IMPROVEMENTS IN THE INSULATION OF SUBMARINE ELECTRIC TELEGRAPH WIRES
Year: 1860

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in
the County of Middlesex, and of 166, Buchanan Street, in the City of
Glasgow, North Britain, Gentleman, for the Invention of "IMPROVEMENTS
IN THE INSULATION OF SUBMARINE ELECTRIC TELEGRAPH WIRES."-A com-
munication from abroad by John M. Batchelder, of Cambridge, in the
State of Massachusetts, United States of America.
Sealed the 16th March 1860, and dated the 17th January 180
PROVISIONAL SPECIFICATION left by the said John Henry Johnson,
at the Office of the Commissioners of Patents, with his Petition, on
the 17th January 1860.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Mid-
dlesex, and of 166, Buchanan Street, in the City of Glasgow, North Britain,
Gentleman, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE INSULATION OF SUBMARINE ELECTRIC TELEGRAPH WIRES," a commu-
nication from abroad by John M. Batchelder, of Cambridge, in the State of
Massachusetts, United States of America, to be as follows:-
This Invention relates to the application and use to and in the insulation of
submarine electric telegraph wires of a new compound, offering the advantages
of greater flexibility and elasticity, and less liability to be softened by heat,
whilst at the same time a better insulation is obtained, as the compound em-
ployed is a more effective non-conductor of electricity.

page_text: According to this Invention, it is proposed to cover the conducting wire in
any convenient or well-known manner, with a compound consisting of pulverized
silex, glass, or other absolute non-conductor of electricity, mixed with india-
rubber and sulphur, and subsequently vulcanized. Or in some cases pure
india-rubber, without sulphur and vulcanizing, may be used, mixed with
pulverized silex, glass, or other non-conductor in suitable proportions.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 'filed
by the said John Henry Johnson in the Great Seal Patent Office on
the 17th July 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOIN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in 'the 'County of Middlesex, and
of 166, Buchanan Street, in the City of Glasgow, North Britain, Gentleman,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of January, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Henry Johnson, Her special license that I, the said John
Henry Johnson, my executors, administrators, and assigns, or such others
as I, the said John Henry Johnson, my executors, administrators, or
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 "IMPROVEMENTS IN THE INSULATION OF SUBMARINE
ELECTRIC TELEGRAPH WIRES," a communication from abroad by John M..
Batchelder, of Cambridge, in the State of Massachusetts, in the United States
of America; upon the condition (amongst others) that I the said John Henry
Johnson, by an instrument in writing under my hand and seal, should par-
ticularly 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the same

page_text: is to be performed, to be particularly described and ascertained in by tho
following statement, that is to say :-
The said Invention relates to the application and use to and in the insulation
of submarine electric telegraph wires of a new compound substance, offering
the advantages of greater flexibility and elasticity, and less liability to be
softened by heat, whilst at the same time a better insulation is obtained, as tho
compound employed is a more perfect non-conductor of electricity.
According to this Invention, it is proposed to cover the conducting wires of
submarine electric telegraph cables in any convenient or well-known manner;
with a compound made of pulverized silex, glass, or other absolute non-con-
ductor of electricity, mixed with india-rubber and sulphur, and subsequentlý
vulcanized. Or in some cases, pure unvulcanized india-rubber, without sul-
phur, may be used, mixed with pulverized silex, glass, or other non-conductor
in suitable proportions. The improved insulating material or compound is
prepared by first thoroughly grinding or masticating the india-rubber and
sulphur, thus forming a paste or dough according to the ordinary process of
making vulcanized india-rubber and then adding thereto a quantity of silex
reduced to a fine powder. The ingredients should be thoroughly incorporated and
uniformly mixed. The proportions I prefer are twenty parts of india-rubber;
five parts of sulphur, and seventy-five parts of powdered silex, such parts being
ascertained by weight. It is preferred to make the powdered silex by grinding
pure quartz in a mill, in the manner commonly practised by manufacturers of
porcelain. In place of silex, glass, or other good non-conductor of electricity
may be used for this purpose. The compound being prepared as above stated,
is in readiness for the vulcanizing process which is conducted in the ordinary
manner, the degree of heat being such as to allow the resulting substance to be
sufficiently flexible when applied to the conducting wire or wires of a telegraph
cable. By using the proportions above given of rubber, sulphur and silex the
specific gravity of the compound obtained is about 1.600; it will not soften at
a lower temperature than 300° Fahrenheit, and is much more flexible than
gutta percha. This compound consisting of a large proportion of glass or
silicious materials, it is a better non-conductor than the gutta percha of the
quality commonly used for this purpose. This compound is to be applied to
the conducting wire either by drawing or forcing it through suitable apertures
by winding the wire with spiral fillets, by passing it through grooved rollers, or
in any other convenient manner. In some cases the sulphur and the vul-
canizing process may be omitted and the insulating compound may be made
simply of pure india-rubber and fine silex in the proportion of twenty-five parts
of india-rubber, and 75 parts of silex, which proportion may be varied so as to

page_text: chango the specific gravity of the mass or give the insulated. wire a greater or
less degree of flexibility. I am aware that the admixture of various earths
and other materials with the compound of india-rubber and sulphur has been
previously effected, and I therefore disclaim all such mixtures or compounds,
confining my improvement-strictly-to-the-mixture-of-an-absolute con-conductor
of electricity with the rubber and sulphur, or with india-rubber alone, whereby
highly non-conducting substance is obtained whilst it is at the same time
well adapted in other respects to the insulation of conducting wires of electric
telegraphs.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that what I consider to be novel and
original, and therefore claim as the Invention secured to me by the berein-
before in part recited Letters Patent, is, the application and use to and in
the covering of the conducting wires of electric telegraph cables of a compound
made of pulverized silex, glass, or other non-conducting material mixed with
india-rubber and sulphur, and subsequently vulcanized, or of a compound made
of pure or unvulcanized india-rubber and powdered silex as herein-before
described.
In witness whereof, I, the said John Henry Henry Johnson, have
hereunto set my hand and seal, this Sixteenth day of July, One
thousand eight hundred and sixty.
J. HENRY JOHNSON (L.S.)