IMPROVEMENTS IN ELECTRIC TELEGRAPH APPARATUS
Year: 1871

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN ELECTRIC TELEGRAPH APPARATUS."-A communi-
cation from abroad by Bernard Meyer and Jonas Haas, both of 13,
Boulevart St. Martin, Paris.
Scaled the 9th April 1872, and dated the 27th October 1871.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 27th October 1871.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
5 County of Middlesex, Patent Agent, do hereby declare tho nature of
the said Invention for "IMPROVEMENTS IN ELECTRIC TELEGRAPH APPARATUS,"
to be as follows:-

page_text: without preliminary arrangement or composition, whereby each wire
may be made to render considerably greater service than hitherto.
The motor which serves to operate all the receiving apparatus consists
of a spring and train A (sec accompanying Drawing) set in motion by a
weight, and regulated by a conical pendulum, consisting of a weighted
ball on an elastic stem suspended from a fixed point.
In order to maintain concordance of the two instruments, a correcting
apparatus is applied to the shaft which carries the printing mechanism
consisting of an escapement wheel mounted loose on the shaft, and
which detaches the pallet from an electro-magnet. There is a collecting
current at each turn of shaft M, N. Two transmission shafts M, N,
and E, F, communicate motion to receivers B¹, B³, B³, one shaft
serving to draw along the paper strip, and the other to operate the helix
or marking instrument H', H³, H³, hereafter described.
.
The transmitting instrument consists, first, of a manipulator having a
key board c' with four long keys separated by an equal number of short
keys. Each long key corresponds to a dash, and each short key to a
half dash or dot. The combination of these two will furnish according
to their intervals a considerable number of different characters, and
without presenting any inconvenience in the use of the Morse alphabet;
secondly, of a distributor consisting of a fixed cylinder, having a
metallic surface over which travels a contact roller or a style or point.
The cylinder is divided into as many equal or proportional parts as
transmitters in the apparatus, three' being shown in the Drawing, the
parts being insulated one from the other. Each portion of the circum-
ference has surfaces and spaces of metal. The surfaces, which are four
in number for each transmitter, consist of insulated metallic divisions
connected by as many conducting wires to the four long keys of the
manipulator. Each of the four is divided into two parts by a thin
insulating partition. These semi-divisions correspond by as many wires
with the four short keys. By depressing a long key the current is
conveyed to the whole division, but by depressing a short key it passes to
a half division only. The roller in its traverse produces emissions of the
current which are registered at the recording instrument by dashes or
half dashes, according as a long or short key has been depressed.
The receiver comprises a helix or screw of about four or more inches in
length divided into as many parts as there are divisions in distributor D.
As three are shown in the Drawing there is consequently one-third

page_text: for each receiver. The helix is supplied with oleic ink from a pad and
marks a straight line transversely on the paper strip. The motion of
the paper is without interruption, and the continuous strip passes in
close contact round the end of a lever, so as to present a projecting
angle to the inking helix, the contact with or withdrawal therefrom of
the paper determines the printing of dashes or dots which form letters,
there being one letter for cach revolution of the screw. The lever over
which the paper passes has at its lower part a bar electro-magnet serving
as the armature of a fixed magnet disposed horizontally beneath the
helix. The successive passages of the current through the electro-
magnet produces the attractions and repulsions which cause the lever to
effect and break contact with the inking helix. The foregoing describes
the method of recording.
.
It will be readily understood that two receivers may be applied on the
same magnet, the helix in this case would be double, the two messages
being read off side by side. An electro-chemical receiver may also
be employed with the same system of transmission in the following
manner: A continuous broad strip of prepared paper receiving motion
from the same transmitting shaft E, F, is caused to pass its mid portion
through a solution which decomposes the current beneath a comb,
having eight points coupled two and two and separated by three
intervals. A dash corresponds to two connected points and half dashes
to one single point, the marks being traced across the strip. The red
lines in the Drawing show the arrangement of the wires and the
direction of the current.
Relays. The transmission of messages over long lines necessitates the
employment of a relay, which is arranged as follows:-A fixed magnet
having arms of unequal length is placed horizontally and having as an
armature a small bar electro-magnet. This electro-magnet is pivoted
to move in a horizontal direction and carries an arm oscillating between
two screws, at which are produced the breaks or passage of the current,
according as the relay acts by attraction or repulsion. A similar system
if doubled would serve as relays at a mid point of the line.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 26th April 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Ohancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh day of October, in the
year of our Lord One thousand eight hundred and seventy-onc, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alexander Melville Clark, Her special
licence that I, the said Alexander Melville Clark, my executors, ad-
ministrators, and assigns, or such others as I, the said Alexander
Melville Clark, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an In-
vention for " IMPROVEMENTS IN ELECTRIC TELEGRAPH APPARATUS," a commu-
nication to me from abroad by Bernard Meyer and Jonas Haas, both of
13, Boulevart St. Martin, Paris, upon the condition (amongst others) that
I, the said Alexander Melville Clark, my executors or administrators, by
an instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Alexander Melville Clark, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying
Drawing, and to the letters marked thereon (that is to say) :-
-
This Invention relates to improved electric telegraph apparatus for
transmitting by a single wire and in the same limit of time several
different messages, the number of which is dependent on the capacity of

