IMPROVEMENTS IN ELECTRIC TELEGRAPHS
Year: 1856

page_text: LETTERS PATENT to Joseph Latimer Clark, of Adelaide Road, Haverstock
Hill, Hampstead, for the Invention of "IMPROVEMENTS IN ELECTRIC
TELEGRAPHS."-Partly a communication.
Sealed the 31st March 1857, and dated the 29th November 1856.
PROVISIONAL SPECIFICATION left by the said Joseph Latimer Clark at
the Office of the Commissioners of Patents, with his Petition, on the
29th November 1856.
I, JOSEPHI LATIMER CLARK, of Adelaide Road, Haverstock Hill, Hampstead,
do hereby declare the nature of the Invention for "IMPROVEMENTS IN ELECTRIC
TELEGRAPHS," to be as follows:-
This Invention consists in an improved method of insulating and supporting
telegraph wires when such wires are suspended in the air. For these
purposes insulators of earthenware, glass or other similar insulating material
are employed. These insulators are of the form of an inverted cup, and are
made double, that is to say, there is a smaller cup contained concentrically
within the exterior insulating cup, and springing from the interior thereof, so
as to be protected by it. On the top of the exterior inverted cup is formed
a notch for receiving the wire. This notch at the top is only wide enough to
allow the wire to pass in, and is cut obliquely to the direction of the wire, but
lower down its sides are undercut in such manner that when the wire is in its
place the insulator can be turned partly round, which renders it impossible for
the wire to escape from the notch. The interior surface of the exterior cup
of the insulator has a series of circular grooves formed on its inner surface,
and the interior cup has similar grooves formed both on its interior and

page_text: exterior surfaces. In this way the distance to be traversed by the electric
current before it can escape is increased. In the centre of the bottom of the
interior cup of the insulator a hole is formed to receive the iron bar, by which it
is carried, and which is cemented into the said hole. This bar is coated with
shellac, marine glue, or other suitable insulating material, and its lower end
is received by a socket at the end of a bracket of cast iron, which is carried
by the telegraph post. It will be seen that by mounting insulators in
this manner they may easily be taken down for cleaning, or replaced by
lifting the bar on which the insulator is mounted out of the socket on the
cast-iron arm, and by turning the insulator so as to separate it from the
wire.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Joseph Latimer Clark in the Great Seal Patent Office on
the 29th May 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
LATINER CLARK, of Adelaide Road, Haverstock Hill, Hampstead, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of November, in the year of our
Lord One thousand eight hundred and fifty-six, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Joseph Latimer Clark, Her special licence that I, the said Joseph
Latimer Clark, my executors, administrators, and assigns, or such others as
I, the said Joseph Latimer 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 Invention for "Iм-
PROVEMENTS IN ELECTRIC TELEGRAPHS," partly a communication, upon the
condition (amongst others) that I, the said Joseph Latimer 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.

page_text: NOW KNOW YE, that I, the said Joseph Latimer 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 thereof, that is to say:-
This Invention consists in an improved method of insulating and supporting
telegraph wires when such wires are suspended in the air. For these
purposes insulators of earthenware, glass, or other similar insulating material
aro employed. These insulators are of the form of an inverted cup, and are
made double, that is to say, there is a smaller cup contained concentrically
within the exterior insulating cup, and springing from the interior thereof, so
as to be protected by it. On the top of the exterior inverted cup is formed
a notch for receiving the wire; this notch at the top is only wide enough to
allow the wire to pass in, and is cut obliquely to the direction of the wire, but
lower down its sides are undercut in such manner that when the wire is in
its place the insulator can be turned partly round, which renders it impossible
for the wire to escape from the notch. The interior surface of the exterior
cup of the insulator has a series of circular grooves formed on it, and the
interior cup has similar grooves formed both on its interior and exterior
surfaces. In this way the distance to be traversed by the electric current
before it can escape is increased.
In the centre of the bottom of the interior cup of the insulator a hole is
formed to receive the iron bar, by which it is carried, and which is cemented
into the said hole. This bar is coated with shellac, marine glue, or other
suitable insulating material, and its lower end is received by a socket at the
end of a bracket of cast iron, which is carried by the telegraph post. It will
be seen that by mounting insulators in this manner they may easily bo taken
down for cleaning, or replaced by lifting the bar on which the insulator is
mounted out of the socket on the cast-iron arm, and by turning the insulator
so as to separate it from the wire.
And in order that the said Invention may be most fully understood and
readily carried into effect, I will proceed to describe the Drawing hereunto
annexed.
ก
DESCRIPTION OF THE DRAWING.
Figure 1 is a vertical section, Figure 2 is a side elevation, and Figure 3 is
plan, of the insulator with the iron bar and bracket, by which it is carried.
a is the exterior cup, and 6 the interior cup of the insulator, and on the
exterior surface of the exterior cup and on both the surfaces of the interior
cup are formed series of circular grooves, as is shown at Figure 1; c is the

page_text: notch in the top of the insulator into which the wire d drops, and the Drawing
clearly shews the way in which this hole is undercut, so as to allow the wire
to assume the position which it there occupies; e is the iron bar, cemented
into the hole in the centre of the bottom of the interior cup of the insulator.
This bar is coated with shellac or marine glue, and is made conical at its
lower end, so that it may fit into the socket formed at the end of the iron
bracket f, which is screwed to the side of the wooden post g. Figure 4 is a
side view, and Figure 5 is a plan of another socket for receiving the end of
the bar e. This socket is made with wings, and is suitable for fixing on the
top of a wooden post, as is shewn by the Drawing.
In witness whereof, I, the said Joseph Latimer Clark, have hereunto set
my hand and seal, this Twenty-ninth day of May, in the year of our
Lord One thousand eight hundred and fifty-seven.
Witness,
S. CARPMAEL.
J. LATIMER CLARK. (LS.)