Year: 1897

page_text: ALFRED SWEETSER, "Garwood," Rosendale Road, Herne Hill, in the County of
Surrey, Consulting Engineer, do hereby declare the nature of this invention to be
as follows:
This invention more especially relates to optical lanterns in which lime light
illuminant is used.
In carrying out my invention I make the base of the lantern preferably of
metal, hollow, and packed with some absorbent material, so that when charged
with some light hydrocarbon, the same forms a carburetter, or saturator, for the
hydrogen supply of the lime light. This base is fitted with two pillars, which are
utilised as valves for the supply of gases to the lime light jet, and to carry joints
for elevating or depressing the optical portion of the lantern. These joints are
fitted with one or more longitudinally sliding arms, carrying the objective, con-
denser, jet, and draws, or screen to blind the rays of light. By these means there
is no necessity to tilt the base of the lantern for registering the disc on screen,
only the arms carrying the objective, condenser, and jet move, so the optical axis
is always on one plane whatever position the arms may occupy. The aforesaid
arms can be lengthened by spare pieces to fit or screw in the ends. The longi-
tudinal movement of arms is for roughly focussing, and they can be fitted with rack
and pinion or screw for fine adjustment instead of being on the objective. The
draws are supported by the arms, so there is no necessity for their fitting tightly
into each other to prevent drooping; or a casing formed of a spiral wire covered
with opaque material could be used in their stead. I dispense with the usual box
body of the lantern by merely blinding the rays of light from the illuminant to
the condenser by draws in the same manner as the rays are blinded from the
condenser to the objective as hereinbefore described. By these means the products
of combustion from the illuminant can escape freely without the vapour condensing
on the condensing lens.
The cramp for holding the lantern slides in position is formed of one or more
loose sleeves, and preferably spiral springs working on the aforesaid arms, fitted
with suitable upright pieces to transmit the pressure from the springs to the lantern
slides.
I dispense with the usual long tubular arms of the jet,' and so shape the mixing
chamber that it forms a pillar upon which is mounted a casing of fire clay, or other
refractory material, in which the lime is placed. The side of this casing is pierced
to allow the flame from the nozzle and the rays of light to pass, but instead of
bending the tube conveying the mixed gases, so that the flame strikes the lime at
an angle from the outside, I sometimes convey this tube direct to the inside of the
fire clay casing, and sometimes keep the tube perpendicular and incline the lime.
Attached to the jet is a plug forming a three way dissolver or cut-off, the cross
handles of which are made hollow and are utilised for the inlets of the gases by
being connected by flexible tubes to the aforesaid valves on the base of the lantern.

page_text: Instead of, or in combination with gauze wire in the mixing chamber to diffuse
the gases, I sometimes employ discs of lint, pads of cotton wool, or asbestos. I
sometimes make the bore of the nozzle oblong in cross section, preventing excessive
pitting of the lime, so dispensing with any lime turning appliance, and the lime
can be of a more simple shape without any pin hole.
The foregoing only describes a single lantern, but by lengthening the pillars on
base, one or two more lanterns can be threaded on, so forming a bi-unial or triple.
Dated th: 09-1 1
T1 1002
Improvements in or relating to Optical Lanterns.
I, ALFRED SWEETSER, of Garwood, Rosendale Road, Herne Hill, in the County of
Surrey, Consulting Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
.
This invention relates to optical lanterns, and an important feature of the said
invention is the construction whereby the jet, the condenser, and the objective are
carried on one frame which is capable of swinging as on a pivot, so that the
optical and illuminative portion of the lantern can be tilted as a whole, for the
purpose of adjusting the position of the disc on the screen, without necessitating
the tilting of the base of the lantern. When tilting the optical and illuminative
portion of the lantern as above indicated the position of the jet with respect to the
condenser and objective remains unchanged so that the adjustment of these parts
is not deranged by such tilting movement. I mount the objective on tubular arms
which can be moved readily to and fro for focussing purposes independently of the
other portion of the lantern.
Another feature of my invention is the utilization of the base of the lantern as a
carburetter or saturator. For this purpose, the said base is made hollow and is
packed with some absorbent material charged with ether or a suitable hydrocarbon
for carburetting the oxygen gas passed through it, which is a substitute for the
hydrogen in the oxy-hydrogen light.
A further feature of my invention is the provision of a cover or hood made of
fire clay or other refractory material for enclosing the light and so dispensing with
the box body usually provided for that purpose. This hood is mounted on the
mixing chamber of the jet which is suitably shaped to receive it, and by preventing
the radiation of the heat it increases the efficiency of the lime jet.
My invention also includes various other improvements in detail as hereinafter
set forth with reference to the accompanying drawings, in which
Fig. 1 is a side view partly in section,
Fig. 2 is a plan, and
Fig. 3 is a rear end view of my improved lantern.
Fig. 4 is a horizontal section on the line x, x, and
Fig. 5 is a vertical section on the line Y, of Fig. 3 illustrating certain details
hereinafter described.
Like letters of reference denote corresponding parts in the several figures.
A is the base of the lantern made preferably of sheet metal and hollow to permit
of being packed with a suitable absorbent material which is intended to be charged
with ether or a light hydrocarbon to serve the purpose of a saturator. Usually a

