IMPROVEMENTS IN SPEAKING TELEPHONES.
Year: 1878

page_text: LETTERS PATENT to Joshua Franklin Bailey, of New York City, in the United
A.
States of America, at present residing at the Grand Hotel, in the City of
Paris, for the Invention of "IMPROVEMENTS IN SPEAKING TELEPHONES.'
communication from Elisha Gray, of Chicago, in the State of Illinois, United
States of America, Electrician.
Sealed the 15th November 1878, and dated the 27th September 1878.
COMPLETE SPECIFICATION filed by the said Joshua Franklin Bailey at the
Office of the Commissioners of Patents on the 27th September 1878.
JOSHUA FRANKLIN BAILEY, of New York City, in the United States of America,
at present residing at
"IMPROVEMENTS IN
SPEAKING TELEPHONES." A communication from Elisha Gray, of Chicago, in the
State of Illinois, United States of America, Electrician.
-
The Specification of the Letters Patent, No. 2646, dated July 29th 1874, granted
to John Henry Johnson, as a communication from the said Elisha Gray, shows
and describes apparatus for transmitting rhythmical vibrations representing com-
posite sounds or musical tones of different pitch telegraphically, and for reproducing
said tones at the receiving end of the line through the medium of animal tissue.
The present Invention constitutes a new application of the principle exemplified
in said Letters Patent, its object being to reproduce articulate sounds at the
receiving end of the telegraphic circuit through animal tissue in gliding contact
with a plate of suitable metal.
Any of the well-known speaking telephones, which transmit with sufficient
intensity, may be employed as a transmitter in the improved apparatus. It is
preferred however for a transmitter, the one known as the water telephone, described
in the Specification of Letters Patent, No. 1882, dated 10th May 1878, granted to me,
the said Joshua Franklin Bailey, as a communication from the said Elisha Gray
or the Edison carbon telephone transmitter, or some instrument used in connection

page_text: with a battery, on account of the greater power which may be obtained from such
a transmitter.
It is preferred to use currents of considerable tension in working the improved
apparatus; the most convenient and economical mode of doing which is by the use
of an induction coil, as shewn and described in the Specification of Letters Patent,
No. 2646 of 1874, above mentioned.
The receiving apparatus is substantially the same in construction and operation
as that heretofore employed by the inventor for reproducing musical tones trans-
mitted through a telegraphic circuit, and is shewn in the Patent last above
mentioned.
The Invention, therefore, consists in combining in an electric circuit telephonic
apparatus capable of transmitting articulate speech with a resonant receiver through
the intervention of animal tissue in gliding or frictional contact with said resonant
receiver. This receiver may consist of a plate of any of the well-known metals,
whether capable of induction or not.
It is preferred, however, to use a plate, disc, or diaphragm of thin sheet metal,
such as zinc or German silver, highly polished and oxidized on the surface exposed
to friction.
The frictional or gliding contact between the animal tissue and the receiving
plate may be produced in various ways, but it has been found in practice the
simplest and most effective to be to mount the receiving plate upon a resonant
box or case mounted upon a shaft so as readily to be revolved by means of a
pulley, crank, treadle, or other well-known moter. By this means an even pressure
and uniform rotation of the receiving plate is secured.
24 17
The animal tissue may consist of one or more fingers of the human hand inter-
posed in the circuit, and pressed against the plate."
bi 20
Various other equivalent substances may be used, such as leather moistened
with acidulated water, animal flesh covered with a membraneous coating, bacon
rind, pork skin, especially pieces taken from the ear or tail, and kid gloves.
The accompanying Drawings show one convenient form of apparatus for carrying
out the object of the Invention, obviously however the details of construction
of both the transmitter and receiver may be greatly varied without departing
from the spirit of the Invention.
Figure 1 represents an axial transverse section through the receiver, and
Figure 2 represents an arrangement upon circuit of the entire apparatus, including
both transmitter and receiver.
The base or supporting stand A is by preference made of metal, and of a weight
and size sufficient to maintain it in position without fastening it to its support.
A shaft B revolves in suitable bearings upon this stand, being driven by a
crank B or by a pulley, clockwork, or other suitable prime mover, and carries
a hollow resonant box or case of wood, or some other resonant substance. The
outer or open end of this box is covered by a thin sheet metal disc, plate, or
diaphragm D, preferably of zinc, as the surface of this metal is usually covered
with a very thin film of oxide, which is highly favorable to the proper action
between the animal tissue and the plate when in gliding contact.
The diaphragm it will be observed is connected with the shaft and base by a
wire e inside the resonant box or case, the base being in turn connected with the
ground by a wire a. The transmitter H in this instance is an ordinary speaking
telephone of the form shewn and described in the Specification of Letters Patent,
No. 1882, above mentioned, known as a "variable resistance telephone" which class
includes the microphone, the carbon transmitter, the water transmitter, and all
other of that class which produce the sound waves, by causing the vibrations of the
diaghragm to vary the resistance of the battery current proportionately to the
amplitude of motion of said diaphragm. The Inventor does not however confine
himself to a transmitter of this class, but contemplates using any form which
will transmit the vibrations with sufficient force.
⋅
The main battery M, B, is shewn in Figure 2 as short, circuited through the trans-
--

page_text: mitter and through the induction coil I, having the usual primary and secondary
circuits in such relation to each other as will produce the best results at the receiving
end of the line.
Starting from the plus pole of the battery the circuit passes through the trans-
mitter point h, thence through the primary helix of the induction coil, and back to
the other pole of the battery. The secondary helix has one of its poles connected to
the line, the other with the ground. At the receiving end of the line the circuit
passes through animal tissue, which may consist of the human body or other equi-
valent material which is in contact with the plate D, from whence the circuit passes
to the ground through the stand, as shewn in Figure 2, and as herein-before
described.
The induction coil may be dispensed with by using a battery of high tension and
small quantity, but this method would not be so economical in practice as the one
herein-before described.
In the Specification of the Patent No. 2646 of 1874, herein-before mentioned, it
was shewn that rhythmical vibrations in a primary circuit corresponding to any
given musical tone, or any given number of tones simultaneously produced are cor-
respondingly. produced inductively in a secondary circuit, and that when these
vibrations were passed through animal tissue in contact with a receiver, such as
described, the tones were audibly and accurately reproduced.
The present Invention contemplates not only the production of musical tones but
sounds of every character and quality, so whatever noise, whether consisting of
spoken words, musical tones, or other sounds that may be made or uttered in the
transmitter or in its immediate vicinity would be reproduced audibly at the receiving
end of the line on the revolving plate. I do not therefore claim the use of an
animal tissue receiver for the reproduction of musical tones in combination with a
transmitter only adapted to send such tones, as this constitutes the subject matter
of the Patent herein-before mentioned.
What I claim herein as new and desire to secure by Letters Patent is, the com-
bination in a telegraphic circuit of a telephonic transmitter capable of transmitting
articulate sounds or spoken words, with a receiver capable of reproducing such
sounds or words through the intervention of animal tissue in frictional contact with
said receiver.
In witness whereof, I, the said Joshua Franklin Bailey, have hereunto set
my hand and seal, this Twenty-fifth day of September, in the year of our
Lord One thousand eight hundred and seventy-eight.
J. F. BAILEY. (L.S.)