IMPROVEMENTS IN THE ART OF TRANSMITTING AND ANALYSING MUSICAL IMPRESSIONS OR SOUNDS TELEGRAPHICALLY, AND IN APPARATUS FOR SO TRANSMITTING AND ANALYSING SUCH. SOUNDS
Year: 1876

page_text: LETTERS PATENT to Edwin Chabot, Executor of George Tomlinson Bousfield,
late of Sutton, in the County of Surrey, for the Invention of." IMPROVEMENTS
IN THE ART OF TRANSMITTING AND ANALYSING MUSICAL IMPRESSIONS OR
SOUNDS TELEGRAPHICALLY, AND IN APPARATUS FOR SO TRANSMITTING AND
ANALYSING SUCH. SOUNDS." A communication from abroad by Elisha Gray,
of Chicago, in the United States of America.
COMPLETE SPECIFICATION filed by the said George Tomlinson Bousfield at
the Office of the Commissioners of Patents on the 4th May 1876.
.GEORGE TOMLINSON BOUSFIELD, of Sutton, in the County of Surroy.
<i IMPROVE-
MENTS IN THE ART OF TRANSMITTING AND ANALYSING. MUSICAL IMPRESSIONS
OR SOUNDS TELEGRAPHICALLY, AND IN APPARATUS FOR SO TRANSMITTING AND
ANALYZING SUCH SOUNDS." A communication from abroad by Elisha Gray, of
Chicago, in the United States of America.
This Invention relates to electro-harmonic telegraphs of the class shown and
described in British Letters. Patent, granted to John Henry Johnson, as a com-
munication from the said Elisha Gray, No. 2646 of 1874, and No. 974 of March 16th
1875.
The object of the first part of the Invention is to insure the transmission of tones
of uniform amplitude of wave whether a greater or less number of tonesbe trans-
mitted simultaneously, which end is attained by combining each musical tone
transmitter with its respective section of the main battery by a short or shunt
circuit in such manner that each section is utilized for the transmission of the
vibrations of its own tone without interfering or drawing upon the other sections
of the battery or opening the main circuit, and when not transmitting the un-
employed sections of the battery flow steadily to line without affecting the working.
transmitters of the other sections.
This part of the Invention thus possesses two distinguishing characteristics.
First, that of a main circuit always closed; and, second, the passage through this.
circuit of a smooth current so to speak when all the transmitters are quiescent, each
transmitter when in operation throwing its respective portion of said current into
vibration, so that there may be a smooth current and one or more vibratory waves

page_text: simultaneously transmitted through the circuit, or the entire current may be thrown
into vibration.
The object of the second part of the Invention is to dispense with local batteries
and all adjustment at the receiving end of the line, which end is attained by means
of an apparatus consisting of a turned bar or reed suitably attached to an electro-
magnet, and the whole mounted upon a resonant box closed at one end, the cavity
of which is tuned to the same fundamental as that of the aforesaid reed or bar,
which apparatus analyzes composite tones transmitted electrically through a wire
whereby the operator is enabled to read directly from the tone transmitted.
The object of the third part of the Invention is to furnish an attachment to the
analyzing apparatus whereby the vibrations of the air column within the resonant
cavity are made to produce a corresponding vibration in a diaphragan suitably
mounted in front of said cavity, which vibrations are communicated to a spring or
bar operating a local circuit, which local circuit may be attached to any of the
various forms of telegraphic recording instruments.
In the accompanying Drawings, Figure 1 is a perspective diagram of so much of
my improved apparatus for insuring the transmission of tones of uniform amplitude
of wave as is necessary to illustrate my Invention.
I have shown three transmitters and their batteries, and corresponding receivers
at each end of the line, so arranged as to transmit three messages each way simul-
taneously, but a greater or less number of transmitters and receivers may be
employed, and they might be so arranged as all to transmit one way instead of in
opposite directions.
It is not deemed necessary to describe in detail the construction of the battery, as
it forms no part of the subject matter claimed, and any of the well-known batteries
of the present day will work effectively with the improved apparatus.
The construction of the transmitters and receivers shown in the diagram,
Figure 1, is fully set forth and described in the aforesaid Patent, No. 974, of
March 16th, 1875, but it is preferred to employ the analyzers or receivers heroin-after
to be described.
Each battery is connected with its respective transmitter by a short circuit or
shunt wire.
Starting with battery No. 1, G is the ground wire connected at the plus (+) pole
of the battery, which battery is connected up in the ordinary way, and runs to line
at the other or minus (-) end through the analyzing receivers F', E', D. The line
connects at the other end through the analyzing receivers C, BI, A' to the plus (+)
pole of battery No. 2, and passes through in the ordinary way to the ground
wire Gat the minus (-) pole of said battery. The circuit thus far is similar to an
ordinary Morse circuit, closed and without a key or other means of making or
breaking the circuit. A, B, C, D, E, F, represent six sets of transmitters, each set
being composed of a common open circuit Morse telegraph key, and a musical tone
transmitter, such, for instance, as that shown in the aforesaid Patent, No. 974, of
1875. These transmitters are all alike in construction, but each one is tuned to a
different pitch, and has a receiver A', B, C, D, E, F, correspondently tuned at
the other end of the line.
Each battery is divided into sections 1, 2, 3, 4, 5, 6, not by separating or dis-
connecting its cells, but by throwing a short circuit or shunt wire around each
section, for instance, the first short circuit of battery 1 consists of the wires a, b;
the second of the wires b, c; and the third of the wires c, c', and so on.
The number of cells in each section is determined by the distance the tone is to
be transmitted.
Each shunt wire runs through its own key and vibrating transmitter, for instance
in section of battery 1, which is at the line end of the battery, a wire a passes
from the minus (-) pole of the battery to one binding screw of the transmitter A,
at which point the circuit divides, one branch connecting to line (L) and the other
to the vibrating bar of the transmitter through the break-point, which is in this