page_text: portion only of the base as indicated by the dotted lines a, a Fig. 1 need be utilised
for the saturator. a¹ is the neck through which the absorbent material and the
ether or hydrocarbon are introduced, the same being closed by a cap when the base
charged. In some instances a separate and removable saturator may be enclosed
in the hollow base A. Secured to the base are two pillars B, B which carry the
optical portion of the lantern, the latter being constructed with sleeves C, C that
are threaded on the pillars B, and rest with their rounded lower ends upon the
blocks b, b. For greater strength I pass the blocks b, b down through the base
and secure them to the bottom base plate as well as to the top. The holes in the
sleeves C are not cylindrical but are elongated in one direction at the top and
bottom, or in other words they are coned from the centre towards the ends as
indicated by the dotted lines Fig. 1 so that the sleeves can rock forward and back-
ward on the pillars. Screws c, c¹ are provided to control the rocking movement
and to lock the sleeves in any desired position. The condenser D) is carried by
plates d, d that are secured to the sleeves C, and the objective E is carried by a
plate e which is secured to the forward ends of two tubular arms F, F which can
slide freely through horizontal tubes C¹ carried by the sleeves C. The tubular
arms can be lengthened by additional pieces screwed therein. The objective is
focussed by seizing the rear ends of the tubular arms F and sliding them back-
wards or forwards in the tubes C. I find that the focussing can be done usually
with sufficient accuracy and speed by simply sliding the arms F as indicated, but if
desired a rack and pinion or screw device of the usual kind may be added to
facilitate the final adjustment of the objective. The jet G projects from the front
of a mixing chamber H which is carried by a pair of sleeves H¹ that are constructed
to slide upon the tubes C¹. It will thus be seen that the whole of the optical and
illuminative part of the lantern is carried by the sleeves C which as above stated
are capable of a rocking movement in a vertical plane. By this means the axis of
the lantern can be tilted very conveniently, and the images or discs from two or
more lanterns thereby easily and quickly registered on the screen. Usually the
forward end of the lantern is made heaviest and the tilting is effected by turning
the upper screws c. When the desired adjustment has been effected, the sleeves
are locked by means of the lower screws c¹.
The ends of the tubes C¹ are split longitudinally and are screw-threaded and fitted
with nuts C by which the tightness of the tubular arms can be regulated so as to
control the ease with which the said arms can slide through the tubes. Similarly
the sleeves H¹ are slit and fitted with nuts H2 to control their tightness on the
tubes C¹.
The plate J for cramping the lantern slide-carrier in its place is carried by
sleeves J¹ that can slide freely on the forward ends of the tubes C, their position being
controlled by springs J2 which keep the cramp pressed rearwardly against the slide-
carrier. The space between the plate J and the objective may be left open, or it
may be enclosed by a light frame covered with opaque material, or it may be
enclosed by telescopic tubes K, K¹, K². The tube K is fixed at its rear end
to the plate J, and the tube K² is fixed at its forward end to the plate e that carries
the objective, and the middle tube K' is supported by the other two tubes. These
tubes fit loosely in each other. In case there are more than three such tubes the
middle ones are provided with a plate such as e for supporting them on the
arms F, F.
The oxygen enters by the tube L secured in the block 6 on the right side of the
lantern. A portion of the gas escapes by the passage 7 Fig. 4 and thence by the
flexible tube passes to the mixing chamber H, and the remainder of the gas
passes down the passage b¹, Figs. 1, 4 and 5, in the block b and enters the saturator.
Thence it escapes by a similar passage in the block b at the other side of the
apparatus and is conducted by the flexible tube 2 to the mixing chamber. In its
passage through the saturator this portion of the oxygen takes up the volatile.
hydrocarbon with which the absorbent material therein is saturated and becomes

