IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1858

page_text: LETTERS PATENT to Edward Clarence Shepard, of Jermyn Street, West-
minster, in the County of Middlesex, Gentleman, for the Invention of
"IMPROVEMENTS IN ELECTRIC LAMPS."-A communication.
Sealed the 24th December 1858, and dated the 23rd October 1858.
PROVISIONAL SPECIFICATION left by the said Edward Clarence Shepard
at the Office of the Commissioners of Patents, with his Petition, on the
23rd October 1858.
I, EDWARD CLARENCE SHEPARD, of Jermyn Street, Westminster, in the
County of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN ELECTRIC LAMPS," to be as follows:-
Figure 1 is a vertical section of a lamp, in which the improvements are
illustrated; Figure 2 is a horizontal section of the same in the line x, x, of
Figure 1. Similar letters of reference indicate corresponding parts in said
Figures.
In the accompanying Drawings, A, A', represent reservoirs constructed of
wood, metal, or other suitable material capable of containing water or other
suitable refrigerating matter, for the purpose of preventing the undue heating
of the electrodes and other parts of the apparatus. These reservoirs are
arranged one directly over the other, and are supported and kept at a suitable
distance apart by a frame B; B, in which they are secured, which frame is
made of wood or other suitable non-conductor, so as to insulate the reservoir

page_text: and their appurtenances from one another. The upper reservoir A has a
vertical opening a through its centre, which receives a tube b, the lower ends
of which receives and holds the upper electrode or carbon pencil c, the said
tube being fitted to slide easily up and down through the opening a, which
arrangement serves as a guide to the upper electrode c. The tube b, being
closed at its lower end by the carbon pencil fitting snugly therein is then
filled with mercury, which serves the double purpose of effecting a perfect
and convenient connection of the electrode c, with the conducting wire d,
conveying the electric current, and weighing the tube b, so as to keep the
point of the carbon pencil c within the seat i, in a metallic bridge plate C,
which bridge plate is secured across the frame B, B. The said seat i consists
of an orifice or circular opening in the centre of bridge plate C, of a size a
trifle less than the body of the carbon pencil c, and which will therefore allow
the point of c to protrude, but will not allow it to pass through, except so fast
as it is reduced. The weight of the tube b, and the mercury contained
therein, will cause the electrode c to be fed down as fast as the reduction of
the point will allow. In the lower reservoir A¹ is secured an iron tube f
about an inch in diameter, bent into the shape of an inverted siphon. The
axis of one limb of this tube is in line with the axis of the tube b, and this
limb receives the lower electrode or carbon pencil c. To the lower extremity
of the carbon pencil c is secured an open or porous thimble g, of a diameter
corresponding and fitting to the inside diameter of the tube f, so as to move
more freely up and down in said tube. Just above the end of the tube fis
secured across the frame B, B, a second stationary bridge plate h, having a
circular opening in its centre corresponding and fitting to the lower carbon
pencil c', which, with the thimble g, serves as a guide to keep
said c¹ exactly in line with the centre of upper electrode c.
nearly filled with mercury, which flows through the porous
surrounds and buoys up the carbon pencil c¹. The buoyancy of the carbon
pencil in the mercury secures a gentle and certain feed upwards, and a sure
contact of the lower electrode c¹ with the upper electrode c. The other limb
of the tube f receives the conducting wire e of the electric current, which is
thus conducted through the mercury to the electrode c¹. It is not essential
that the tube f shall be in the shape described, as a straight tube would
answer the purpose.
the centre of
The tube fis
thimble g, and
In the accompanying Drawings, a pole changer is represented to change at
intervals the direction of the electric current, supposing the current employed
to be generated by a galvanic battery. This pole changer is of the usual
construction, the wires j, k, from the battery connecting with the two metal

page_text: standards 1, 1, of the rotary brake plate p, and the spring brakes m, m, con-
necting with the conducting wires d, e. The brake plate may be rotated by
the means of electricity or otherwise, and its effect is well understood. The
improvements herein consist in certain means of controlling the positions of
the electrodes, by which they are kept properly in contact with each other as
they are reduced by oxydation, and by the disengagement of particles when the
current of electricity used is of large volume and low intensity. When a
magneto-electric machine is used a pole changer is not required. What I
claim is the employment in an electric lamp of an open seat i, contained in
a stationary bridge plate C or its equivalent, and receiving the electrode in such
a manner that the point only will protrude through it the distance required,
and allowing the said point to advance only as fast as it is oxydised and
reduced by the electric current, substantially as herein described. I also claim
the loaded tube b carrying the upper electrode c, the open seat i, and the
mercury tube f, in which floats and is secured the lower electrode c¹, substan-
tially as described, so that while the upper tube b feeds the upper electrode
down to the open seat as fast as it is reduced, the lower electrode c¹ is also fed
up as fast as reduced, and kept in its proper position with reference to the upper
electrode c.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edward Clarence Shepard in the Great Seal Patent Office
on the 7th April 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
CLARENCE SHEPARD, of Jermyn Street, in the County of Middlesex, Esquire,
send greeting.
WHEREAS Her most. Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of October, in the year of our
Lord One thousand eight hundred and fifty-eight, in the twenty-second year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Edward Clarence Shepard, Her special licence that I, the said
Edward Clarence Shepard, my executors, administrators, and assigns, or such
others as I, the said Edward Clarence Shepard, 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 vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an Inven-

