IMPROVEMENTS IN ELECTRIC TELEGRAPHS, AND IN APPARATUS CONNECTED THEREWITH
Year: 1850

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, EDWIN
CLARK, of Palace New Road, in the County of Middlesex, Civil Engineer, and
HENRY MAPPLE, of Child's Hill, Hampstead, in the County of Middlesex,
Electric Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twelfth day of
November, One thousand eight hundred and fifty, in the fourteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto us,
the said Edwin Clark and Henry Mapple, our exors, admors, and assigns,
Her especial licence, full power, sole privilege and authority, that we, the said
Edwin Clark and Henry Mapple, our exors, admors, and assigns, or such
others as we, the said Edwin Clark and Henry Mapple, our exors, admors, or
assigns, should at any time agree with, and no others, from time to time and
at all times during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, within England, Wales, and the Town of
Berwick-upon-Tweed, in the Islands of Guernsey, Jersey, Alderney, Sark, and
Man, and also in all Her said Majesty's Colonies and Plantations abroad, savę
and except the Provinces of Novia Scotica and New Brunswick, and the Island
of Prince Edward in North America, our Invention of "IMPROVEMENTS IN
ELECTRIC TELEGRAPHS, AND IN APPARATUS CONNECTED THEREWITH;" in which
said Letters Patent is contained a proviso that we, the said Edwin Clark and
Henry Mapple, or one of us, shall cause a particular description of the nature
of our said Iuvention, and in what manner the same is to be performed, by an

page_text: instrument in writing under our hands and seals, or under the hand and seal
of one of us, to be enrolled in Her Majesty's High Court of Chancery within
six calendar months next,and immediately after the date of the said in part
recited Letters Patent, as in and by the same, reference being thereunto had,
will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, we, the said
Edwin Clark and Henry Mapple, shall cause a particular description of the
nature of our said Invention, and the manner in which the same is to be
performed, to be fully described and ascertained in and by the following state-
ment thereof, reference being had to the Drawings hereunto annexed, and to
the figures and letters marked thereon, that is to say:―
The ordinary insulators for such purposes, where the wires are suspended in the
air, have been constructed of glass, earthenware, or glazed surfaces, which have
been made in various forms, so as to throw off the rain, to maintain a dry zone
between the point of suspension of the wire and the part of the insulator attached
to the posts or poles or supports employed. In all these cases the earthenware,
glass, or enamel being a good radiator of heat, parts rapidly with its caloric;
and becoming cooled when the air is nearly or quite saturated with moisture,
such insulators are liable to have their surfaces covered with a film of moisture,
which renders the surface partially conductive of electricity, and impairs the
insulation of the wire suspended thereto. Now it is found that metals being
bad absorbents of heat, if a band, cap, or surface of metal be so placed
very
that a zone of the insulator shall radiate its heat directly to the metal, this,
from its imperfect absorbent qualities, will scarcely receive any of the heat of
the earthenware, the heat will therefore be prevented from escaping from the
insulator; this, therefore, retains the temperature of the air in contact with
the insulator, and there is, in consequence, no tendency for moisture to
condense on the surfaces. It is obvious that the band, cap, or surface of
metal may be placed in various ways about different forms of insulator, so as
to form protected insulators adapted for attachment to various places and
surfaces.
We do not confine ourselves to particular forms of metal or insulators
as they will vary according to circumstances.
Figure 1, 2, shews a section and side views of one form of insulator con-
structed and protected in this manner. The carthenware (a) may be described
as a short bulbous-ended rod, having a deep horizontal notch cut into its side,
.near the end, as represented. In this notch the wire brests.
At the upper
end of the earthenware is an under-cut hole, into which the head of a bolt
or screw is fixed, with lead poured round it. This bolt c passes through a