page_text: ng point. The circuit then passes to the other binding screw, and
thence to the key lever.
The anvil or lower point of the key is connected directly with the ends of tho
wire b, which forms the dividing line between sections 1 and 2, forming part of the
short circuit of each section, and so on.
Now if the reed or bar of transmitter A be vibrated by its local battery, which is
omitted from the Drawing to avoid complication, but the operation of which is well
understood, and the key belonging to and in the same circuit with it be depressed,
the shunt circuit around section 1 will be completed every time the vibrating bar
or reed makes contact with its break-point, thus producing a set of waves or
electrical vibrations throughout the line, the waves succeeding each other at the
rate per second corresponding to the vibrations of the transmitting reed or bar,
which waves will induce corresponding impulses in all the magnets of the power
approximating one-sixth of the whole battery. Although these magnetic impulses
are induced in all the magnets in the circuit, one only will make an audible response
except to a very delicate test, which one in this instance will be the receiver marked
A', as one whose reed or bar is tuned correspondently to the transmitter in
operation.
All the other sections of the apparatus are connected up and operated in a manner
precisely similar, cach operating on its own section of battery. Each transmitter
differs in pitch and has its complement in its own corresponding receiver.
It will be observed that by working with this system the main circuit is never
opened, owing to which fact the integrity of each set of waves is preserved intact,
thus rendering analysis easy at the receiving end of the line.
I will now describe the receiving instrument or analyzer which is employed in
preference to that described in the aforesaid Patent, No. 974 of 1875, as by it local
batteries may be dispensed with, and all adjustment at the receiving end of the
line, the operator reading directly from the tone transmitted.
This instrument is illustrated by Figures 2 to 4, inclusive of which Figure 2 is a
plan or top view, Figure 3 a side elevation partly in section, and Figure 4 a diagram
showing the transmitting and receiving apparatus as adapted to the transmission of
several tones simultaneously.
A resonant box I such as used for intensifying the sound of tuning forks is shown
as closed at one end. A screw bolt or other suitable support J secured upon this
box sustains an electro-magnet K of well-known construction. A vibrating tongue
reed, or bar M of steel, is also fastened upon the support J, and is united with one
pole of the magnet K. The free end of the reed passes close to, but does not touch
the other pole of the magnet.
For convenience of removal or replacement all the parts of the apparatus may bo
united by means of a common bolt and nut.
The box is tuned to produco a maximum resonance of the desired tone, and the
eed or bar is accurately tuned correspondently; consequently as the reed or bar
ibrates the sound of its fundamental tono is intensified by the resonance of the
ox in accordance with well-known laws of acoustics.
If now the electro-inagnet be connected in a telegraphic circuit in the same way
s one of the analyzers described in the aforesaid Patent, No. 974 of 1875, and a
oto be transmitted by one of the transmitters, the note will sound in the box
rovided the tone transinitted corresponds with that of the box, otherwise the note
ill not be heard. Should a second analyzer be similarly placed in the circuit and
aned to a different pitch and a second note of corresponding pitch be transmitted
will sound in the box of corresponding pitch without affecting the other.
The same rule holds with a larger number.
In practice as many as eight different tones simultaneously transmitted through
single wire have been thus analyzed and reproduced, and as it has been demon-
rated by using the Morse signals that eight messages can simultaneously be sent
er each wiro as rapidly as cach operator can transmit with the common tele-
aphic key the advantages of the Invention are obvious.

