IMPROVEMENTS IN THE PRODUCTION OF ELECTRIC LIGHT AND IN APPARATUS THEREFOR
Year: 1875

page_text: LETTERS PATENT to Stephan Alexandrovitch Kosloff, of St. Petersburg,
in the Empire of Russia, but at present of the City of London, for
the Invention of "IMPROVEMENTS IN THE PRODUCTION OF ELECTRIC LIGHT
AND IN APPARATUS THEREFOR."
Sealed the 2nd April 1875, and dated the 5th February 1875.
PROVISIONAL SPECIFICATION left by the said Stephan Alexandrovitch
Kosloff at the Office of the Commissioners of Patents, with his
Petition, on the 5th February 1875.
I, STEPHAN ALEXANDROVITCH - KOSLOFF, of St. Petersburg, in the
Empire of Russia, but at present of the City of London, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE
PRODUCTION OF ELECTRIC LIGHT, AND IN APPARATUS THEREFOR," to be as
follows:
1
These improvements consist essentially in the subdivision of the
electric light, which is produced by means of an electric current heating

page_text: to a white heat sticks of carbon placed in the circuit, and being herme-
tically enclosed in a globe filled with nitrogen gas, all as herein-after set
forth.
1st. The unequal expansion by heat of different substances employed
in electric light apparatus has not been hitherto sufficiently considered by
other Inventors; they therefore placed their carbons on metal conductors,
which served as supports, and fix them firmly thereto either by pincers
or by being screwed to the same, or by other means. This way of
joining together two different substances, subject to different tempera-
tures, produced the breakage of the carbon, the latter not expanding in
the same ratio as the metal; or because the expansion of the metal being
greater than that of the carbon the metal in heating detaches itself
gradually from the carbon and produced electric sparks. In my system
the carbon is placed between two insulating supports, either of china,
clay, crystal, calcined magnesia, or other insulating substances, the carbon
fitting in and being allowed to move a little in the hollow of the said
supports.
2nd. Every metal which is outwardly attached, screwed, or fixed in
any other way to the carbon detaches itself in heating, and produces
electric sparks, and consequently the melting of the metal. In my
system I introduce the metal wires into the carbon, which gives me a
better contact when the carbon is heated by the current and does not
produce electric sparks. But in order not to put the metal into direct
contact with the white-hot carbon thicker end pieces of carbon with
holes crosswise (that is to say, through the length and the thickness)
serve as communicators of the electric current, and these thicker pieces
of carbon not being such bad conductors as the thinner sticks of carbon,
which are destined to give the light, and fit into the thicker pieces of
carbon, heat to a lesser degree the metal introduced into them.
3rd. The connection of the principal conductors with the metallic
wires which are introduced into the thick end pieces of carbon I effect
by means of hinges or fastenings of fine twisted metallic wire, leaving a
little space to move about in case of dilatation, and resting thereon with
their own weight; I thus obtain a sufficient contact without producing
electric sparks. My connections cannot increase the loss of electric
current, because the heat produced by an electric current passing through