page_text: hole in the metal cap or cover. d, and by it the earthenware is firmly held up.
to the arm or cross piece of wood e, pinching the cap between it and the wood
so tightly, that, with the aid of a little white lead or other cement, the joint
between the cap and wood is made perfectly water-tight. To guard further
against leakage. into the interior of the cap, the head of the screw and its nut
on the upper surface of the arm are covered with some resin or cement, and
the edge of the hole in the cap is strongly burred upwards, so that this bur,
cutting into the wood by the pressure, makes a most secure joint. The lower
edge of the cap is turned out all round to stiffen it. The wire is prevented
from rising up and slipping out of the notch by a short piece of smaller wire
being passed under the notched bottom of the earthenware, and tightly bound
round and soldered to the main wire on each side. If the wires are following a
curve in the line, the cut is turned outwards from the curve in screwing up the.
insulator, so that the side strain may tend to keep the wire in the notch.
Figure 3, 4, shew another form of insulator. Here the earthenware stands
above its support, and the metal cap surrounds its stem, while the edge of the
earthenware turning over the edge of the zinc cap effectually prevents the
entry of rain, and should any water find access to the interior; it escapes by one
or. two small holes made near the bottom of the metal cap. The wire lies in
the notch at the top of the insulator, and is prevented from rising out by a pin
passed through holes in the sides of the notch over the wire. This pin may
have its small end split and sprung open to prevent it from slipping from the
hole. The insulator, may be fastened to its support by a bolt, as shewn in
Figures 3 and 4; or it may be fitted, as Figure 5, to stand in an iron ring
fitted for attachment to a wall or post. The weight of the wire may suffice to
keep it in its place; or it may be secured by a pin passed through the hole.
in the earthenware stem under the ring.
Figure 6 shews another form, which may be used where great strain must
be applied to the wire. The earthenware is here a short stout tube, moulded
outside, as shewn in the Figure. An iron bolt passing through it holds it. firm
between two wooden arms or cross pieces. The upper cap- is put on as in.
Figure 1, 2. The lower is made with a hole large enough for it to slip over
the upper part of the insulator, and the cap then drops on the projecting
collar of the earthenware, which is dotted in. It may be secured there, and
the joint with the earthenware made secure;. by driving on a ring of, lead,
which, when hot, will only just go over the earthenware, and filling the joint
between this lead ring the earthenware and: the zinc cap with some resinous
cement or varnish. Many other ways of fastening this lower cap will readily

page_text: occur.
effectual.
This is only mentioned as a very easy one, which is found simple and
The insulators have been described as made in all cases of earthenware, but
they may equally well be made of glass or enameled wares, and other forms of
insulators may be employed, provided that the distinctive features of our Inven-
tion, which is the guarding them from the access of rain, and also, by the
proximity of metal surface, against the radiation of heat, and therefore, if the
deposition of dew be adhered to.
The next part of our Invention relates to certain means of applying the
inducing power of electric coils on soft iron or nickel in combination with
magnets. It is well known that a piece of soft-iron or other metal susceptible
of magnetic power can be rendered and kept magnetic by placing it within
the influence of an electric coil, and that so long as it is within this influ-
ence it resembles a permanent magnet, all which is well understood. And
this part of our Invention consists of so arranging apparatus that a magnet
may give motion to instruments made temporarily magnetic.
On
Figures 7 and 8 shew so much of an instrument as will enable us to explain
this part of our Invention. a is an electric coil suitably arranged for having
electric currents passed through in either direction. 6 is an axis of soft iron
or nickel, which is mounted in bearings so as to turn freely. 6¹ is a cross
head or bar of like metal with the axis. These will be rendered magnetic
when electric currents are passed in either direction through the coil a.
this axis b may be applied a pointer suitable by its vibrations to be used
as a telegraphic instrument in place of employing magnetic needles as hereto-
fore. c is a magnet; which, when the parts. b, b', are rendered magnetic, will
by the two. poles attract and repel the part 6, and the axis 6 will be caused to
turn in one or other direction by the magnet c, according as the current is
passed in one or other direction.
We would remark that we are aware that soft iron and nickel have before
been temporarily magnetised and used: for electric telegraphic purposes; and
we are also aware that magnets have been before used in combination with
temporary magnets; we do not; therefore, claim either separately or combined,
but only the manner here described of combining them.
Having thus described the nature of our Invention, and the manner of
performing the same, we would have it understood that we do not confine
ourselves to the details herein described, as the same may be varied' without
departing from our Invention, so long as the peculiar character of either of our
improvements be retained. But what we claim is,

page_text: First, the employing metal in combination with earthenware, glass, or
enameled ware insulators, as explained. And,
Secondly, we claim the mode of combining means for rendering metallic
parts of apparatus temporarily magnetic, with suitable magnets to give motion
to such temporarily magnetised parts.
In witness whereof, I, the said Edwin Clark, have hereunto set my hand
and seal, this Twelfth day of May, in the year of our Lord One thousand
eight hundred and fifty-one.