IMPROVEMENTS IN LAMPS FOR RAILWAY CARRIAGES, ALSO APPLICABLE TO MINING LAMPS
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by Thomas Martin at the Office
of the Commissioners of Patents, with his Petition, on the 16th
September 1874.
I, THOMAS MARTIN, of the Grove, Box Grove, Guilford, 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 LAMPS," to be as follows :—
In the lamps usually employed for railway carriages the air for sup-
porting combustion is supplied to the flame through openings or passages
leading to the top or upper part of the lamp, and communicating with
the external atmosphere. By this arrangement the flame is caused to
flicker or is rendered unsteady, and is even at times extinguished owing
to the unsteadiness of the air supply, due to gusts of wind or to
the movement of the train, and this is more particularly the case with
lamps in which volatile oils are burnt, and the external air is supplied to
the burner through tubes.
Now according to my Invention I obviate this defect by admitting the
air to the lamp from the inside of the carriage or compartment, whereby
a uniform air supply and consequently a steady flame is ensured. For

page_text: this purpose I arrange the tube or tubes that supply the air to the
burner to communicate with an opening or openings formed in the
lower part of the lamp casing at a point just above the rim of the glass
globe and under the ceiling of the compartment, which openings may
be covered with perforated metal or wire gauze. Other air holes may be à
provided in the said portion of the lamp casing for admitting air from
the inside of the carriage to pass upwards in a space between the outside
of the chimney and the oil reservoir, in order to cool the chimney and to
prevent the reservoir from being over heated.
In some cases I dispense with the tubes for conducting the air to the 1
burner, and I admit the air through holes formed either in the side of
the lower part of the casing within the carriage, or at the upper edge of
the glass globe, in which case I provide such holes with deflecting plates
inside the lamp in order to direct the incoming air downwards.
When the air is conducted to the burner through holes, as above 1
described, I prefer to place the oil tubes to the burner inside the air
tube, and I make the air tube of oval shape in transverse section
with a flat side next the glass, whereby the light is most effcctually
reflected from the surface of the tube; or I enclose a small tube for
the air supply, and the tube for the oil supply within a larger tube of 3
the above described shape.
I also in some cases arrange the glass globe of the lamp to open
inside the carriage, for which purpose I provide the globe with a hinge
on one side and a catch on the other side, to be opened by a key. By
this arrangement the lamp can be trimmed and the globe cleaned from 2
the inside of the carriage, thus obviating the necessity of having to
remove the lamp for this purpose through the roof of the carriage.
The above described improved construction of railway lamps wherein
the air is supplied to the burner from points at or about the upper edge
of the glass globe instead of from the top of the lamp, may also be a
employed as mining lamps by covering the holes for the air supply,
as also the openings through which the burnt air escapes with fine wire
gauze.