IMPROVEMENTS IN INSULATING TELEGRAPHIC WIRES
Year: 1858

page_text: LETTERS PATENT to John Macintosh, of North Bank, Regent's Park,
in the County of Middlesex, for the Invention of "IMPROVEMENTS IN
INSULATING TELEGRAPHIC WIRES."
Sealed the 9th November 1858, and dated the 14th May 1858.
PROVISIONAL SPECIFICATION left by the said John Macintosh at the
Office of the Commissioners of Patents, with his Petition, on the
14th May 1858.
I, JOHN MACINTOSHI, of North Bank, Regent's Park, in the County of
Middlesex, do hereby declare the nature of the Invention for "IMPROVEMENTS
IN INSULATING TELEGRAPHIC WIRES," to be as follows:-
This Invention has for its object improvements in insulating telegraphic
wires. For this purpose I lap round the wire to be insulated a yarn made
from gun-cotton, or other fibre or substance similarly prepared; and I then
subject the coated wire to the action of a fluid, which acts as a solvent to
the gun-cotton or similar substance, so as to cause it to adhere firmly to the
wire. Sometimes I dissolve gun-cotton or other similar substance in the
solvent before applying it to the coated fibre or substance lapped round the
wire; and gutta percha, india-rubber, and other substances may be added to
the solution. In this manner a coating of collodion is given to the wire,
which is very impervious to moisture. Over this coating, or sometimes to
wire not so prepared, I apply a coating of india-rubber, or of india-rubber

page_text: mixed with other substances, and afterwards I submit the wire so coated to
the action of sulphuric acid or of chloride of sulphur and a solvent, by which
the coating will be so changed as to be no longer liable to be injured by
tropical heat or like temperatures. In order to apply the coating of indin-
rubber to the wire, I employ apparatus which I will presently describe, for I
have found that a coating of india-rubber cannot be satisfactorily applied by
the ordinary method of expressing through a die; in fact, in order to obtain a
good coating in this manner when using india-rubber, it is necessary to mix
it largely with gutta percha or other substance. The apparatus which I
employ consists of two rollers mounted on parallel axes, and revolving in
.contact with each other; each of these rollers is grooved on its periphery, and
the grooves on the two rollers meet, to form an eye of the size of the covering
desired, such grooved rollers being similar to what have been used in other
manufactures. Against the rollers are placed hoppers, in which india-rubber
is placed in the state in which it comes from the masticator. The india-
rubber enters and fills up the grooves of the two rollers, and where the
rollers come together the india-rubber in the grooves is brought together, so
as to form one piece enclosing the conducting wire; sometimes immediately
in advance of this pair of rollers I place a second pair of rollers, to put on a
second covering in a similar manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Macintosh in the Great Seal Patent Office on the
13th November 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
MACINTOSII, of North Bank, Regent's Park, in the County of Middlesex, send
greeting.
WHEREAS Iler most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of May, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-first year of Her
reign, did, for Herself, ler heirs and successors, give and grant unto me,
the said John Macintosh, ler special licence that I, the said John Mac-
intosh, my executors, administrators, and assigns, or such others as I, the
said John Macintosh, 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 yend, within the United Kingdom of Great Britain aud

page_text: Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN INSULATING TELEGRAPHIC WIRES," upon the condition (amongst others):
that I, the said John Macintosh, 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 bo
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 John Macintosh, 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. has. for its object improvements in. insulating telegraphic
wires. For this purpose I lap round the wire to be insulated a yarn made
from gun-cotton, or other fibre or substance similarly prepared, and I then
subject the coated wire to the action of a fluid, which acts as a solvent to the
gun-cotton or similar substance, so as to cause it to adhere firmly to the wire;
sometimes I dissolve gun-cotton or other similar substance in the solvent
before applying it to the coated fibre or substance lapped round the wire and
gutta percha; india-rubber and other substances may be added to the solu-
tion. In this manner a coating of collodion is given to the wire which is
very impervious to moisture. Over this coating, or sometimes to wire not so
prepared, I apply a coating of india-rubber, or of india-rubber mixed with other
substances, and afterwards I submit the wire so coated to the action of sul-
phuric acid, or of chloride of sulphur and a solvent, by which the coating will
be so changed as to be no longer liable to be injured by tropical heat or like
temperatures. In order to apply the coating of india-rubber to the wire, I.
employ apparatus which I will presently describe, for I have found that a.
coating of india-rubber cannot be satisfactorily applied by the ordinary method
of expressing through a die; in fact, in order to obtain a good coating in this
manner when using india-rubber, it is necessary to mix it largely with gutta...
percha or other substance. The apparatus which I employ consists of: two-
rollers mounted on parallel axes, and revolving in contact with each other;.
cach of these rollers is grooved on its periphery, and the grooves on the two
rollers meet to form an eye of the size of the covering desired, such grooved
rollers being similar to what have been used in other manufactories; against
the rollers are placed hoppers in which india-rubber. is placed in the state in
which it comes from the masticator; the india rubber enters and fills up tho
grooves of the two rollers, and where the rollers come together, the india-

