DAMENTERICAL CONDUCTORS & THEIR FITTINGS
Year: 1860

page_text: LETTERS PATENT to James Spratt, of Camden Road Villas, Camden
Town, in the County of Middlesex, Gentleman, for the Invention of
TODAMENTERICAL CONDUCTORS & THEIR FITTINGS."
Sealed the 1st March 1861, and dated the 7th September 1860.
PROVISIONAL SPECIFICATION left by the said James Spratt at the Office
of the Commissioners of Patents, with his Petition, on the 7th September
1860.
I, JAMES SPRATT, of Camden Road Villas, Camden Town, in the County of
Middlesex, Gentleman, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN ELECTRICAL CONDUCTORS & THEIR FITTINGS," to be as
follows:-
The first part of my Invention relates to improvements in the insulators for
fixing or sustaining lightning conductors, which I make of glass. They consist
of short cylinders having a passage through the axis for the lightning rod or
conductor, as also a projecting shoulder or flange at one end; these cylinders I
place in a ring or eye having a screw or straight stem driven or screwed into
the support. The ring has an opening on one side to admit a projecting nib
formed on the cylinder, which is dropped therein, and turned round so that the
nib passes under the ring and prevents the glass cylinder rising; it is turned
round until it comes in contact with a nib on the under side of the ring pro-
jecting downwards, which forms a stop; simultaneously with this stop a catch
stop enters into a notch on the under side of the flange of the insulator, and

page_text: prevents it turning in the backward direction, unless raised from the ring.
This catch is a raised tooth or projection on the top of the ring. Instead of
the latter catch the under side of the flange may be undulated, and the upper
surface of the ring or eye undulated to correspond. These catches and stops
prevent any tendency to turn round in the insulator when acted on by wind
or other disturbing cause. I further make the external surface of the cylinder
of glass (the insulator), notched or indented, as also the inner surface of the
ring or eye in such insulators as are placed horizontally, having the same
object in view, in other respects the insulators & their supporting eyes or rings
may be the same as before.
The second part of my Invention relates to alloys for points of lightning
rods, and consists of a new combination or alloy of metals for the manufacture
of spears or points of lightning conductors. I form an alloy of the metals
herein-after mentioned in the following proportion, viz., I fuse together,
60 lbs. of English block tin,
10 of oxide of tin,
"
20 of antimony,
"
1 of bismuth,
99
1,
of refined silver,
12 oz. of platinum,
and as much silex as the metals will take up.
I arrange the metals in the melting pot as follows:-I put the silex when
pulverized and mixed with a little potash to serve as a flux at the bottom of
the crucible, on the top of this flux I pour on the oxide of tin, to which I add
the block tin and bismuth, when the above assume a fluid state, I add the
antimony, and when it has got to its proper heat I add the silver, and, lastly,
the platinum, the whole of which forms the said alloy for lightning rod points,
being an excellent conductor and not liable to tarnish.
The third part consists of a compound-lightning-rod-point, the object of
which is to provide against the destruction of the fine point of lightning rods by
melting, as is not unfrequently the case from a sudden overcharge of the
electric fluid. I effect this by forming my lightning rod points of different
metals or alloys embedded one within another, arranging the most fusible on
the outside, and so on in succession, and each metal terminating in a fine
point. The effect of this arrangement is, that the fusing action of an excessive
shock of electricity is confined to the outer metallic layer or coating, which it
melts, and in flowing may be said to carry the electric fluid with it, or rather,
it receives in the act of melting an additional conducting power. The metal
so melted, although destroying the outer casing and point, at the same time

