the levers, and
pressed against the diaphragm. Fig. shews diagrammatically the arrangement
for protecting the telephonic line by the diffusing apparatus Z operating as a
lightening conductor, so as to clear the line from the influence of earth or
atmospheric currents.
Having thus described the nature of the said Invention, and in what manner the
same is to be performed, as communicated to me by my foreign correspondent, I
claim, in respect of telephonic apparatus and conductors,-
First. The use of condensers introduced into the line, either in combination with
receiving instruments, or to operate themselves as receiving instruments, as and
for the purposes herein set forth

page_text: Second. The use of metallic ores and sulphides as contact pieces for a microphonic
transmitter, as herein described with reference to Figs. 5, 6, and 7..
Third. The methods of connecting the battery cells with the microphonic contacts,
herein described with reference to Figs. 3 and 4.
Fourth. The use in combination with a telephonic line of diffusing apparatus Z,
Fig. 8, as and for the purposes herein set forth.
In witness whereof, I, the said John Imray, have hereunto set my hand and
seal, this Sixth day of July, in the year of our Lord One thousand eight
hundred and eighty one.
JOHN IMRAY. (L.S.)