IMPROVEMENTS IN LAMPS ADAPTED TO THE ELECTRIC LIGHT, AND IN THE MANIPULATION OF THE MEANS EMPLOYED FOR THE SUPPLY OF THE ELECTRIC FLUID THERETO.
Year: 1875

page_text: LETTERS PATENT to William Prosser, of the Parish of St. Luke,
Chelsea, in the County of Middlesex, Gentleman, for the Inven-
tion of "IMPROVEMENTS IN LAMPS ADAPTED TO THE ELECTRIC LIGHT, AND
IN THE MANIPULATION OF THE MEANS EMPLOYED FOR THE SUPPLY OF THE
ELECTRIC FLUID THERETO.'
"
Sealed the 4th April 1876, and dated the 6th October 1875.
PROVISIONAL SPECIFICATION left by the said William Prosser at the
Office of the Commissioners of Patents, with his Petition, on the
6th October 1875.
I, WILLIAM PROSSER, of the Parish of St. Luke, Chelsea, in the
3 County of Middlesex, Gentleman, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN LAMPS ADAPTED TO THE ELECTRIC
LIGHT, AND IN THE MANIPULATION OF THE MEANS EMPLOYED FOR THE SUPPLY OP
THE ELECTRIC FLUID THERETO," to be as follows :—
My Invention relates to the construction of lamps adapted for the
O exhibition of the electric light by which the light is rendered more
permanent and certain in its action than in the lamps hitherto employed

page_text: for that purpose, and also has reference to the manipulation of the
means by which the light is produced. And my Invention consists,
firstly, in effecting a continuous connection between the poles of the
apparatus, so that the continuity of the light is not effected by the
variable consumption of the electrodes, and this desideratum I effect by
employing a stream or jet of mercury which is continuously discharged
upon the end or apex of the carbon negative electrode (where only one
is used) or against the ends or apices of the electrodes (where more than
one is used). And although by reason of the constant action of the
electric current the end or ends of the carbon electrode or electrodes is
or are nevertheless maintained in their required relative position so as
to preserve the focus of the light as well as the condition of the
apparatus for producing a continuous light.
It is obvious that the stream or jet of mercury which I employ to
establish the current of electricity from itself, as the positive pole to
the carbon or negative pole will on its escape from the nipple through
which it is discharged assume a solid form for some distance from the
discharging aperture, and it is then disturbed or broken up into spray
which becomes dissipated and falls into a cup or dish beneath the
carbon electrode, from whence it is conveyed into a suitable receptacle,
there to be reserved for subsequent cleansing and further use.
In order to produce the light I adopt the ordinary mode or modes for
separating the electrodes to a suitable distance from each other, so that
the apparatus may readily be adjusted to the greatest nicety for
producing a light of maximum intensity.
Where a single carbon electrode is used I preserve the uniformity of
the focus of the light by causing the end of the carbon electrode to
abut against an indestructible permanent stop which is unaffected by the
current of electricity, but when more than one carbon electrode is used,
I cause them to abut the one against the other and maintain their
position by the pressure of springs, weights, or other suitable and
equivalent device.
In cases where mercury is employed for the positive electrode it is
absolutely necessary that the apparatus herein-before described should
be enclosed in a glass shade or case, but as heretofore it has been found
impossible to procure a glass shade that would resist the intense internal
heat without fracture such lamps have been practically useless.

