IMPROVEMENTS IN COATING AND INSU- LATING WIRE
Year: 1852

page_text: LETTERS PATENT to Thomas Earl of Dundonald, of Belgrave
Road, in the County of Middlesex, Admiral in Her Majesty's
Navy, for the Invention of "IMPROVEMENTS IN COATING AND INSU-
LATING WIRE."
Sealed the 12th January 1853, and dated the 6th October 1852.
PROVISIONAL SPECIFICATION left by the said Thomas Earl of
Dundonald at the Office of the Commissioners of Patents, with
his Petition, on the 6th October 1852.
I, ADMIRAL THE EARL OF DUNDONALD, of Belgrave Road, in the
County of Middlesex, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN COATING AND INSULATING WIRE" to be as
follows:-
My improvements consist in various particulars whereby ordinary
concrete bituminous substances are rendered applicable to guide and
transmit the galvanic or electric fluid through subterranean excavations,
as effectually as the well-proved bitumen of Trinidad or that of the
British North American provinces.
In lieu of the ordinary process of fusing such bitumens by the direct
action of fire as hitherto practised, which by carbonizing a portion and

page_text: dissipating its oleaginous or volatile components, and applying it to
purposes to which by reason of its indurable and brittle state it is
unfit, I fuse or melt the said bituminous substances in a vessel placed
in a steam or water bath; and if when melted it shall appear, notwith-
standing the said process, to be too stiff' for the intended purpose, I add
thereto one or more solvents, such as naptha, petroleum, tar, or others,
in such proportion as to suit the bitumen for its intended use. When
sufficiently cool not to destroy filamentous matter, I add waste cotton
fibres, wool, hair scraped off hides, or such like causes of tenacity, on
the principle familiar in mixing hair with mortar.
The bitumen thus treated may be worked like wax, by hand or by
machinery. In either case the coating of the wire in the rough or
first application of the bituminous coating may advantageously be
passed through sheaves or rollers, each having a semicircular groove
on its periphery, so that, by combination, a circular coating is formed
around the wire. Tape, or the strips or parings off the edges of
cloth or other such. material, may simultaneously be passed through
the said sheaves or rollers, which will surround and form an adhesive
binding to protect the bituminous coating. This binding may advan-
tageously be varnished or lackered with dissolved bitumen, or other
suitable preservative.
The coil or hanks of covered wire ought then to be exposed to the
atmosphere to dry, after which it is advantageous to immerse the whole
in water, wherein it will lose any inconvenient adhesiveness, especially
if a portion of fullers earth is therein dissolved.
Numerous wires may be laid down in one envelope by placing
them on strips of coated canvass, and running prepared and heated
bitumen thereon, of a consistence which, when cool, shall neither crack

page_text: County of Middlesex, but now of Belgrave Road, in the same County,
Admiral in Her Majesty's Navy, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of October, in the year
of our Lord One thousand eight hundred and fifty-two, in the six-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Thomas, Earl of Dundonald, Her
special licence that I, the said Thomas, Earl of Dundonald, my
executors, administrators, and assigns, or such others as I, the said
Thomas; Earl of Dundonald, 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 nake, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for "IMPROVEMENTS IN COATING AND INSULATING
WIRE," upon the condition (amongst others) that I, the said Thomas,
Earl of Dundonald, by an instrument in writing under my hand and
seal, 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 Thomas, Earl of Dundonald, 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):
My improvements consist in various particulars tending to accom-
plish a combination of bituminous substances, with gums and resins for
coating and insulating wire.
In order fully to understand my process whereby such substances are
rendered applicable to the aforesaid purpose, I refer first to the treat-
ment and applications of the bitumens of Trinidad and New Brunswick,
set forth in the Specification of my Patent enrolled on the Twenty-
second of January, One thousand eight hundred and fifty-two, and now
proceed to describe my improvements.

