IMPROVEMENTS IN APPARATUS FOR TESTING THE INSULATION OF ELECTRIC TELEGRAPH WIRES
Year: 1853

page_text: LETTERS PATENT to William Reid, of University Street, in the
County of Middlesex, Electric Telegraph Engineer, for the
Invention of "IMPROVEMENTS IN APPARATUS FOR TESTING THE
INSULATION OF ELECTRIC TELEGRAPH WIRES."
Sealed the 22nd September 1853, and dated the 27th April 1853.
PROVISIONAL SPECIFICATION left by the said William Reid
at the Office of the Commissioners of Patents, with his Petition,
on the 27th April 1853.
I, WILLIAM REID, of University Street, in the County of Middlesex,
Electric Telegraph Engineer, do hereby declare that the nature of my
said Invention for "IMPROVEMENTS IN APPARATUS FOR TESTING THE INSULA-
TION OF ELECTRIC TELEGRAPH WIRES" to be as follows;
This Invention is for testing electric telegraph wires prepared for
submarine and subterraneous telegraphs by exhaustion and pressure,
and to determine the soundness and capability of the covering as a
non-conductor of electricity when applied for the above-named pur-
poses. I take a strong vessel, in which I place a coil or coils of wire

page_text: about to be tested from the said vessel, and exhaust the air by means
of a pump attached, and thus open a sluice cock, which instantly fills
the vessel with water. I then apply a force pump to produce any
given amount of pressure on the square inch; or a column of water, or
any other means, may be used to produce this pressure. One end of
the wires pass up through a stuffing box, the inside end of which is
sealed up, and made perfectly waterproof. A galvanometer is placed
in circuit with the wire to be tested, and the water in the vessel,
when the smallest imperfections in the covering will instantly be dis-
covered, which is of immense importance in submarine and subter-
raneous telegraphs.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said-William-Reid,-in-the-Great-Seal Patent Office,
on the 25th October 1853.
on
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
WILLIAM REID, of University Street, in the County of Middlesex,
Electric Telegraph Engineer, send greeting.
WHEREAS Her most. Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh Day of April, in the
Year of our Lord One thousand-eight-hundred and fifty-three, in the
sixteenth year of Her, reign, did, for Herself, Her heirs and,.suc-
cessors, give and grant unto me, the said William Reid, Her special
licence that I, the said William Reid, my executors, administrators,
and assigns, or such others as I, the said William Reid, my execu-
tors, 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 "IMPROVE-
MENTS IN APPARATUS FOR TESTING THE INSULATION OF ELECTRIC TELEGRAPH
WIRES," upon the condition (amongst others) that I, the said William
Reid, by an instrument in writing under my hand and seal, should
particularly describe and ascertain the nature of the said -Invention,

page_text: 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 William Reid, 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):
One end of the covered wire is
This Invention has for its object improvements in apparatus for testing.
the insulation of wire to be used in constructing submarine, subter-
ranean, and other electric telegraphs, and consists of arranging apparatus
so as to subject coated wire to exhaustion and pressure. For this pur-
pose I employ a strong vessel of malleable or cast iron, though other
material may be used, provided the vessel is strong enough to resist the
pressure of the atmosphere when exhausted, and to resist the hydrostatic
pressure to which the covered wire is intended to be subjected. This
vessel is to be made witli a cover, to allow of a coil of covered wire
being introduced and inclosed therein.
conducted from the interior; through a stuffing box, to the outside of the
vessel; the other end of the wire is to be coated over and well insulated.
The vessel. containing the wire is then to be exhausted of air, and a
vacuum formed by means of an air pump, or otherwise. The stop cock
to the air pump is then to be shut, and the passage for water is to be
opened in order to fill the vessel; or a quantity of water may be
introduced into the vessel, so as to fill or nearly to fill it, before ex-
hausting the air. One end of the wire of a galvanometer is to be con-
nected with the outer end of the wire which has been brought through
the vessel. Pressure is then to be exerted by pumping water into the
vessel or otherwise, when, on connecting up the two poles of the
battery with the galvanometer and the water in the vessel respectively,
if the insulation be perfect, no action will take place in regard to the
needle of the galvanometer, by reason of no complete electric current
being formed; but if there be any defect in the coating of the wire,
however small it may be, it will be indicated by the deflection of the
needle of the galvanometer, thus indicating that a circuit has been
formed by the water in the vessel getting in contact with some part of

page_text: the wire which is being tested. It is recommended that the exhaustion
should be as perfect as possible, and that the pressure to which the
coated wire is thus subjected should for submarine telegraphs exceed
the pressure which the depth of water in which it is to be submerged
can ever offer to such wire. For subterranean and other electric
telegraphis a few pounds on the square inch will suffice; but as excess
of pressure over that to which it is likely to be subjected when laid
down does not injure, nor does it cost much, at the same time more
certainly insures detection of defects, or what are likely to become
defects, it is recommended that the pressure should be at least 20 lbs.
on the square inch.
Having thus described the nature of my Invention, and the manner
of performing the same, I would have it understood that I do not con-.
fine myself to the details herein given, provided the peculiarity of my
Invention, as herein explained, be retained. But what I claim is the
mode herein described of arranging or combining apparatus for testing
the insulation of electric telegraph wires.
In witness whereof, I, the said William Reid, have hereunto
set my hand and seal, this Twenty-fourth day of October, in
the year of our Lord One thousand eight hundred and fifty-
three.
Witness, B. GOBEY,
Clerk to Messrs. Carpmael,
4, Old Square, Lincoln's Inn.
W. REID. (L.S.)