page_text: discloses the fine point contained within the first, therefore, the point is equally
efficient as before as a collector of the electricity. Thus, by means of a
sufficient number of layers, each terminating in a point, the conductor may be
made capable of surviving as many extraordinary shocks as any one point is
likely to be subject in the duration of any kind of lightning conductor now used.
The number of layers may vary from one or more, according to the desired
completeness of the instrument, but the following I have found suitable :-
The innermost point may be of steel, and this may be encased in brass, the
brass in zinc, and, lastly, the zinc may be coated with the alloy of platinum,
silver, &c., above described, which alloy is a superior conducting medium, and
capable of receiving and preserving a high finish.
The fourth part of my Invention relates to flexible flat web lightning con-
ductors, which I weave of metal wire, or other form of metal. For this
purpose I employ copper or other negative metal wires as the warp or longi-
tudinal part running in the direction of the length of the conductor, while I
form the weft or cross wires of zinc, or other positive metal; the effect of this
is, that oxidation is prevented, and the condition of the conductor maintained
intact for electrical conduction.
The fifth part of my Invention relates to the conducting rods of lightning
conductors, and consists in making them in the form of a cross in their cross
section, in which form a small amount of metal presents a large surface, and
also affords great strength. The leaves or bars of this form of rod may be
either straight or in a spiral form, which latter I prefer.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Spratt in the Great Seal Patent Office on the
4th March 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
SPRATT, of Camden Road Villas, Camden Town, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Iler most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of September, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her reign,
did, for Herself, Her heirs and successors. give and grant unto me, the said
James Spratt, Her special licence that I, the said James Spratt, my executors,
administrators, and assigns, or such others as I, the said James Spratt, my
executors, administrators, and assigns, should at any time agree with, and no

page_text: 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 ELECTRICAL CONDUCTORS AND THEIR
FITTINGS," upon the condition (amongst others), that I, the said James
Spratt, 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 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 James Spratt, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Sheet of Drawings hereunto annexed
and to the letters and figures marked thereon (that is to say) :-
The first part of my Invention relates to improvements in insulators for fixing
or sustaining lightning conductors, which I make of glass. They consist of
short cylinders having a passage through the axis for the lightning rod or con-
ductor, as also a projecting shoulder or flange at one end; these cylinders I
place in a ring or eye having a screw or straight stem screwed or driven into
the support. The ring has an opening on one side to admit a projecting nib
formed on the cylinder, which is dropped therein and turned round, so that
the nib passes under the ring and prevents the glass cylinder rising; it
is turned round until it comes in contact with a nib on the under side of the
ring projecting downwards, which forms a stop; simultaneously with this stop
a catch stop enters into a notch on the under side of the flange of the insulator
and prevents it turning in the backward direction unless raised from the ring.
This catch is a raised tooth or projection on the top of the ring; instead of the
latter catch, the under side of the flange may be undulated, and the upper sur-
face of the ring or eye undulated to correspond. These catches and stops
prevent any tendency to turn round in the insulator when acted on by wind or
other disturbing cause. I further make the external surface of the cylinder of
glass (the insulator) notched or indented, as also the inner surface of the ring
or eye of such insulators as are placed horizontally, having the same object in
view; in other respects the insulators and their supporting eyes or rings may
be the same as before.
The second part of my Invention relates to alloys of metals used as the
points of lightning rods, consisting of a new combination or alloy of metals for