page_text: tion for "IMPROVEMENTS IN ELECTRIC LAMPS," upon the condition (amongst
others) that I, the said Edward Clarence Shepard, my executors or adminis-
trators, 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 Edward Clarence Shepard, do hereby
declare the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, and the accompanying Drawings:-
Figure 1 is a vertical section of a lamp, in which my improvements are
illustrated; Figure 2 is a horizontal section of the same, in the line of x, x,
of Figure 1. Similar letters of reference indicate corresponding parts in said
Figures.
My improvements consist in certain means of controlling the positions of
the electrodes by which they are kept properly in contact with each other, as
they are reduced by oxydation and by the disengagement of particles, when
the current of electricity used is of large volume and low intensity, or pre-
serving a proper and uniform distance of separation when the current used is
of high intensity. The difficulty of keeping the carbon pencils pointed has
resulted, in part, from many of the particles of carbon being carried over from
the positive to the negative electrode by the current of electricity, which
current, as generated by the ordinary galvanic battery, is constant in one
direction; therefore, with a view to obviate this objection, we apply to the
conducting wires of an ordinary galvanic battery, a mechanical pole changer
to traverse the current of electricity at frequent intervals. In using a current
of electricity generated by a magneto-electric machine, the change of direction
in the current is accomplished by dispensing with the use in said machine of
the frottem plate or pole changer, which is generally used in such machines,
to produce a constant current.
In the accompanying Drawings, A, A¹, represent reservoirs constructed of
wood, metal, or other suitable material, capable of containing water, or other
suitable refrigerating matter, for the purpose of preventing the undue heating
of the electrodes and other parts of the apparatus. These reservoirs are
arranged one directly over the other, and are supported and kept a suitable
distance apart by a frame B, B, in which they are secured; which frame is
made of wood, or other suitable non-conductor, so as to insulate the reservoir
and their appurtenances from one another. The upper reservoir A has a

page_text: vertical opening a through its centre, which receives a tube b, the lower end of
which receives and holds the upper electrode or carbon pencil c, the said tube
being fitted to slide easily up and down through the opening a, which arrange-
ment serves as a guide to the upper electrode c; the tube b being closed at its
lower end by the carbon pencil fitting snugly therein, is then filled with
mercury, which serves the double purpose of effecting a perfect and convenient
connexion of the electrode c with the conducting wire d, conveying the electric
current, and weighing the tube b, so as to keep the point of the carbon
pencil c within the seat i, in a metallic bridge plate C, which bridge plate
is secured across the frame B, B. The said seat i consists of an orifice or
circular opening in the centre of bridge plate C, of a size a trifle less than the
body of the carbon pencil c, and which will therefore allow the point of c to
protrude, but will not allow it to pass through, except so fast as it is reduced.
The weight of the tube b and the mercury contained therein, will cause the
electrode c to be fed down as fast as the reduction of the point will allow.
In the lower reservoir A¹, is secured an iron tube f, about an inch in
diameter, bent into the shape of an inverted syphon; the axis of one limb of
this tube is in line with the axis of the tube b; and this limb receives the
lower electrode or carbon pencil c¹; to the lower extremity of the carbon
pencil c¹ is secured an open or porous thimble g, of a diameter corresponding
and fitting to the inside diameter of the tube f, so as to be allowed to move
more freely up and down in said tube. Just above the end of the tube fis
secured across the frame B, B, a second stationary bridge plate h, having a
circular opening in its centre corresponding and fitting to the lower carbon
pencil c¹, which, with the thimble 9, serves as a guide to keep
said exactly in line with the centre of upper electrode c.
nearly filled with mercury, which flows through the porous thimble g, and
surrounds and buoys up the carbon pencil c¹. The buoyancy of the carbon
pencil in the mercury secures a gentle and certain feed upwards, and a sure
contact of the lower electrode with the upper electrode c. The other limb
of the tube f receives the conducting wire e of the electric current, which is
thus conducted through the mercury to electrode c¹. It is not essential that
the tube f shall be in the shape described, as a straight tube would answer the
purpose.
the centre of
The tube f is
In the accompanying Drawing is represented a pole changer, to change at
intervals the direction of the electric current, supposing the current to be
employed to be generated by a galvanic battery. This pole changer is of the
usual construction, the wires j, k, from the battery connecting with the two
metal standards 1, 1', of the rotary brake plate P, and the spring brakes m, m³,

page_text: connecting with the conducting wires d, e. The brake plate may be rotated
by the means of electricity, or otherwise, and its effect is well understood.
I do not claim the feeding together of the electrodes in an electric lamp by
means of floats, springs, or other mechanical appliances, nor the mechanical
pole changer, as heretofore used, but only as applied to an electric lamp in the
manner described; but what I claim as my Invention is, "the employment in
an electric lamp of an open seat i, contained in a stationary bridge plate C, or
its equivalent, and receiving the electrode in such a manner as to allow the
point only thereof to protrude through it the distance required, and permitting
the advance of the said point, so fast only as it is oxydized and reduced by the
electric current, substantially as herein described.
And I also claim the combination of the loaded tube 6 carrying the upper
.electrode c, the open seat i, and the mercury tube f, in which floats and is
secured the lower electrode c', substantially as described, so that while the
upper tube b feeds the upper electrode c down to the open seat i as fast as it is
reduced, the lower electrode c' is also fed up as fast as reduced, and kept in its
proper position with reference to the upper electrode c, as herein-before
described and set forth.
In witness whereof, I, the said Edward Clarence Shepard, have here-
unto set my hand and seal, this Sixth day of April, in the year of
our Lord One thousand eight hundred and fifty-nine.
EDWARD CLARENCE SHEPARD. (L.S.)