IMPROVEMENTS IN THE TREATMENT OF CARBON FOR ELECTRIC LIGHTING AND OTHER PURPOSES
Year: 1881

page_text: LETTERS PATENT to James Grieve Lorrain, of Lancaster House, Savoy, in the
County of Middlesex, Civil Engineer, for an Invention of "IMPROVEMENTS
IN THE TREATMENT OF CARBON FOR ELECTRIC LIGHTING AND OTHER
PURPOSES."
PROVISIONAL SPECIFICATION left by the said James Grieve Lorrain at
the Office of the Commissioners of Patents on the 29th June 1881.
JAMES GRIEVE LORRAIN, of Lancaster House, Savoy, in the County of Middlesex,
Civil Engineer. "IMPROVEMENTS IN THE TREATMENT OF CARBON FOR ELECTRIC
LIGHTING AND OTHER PURPOSES."
The object of this Invention is the improvement of carbon filaments, rods, pencils,
plates, asses, or electrodes employed in electric lighting, and for other purposes.
In carrying out this Invention the carbon filaments, rods, pencils, plates, masses,
or electrodes prepared by any known process are impregnated or coated with
precipitated or deposited carbon by the following means, videlicet:-They are
impregnated with a substance or compound or chemical reagent, such for example
as hydro carbons, in which the chemical element carbon exists, and this is acted
upon by another substance or compound or chemical reagent or chemical element,
such for example as sulphuric acid, hydrochloric acid, or chlorine gas, so that
carbon is separated and precipitated or deposited in the pores or interstices, and on
the surface of the said carbon filaments, rods, pencils, plates, masses, or electrodes.
Or this process may be reversed, that is to say, the carbon filaments, rods, pencils,
plates, masses, or electrodes may be impregnated with a substance or compound or
chemical reagent or chemical element which is capable of acting on or of being
acted upon by another substance or compound or chemical reagent containing the
chemical element carbon, so that carbon is separated and precipitated or deposited
in the pores or interstices, and on the surface of the carbon filaments, rods, pencils,
plates, masses, or electrodes, that is to say, the chemical element carbon may exist
either in the body with which the carbons are first impregnated, or in the body
which is afterwards applied.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Grieve Lorrain in the Great Seal Patent Office on the
29th December 1881.
JAMES GRIEVE LORRAIN, of Lancaster House, Savoy, in the County of Middlesex,
Civil Engineer. "IMPROVEMENTS IN THE TREATMENT OF CARBON FOR ELECTRIC
LIGHTING AND OTHER PURPOSES."
The object of the said Invention is the improvement of carbon filaments, rods,
pencils, plates, masses, or electrodes employed in electric lighting, and for other
purposes.
In carrying out the said Invention, the carbon filaments, rods, pencils, plates,
masses, or electrodes prepared by any known process are impregnated or coated
with precipitated or deposited carbon by the following means, videlicet:-
They are impregnated with a substance or compound or chemical reagent, in
which the chemical element carbon exists, and this is acted upon by another
substance or compound, or chemical reagent or chemical element, so that carbon
is separated and precipitated or deposited in the pores or interstices, and on the
surface of the said carbon filaments, rods, pencils, plates, masses, or electrodes.
Or this process may in some cases be reversed, that is to say, the carbon filaments,
rods, pencils, plates, masses, or electrodes may be impregnated with a substance or
compound, or chemical reagent or chemical element which is capable of acting on or
of being acted upon by another substance or compound or chemical reagent
containing the cheinical element carbon, so that carbon is separated and precipitated
or deposited in the pores or interstices, and on the surface of the carbon filaments,
rods, pencils, plates, masses, or electrodes, that is to say, the chemical element
carbon may exist either in the body with which the carbons are first impregnated,
or in the body which is afterwards applied.
In order that my said Invention may be perfectly understood, I shall describe
by way of types or examples two processes by which it may be carried into effect,
and which have been found to give good results in practice, but it is to be under-
stood that the Invention is not limited to the substances, compounds, or chemical
reagents herein referred to, as any hydrocarbon or carbonacious substance may be
used, which in the presence of chlorine gas, or of an acid, or of any equivalent
agent, will be decomposed and deposit carbon upon the body under treatment.
According to one mode of carrying out my said Invention into effect I tako
carbon rods, filaments, pencils, plates, masses, or electrodes, that is to say, carbons
in any form used for electric lighting in galvanic batteries, and in microphones or
telephonic transmitters, or for other purposes already prepared by some known
process, and boil the same in turpentine, say, for about half an hour, or until
occluded water ceases to be evolved from the carbon. I next submit the carbons
so treated to the action of gaseous cblorine, first at the ordinary temperature, say,
for example, for about five minutes, and then to a gradually increasing temperature,
until bright redness is attained.
The chlorine gas may be prepared by any suitable known process. In the
treatment of the smaller description of carbons, such as filaments, pencils, and small
rods, I employ a cylindrical or other conveniently shaped vessel made of glass or
other material. In this vessel the carbons to be operated upon (already saturated
with turpentine), are placed in such a manner as to complete an electric circuit.
The vessel also contains water, provision being made so that the water may be
drawn off and replaced by fresh water when desirable. The vessel is next exhausted
of air by means of an air pump or otherwise, and is then filled with chlorine, or the
chlorine may be introduced without first exhausting the air which is then expelled

page_text: by displacement. An electric current is now passed through the carbons, and their
temperature very gradually raised until they reach bright redness by gradually
increasing the current. By this means complete union of the hydrogen of the
hydrocarbon with the chlorine will take place, the hydrochloric acid produced being
absorbed by the water, and a large part of the carbon liberated will be deposited in
the pores and interstices of the carbons.
For the treatment of larger carbons a porcelain or earthenware tube capable of
being heated by means of a furnace is by preference used, and the chlorine gas is
caused to pass through such tube which contains the carbons previously saturated
with turpentine. The tube is very gradually raised in temperature to bright
redness by means of the furnace, in place of being heated by the electric current.
This process of saturating the carbons with turpentine and gradually heating in
presence of chlorine, is repeated until the carbons are of the required quality.
According to another mode of carrying my said Invention into effect, I boil the
carbons in strong sugar syrup, say, for about an hour, or until they are free from
occluded gases. I then soak them, say, for a period of two or three days in dilute
sulphuric acid (I prefer to use a mixture of four volumes concentrated acid to one
of water), and then soak them, say, for a like period in concentrated sulphuric acid.
By this means the elements of water contained in the sugar will have been
abstracted, and much of the carbon will be deposited in the pores and upon the
surface of the carbons operated upon; after having been well washed the carbons
are heated to redness out of contact with the air. Or this process may be reversed,
that is to say, the carbons may be steeped first in sulphuric acid and afterwards in
syrup, and then washed and heated out of contact with the air, whereby a similar
result will be obtained.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original,
and therefore claim as the Invention secured to me by the herein before in part
recited Letters Patent is,-
The treatment of carbon rods, filaments, pencils, plates, masses, electrodes, or
other forms of carbon for electric lighting and other purposes, by the employment
of a substance, compound, or chemical reagent containing carbon in conjunction
with a substance, compound, chemical reagent, or element which will act upon or be
acted upon by the foriner, so that decomposition shall take place, and carbon shall
be deposited in and upon the body under treatment, substantially as hereinbefore
described.
In witness whereof, I, the said James Grieve Lorrain, have to this my
Specification set my hand and seal, this Twenty fourth day of December,
J. G. LORRAIN. (L.S.)