Multiple Telegraphy.
Year: 1893

page_text: Date of Application, 28th Nov., 1893-Accepted, 24th Feb., 1894
Multiple Telegraphy.
JEREMIAH MCCRAITH The Elms Melton Mowbray Leicestershire Medical
Practitioner do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement :-
The invention has reference to telegraph messages and is designed with a view
of producing an apparatus which can be worked in connection with telegraph lines
so that two or more messages cau be transmitted at one and the same time through
one and the same wire or cable.
(1) It consists of a metallic disk drum or cylinder faced with non-conducting
material except in part or parts which are left good conductors of electricity.
This disk drum or cylinder is in electrical contact with end of telegraph wire or
cable one such at each end of wire or cable.
(2) A series of insulated levers so arranged round each disk drum or cylinder
that one end of each is in constant contact with the surface of the disk, drum or
cylinder, and the other end is in electrical contact with the key, or receiver, of a
telegraph instrument.
The drums disks or cylinders are made to revolve at a uniform rate by means of
spring weight or other motive power, so that the metallic or conducting portion of
the surface comes into contact with the ends of the levers successively, and at
regular intervals, and are so adjusted before messages are sent that when a
particular lever is in contact with the metallic portion of the disk, drum, or
cylinder, at one end of the cable or wire, a particular corresponding lever is in
contact with the metallic surface of the disk, drum, or cylinder, at the other end.
Thus as the disks, drums, or cylinders revolve at a uniform speed, each successive
lever, at one end of the cable or wire, forms in turn with each corresponding lever
at the other end, a complete circuit for transmission; and as each lever at one end
can never be in electrical contact with any other lever than its particular corre-
sponding one at the other end, so long as the disks drums or cylinders revolve
uniformly, as many separate and independent circuits can be constituted and
simultaneously used, as there are levers round the disks, drums or cylinders.
By using one of these machines with four levers each at each end of a cable,
and supposing that the disks revolve so as to make and break connection twenty
times a second, each of these levers will be able to act on a Morse machine
causing it to make twenty dots a second if necessary so that the Morse alphabet
could be used and would be represented by a series of consecutive dots-several
for a dash and less for a dot.
In the accompanying drawings
A represents the revolving disk
B the metallic surface thereof.
C the insulated levers.
D the adjustable table.
I N
314

page_text: Every revolution in No. 2. makes three contacts with each lever and the wire or
cable.
These arrangements can be altered to suit circumstances.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is―
The transmission by means of my invention of more than one telegraphic
message at practically one time through one telegraph wire or cable without the
necessity of altering any of the existing arrangements of telegraph stations.
Dated this 29th day of January 1894.
J. MCCRAITH.