page_text: two pieces of metal not firmly attached to each other, but closely
touching each other, is much smaller than the heat caused to my con-
nections by the contact with a white-hot body in a high temperature.
4th. In order to avoid the inconvenience of the preparation of nitrogen
gas and its introduction into the lamp after the air has been withdrawn
from it, I according to my Invention produce the gas by rarifying the
air in the globe in which the apparatus is placed by means of the carbon
itself, which is heated by the electric current, and which at the same
time is to give me the light. By dilating the air, which could not
occupy the same space in the globe, it is caused to escape out of the.
globe through a valve or valves, and then cannot re-enter the globe..
The small quantity of oxygen remaining in the rarified air in the globe
is transformed into oxido of carbon. In order to have as little air as
possible in my lamps I fill the superfluous space in the globe with
massive pieces, or pieces in the shape of tubes closed at one end, of
china, clay, calcined magnesia, crystal, or any other insulating substance,
with a hollow through their whole length for their metallic conductors,
or even of carbon, with insulators, instead of employing metallic con-
ductors; I also make use of these massive pieces as supports for the
carbon bearers of the sticks of carbon, which are destined to give the
light. If I make the said filling pieces as insulated pieces of carbon,
carbon connections may be employed for connecting with the thin carbon
sticks. The globe and the said massive pieces must be of sufficient
length, according to the strength of the light which it is intended to
produce, in order that the valve or valves may not be exposed to too
great a heat, and in order that, by employing a hydraulic joint or closing
of any liquid, which being exposed to a certain heat does not produce
vapours, which would consume the carbon. I altogether avoid mercury
as being dangerous to the health. The said massive pieces may also be
of metal, but in that case I introduce insulators in order that the
currents may meet in the sticks of carbon.
5th. When I have not at my disposal a stronger electric source to
enable me to light thicker sticks of carbon, then I place several thin
sticks of carbon into the same lamp, and I light them successively the
one after the other, and in order to cause the clectric current to pass
automatically from one carbon to another I employ the following

page_text: system I introduce the metallic wires which traverse the thick pieces
of carbon, not at the same height, but gradually a little lower than in
the preceding piece of carbon. In case of breakage of one of the
lighted carbons, the thick piece of carbon, being fastened on one side
only, will incline through its weight towards the wire extending in the
shape of a ring from the second carbon, and having a wire in the form
of a hook or a plate, place itself into the ring of the second carbon.
The current being interrupted in the first carbon is communicated to the
second carbon, and from the second to the third, and so forth.
In lamps with several carbons the insulators between which the thick
pieces of carbon repose are of a round shape, with a small opening to
allow guards to be placed into them, which prevent the thicker pieces of
carbon from descending lower than they ought. After having put the
carbon into its place the opening is shut up by means of a bolt or hook.
In lamps with several carbons one pole is in communication. with one
end of all the carbons, whilst the other pole is put into.communication
with all the carbons which are to be lighted first, that is to say, with the
carbons where the aforesaid metallic wire is highest.
If I do not want to make use of the automatic mechanism in the
lamps with several carbons I employ a commutator, where one pole is in
communication with the one end of all the carbons, whilst the other.pole
may be put into connection with each series of carbons in the different
lamps, having separate conductors.
The system of placing the lamps into the circuit may be effected in
two ways, namely, either by placing one series of lamps united by a
metallic wire in such a way that the current traverses all the carbons,
the conductor of one pole being in communication with the first lamp,
and the conductor of the other pole in communication with the last
lamp; or by subdividing the current, that is to say, the current of one
pole is subdivided from one point and conducts the current by separate
conductors to cach lamp. The current of the other pole subdivided in
the same way meets the current of the first pole in each lamp..

page_text: SPECIFICATION filed in pursuance of the conditions of the Letters
Patent, and of an Order of the Lord Chancellor, by the said Stephan
Alexandrovitch Kosloff in the Great Seal Patent Office on the
26th August 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, STEPHAN
ALEXANDROVITCH KOSLOFF, of Saint Petersburg, in the Empire of
Russia, but at present of the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of February, in the year
of our Lord One thousand eight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Stephan Alexandrovitch
Kosloff, Her special licence that I, the said Stephan Alexandrovitch
Kosloff, my executors, administrators, and assigns, or such others as
I, the said Stephan Alexandrovitch Kosloff, my executors, admini-
strators, 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 THE PRO-
DUCTION OF ELECTRIC LIGHT, AND IN APPARATUS THEREFOR," upon the condition
(amongst others) that I, the said Stephan Alexandrovitch Kosloff, 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 Stephan Alexandrovitch Kosloff,
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, reference being had to the accom-
panying Drawings, and to the letters of reference marked thereon, that
is to say:
-