page_text: charged with the vapour, so that after mixing in the chamber H with the oxygen
entering by the tube it produces the heat suitable for generating the desired
brilliant light. The proportions of oxygen gas passing direct to the mixing
chambers and out of the saturator are regulated by cocks m, m¹ which are provided
to control the respective passages. Instead of connecting the flexible tubes 1', 12
directly to the mixing chamber, I prefer to connect them to the hollow radial
arms n of a plug n which is centered at the rear of the mixing chamber and
communicates with said chamber by suitable passages in their adjoining faces. By
turning or tilting the plug, as indicated by the dotted lines in Fig. 3, the communica
tion with the mixing chamber is cut off, except for a small bye-pass provided to
keep the light in, and full communication is established again on turning the plug
back to its normal position. This device forms a very convenient form of cut-off
or dissolver. The mixing chamber is constructed to receive a fire clay cover or
hood O for enclosing the jet and the lime light illuminant. This cover is per-
forated at O¹ to allow of the escape of the heat and fumes from the jet, and is open
at the front to allow the light to pass to the condenser. P, P are telescopic screens
to confine the light between the condenser and the hood O and thus prevent
diffusion in the room, while at the same time allowing the products of combustion
to escape freely without settling on the condenser lens; a similar screen may be
placed for the same purpose at the back of the fire clay lime cover.
The pillars B are shown broken. They may be extended by suitable pieces (that
screw on and off) to receive two or more lanterns constructed as above described,
and so forming a bi-unial or a triple lantern. The pillars B and their extension
picccs arc made hollow and communicate at their lower ends with the passages in
the blocks b, b, as shown in Fig. 5, and thus serve to convey the gases to the upper
lantern or lanterns.
I sometimes make the bore of the nozzle or jet oblong in cross section, to prevent
excessive pitting of the lime, and thereby dispense with the necessity for a turning
appliance for the lime.
My improved lantern can be used with oxygen and coal gas from bags or
cylinders in the usual way (the saturator in such cases being dispensed with), or
as an oil lantern.
An important advantage possessed by my lantern is that it lends itself very
readily for production by means of press tools, by which it can be made very
cheaply.
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:
1. The optical and illuminative portion of the lantern constructed to tilt as on
a pivot, and arranged to carry the jet, the condenser, and the objective, substantially
as, and for the purpose, specified.
2. The construction of the optical portion of the lantern with sleeves C mounted
on vertical pillars B and so arranged that the sleeves can tilt, substantially as
described, and for the purposes specified.
3. The construction of the lantern with a hollow base, that serves as a saturator,
substantially as described.
4. The blocks b adapted to receive the hollow pillars B which can be extended to
receive two or more lanterns, and constructed with passages and cocks for dividing
the oxygen gas and causing some of it to flow through the saturator, and some to
the lantern or lanterns, substantially as described.
5. The refractory hood for enclosing the light, with or without the telescopic
screens, substantially as described, and for the purposes specified..
6. The radial arms n' arranged as levers to turn the plug n, and as inlets for the
gases, substantially as, and for the purpose, specified.
7. The construction of the loosely fitting telescopic tubes K, K', K2, substantially
as, and for the purpose, specified.

page_text: 8. An optical lantern constructed substantially as described with reference to
the accompanying drawings, and operating as, and for the purposes, specified.
Dated this 22nd day of April 1898.
GEORGE HARRISON,
35, Therapia Road, Honor Oak, London, Agent for the Applicant.