page_text: rubber in the grooves is brought together, so as to form one piece enclosing
the conducting wire; sometimes immediately in advance of this pair of rollers
I place a second pair of rollers, to put on a second covering in a similar
manner.
And in order that my said Invention may be most fully understood and
readily carried into effect, I will proceed to describe the manner in which
I prefer to conduct the several operations.
The gun-cotton which I employ is prepared in such a manner (as is well
understood by chemists) as to be readily soluble in ether and its other
solvents, and I prepare from such cotton a roving by means of machinery of
the description employed in preparing cotton for spinning. This roving is
lapped around the wire (or it may be strand of wires) to be insulated, so as
completely and uniformly to cover it, and the wire so covered is then passed
through a closed trough containing a suitable solvent, which trough may be
fitted with a pipe to carry off the vapour to a condenser; it enters and leaves
this vessel through funnel-shaped dies, which fit sufficiently closely to the
covered wire to prevent the solvent escaping, excepting the quantity imbibed
by the gun-cotton. The solvent which I prefer to employ consists of equal
parts of wood spirit and coal naptha, and before using it I carefully neutralize
any acid it may contain. The solvent may be used without any addition
being made to it, but I prefer to dissolve therein sufficient gun-cotton just to
thicken it. Before use I warm the solvent to about 120° Fahrenheit or
higher, and the speed at which the covered wire is passed through it I so
adjust as to avoid dissolving off the covering of yarn by the solvent, and
yet to secure the complete impregnation of the yarn. In some cases, in order
to give additional toughness to the coatings, I add a small quantity of gutta
percha or india-rubber to the solvent; this may be done by allowing the
same to stand in contact with either of these substances, and filtering it off
when required for use, or a small quantity of gum copal or other gum may be
substituted. In place of obtaining a coating of collodion to the wire in this
manner, it may be done by making a very thick sollution or thin paste with
gun-cotton and the solvent above mentioned, and causing the bare wire to
pass through it, the collodion being kept heated during the operation. By
either of these methods the wire may, if desired, after being once coated,
receive another coat or other coats of collodion. I would remark, that in
place of gun-cotton, other vegetable fibres prepared in a similar manner may
be employed, but not, I believe, so advantageously.
. In order to apply a coating of india-rubber to a wire previously coated with
collodion or otherwise, I employ a pair of metal rollers similar to those

page_text: described in the Specification of a Patent granted to me, dated 24th October
1857, about one foot in diameter, and mounted one over the other; they
have semicircular grooves formed in their peripheries, which meeting form
a circular eye sufficiently large to allow the wire to pass, together with a
coating of the desired thickness; over the upper roller and under the lower
roller of this pair I mount two other rollers of the same size, but plain; all
the four rollers are mounted in a strong frame, and are geared together so as
to run at the same speed. Steam or other hot fluid is admitted to the interior
of each of them to maintain the necessary temperature. The india-rubber in
the state in which it comes from the masticator is fed in between the two
upper and the two lower rollers, hoppers being formed at these points to
receive it. As the rollers revolve the india-rubber is drawn into the spaces
between them, these spaces being only the groves before mentioned. The
two fillets of india-rubber when they meet at the eye close over the wire. This
wire is drawn from a reel, and passes through a guide placed just before
the eye, so as to keep it truly central, and after being coated it passes round a
drum at a distance (or is otherwise taken away when it is sufficiently set to
bear it), which revolves at the same surface speed as the covering rollers, and
keeps the wire taut. I prefer to apply two or more coatings of india-
rubber in this manner to the wire, each coating being about 15 of an inch
thick; the subsequent coatings being applied by other rollers placed imme-
diately in front of the first; and for cach coating after the first I employ (as
is described in my Provisional Specification dated the Twenty-fourth day of
August last.) in place of plain top and bottom rollers, rollers having projecting
beads on them, so as to make indentations in the fillets of india-rubber, which
coming together leave a space corresponding with the size of the covered
wire receiving the additional coat. In the last coating of india-rubber I prefer
to combine fibrous materials in the manner described in the Specification of
my Patent dated Twenty-fourth day of October 1857; and I finish the wire,
after all the coatings have been applied, by passing it again between grooved
rollers. In order to render india-rubber covered wire less liable to injury from
heat, and to remove the tacking of the surface, I cause it to pass through a
trough containing commercial sulphuric acid of as great a specific gravity as it
is ordinarily made, at such a speed as to remain about twenty seconds in the
acid, but this varies according to the quality of the india-rubber; if it is kept
in for too long a time it becomes charred. The wire passes from the acid
trough into a water trough through a partition which divides the two, the
aperture through which it passes being packed around it with asbestos, or being
otherwise rendered fluid-tight or nearly so; or in place of applying sulphuric

page_text: acid in this manner, a coil of the covered wire may be dipped into the acid,
and afterwards into water. In place of sulphuric acid, bisulphuret of carbon
mixed with from two to four per cent. of chloride of sulphur may be employed.
A shorter period of immersion than that necessary with sulphuric acid will
suffice when this mixture is employed, but no injurious effect ensues if the
immersion is continued somewhat longer than the requisite time. When this
process is employed the water trough is uot used.
In witness whereof, I, the said John Macintosh, have hereunto set my
hand and seal, this Thirteenth day of November, in the year of our
Lord One thousand eight hundred and fifty-eight.
Witness,
GEO. PITT.
JOHN MACINTOSHI. (L.S.)