An Improved Lamp for Lanterns.
Year: 1893

page_text: Date of Application, 2nd Oct., 1893-Accepted, 28th Oct., 1893
COMPLETE SPECIFICATION.
An Improved Lamp for Lanterns.
I, FREDERIC NEWTON of 3 Fleet Street in the City of London, Scientific
Instrument Maker, 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 :-
This invention relates to improvements in lamps for lanterns, the object being to
increase their efficiency and to add to illuminating power.
In order to avoid the destruction of the glass panel at the back end of the lamp
chamber, from the action of the heat of the flame, in the Specification of a Patent
granted to me dated 18th May 1877, No. 1957, I described the adaptation of the
reflector to the back end of the lamp chamber, setting it in place of the ordinary
glass panel, but although the frequent breakage of the glass panel was thereby
avoided, I found that the silvered surface of the reflector had frequently to be
renewed, owing to the destructive action of the lamp flame. Subsequently, I
found that by changing the shape of the glass panel through which the light was
transmitted to the lantern lenses, the destructive action of the heat of the lamp
flame could be effectually resisted, and availing myself of the discovery, I now
propose to use a glass screen of like character, to protect the reflector from the
deteriorating action of the flame. I further propose to avail myself of the idea of
a divided or composite chimney, to secure two different kinds of draught for the
lamp, one draught suiting the lamp when the wick is low and the heating up of the
lamp is being effected, and the other to suit the requirements of the lamp when
the wick is raised to its full height for maintaining the required intensity of light.
In the accompanying drawing, I have shewn my improved lantern lamp in
sectional plan view at Fig. 1, and in side elevation at Fig. 2.
In these figures, a a is a metal case forming the lamp chamber; bb is the divided
chimney; c is the four wick'd burner. d is the glass panel set in the front of the
chamber, as usual. d'is the back glass panel, and e is the reflector. The glass
panels d d', it will be seen, instead of being flat, take a curved form in horizontal
section, the concave surfaces being presented to the burner; they are held in clips
in the usual manner, and close respectively the front and back of the lamp
chamber.
When subjected to the heat of the flame, the glass panels instead of flying to
pieces, will expand in the direction of their curvature, and, on cooling, return to
their original or set shape. This peculiarity of the curved glass, renders it
efficient as a screen, to protect the reflector from the injurious action of the flame,
and thereby maintain the efficiency and lengthen the life of the reflector. The
reflector, it will be seen, is formed with a central sight hole, as usual, and is carried
by a stem fitting into a socket in the bottom of the lamp chamber. The fitting
of this stem in its socket is made sufficiently tight to ensure its retaining the
position in which it is set. I am thus enabled to provide, without the use of
mechanism, for the adjustment vertically and axially of the stem, and consequently
of the reflector which it carries, to secure the proper reflection of the light.
As the reflector no longer closes the back of the lamp chamber, it will be seen
that I can place the reflector at any distance from the flame, and consequently
can use a reflector of such curvature as I find experimentally to give the best
results.
The upper & lower parts of the divided chimney 66 I preferably connect
together by a hinge or swing joint, and give to them the usual sectional area, but I
construct the chimney some six inches higher than heretofore, giving to the part
forming the base a height which will suffice to create a draught sufficient to

page_text: supply the burner while the lighted wicks are low & the lamp is being heated up
ready for use. When this is effected, which will take some two or three minutes,
I set the upper part of the chimney in line with the base part, & thus secure a
draught sufficient to maintain the long bright flame required.
The base portion of the chimney for creating the temporary draught should
measure some 10 inches in height for a four wick burner such as that shewn in the
drawing.
By the above described modifications, I find that the illuminating power of the
lamp is greatly increased and efficiently maintained.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :--
The construction of lamp for lanterns with a divided chimney and reflector fitted
as described, the base portion of chimney being designed to provide a temporary
efficient draught, as and for the purpose above set forth.
Dated this 2nd day of October 1893.
NEWTON & SON,
Agents for the Applicant.