IMPROVEMENTS IN TELEPHONY AND TELEPHONIC APPA- RATUS FOR TRANSMITTING OR CAUSING SOUND BY MEANS OF THE ELECTRIC CURRENT OR CURRENTS, FOR THE PURPOSE OF CONVEYING MESSAGES, AND OTHER USEFUL PURPOSES
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Theodor Wiesendanger at the Office
of the Commissioners of Patents on the 23rd November 1877.
THEODOR WIESENDANGER, of 31, De Foe Road, Stoke Newington, in the County
of Middlesex, Teacher. "IMPROVEMENTS IN TELEPHONY AND TELEPHONIC APPA-
RATUS FOR TRANSMITTING OR CAUSING SOUND BY MEANS OF THE ELECTRIC
CURRENT OR CURRENTS, FOR THE PURPOSE OF CONVEYING MESSAGES, AND OTHER
USEFUL PURPOSES."
All telephones previously known differ from this one in so far as both the trans-
mitters and receivers were more complicated and more costly, and either the sound
reproduced by these former telephones was of inconsiderable intensity only as
coinpared to the volume of sound reproduced by the receiver of this telephone, or a
great many transmitters and receivers were needed to send a certain number of
sounds of different pitch, each transmitter sending one sound of one pitch only, and
each receiver reproducing one such sound only.
In my instrument one transmitter and one receiver will convey any number of
sounds of different pitch, and reproduce sounds each of the same pitch as a given
sound of many with great intensity. On the other hand several transmitters and
several receivers may be included in one circuit with this arrangement, and all can
be worked simultaneously.
This telephone also differs from other telephones previously known, in possessing
simplicity of construction and cheapness, and greater intensity of the sound
reproduced.
Its claims as to novelty are,-
The simple contact breaker and its particular use as herein-after described.
The arrangement for increasing the intensity of the sound reproduced, as herein-
after set forth, and the extreme portability of the whole apparatus.
This telephone is an instrument for reproducing at any distance, and with great
intensity, sounds of different pitch as uttered by the human voice, or produced by
other means at the receiving station. It consists of four essentially different
parts,―
1st. A transmitter which converts the sound vibrations into series of electric
currents or shocks.
2nd. An electric wire line to convey the currents.

page_text: 3. A battery or batteries, or any other source or sources of electricity.
4th. A reproducing instrument by which the said series of currents are recon-
verted into sounds.
I will now proceed to describe the same with reference to the annexed
Ine transmitter or sending instrument consists 01,
(e) A mouth-piece, or speaking orifice, or speaking tube.
(b) A tympanum or inembrance, which will faithfully render the sound vibrations.
(c) A contact breaker attached to or worked by the tympanum. The trans-
mitter can be made in various forms and sizes, two of which are represented in the
accompanying illustrations.
a, b, c, d, in Fig. 1a, is a sliding tube made of wood, or metal, or any
suitable substance, with a speaking orifice i, k. Over the other opening of this
tube a membrane of india-rubber, goldbeater's skin, or any other suitable material
is stretched and fastened to the tube. The outer tube (H, t, e,) is closed at the
back, and goes over the inner tube as illustrated. Through the back a conductor
(8, w,) is introduced, made of brass or other suitable material, and pointed. The top
of it (w) is gilt, or platinized, or otherwise protected against oxidation under the
influence of the currents. A strip of copper (t), or any other conducter, joins the screw
"s" to a terminal q; over the centre of the membrane is fastened a disc of platinum
or any other material that will conduct electricity, but not oxidize under its action,
and this disc, which will act as a contact breaker, together with the top (w) of the
screw adjustment (s) is connected by means of a good conducter with the other
terminal ""outside the instrument. The two terminals of the circuit of wire
line, which includes the battery (B) or batteries, or any other source or sources of
electricity, and the reproducer (R, S,) are connected with the terminals of the trans-
mitter and q. If then the point (w) touches the disc (z, n,) in any point, the
circuit is closed, and the current can pass through; but when the membrane
vibrates, the moment when it recedes from the point w, contact is broken.
