IMPROVE- MENTS IN LAMPS FOR RAILWAY CARRIAGES, ALSO APPLICABLE TO MINING, SIGNALLING, AND OTHER EXPOSED LAMPS.
Year: 1874

page_text: LETTERS PATENT to Thomas Martin, of Box Grove, Guildford, in
the County of Surrey, Lieutenant-Colonel, late commanding Fourth,
the King's Own Royal Regiment, for the Invention of "IMPROVE-
MENTS IN LAMPS FOR RAILWAY CARRIAGES, ALSO APPLICABLE TO MINING,
SIGNALLING, AND OTHER EXPOSED LAMPS.'
PROVISIONAL SPECIFICATION left by the said Thomas Martin at the
Office of the Commissioners of Patents, with his Petition, on the
22nd September 1874.
I, THOMAS MARTIN, of Box Grove, Guildford, in the County of
Surrey, Lieutenant-Colonel, late commanding Fourth, the King's Own
Royal Regiment, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN LAMPS FOR RAILWAY CARRIAGES, ALSO APPLICABLE TO MINING,
SIGNALLING, AND OTHER EXPOSED LAMPS," to be as follows:-
In the lamps usually employed for railway carriages the air for sup-
porting combustion is supplied through openings or passages in the
upper part of the lamp communicating with the external atmosphere.

page_text: be perforated with holes for the admission of air to its interior, or the
bottom of the casing may be left open.
I sometimes arrange the glass globe of the lamp to open inside the
carriage, hinging it at one side to the upper casing, and providing it at
the other side with a catch that can be opened by a key. Thus the lamp
can be trimmed from the interior of the carriage without the necessity
for removing it for this purpose through the roof.
In order to render frequent trimming unnecessary I prefer to make
the upper part of the wick of asbestos woven into a fabric of wick
character, a short piece of which I attach by stitching or otherwise to a
cotton wick, the latter lying in the oil, and serving to supply the
former, which alone is exposed to the heat of the flame. In attaching
the asbestos wick to the cotton I prefer to make the latter either tubular
or to fold it over, so as to make it double, the asbestos wick being
enclosed at the point of its attachment within the two folds of cotton,
whereby it is more fully supplied with oil.
It may be readily understood that the improvements which I have
described above are applicable to other than railway carriage lamps, as, for
example, to lamps for ordinary carriages, or for lighting the galleries or
workings of mines, or for signalling, and generally in cases where lamps
are exposed to gusts of wind.
When applied in mines, where there may be an explosive atmosphere,
I cover the openings for ingress of air to supply the flame, and also
those for the egress of the products of combustion with fine wire gauze
to prevent the communication of flame to the exterior.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Martin in the Great Seal Patent Office
on the 19th March 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
30 MARTIN, of Box Grove, Guildford, in the County of Surrey, Lieutenant-
Colonel, late commanding Fourth, the King's Own Royal Regiment,
send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of September, in the
year of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Thomas Martin, Her special
license that I, the said Thomas Martin, my executors, administrators,
and assigns, or such others as I, the said Thomas Martin, 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 FOR RAILWAY CARRIAGES, ALSO APPLICABLE TO MINING, SIGNALLING,
AND OTHER EXPOSED LAMPS," upon the condition (amongst others) that I,
the said Thomas Martin, my executors or administrators, by an instru-
ment 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 Thomas Martin, 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, reference being had to the accom-
panying Sheet of Drawings, and to the figures and letters marked
thereon, that is to say :-
In the lamps usually employed for railway carriages the air for sup-
porting combustion is supplied through openings or passages in the
upper part of the lamp communicating with the external atmosphere.
Owing to the unsteadiness of the air supply, due to gusts of wind or
to the movement of the train, the flame is caused to flicker, or is ren-
dered unsteady, and even at times is extinguished, and this more
particularly the case when volatile oils are employed, and the air is
supplied to the burner by tubes.
Moreover, it is found that by causing the air to pass down through
the space in the upper part of the lamp in which the hot products of