page_text: In pursuance of my Invention I-apply a glass shade or case which
has been subjected to a process or treatment whereby this difficulty is
obviated, and thereby rendering it capable of resisting the effects of the
alternations and inequalities of temperature to which it may be sub-
jected. And with a view still further to protect the apparatus against
the contingency of a fractured glass I place a second glass surrounding
that which immediately encloses the light, having an intervening space
between them so that the inner glass is shielded from contact with the
external atmosphere, and is thereby protected from the detrimental
effect of the air upon the external surface of the inner glass, while its
inner surface is exposed to the higher temperature produced by the
light. The mercury used as before described may be filtered and used
over again so that little loss will be sustained.
My improvements also embrace the means of producing a uniform
and continuous light without employing a fluid positive electrode, by
which arrangement the glass shade is dispensed with, and this I effect
by forming both electrodes of carbon of suitable shape, each in two or
more parts abutting against each other, each part becoming the stop for
the other part or parts as the case may be, contact being maintained by
) means of springs, weights, or other suitable and equivalent device.
In some cases I regulate the contact of the electrodes by means
altogether removed from the point of ignition, and not therefore subject
to uncertainty of action which the intense heat would tend to produce,
but nevertheless in all the modifications which I employ for insuring
5 the required condition of the electrodes which is the essential feature of
the apparatus, and by which alone a light of combined maximum and
uniform intensity is maintained. And further I apply this system of
permanently abutting electrodes to lamps, in which a fluid positive
electrode is used as well as to those in which I entirely dispense with it,
> thereby getting rid in all applications-of my Invention of the hitherto
experienced difficulty of maintaining those conditions of the electrodes
which are necessary to insure a perfect continuity of the light.
And, lastly, in applying the means whereby the lamps are charged
and supplied with the electric fluid, I perform various important
5 operations which materially reduces the actual cost of the light, and
thus rendering the production of the light (which is one of unequalled

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Prosser in the Great Seal Patent Office
on the 6th April 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
PROSSER, of the Parish of St. Luke, Chelsea, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of October, in the year
of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said William Prosser, Her
special license that I, the said William Prosser, my executors, admini-
strators, and assigns, or such others as I, the said William Prosser,
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 Invention
for "IMPROVEMENTS IN LAMPS ADAPTED TO THE ELECTRIC LIGHT, AND IN THE
MANIPULATION OF THE MEANS EMPLOYED FOR THE SUPPLY OF THE ELECTRIC FLUID
THERETO," upon the condition (amongst others) that I, the said William
Prosser, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and scals, 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 William Prosser, do hereby declare
the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say :—
This Invention relates to certain improvements in lamps adapted for

page_text: the exhibition of the electric light, and consists in the combination of a
fluid electrode (such as mercury) with one of charcoal or other suitable
material; likewise an arrangement in which both electrodes are of
carbon or other suitable material, and also in the manipulation of the
means employed for the supply of the electric fluid thereto.
With regard to the first of these applications where a fluid electrode
is used I propose to adopt, as has been heretofore employed, a stream or
jet of mercury, the rate of flow or discharge of which is adjusted by a
suitable valve or other equivalent device being sufficient to ensure the
requisite discharge so that the light may be preserved in a uniform and
permanent state.
It is desirable that the head of mercury should be in excess of that
which is required, as the velocity of the fluid may be graduated to the
greatest possible nicety by the before-mentioned valve.
The stream or jet of mercury issuing from an indestructible nipple
formed of calcarious or other suitable material assumes a solid form for
some little distance from the discharging aperture, and then separates
itself or is broken up into spray which becomes partly dissipated in
vapour, falling on to the negative carbon electrode (where such is used)
or into a cup or dish prepared to receive it (when a fluid electrode is
used), and from thence is conveyed into a suitable receptacle where it is
cleansed (by filtration or otherwise), and from whence it is returned to
the cistern head forming the supply so that there will be little or no
waste of the mercury.
With a view of preventing the escape of the mercurial vapour arising
from the volatilization of the fluid into the surrounding atmosphere it is
necessary to enclose the electrodes in a glass case, but hitherto no means
have been discovered for successfully preventing the glass from being
fractured by the excessive internal heat whilst the internal surface is
exposed to the impinging of the cooler atmosphere upon it. To obviate
this difficulty I employ firstly a second glass surrounding that which
immediately encloses the light, having an intervening space of about
half an inch between them so as to protect it from the detrimental effect
of the external atmosphere upon it.
It is obvious that the ends of the inner glass enclosure should be
hermetically sealed by cementing or otherwise bedding it in a groove
formed in the top and bottom plates of the frame of the lamp.