The reproducing instrument contains one or more bar or horse shoe electro-
magnets, each consisting of a core of soft iron or steel, or a bundle of wires or
iron sheeting rolled up so that the ends overlap, and a coil of insulated wire round
the core.
Close to the 2 poles 5 & 4 of the magnet or magnets is fixed by means of
strips of metal 9 & 10 the bottom of a square or circular bell, or cylinder of
metal, closed at one end, open at the other, or a strip, or rod, or tube of tin (tinned
iron), or any suitable metal. The transmitter may be made also with two flat
spiral coils, one of them fixed on the membrane.
When the instrument is used one or many of either,-
1. The transmitter,
2 The reproducer,
3. The source of electricity (battery),
may be included consecutively in one divided circuit at the same time.
By the divided circuit arrangement, as shown in Drawing, Fig. 3, the reproducer
may be made to render several different tunes, or the different parts or voices of a
song, at the same time.
The transmitter may be also constructed as shewn in Fig. 2, or in any other
suitable shape, form, and size.
In the Drawing, Fig. 2, a, b, c, d, is a tube made of brass, or wood, or any suitable
substance, be a membrane of india-rubber, or any other suitable material, fastened
over a bed as indicated; f is a disc of a conductor fixed on the centre of the
membrane f; g, a connecting conductor, which joins e, f, to the terminal h; i is a
3. The source of electricity (battery),
may be included consecutively in one divided circuit at the same time.
By the divided circuit arrangement, as shown in Drawing, Fig. 3, the reproducer
may be made to render several different tunes, or the different parts or voices of a
song, at the same time.
The transmitter may be also constructed as shewn in Fig. 2, or in any other
suitable shape, form, and size.
In the Drawing, Fig. 2, a, b, c, d, is a tube made of brass, or wood, or any suitable
substance, be a membrane of india-rubber, or any other suitable material, fastened
over a bed as indicated; f is a disc of a conductor fixed on the centre of the
membrane f; g, a connecting conductor, which joins e, f, to the terminal h; i is a
conductor with an adjustment; its point w forms a contact breaker together with
the platinum disc. This transmitter may be used as described, or enclosed in a box

page_text: with a hole to admit a, d, or a speaking tube to pass through the box into α, d; B is
the battery or other source of electricity; n, m, r, y, is the line; m is an electrio
magnet.
By means of two pieces of wood and bracketts, or any other arrangement, the
tubes T and T are fixed to the poles of the magnet so as either to allow the
poles to touch the bottoms of the tubes, or as to act upon them magnetically
without touching.
The working of the instrument depends upon the fact that musical or other
sounds are produced by a series of vibrations occurring in regular succession, and at
well known rates.
If a certain note be sung into the mouth piece i, k, the membrane vibrates, say,
560 times per second; 560 times the platinum discs (touches the point w, and again
recedes from it, making and breaking the circuit 560 times per second.
A series of
560 currents is started and arrested in the circuit, and 560 times the cores of the
magnets are rendered active. It is a well known fact that every time a current
passes through the coil the core grows longer and thinner by molecular change, and
it takes its former shape when the current ceases. If the currents succeed each
other in regular rapid succession, the impulses given to the air around the cores by
these changes cause audible musical sounds, the pitch of which depends upon the
number of currents or shocks per second.
By means of many experiments I found that the intensity or loudness of the
sound can be greatly increased if the vibrations are taken up by a vessel of peculiar
shape and size, and that a bell, or cylindrical or conical tube, open at one end and
closed at the other, made of tinned iron, or soft iron, or any other good conductor
of electricity or magnetic body, will best reproduce the sounds; the bell, or tube, or
bar, or strip, or rod, will, under the influence of magnetism, become a magnet, and
show polarity. It will act as a magnet, and alter in shape, and act upon a much
larger column of air than the core would do by itself.