page_text: electric light, which is produced by means of an electric current heating
to a white heat sticks of carbon placed in the circuit and being hermeti-
cally enclosed in a globe filled with nitrogen gas, all as herein-after set
forth.
First. The unequal expansion by heat of different substances employed
in electric light apparatus has not been hitherto sufficiently considered by
other Inventors, they therefore placed their carbons on metal conductors,
which served as supports, and fixed them firmly thereto either by pincers or
by being screwed to the same, or by other means. This way of joining
together two different substances subject to different temperatures pro-
duced the breakage of the carbon, the latter not expanding in the same ratio
as the metal, or because the expansion of the metal being greater than that
.of the carbon the metal in heating detached itself gradually from the
carbon and produced electric sparks. In my system, as illustrated upon
the appended Sheet of Drawings at Figure 1, the carbons A and B are
placed between two insulating supports C, D, either of china, clay,
.crystal, calcined magnesia, or other insulating substances, the carbons A
fitting in and being allowed to move a little in the hollow of the said
„supports C, D.
. Second. Every metal which is outwardly attached, screwed, or fixed
in any other way to the carbon detaches itself in heating and produces
electric sparks, and consequently the melting of the metal. In my system
I introduce the metal wires E, E¹, (see Figure 2) into the carbon A,
which gives me a better contact when the carbon is heated by the
current, and does not produce electric sparks. In order not to put the
metal into direct contact with the white-hot carbon I employ the thicker
end pieces A of carbon with holes crosswise, which serve as communi-
cators of the electric current to the smaller carbon sticks B, and these
thicker pieces of carbon A not being such bad conductors as the thinner
sticks of carbon B, which are destined to give the light, and which fit
into the thicker pieces of carbon A heat to a lesser degree the metal
introduced into them. These insulators C, D, are secured to a screwed
support or standard F by means of the nuts G, G¹, and H, the whole
being placed upon a seat I.
Third. The connection of the principal conductors with the metallic
wires E, E', which are introduced into the thick end pieces of carbon is
illustrated at Figure 3, and consists of hinges or fastenings J, J¹, of fine

page_text: twisted metallic wires, which are placed upon the metallic con-
ductors K, K¹, from the different poles, and held there at the required
height by nuts M, their other ends being placed upon the wires E, E¹,
nuts N preventing them from coming off, but leaving a little space to
move about in case of dilatation, the hinges resting on the wires with
their own weight. I thus obtain a sufficient contact without producing
clectric sparks. My connections cannot increase the loss of electric
current because the heat produced by an electric current passing through
two pieces of metal not firmly attached to each other but closely
touching each other is much smaller than the heat caused to my
connections by the contact with a white-hot body in a high temperaturo.
Fourth. In order to avoid the inconvenience of the preparation of
nitrogen gas, and its introduction into the lamp after the air has been
withdrawn from it according to my Invention, I produce the gas by
rarifying the air in the globe in which the apparatus is placed by means
of the carbon itself, which is heated by the electric current, and which
at the same time is to give the light. This part of my Invention is
shewn at Figure 4. By dilating the air, which could not occupy the
same space in the globe O, it is caused to escape out of the globe Ọ
through a valve or valves P so arranged as to admit of the passage of
air out of but not into the globe O. The small quantity of oxygen
remaining in the rarefied air in the globe is transformed into oxide of
carbon. In order to have as little air as possible in my lamps I fill the
superfluous space in the globe with massive pieces Q, or pieces in the shape
of tubes closed at one end, of china clay, calcined magnesia, crystal, or
any other insulating substance, with a hollow through their whole length
for their metallic conductors, or even of carbon with insulators instead
of employing metallic conductors. I also make use of these massive
pieces as supports for the carbon bearers of the sticks of carbon which are
destined to give the light. If I make the said filling pieces as insulated
pieces of carbon, carbon connections may be employed for connecting
with the thin carbon sticks. The globe O and the said massive pieces Q
must be of sufficient length, according to the strength of the light
which it is intended to produce, in order that the valve or valves P may
not be exposed to too great a heat, and in order to avoid vaporization
when I employ a hydraulic seal joint or closing of any liquid, which
being exposed to a certain heat does not produce vapours, which would