page_text: And, Secondly. I sometimes adopt a malleable glass shade treated
according to a Patent which has been recently taken by M. R. de la
Bastie, No. 2783, A.D. 1874, for rendering glass malleable, and I
therefore propose in some cases to substitute a glass of this description,
by which I get rid of the refraction of two glasses and thereby offer less
obstruction to the passage of the light.
In describing this arrangement of lamp I have confined myself to the
description of one in which a single jet mercury only is used, but when
I require an increased volume of light I propose to employ a plurality
of jets arranged in such form or forms as may best suit the requirements
of the case, and these jets I arrange (when two or more in number) in a
straight line similar to the flat wick of an ordinary lamp, or I dispose
them (as may be desirable) in an angular, curved, circular, (argand),
or polygonal form, thereby presenting not only as heretofore (in electric
lamps) a simple radiant point of light, but a series of such points which
in the distance will assume the appearance of a sheet of flame possessing
volume as well as intensity. Theso jets may either be actuated
separately from different heads or combined in any way most suitable
for the purpose, the negative carbon electrodes being arranged in a
manner most suitable for producing the maximum effect by the focal
distance being adjusted to any desired quantity by a spring, screw, or
other equivalent device; with a view to equalizo the consumption of
the electrodes I cause them to rotate slowly.
As the distance of the carbon point from the fluid electrode must be
definite it is in some cases limited by a permanent stop of viridium
against which it is continuously pressed to ensure a light of maximum
intensity.
In some cases I employ two negative carbon electrodes, the one
opposite the other, with advantage, or placed at an angle with each
other, the point of junction being immediately beneath the positive
electrode, each one of these electrodes (which move in opposite
directions) becoming the stop for the other. These are kept in contact
by a spring or balance weight behind each (as before described). In
such a case I prefer to employ (where mercury is used) a flat enclosure,
the glass being similar to a clock glass and may be made either of the
malleable glass before mentioned, or consist of two glasses when of
ordinary material; this form being more convenient than the small
cylindrical glass before described.

page_text: I sometimes construct the negative electrode of a circular form (as a
disc) and cause it to rotate slowly, thus bringing a fresh position of the
negative electrode into action.
In some cases I employ two or more carbon electrodes for both the
positive and negative poles, radially abutting against each other beneath
the positive electrode like a star either in the same plane or angularly
disposed and radiating, being kept in their places as before described.
It is obvious that where a fluid electrode is not used a carbon positive
electrode or electrodes, similarly constructed and impelled, may be
substituted.
It is also obvious, in cases where a fluid electrode is not adopted, the
glass enclosure becomes unnecessary.
In using electric batteries great difficulty has heretofore been
experienced in checking their irregular action, this I propose to obviate
by subdividing the battery into a number of compartments or series,
making the conducting wires of each cell sufficiently large in section to
carry off all the electricity, generated and uniting these individually,
in couples, or otherwise with a main conductor of a section, sufficient
to pass all the electric fluid which may be generated by the several
series of cells. The main conductor should in this case be of a
progressive increasing section according to the number of cells
employed.
It is obvious to all who have employed electric batteries that the
boiling over or other derangement of the apparatus is due to the fact
of the electricity having been generated faster than it could be conveyed
away.
By a judicious' mode (such as is well known) of connecting the several
series with the main conductor, the action of any one or more series
may be suspended at pleasure, care being taken at the same time to
suspend the generating action of the battery.
Having now described the several forms in which I propose to
construct these electric light apparatus and the mode of working the
improved batteries, I proceed to state that in using the electric fluid so
generated for the purposes of the light, I make use of the said fluid
“in transitu” to operates upon various substances so as to alter their
condition and character, and among these objects I may name the

page_text: manufacture of steel and colours, desulphurizing coke, and treating
such substances as admit of a chemical change by the passage of the
electric fluid through them.

page_text: 5thly. I claim the use of the electric fluid "in transitu," for the
purpose of operating upon a variety of substances by which useful
products in the arts are obtained.
In witness whereof, I, the said William Prosser, have hereunto
set my hand and seal, this Sixth day of April, in the year
of our Lord One thousand eight hundred and seventy-six.