page_text: the manufacture of spears or points of lightning conductors. I form an alloy
of the metals herein-after mentioned in about the following proportions, viz., I
fuse together sixty pounds of English block tin, ten pounds of oxide of
tin, twenty pounds of antimony, one pound of bismuth, twelve pounds of refined
silver, & about one pound or more of platinum, and as much silex as the
metals will take up. I arrange the metals in the melting pot as follows:-I
put the silex, when pulverized and mixed with a little potash to serve as a flux,
at the bottom of the crucible; on the top of this flux I pour in the oxide of
tin, to which I add the block tin and bismuth; when the above assume a fluid
state I add the antimony, and when it has arrived at its proper heat I add the
silver, and lastly the platinum, the whole of which forms the said alloy for
lightning rod points, being an excellent conductor and not liable to tarnish,
and may be formed and fashioned of any form and dimensions requisite for
those purposes.
It is not essentially necessary to adhere to the exact propor-
tions herein-before described, as they may be varied, the greater the proportion
of silver and platinum the better will be the conductor.
The third part consists of a compound lightning rod point, the object of
which is to provide against the destruction of the fine point of lightning rods
by melting, as is not unfrequently the case from a sudden overcharge of the
electric fluid. I effect this by forming my lightning rod points of different
metals or alloys embedded one within the other, arranging the most fusible on
the outside, and so on in succession, each metal terminating in a fine point.
The effect of this arrangement is, that the fusing action of an excessive shock
of electricity is confined to the outer metallic layer or coating which it melts,
and in flowing may be said to carry the electric fluid with it, or rather, it
receives in the act of melting an additional conducting power. The metal so
melted, although destroying the outer coating and point at the same time, dis-
closes the fine point contained within the outer coating, therefore the point is
equally efficient as before as a collector of the electricity. Thus by means of a
sufficient number of layers, each terminating in a point, the conductor may be
made capable of surviving as many extraordinary shocks as any one point is
likely to be subject to in the duration of any kind of lightning conductor now
used. The number of layers may vary from one or more according to the
completeness of the instrument desired; but the following I have found suffi-
ciently suitable. The innermost point may be of steel, and this may be encased
in brass, the brass in zinc, and lastly, the zinc may be coated with the alloy of
platinum, silver, &c. above described, which alloy is a superior conducting
medium, and capable of receiving and preserving a high finish.
The fourth part of my Invention relates to flexible flat web lightning con-

page_text: ductors, which I weave of metal wire or other form of metal. For this purpose
I employ, by preference, copper or other negative metal wires, as the warp or
longitudinal part running in the direction of the length of the conductor, while
I form the weft or cross wires of zinc or other positive metal; the effect of
this is, that oxidation of the conductor (the longitudinal wires) is prevented,
and its condition is improved as a conductor by reason of the electricity induced
by the combination of metals described, and the action of the air.
The fifth part of my Invention relates to the conducting rods of lightning
conductors, and consists in making them in the form of a cross (+) in their
cross section, in which form a small amount of metal presents a large surface,
and also affords great strength. The leaves or bars of this form of rod may
be either straight or in a spiral form, which latter I prefer to adopt.
DESCRIPTION OF DRAWINGS.
Fig. 1 represents a side elevation of a lightning rod insulator according to
my Invention, & Fig. 2, an under side plan of the same; it is formed of glass
or other suitable material, if of glass by casting or forming it in suitable moulds
and punching the hole or passage a for the lightning conductor while still
hot; on the cylindrical body part b is formed a projection 1 and under the
flange c a notch d, seen best in Fig. 1, and I also form at that point on the
body serrations as seen, but these are not essential for conductors in vertical
positions; Fig. 3 is a side view, and Fig. 4, a plan of the holder of the insulator
consisting of a stem e screwed, if to be fixed by screwing, into wood, or it may
be simply a spike and driven like a nail or a bolt, or of any other suitable form;
fis the ring which receives the insulator shown dotted, the body b dropping
loosely into the internal diameter thereof; and in order to allow the projection
1 to pass, a space is formed, as shown dotted, or cut from the ring as at
2 seen in the plan; the projection 1 after passing through the ring f is turned
round till it meets with a stop 3 formed on the holder. At same time that
projection 1 comes in contact with 3, a projection 9, formed on the upper
part of ring f, enters notch d which retains the insulator in position and prevents
its being dislodged by vibration resulting from the action of the wind or other
disturbing causes that may operate upon it; at some time it will be seen that
the insulators are very easily entered and removed by hand when it is desired
to do so. Instead of the notch d and projection g, the insulator may be of
an undulating form on the under side or shoulder of the flange c, and the upper
part of the ring f, pointed to correspond as seen in side view at Fig. 5. In
this way the insulator will be prevented turning round at any point instead of
.only at one point of its circumference, as before explained.