page_text: consume the carbon. I altogether avoid mercury as being dangerous to
the health. The said massive piece or pieces Q may also be of metal,
but in that case I introduce insulators in order that the currents may
meet in the sticks of carbon. The lower part of the globo O is situated
in a reservoir R. A lid S is provided, and springs T attached thereto
hold the globe in position; U, U', are conductors in the form of an
incrusted metallic piece, and are put in communication with external
conductors by means of metallic buttons V.
Figure 5 shews an arrangement which I employ when I have not at
my disposal a sufficiently strong electric source to enable me to light
thicker sticks of carbon; then I place several thin sticks of carbon into
the same lamp, and I light them successively the one after the other,
and in order to cause the electric current to pass automatically from one
carbon to another I employ the following system:-I introduce the
metallic wires E, E³, which traverse the thick pieces of carbon A not at
the same height, but gradually a little lower than in the preceding piece
of carbon. In case of breakage of one of the lighted carbons B the
thick piece of carbon A being fastened on one side only, will incline
through its own weight towards the wire E* (extending in the shape of a
ring from the second carbon), and having a wire in the form of a hook
or a plate, and place itself into the ring of the second carbon. The current
being interrupted in the first carbon is communicated to the second
carbon, and from the second to the third, and so forth.
In lamps with several carbons the insulators between which the thick
pieces of carbon repose are of a round shape, with a small opening to
allow guards to be placed into them, which prevent the thicker pieces
of carbon from descending lower than they ought. After having put
the carbon into its place the opening is shut up by means of a bolt or
hook.
In lamps with several carbons one pole is in communication with one
end of all the carbons, whilst the other pole is put into communication
with all the carbons which are to be lighted first, that is to say, with the
carbons where the aforesaid metallic wire is highest.
If I do not want to make use of the automatic mechanism in the
lamps with several carbons; as described with reference to Figure 5, I
employ a commutator where one pole is in communication with the one

page_text: end of all the carbons, whilst the other pole may be put into connection with
cach series of carbons in the different lamps having separate conductors.
The system of placing the lamps into the circuit may be effected
in two ways, namely, either by placing one series of lamps united by a
metallic wire in such a way that the current traverses all the carbons,
the conductor of one pole being in communication with the first lamp
and the conductor of the other pole in communication with the last
lamp, or by subdividing the current, that is to say, the current of one
pole is subdivided from one point and conducts the current by separate
conductors to each lamp. The current of the other pole subdivided in
the same way meets the current of the first pole in each lamp.
Having now described my said Invention and the mode in which it
may be carried out, I would observe in conclusion that I claim as the
Invention secured to me by the foregoing Specification of Letters
Patent,-
-
First. Placing the carbons which are to be lighted on insulators in
order that the metallic conductors of the electric current may not be
used as supports, and to allow the said carbons a little space to move
about in the hollow of the insulators, as herein-before described.
Second. Effecting the contact of the carbons with the metal by intro-
ducing the metal wire into the carbon, and not by fixing or attaching the
same outwardly to the carbon.
Third. Connecting the principal conductors with the wire introduced
into the thick end of the carbon, and which are exposed to the heat in
the lamp by hinges or fastenings of metal, which leave them a little
space to move about, substantially as herein-before described.
Fourth. Producing nitrogen gas by rarifying the air in the globe by
means of the lighted carbons lighted by the electric current, and trans-
forming the remainder of oxygen into oxide of carbon by employing an
hydraulic closing and valves through which the heated air would escape,
and which would not allow the outward air to introduce itself again into
the lamp, all substantially as herein-before set forth.
Fifth. Introducing massive pieces or pieces in the shape of tubes
closed at one end into the globe in order to retain a certain length of the
globe indispensible for the closing, and which at the same time afford

page_text: STEPHAN
ALEXANDROVITCH KOSLOFF. (L.S.)
Signed by the within-named Stephan
Alexandrovitch Kosloff in my pre-
sence this 1/13 day of August
1875.
FREDK. LESLIE,
Consulate
British Vice-Consul.
Scal.