page_text: For instance, if I wish to produce an insulating and flexible covering
for wire by a compound of gum shellac (which gum is perhaps the
best nonconductor), I blend therewith rosin (say) in the ratio of four
or five to one of shellac) by pounding and sifting, and thereunto I
add as a solvent about a tenth of their joint weight of unctuous or
viscid oil of petroleum, or of distilled tar, (in preference to petroleum,
tar, naptha, or other partly volatile solvents,) and subject them to gentle
heat in a vessel surrounded by steam or hot water, stirring the mixture
to produce solution, amalgamation, and permanent plasticity.
If I prefer to insulate and coat by combining THIS adhesive com-
pound with bitumen, I pound, sift, and melt the bitumens before adding
the shellac and rosin mixture, by reason that bitumen requires more
heat to dissolve it than vegetable gums or rosins can be exposed to,
without deterioration, especially if rosin with unctuous oil are used
without indurated gum as a mixture.
If in any stage of preparation the combination of materials for
coating is found to be too soft for its intended purpose, I add dry
pounded bitumen, or if too indurated I mix more of the unctuous or
viscid oil, or in the case of deficient tenacity or flexibility I add caout-
chouc, to impart the qualities required.
The constituent proportions of an insulating coating for wire, may
advantageously be seventy-five parts of bitumen, ten parts of shellac
and rosin mixture, and fifteen parts of caoutchouc, which proportions
will ensure the essential qualities of tenacity, flexibility, and cohesion.
The proportions, however, may be varied to suit the destination of the
coated wire, whether it is to be laid in dry land or under water, in a
hot or in a cold climate.
All the substances composing the coating must be thoroughly amal-
gamated by mastication, crushing, and rolling, besides pounding,
sifting, and stirring. It is proper, however, to notice, that separate
solutions; or indeed any solution of the materials by heat previous to
their mastication, may be dispensed with, and their combination effected
by the steam or hot water surrounding the masticator, jointly with that
produced by the friction of the forcibly combining substances, during a
lengthened process.

page_text: My mechanical means of coating and insulating wire differs from
that hitherto practised, by causing the coating of the wire to adhere
thereto by heat.
J
The process may be better understood by reference to Figure 1st,
which represents a case or box A, B, C, D, into which the coating is
compressed (after the manner practised in various branches of manu-
facture). Into this box there is an aperture e, by which the wire enters,
heated by a gas frame G, or by any other device, in order that the cir-
cumjacent material h, h, may be melted, and form a closely adhesive
covering before the wire issues at f, k.
Figure 2nd is a transverse section, exhibiting by the central dark
circle the wire, with its adhesive coating, in process of being stripped
of any superfluous material by the circumference of the hole through
which it passes. There is also an outer dark ring, denoting an annular
orifice, for the purpose of forming a pipe or tube, incasing the coating
of the wire, thereby constituting what may be considered a third
envelope, to insure insulation and protection.
The materials of the external pipe may be derived from the same
box or case, or from another, into which filamentous, metallic, or
other substances may be introduced, to strengthen the covering and
resist friction, or to increase its weight when deemed necessary.
Grooved or plain rollers may also be employed to coat wire singly or
in groups, guided (on their entrance between sheets of bituminous
coating) by pins or holes, so that they shall be deposited in parallel equi-
distant lines. These sheets may be combined with textile or fibrous
substances, in certain cases, with advantage..
Lastly, the predominant portion of my coating being mineral, and an
antiseptic solvent amalgamated with the vegetable gums and resins,
renders the insulating coating secure from decomposition by heat, damp,
or destruction by insects.
I claim the adaptation and manipulation of gums and resins,
combined and treated as aforesaid, for coating and insulating wire.
I claim the means of producing an insulating covering by the in-
fluence of heat applied to wire, whether such coating should be effected
under pressure, or simply by the solution of coating materials in contact
with the wire.

page_text: I claim the means of preserving vegetable gums and rosins
from being decomposed or destroyed by humidity and heat, or the
ravages of insects, by combining them with antiseptic oils and mineral
substances.
In witness whereof, I, the said Thomas, Earl of Dundonald, have
hereunto set my hand and seal, this Fourth day of April, One
thousand eight hundred and fifty-three.
DUNDONALD. (L.S.)
Witness,
S. CARPMAEL.