Improvements in Electric Lamps.
Year: 1888

page_text: Date of Application, 10th Aug., 1888
Complete Specification Left, 3rd May, 1889-Accepted, 22nd June. 1889
PROVISIONAL SPECIFICATION.
Improvements in Electric Lamps.
We, HENRY HASWELL HEAD, of 7 Fitzwilliam Square Dublin, Doctor of Medicine
and LLEWELLYN SAUNDERSON, of 10 De Vesci Terrace Kingstown Co. Dublin Justice
of the Peace, do hereby declare the nature of this invention to be as follows :-
Our invention of improvements in electric lamps relates especially to improving the
colour of the light given out by the electric arc and incandescent glow lamps.
The carbon electrodes of arc lamps are prepared to suit the colour required in the
flame with either of the following substances viz. Sodium, Lithium, Strontium,
Calcium, Copper, Thallium, Barium, Indium, Lead, Boron, Caesium, Rubidium,
Potassium, or any of their salts, or the carbons may be perforated and the channels
filled with the substances innumerated above.
Or either or any of the above named substances in solution may be injected into
over or under the flame of the arc light, to change it into the colour required, the
solutions to be held in vessels attached to the lamp, and to be injected into over or
under the flame, by means of an automatic apparatus suitable for the purpose or by
means of a steam jet spray.
The carbons in incandescent lamps are prepared in the same way as mentioned
above.
When the electrie light is used in a lighthouse, the person in charge can in thick
weather (when yellow light is required) either use sets of these prepared carbon
electrodes which have been prepared with sodium salt or he can use a vessel con-
taining a sodium solution and inject the solution into the flame. In fine weather,
when white light is required, these prepared carbon electrodes and solutions are
replaced by the common carbon electrodes.
Light houses, streets, yards, ships, theatres, &c. may be fitted with arc lamps using
either these prepared carbon electrodes, or, the above named solutions can be made to
give any coloured light required. For signalling purposes, according to the number
of colours required, two or more lamps can be used which are fitted with a set of the
above named carbons, or a set of the above named solutions, in order to change the
colour of the light at each moment.
In the case of the incandescent lamps, the prepared carbons or the above named
substances will give the colour required to the glow light.
Dated this 10th day of August 1888.
CARPMAEL & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in Electric Lamps.
We, HENRY HASWELL HEAD, of 7 Fitzwilliam Square, Dublin, Doctor of Medicine,
and LLEWELLYN SAUNDERSON, of 10 De Vesci Terrace, Kingstown, Co. Dublin,
Justice of the Peace, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained in
and by the following statement :-
Our invention of improvements in electric lamps relates especially to improving
the colour of the light given out by the electric arc and incandescent glow lamps.
The manner of manufacturing the carbons is as follows:-In order to make a
compact coke difficult to burn, powdered gas coke is mixed with powdered caking
coal in the proportion of coke varying from 80 to 50%, coal varying from 20 to 50%
To this mixture is added 1 to 10% of one of the following infusible or difficultly
[Price 4d.1

page_text: fusible substances viz. :-glass, silica, cyanite, kaolin, bauxite, asbestos, pumice,
felspar, gadolinite, samarskite, zircon, limestone, dolomite, witherite, phosphate of
lime, strontianite, brannite, titanic iron, chrome iron ore, wolfram, molybdenite,
fluorspar, cerite, cryolite, phosphate of aluminium, magnesite, or compounds of nickel
and cobalt.
This mixture forms the ground work of the carbon rods.
These substances are used in order to make the impurities in the above named
mixture difficult to fuse, and hence increase the intensity and steadiness of the light.
This mixture is then mixed with 1 to 20% of one of the following bodies or
mixture thereof viz.: sodium, lithium, strontium, calcium, copper, thallium, barium,
indium, lead, boron, caesium, rubidium, potassium or any of their salts, according to
the colour of the light required. The whole after careful mixing is introduced
into an iron mould and heated under pressure, at first gently but finally very
strongly. The carbon rod so made if found too porous is heated and introduced
into hot coal tar, and the whole heated (preferably in vacuo) for some time. It is
then taken out and its surface cleaned, and then introduced into a mould and again
heated under pressure. These operations are repeated until the required density is
obtained.
For some purposes, in order to render the effect most satisfactory, the outer
portion of carbon rod should contain no fusible colouring bodies. When this is
the case, from the mixture of coke, coal and refractory substances hollow carbon
rods are made by introducing the mixture into proper moulds, and heating under
pressure, at first gently, but finally very strongly. The hollow carbon rods so made.
are filled with a mixture consisting of 30 to 50 parts of anthracite or coke, 10 to
20 parts of powdered coal, 1 to 20 parts of calp limestone or one of the above named
refractory bodies, and 1 to 20 parts of one of the above named salts or mixture
thereof. The carbon rods are again heated, at first gently but lastly very strongly
for some time as before.
In the case of already manufactured carbons, they are treated in such a manner
as to fill in their interstices, and to coat their surfaces, and in the case of hollow
carbons, to coat their outer and inner surfaces with one of the above named salts
or mixture thereof. This is effected by boiling the said carbons in strong solutions
of any of the above named salts or mixture thereof and afterwards by drying and
heating, or when possible by steeping them in any of the said salts or mixture
thereof in a molten state.
In the case of already manufactured incandescent lamps, the filaments are steeped
in strong solutions of one of the above named chemicals and then carefully dried
and heated, or the filaments may when possible be dipped into one of the above
mentioned salts or mixture thereof in a molten state. The globe is then exhausted
and a very small quantity of dry chlorine gas admitted.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
Impregnating or mixing the carbons of electric lamps with colouring matters.
HENRY HASWELL HEAD.
LLEWELLYN SAUNDERSON.