page_text: It is believed, however, to be practicable simultaneously to transmit a number of
messages even greater than that above mentioned.
The reed M is made of a steel bar with parallel sides, the turning being done by
cutting away the sides near the fixed ends, as shown, which construction is found
in practice to obviate the tendency of the reeds to break into nodes or to respond 5
to notes other than its own, as has been the tendency of other forms of reeds
tried.
To enable the operator to derive the double advantage of being able to read
directly from the tone transmitted while he may or may not be using recording
apparatus, there is attached to the resonant box I (see Figure 5, which represents
a perspective view of a receiver and its attachment for operating a recording appa-
ratus) a short section N of a box, over one end of which is stretched a diaphragm N¹
made of some thin substance, such as parchment or "gold beater's skin," the whole
forming a chamber with its mouth facing that of the resonant box I, which section
or chamber is held in place by the bars or guides C', G. These bars G¹, G¹, are
rigidly attached to the inside of the short box or chamber N and fit closely and
slide inside of the resonant box I.
By means of these slides the position of the box or chamber N with its diaphragm
can readily be adjusted to such distance as will produce a maximum effect upon the
diaphragm when a tone is sounding in the resonant box I.
A vibrating bar or spring O, mounted on the sliding section, is provided with an
adjusting screw to regulate its tension.
In the centre of the diaphragm N' is fastened a small metal plate containing a
platina point against which the end of the vibrating bar or spring O rests. This
small metal plate is connected with a binding post P by means of a small wire,
and by the same means the binding post Q is electrically connected with the
vibrating bar O.
The operation of this attachment is as follows:-When a note is transmitted to
the magnet K which is in unison with the reed M and resonant cavity of the box I,
said note will sound and throw into sympathetic vibration the air column in the
box I. The vibrations will be transmitted from the mouth of the box with sufficient
force to throw into vibration the diaphragın N¹, and if the bar or spring O is suitably
adjusted so that its natural rate of vibration is slower than that of the diaphragm O
and of the air column, it will rattle or jar upon the metal plate and will open or
close a local circuit that may be attached to the binding posts P and Q and operate
any recording apparatus that may be attached.
It is obvious that two or more sounding boxes and circuit breakers such as
described capable of producing tones of different pitch may be used for analyzing
a series of corresponding tones of different pitch simultaneously transmitted over a
single wire.
And having thus fully described and ascertained the nature of this Invention I
declare that I claim-
First. The improvement in the art of telegraphically transmitting composite tones
herein-before set forth, which consists in working a closed circuit with a continuous
current from a main battery, portions of the whole of which current are thrown
into vibration at will by the transmitters.
Second. The improvement in the art of telegraphically transmitting and analyzing
composite tones herein-before set forth, which consists in working a closed circuit
with a continuous current from a main battery, portions of the whole of which
current are thrown into vibration at will by the transmitters, each set of vibrations
being audibly reproduced by a corresponding receiver.
Third. The combination substantially as herein-before set forth of a series of
transmitters, each operated by a local battery, a main battery, an electric circuit
through which a continuous current flows from said battery and shunt or short
circuits between the main battery and transmitters.
Fourth. The combination substantially as herein-before set forth of a series o
transmitters, a main battery connected therewith by short or shunt circuits,

page_text: closed clectric circuit through which a current continuously passes from the
main battery and a series of analyzing receivers included in the circuit.
Fifth. The herein-before described art of transmitting musical sounds tele-
graphically by reproducing such sounds at the receiving end of the line by
means of a vibrating reed and a sounding box of corresponding pitch.
-
Sixth. The combination substantially as hercin-before set forth of an electro-
magnet, a vibrating reed, and a sounding box of corresponding pitch united at the
receiving end of an electric circuit.
Seventh. The combination substantially as. herein-before set forth with an
electric circuit of a series of electro-magnets, a series of vibrating reeds producing
musical tones of different pitch, and a series of correspondently tuned sounding
boxes, whereby each box is caused to sound its own noto while rejecting all
others.
Eighth. The vibrating reed constructed substantially as herein-before set forth
with parallel sides and with recesses near its fixed end whereby its tendency to
vibrate in unison with tones other than its own is prevented,
Ninth. The combination substantially as herein-before set forth of an electro-
magnet, a vibrating reed, a sounding box of correspon ding pitch, and a local
circuit breaking apparatus actuated by the vibrations of a column of air in said
Bounding box.
•
Tenth. The combination substantially as herein before set forth of a sounding
box the column of air contained in which is thrown into vibration by tones
transmitted through an electric circuit, an adjustable box or chamber across which
a diaphragm is stretched and a local circuit breaking mechanism, mounted on said
adjustable section.
Eleventh. The combination substantially as herein-before set forth of a sounding
box, a diaphragm, a local circuit and a circuit breaking lover vibrating more
slowly than the diaphragm by which said local circuit is controlled.
In witness whereof, I, the said George Tomlinson Bousfield have hereunto
set my hand and seal, this 29th day of April, in the year of our Lord Ono
thousand eight hundred and seventy-six.