Telephonic Systems
Year: 1886

page_text: I, ALFRED JULIUS BOULT, of 323 High Holborn, in the County of Middlesex,
Engineer, do hereby declare, the nature of the said invention (a communication
from William Marshall, of New York City, United States of America,). and in what
manner the same is to be performed, to, be particularly described and ascertained
in and by the following statement :-
This invention relates to Telephonic Systems.
The prime object of the invention is to produce a telephonic system with
speaking: condensers, in which a more perfect transmission of the volume of speech
can be accomplished than has been possible heretofore in systems of this kind.
The invention consists essentially in a telephonic system comprising speaking
condensers and an induction coil at each station, each induction-coil having two
secondary wires and a primary wife, and the opposite ends of each secondary wire
being connected to the opposite poles of the speaking condensers. Furthermore,
the invention consists in various novel details of construction.
.
In the accompanying drawings.
Figure 1 is a diagram representing a telephonic circuit connecting two stations,
each with its transmitting devices; and receiving telephones:
.
Figure 2 is a cross:section of the receiving telephone.
Figure 3 shows. the telephone encased in the sounding box with its electrical
connections,
Figure 4 shows another system of circuits in which the receiving. telephone is
placed in a local circuit.
Figure. 5 represents the receiving telephone formed in the shape of a book,
having its leaves connected at one extremity only, and having the other ends loose
as shewn in cross section Figure 6.
Similar letters indicate the same parts in the several Figures.

page_text: •
In a previous patent No. 6035, dated May 4th 1886 I have described a.receiving
speaking condenser telephone, the opposite poles of which are connected with the
line wire and a shunt, or resistance coil.
In this invention I connect the condenser plates at either pole with the opposite
side of two secondary wires of an induction coil, or I insert the receiving telephone
in a local circuit containing a polarizing battery, as herein after described and
specially shown in Figure 4 of the drawings.
It has been claimed that a condenser can be made to speak, but I have discovered
that unless the line wire connecting the stations is made continuous, as by shunting
the speaking condenser, or by the method described in this application, the
articulation and volume of speech is not perfect, being scarcely audible when more.
than one speaking condenser inserted in the line of communication..
In the diagram represented in Figure 1 the holes of the speaking condensers C C,
are connected with the opposite ends of the secondary wires S S¹, of the induction
coil I, the primary of which includes the battery B and microphone transmitter M.
The line wire has in circuit the battery B¹ which polarizes the speaking con-
densers C C.
When the microphone M at the station Y is spoken to, the current induced into
the line reaches the induction wire S¹ at the station X, changing the polarization
of the plates of the condenser C directly, and the opposite plates of the same
condenser inductively, with the same direction of current through the other.
secondary wire S.
.:...
14.
With this organization of circuit the opposite plates of the condenser vibrate in
unison and with much greater force as will be readily understood..
The condensers C C, speak much louder when the metallic plate are in part not
touching or in contact with the insulator, allowing a space sufficient to vibrate
freely and impart to the air the sound which is transmitted from a distant station,
so as to be easily heard. In fact the speaking condenser should be built up in the
same manner as if the leaves of electrometers were intersected into each other,
substantially as shown in Figure 6; one end only of the plates being fastened. In
Figure 3 the middle of the plates are made loose by pressing the circumference
together, the plates and insulators bulging sufficiently in the centre to seperate
themselves.
In Figure 4 another organization of circuit is shown wherein the polarizing
battery for the condenser is placed in a local circuit, instead of being placed in the
line wire. The induction coil has two secondary wires as that shown in Figure 1.
The current induced into the line by the action of the microphone affects the
speaking condenser inductively through the two secondary wires of the induction
coil.
The two methods of circuit shown in Figures 1 and 4 can be combined if desired,
by organizing one station, as shown in Figure 1, and the other station as shown in
Figure 4, or one of the speaking condensers may be placed directly on the line
wire, the line having its polarizing battery, and the other speaking condenser
placed in a local circuit, as shown in Figure 4.
Having now particularly described and ascertained the nature of the said
invention as communicated to me by my foreign correspondent and in what
manner the same is to be performed I declare that what I claim is
1. In a telephonic system with speaking condensers, an induction coil at each
station, said induction coil having two secondary wires, and a primary wire, the
opposite ends of each secondary wire being connected to the opposite poles of the
speaking condenser for the purpose substantially as described.
2. In a telephonic system, the within described induction coil having two
secondary wires and a primary wire, one of the secondary wires being connected
with a speaking condenser and the other with the line wire and a polarizing
battery, substantially as and for the purpose specified.

page_text: 3. In a telephonic system the within described induction coil having two
secondary wires and a primary wire, the primary wire being connected with the
microphone M and the battery B, substantially as and for the purpose specified.
4. A speaking condenser, the opposite plates of which are loose except at one
end and formed as intersected electrometers, the electrodes having independent
connections, substantially as described and shown.
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