page_text: I also make the ring f with a small internal projection h, which takes into
one of the serrations in the body 6 of the insulator, this assists to prevent
any tendency to turn round. In insulators used for lightning conductors.
laid in horizontal positions, the projection g on the ring f may be dispensed
with, and to prevent turning, I form the body with longitudinal grooves or
serrations entirely round it, and make the internal circumference of the
ring f to correspond, as seen in Fig. 6; in these insulators it is of advantage to
form two projections 1, the one being diametrically opposite to the other, and
in that case I form the opening 2, in the ring f, nearer the stem e, so that
the projection 1, which is last to enter at notch 2, may be turned some little
distance therefrom. The undulations on the body of the insulator and on the
interior of ring f may be of other form than that represented at Fig. 6, or one
or two projections inside of a plain ring f will answer the purpose of the
undulations represented as formed therein.
The third part of my Invention, which relates to the compound points of
lightning conductors, is represented in Fig. 7, which exhibits the compound
point partly in section. The base or inner metal k, of the conductor is
of steel represented blue, the next of brass, a third m of zinc, a fourth
and outer one n of the alloy herein described; these layers or coatings,
should be metallically united to each other by soldering or in other suit-
able manner. This spear or point is screwed into the socket p; on the
end of the lightning rod, of which it forms the termination; q, q, are small
auxiliary points which may or may not be used.
requiring different degrees of heat to fuse them,
to melt on receiving an extraordinary charge of
to the larger part of the spear rod, which conveys
harm, at same time presenting a new point equally perfect as a conductor
to that before presented to receive the lightning, which point has been pro-
tected by the ready fusibility of the outer coating.
By these layers of metal
the outer one is the first
electricity, & conducts it
it thence without further
The fourth part of my Invention, which relates to the combination of differ-
ent metals for producing constant electrical excitation in electrical conductors,
and at same time preserving the principal conducting part (the longitudinal wires)
is represented at Fig. 8 in side view, and in edge view at Fig. 9. It is repre-
sented as being a flat web, and as being made of wire; other forms of the con-
ductor, as also of the component parts, may be adopted. This conductor is formed
simply by interlacing or interweaving longitudinal strands of copper wire r,
with transverse wires of zinc s, as seen in the Figures, and combined in sufficient
number to give the power of conduction required, which is enhanced by the
electrical excitation produced by the action of the atmosphere on the combined

page_text: metals before described. The arrangement of metals may be reversed, but
as the copper conductor is preserved at the expense of the oxidation of the
zinc, I prefer the arrangement set forth.
The fifth part of my Invention is illustrated at Figs. 10, 11, 12, & 13, Figs.
10 & 11 being a side view and cross section of one form of rod, and Figs. 12
& 13 like views of another form; u, u, are sockets screwed or otherwise united
to the ends of the several lengths of the rod in order to unite them. Figs. 10
& 11 are in the form of a cross with the leaves straight, while Figs. 12 & 13
are also a cross with the leaves of a somewhat different form and running
spirally, which may be effected by twisting or otherwise.
Having described the nature of my Invention and the manner of performing
the same I declare that what I claim as my Invention to be protected by the
herein-before in part recited Letters Patent is,-
First, the combination and arrangement of the parts constituting the insula-
tors and their holders, as herein-before described.
Secondly, the alloy or compound of metals herein-before described to form
the forks or spear points, of lightning conductors.
Thirdly, the compound metal points for lightning conductors herein-
before described and represented in Fig. 7 of the Drawings annexed.
Fourthly, I claim the use and application of compound metal lightning
conductors described with reference to Figs. 8 & 9 of the Drawings annexed.
Fifthly and lastly, I claim lightning rods or conductors having a cross
section in the form of a cross or other analogous figure whereby to render it
light and stiff, and at same time present a great extent of surface.
In witness whereof, I, the said James Spratt, have hereunto set my
hand and seal, this Second day of March, in the year of our Lord
One thousand eight hundred and sixty-one.
Witness,
W. CLARK.
Patent Agent,
53, Chancery Lane,
London.
JAMES SPRATT. (L.S.)