page_text: the said conducting wire. The principle of multiple transmission of
this Invention is based upon the equal division amongst several operators
of the time usually occupied in sending a single message. It has
therefore nothing in common with the system of simultaneous trans-
mission of the electric currents, already known. In the present system
the emissions of the current are successive and distinct, and are received
or collected in the receiving instrument by a distributor, which apportions
the currents to the divisions of the receiving instrument appropriated
to cach operator.
Thus if the distributor makes one revolution per
minute, for example, and there are four operators to make use of the
line wire for transmission, each would have the line at his disposition for
a quarter of a minute for transmitting his message. At each rcvo-
lution the collector receives these messages, and distributes them in the
desired order to their respective receivers. If there are five operators
and the speed of the distributor is the same, each would have a fifth
part of a minute to make use of the line, and so on. The simulta-
neous systems above alluded to depend on electrical combinations,
whilst according to the present Invention mechanical combinations are
employed, which thus enablo several operators to send each his message
in the same space of time that one operator would require, and
that without preliminary arrangement or composition, thus several
operators can use the same line wire at one time by sending several
distinct emissions of the current, so that the wire can be made to render
considerably greater service. The motor which serves to operate all the
receiving apparatus consists of an arrangement of clockwork at A (sco
accompanying Drawing) set in motion by a weight, and regulated by a
conical pendulum consisting of a weighted ball on a flexible stem
suspended from a fixed point, or any other suitable arrangement may bo
employed.
°
In order to maintain the concordance of the two instruments, viz.,
between the manipulator and the receiver at the distant station, a
correcting apparatus is applied to the shaft which carries the marking
instrument, whereby at cach revolution the pallet of an electro-magnet
being moved or attracted permits the said shaft (on which is mounted
an escapement wheel) to make one revolution only, so that the receiving
apparatus cannot work more or less quickly than the transmitter:
For this purpose there is a correcting current at each revolution of tho
shaft M, N. This shaft M, N, and another E, F, operate the marking

page_text: apparatus of receivers B', B³, B³, B', one shaft serving to draw along the
paper strip, and the other to operate the helices or marking instruments
„II', H³, H³, H', hereafter described.
The transmitting instrument consists, 1st, of a manipulator, having a
key board with four long keys separated by an equal number of short
keys; four, C¹, 0, 0³, C', are shown in the Drawing. Each long key
corresponds to a dash, and each short key to a half dash or dot. The
combination of these two signals furnish according to their intervals a
considerable number of different characters without presenting any
inconvenience in the use of the Morse alphabet. Secondly, of a dis-
tributor consisting of a fixed cylinder D having a metallic surface over
which travels a contact roller P or a style or point carried on shaft M, N,
and communicating with the line wire. The cylinder is divided in its
section into as many equal or proportional parts as there are transmitters
in the apparatus (four being shown in the Drawing), the parts being
insulated one from the other. Each of the four portions of the cir-
cumference is divided into sections and spaces of metal. The sections,
which are four in number for each transmitter, consist of insulated
metallic divisions connected by as many conducting wires to the four
long keys of the manipulator. Each of the four is divided into two parts
by a thin insulating partition. These semi-divisions correspond by as
many wires with the four short keys. By depressing a long key the
current is conveyed to a whole section, but by depressing a short key
it passes to a half section only. The roller P in travelling round the
cylinder produces emissions of the current, which are registered at
the recording instrument by dashes or half dashes according as a long
or short key has been depressed. The receiver comprises a helix or
single convolution of a screw thread of about four or more inches
in length divided into as many separate parts as there are principal
divisions in distributor D to receive separate messages. As four arc
shown in the Drawing, there is consequently a fourth of a convolution
for each of the markers, which come into operation successively when
the printing apparatus of which they form part corresponds through the
medium of the distributor with its transmitter. The helix is supplied
with oleic ink from a pad and marks a straight line transversely on
the paper.
The motion of the paper is uninterrupted and the con-
tinuous strip passes round an arm at the end of a lever in close contact,
so as to present a projecting angle to the inking helix, the contact with

page_text: or withdrawal therefrom of the paper determining the printing of dashes
or dots which form letters, one letter being made at each revolution of
the helix. The lever over which the paper passes serves as armature
to an electro-magnet disposed horizontally beneath the helix. The
successive passages of the current through the clectro-magnet attract
the lever, and cause it to bring the paper into contact with the inking
helix, whereby the printing of the signals is effected, the lever being
withdrawn immediately the current of the electro-magnet ceases.
It will be readily understood that two receivers may be applied in
connection with the same magnet. The helix in this case would be
duplicated, the two messages being read off side by side.
An electro chemical receiver may also be employed with the same
system of transmission in the following manner :-A continuous broad
strip of paper receiving motion from the same transmitting shaft E, F,
is employed, whose middle portion has been prepared with a chemical
solution which is capable of being decomposed by the electric current.
In this case the marking cylinder H is provided with a comb having
eight points coupled two and two, and separated by three intervals with
which the paper is brought into contact. A dash corresponds to two
connected points, and half dashes to one single point, the marks being
made across the strip by the decomposition which takes place when the
electric current is emitted at the points as usual in clectro chemical
telegraphy.
The dotted lines in the Drawing show the arrangement of the wires
and the direction of the current.
Relays. The transmission of messages over long lines necessitates
the employment of a relay, which is arranged as follows:-A magnet
having arms of unequal length is fixed horizontally and has as an
armature a small bar electro-magnet. This electro-magnet is pivoted to
move in a horizontal direction, and carries an arm oscillating between
two screws at which are produced the breaks or passages of the current
according as the relay acts by attraction or repulsion. A similar system
if duplicated would serve as relays at an intermediate point of the line.
Having described the nature of the Invention and the manner of per-
forming the same, I declare that what claim as the Invention to be pro-
tected by the herein-before in part recited Letters Patent is, transmitting
several messages at a time through a single line wire, substantially in the

page_text: manner and by the means herein-before set forth and shown in the
Drawings, the Invention being applicable to printing, writing, and other
telegraphic apparatus generally.
In witness whereof, I, the said Alexander Melville Clark, have here-
unto set my hand and seal, this Twenty-sixth day of April, in
the year of our Lord One thousand eight hundred and seventy-
two.