page_text: combustion ascend it becomes heated, and thus produces a less perfect
combustion with hydrocarbon liquids than if the air were supplied in a
cold condition.
According to my Invention I obviate these defects by admitting the
air to the burner from the inside of the carriage or compartment through
apertures in the side of the lamp casing, whereby a uniform supply of
comparatively cold air, and consequently a steady and brilliant flame is
ensured, and the ventilation of the carriage is aided. For this purpose
I arrange the tube or tubes supplying air to the burner in communi-
cation with an opening or openings formed in the lower part of the lamp
casing just above the rim of the glass globe, and under the ceiling of
the compartment, such openings being covered, if desired, with per-
forated metal or wire gauze. Other holes may be provided in the said
portion of the lamp casing, admitting air from the inside of the carriage
to pass upwards in a space between the chimney and the oil reservoir, in
order to keep the chimney cool, and to keep the reservoir from being
overheated.
In some cases I dispense with tubes for conducting air to the burner,
admitting the air to the interior of the globe by holes either in the lower
part of the casing above the globe or in the globe itself; and when such
holes are at the upper part of the globe they may be provided with
deflectors to direct the entering air downwards.
•
When tubes are employed to conduct the air to the burner I prefer to
enclose the oil tubes wholly or partially within the air tubes, making
the latter of triangular section with a flat side towards the glass, so
so as to aid reflection of the light, or the oil and air tubes may both be
enclosed in an outer tube of the form above described.
The air supply may either be led into the interior of a deflecting dome
of any known construction surrounding the wick, or when it is provided
for a burner wherein the wick is enclosed in the usual manner within a
casing closed at bottom to form an oil receptacle, I prefer to enclose
such casing wholly or partially within an air casing into which the air
tube is led.
When the air is supplied simply to the globe without air tubes con-
ducting to the burner the periphery of the casing above described may
be perforated with holes for the admission of air to its interior, or the
bottom of the casing may be left open.

page_text: I sometimes arrange the glass globe of the lamp to open inside the
carriage, hinging it at one side to the upper casing, and providing it at
the other side with a catch that can be opened by a key. Thus the lamp
can be trimmed from the interior of the carriage without the necessity
for removing it for this purpose through the roof.
In order to render frequent trimming unnecessary I prefer to make
the upper part of the wicks of asbestos woven into a fabric of wick.
character, a short piece of which I attach by stitching or otherwise to a
cotton wick, the latter lying in the oil, and serving to supply the
former, which alone is exposed to the heat of the flame. In attaching
the asbestos wick to the cotton I prefer to make the wick either tubular
or to fold it over, so as to make it double, the asbestos wick being
enclosed at the point of its attachment within the two folds of cotton,
whereby it is more fully supplied with oil.
It may be readily understood that the improvements which I have
described above are applicable to other than railway carriage lamps, as,
for example, to lamps for ordinary carriages, or for lighting the galleries
or workings of mines, or for signalling, and generally in cases where
lamps are exposed to gusts of wind.
When applied in mines, where there may be an explosive atmosphere,
I cover the openings for ingress of air to supply the flame, and also
those for the egress of the products of combustion with fine wire gauze
to prevent the communication of the flame of the lamp to the exterior
atmosphere.
Fig. 1 shews a vertical section of a railway carriage lamp with my
before-described improvements applied thereto, and Fig. 2 shews a
sectional plan of the same on line X, X, Fig. 1.
A is the burner, consisting of a wick holder, enclosing which is a
casing for supplying air to the flame, constructed in a manner well
understood; B, B, are the air tubes for supplying the cold air to the
interior of the casing. These tubes are of a triangular section, as shewn
at Fig. 2, with the apex towards the burner, so as effectually to reflect
the light therefrom; they pass through the reflector C, to which they
are joined in an air-tight manner, and just above the reflector the tubes
are bent round, so as to fit with their open ends closely against the side

page_text: 1
of the casing D opposite holes E, E, formed in the latter just below
the ceiling P of the carriage, so that the air passes from the interior of
the carriage through the holes E and tubes B to the burner, as indicated
by the arrows. Over the holes. E may be fixed tubular pieces F, the
ends of which may be open or covered with perforated metal or .wire
gauze, so that the air passes through the ends of these tubular pieces to
the holes E, as indicated at Fig. 2, and thus any disturbance of the
currents of air by the opening and closing of the carriage doors is
more or less prevented, or the pieces F may be perforated and closed at
the ends.
The oil tubes G from the reservoir H pass through the air tubes B to
the burner, as shewn. The reflector C is formed in one with the
chimney I, and fits with its outer rim closely, and by preference in an
air-tight manner upon a rim K on the inside of the casing D, so that
the space inside the glass globe L is practically closed against any ingress
of air beyond that which enters through the air tubes B for the supply
of the burner. By this means the rarefaction of the air inside the globe,
due to the heat of the flame, will tend to produce an increased draught
through the air tubes B, and a more perfect combustion and an increased
brilliancy of the flame will consequently result.
The glass globe L may be fixed to the casing D in the ordinary
manner, but by preference I arrange the same to open on a hinge inside
the carriage, as shewn, so that the lamp can be trimmed and cleaned
from the inside of the carriage, as before described. In this case the
metal ring M, to which the globe is secured, is formed with a projecting
fillet fitting into a corresponding hollow in the rim N on the casing, so
that when the globe is closed and secured by any suitable fastening at O
the ingress of air between the globe and the casing is prevented.
When the lamp is used for mining purposes the openings of the
tubular pieces F through which the air enters, as also the top of the
chimney I, are closed by means of fine wire gauze.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I claim,-
First. The use of railway carriage lamps wherein the air is admitted
to the burner from the inside of the carriage, substantially as herein
described.