IMPROVEMENTS IN INSULATED CONDUCTANG HAR "
Year: 1881

page_text: LETTERS PATENT to Willoughby Smith, of Wharf Road, City Road, in the
County of Middlesex, for an Invention of IMPROVEMENTS IN INSULATED
CONDUCTANG HAR
"
TT
PROVISIONAL SPECIFICATION left by the said Willoughby Smith at the
Office of the Commissioners of Patents on the 21st December 1881.
WILLOUGHBY SMITH of Wharf Road City Road in the County of Middlesex.
"IMPROVEMENTS IN INSULATED CONDUCTORS FOR TELEGRAPHIC AND OTHER
USES."
This Invention has for its object improvements in insulated conductors for
telegraphic and other uses.
The insulated conductors now used in submarine subterranean and other
telegraphs consist for the most part of copper wire covered with gutta percha and
the gutta percha is used in as pure a state as it can be obtained.
Now for this pure material which is expensive I substitute a compound of gutta
percha with zinc white.
This substitution may be made to considerable extent not only for the sake of
economy, but also with advantage having regard to the purpose for which the
conductor is employed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Willoughby Smith in the Great Seal Patent Office on the 20th June
1882.
WILLOUGHBY SMITH of Wharf Road City Road in the County of Middlesex.
"IMPROVEMENTS IN INSULATED CONDUCTORS FOR TELEGRAPHIC AND OTHER
USES."
This Invention has for its object improvements in insulated conductors for
telegraphic and other uses.
The insulated conductors now used in submarine subterranean and other
telegraphs consist for the most part of copper wire covered with gutta percha and
the gutta perchn is used in as pure a state as it can be obtained.
Now for this pure material which is expensive I substitute a compound of gutta
percha with zinc white. This substitution may be made to a considerable extent
not only for the sake of economy but also with advantage having regard to the
purpose for which the conductor is employed.
I prefer to admix the gutta percha with about an equal proportion by weight of
zinc white, the admixture is made whilst the gutta percha is being masticated in an
ordinary masticating machine.
The compound may be used alone for covering the metallic wire conductor
and it may be put on to the conductor in any desired number of concentric
layers just as gutta percha is now laid on to metallic conductors preferably
however I first coat the metallic conductors with one or more concentric layers
of gutta percha and outside these I apply one or more layers of the compound-the
great advantage the compound possesses over gutta percha is that it is not
liable to change and decay by long exposure to air but remains unaltered
whereas gutta percha deteriorates in quality and perishes. The compound can there-
fore be used with great advantage for giving an outer covering to metallic
conductors after they have had one or more coatings of gutta percha applied
to them as it will not only protect these inner coatings but will also aid in
insulating the wire for although the insulating property of the compound is not so
high as that of pure gutta percha, still its insulating power is bigh as compared
with other compounds used for insulating purposes.
For long lines especially it is better to give the wire conductors one or more
layers of pure gutta percha before giving them an outer coating of the compound
as the inductive capacity of the compound is high-this however is not of
importance for short lines."
Having thus described the nature of my Invention and the manner of performing
the same I would state that I do not make claim to the admixture of zinc white
with gutta percha but I claim―
First. The insulated electric conductor consisting of an inner metallic conductor
and an outer covering of a compound of gutta percha and zinc white substantially
as herein described.
Second. The insulated electric conductor consisting of an inner metallic
conductor covered with gutta percha or other insulating substance and an outer
covering of a compound of gutta percha and zine white substantially as described.
In witness whereof I the said Willoughby Smith have bereunto set my hand
and seal this Seventeenth day of June in the year of our Lord One
thousand eight hundred and eighty two.
WILLOUGHBY SMITH. (L.S.)