Improvements in Bi-unial or Dissolving-view Lanterns.
Year: 1889

page_text: Date of Application, 11th Dec., 1889
Complete Specification Left, 31st July, 1890-Accepted, 6th Sept., 1890
PROVISIONAL SPECIFICATION.
Improvements in Bi-unial or Dissolving-view Lanterns.
I, HENRY BOND of 126 Wilderspool Road, Warrington, Newspaper Manager do
hereby declare the nature of this invention to be as follows:-
My invention consists of a device for utilising the light derived from an oil lamp, or
other suitable illuminant, in two directions, in such a manner as to produce and.con-
verge upon the screen, two independent and simultaneous discs or fields of view from
one light.
The rays utilised are those shining in the directions right and left of the operator
standing behind the illuminant and facing the screen.
Condensers are placed on each side of the illuminant with their edges towards
the screen, their axes corresponding with the two lines of light from the central
source.
The slides or transparencies to be thrown upon the screen intervene in front of
the condensers in the usual way.
Images of the slides are reflected to the objective lenses (placed with their axes
at right angles and in a horizontal plane with the axes of the condensers) by
plano-mirrors or specula placed vertically between the slides and the objective
lenses and fixed in regard to the axes of those lenses and of the condensers at an
angle of 15 degrees.
Means for bringing the two discs of light together, at varying distances of the
lantern from the screen, are provided by the movement of one or both optical
systems independently on a common pivot under the illuminant, the axis of which
pivot lies in a vertical line drawn through the centre of the illuminant.
An alternative method is to preserve the condensers in a fixed position in regard to
the source of light, and to adjust one or both mirrors and their associated objectives on
separate centres or pivots with vertical axes, which axes lie in the planes of the
reflecting surfaces and cut the horizontal axes of the condensers.
1000
COMPLETE SPECIFICATION.
Improvements in Bi-unial or Dissolving-view Lanterns.
1, HENRY BOND of 126 Wilderspool Road, Warrington in the County of Lancaster,
Newspaper Manager & Cashier 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 that class of appliances known as bi-unial or dissolving-
view lanterns. Its object is the construction and arrangement of a lantern in
which the light proceeding from the oil lamp or other suitable illuminant is
utilised in two directions in such a manner that there are produced upon the
screen, from the one light, two independent and coincident discs or fields of view.
The rays utilised are, by preference, those which proceed in directions to the right
and left of the operator who stands behind the illuminant and faces the screen.
The invention may be described by reference to the accompanying drawing, in

page_text: A is the lamp case having a chimney a and glazed sides a¹ only one of the latter
being shown. B are the wicks or other suitable illuminating device.
A condenser is located at each side of the lamp case opposite its glazed sides, the
edges of the condensers 'facing towards the screen and their axes passing through the
central source of light within the lamp.
The slides or transparencies are located as usual opposite to the condensers as at D,
but they are inserted from the rear of the lantern instead of from the sides, as has
generally been the case heretofore.
The objective lenses E, which may be of any ordinary construction, are placed
with their axes at right angles to, and in the same horizontal plane as, the axes of
their respective condensers C.
The light passing through each condenser and its adjacent slide is reflected to the
corresponding objective lenses E by a fixed plain mirror or speculum F, which is
placed vertically between the slide and lenses, with its reflecting surface inclined at
an angle of 45 degrees to the axes of the objective lenses and of the condenser. A.
reflecting prism with an angle of 45 degrees can be used instead of a mirror, if
desired.
In order to enable the operator to superpose the two discs of light upon the screen
at varying distances of the lantern therefrom, I mount each optical system, consisting
of the condenser C, mirror F and objective lenses E, upon a separate frame G, the
said frames being capable of movement about a vertical pivot g, Figure 2, located
directly below the centre of the illuminant. Each frame G may be adjusted inde-
pendently of the other and may be securely held in position by a binding screw g'.
The casing H surrounding each condenser is provided with a suitable device. such as
the curved flanges h h', whereby the light is prevented from escaping between the end
of the condenser and the adjacent glazed side of the lamp, while at the same time, the
optical system is allowed perfect freedom of movement.
As an alternative arrangement, 1 may make the condenser C to have a fixed position
- that is, to be non-adjustable-with respect to the source of light B, as illustrated in
Figure 3, and I may mount the mirror F and its associated objectives E in such a
manner that they may be adjusted independently upon a fixed vertical pivot J having
an axis lying in the reflecting plane of the mirror and passing through the point of
intersection of the axes cand e of the condenser C and objectives E respectively. As
in the arrangement shown in Figure 2, the surface of the mirror must be at right
angles with a line bisecting the angle d formed between the axes e and e. In making
the adjustment, it will be found that the mirror must be turned through exactly one
half the angle through which the objectives have to be moved.
When the lantern is provided with a "dissolving" device, the latter may consist of
the well-known comb-shaped plates M whose form (in elevation) is shown in dotted
lines in Figure 2. These plates are carried by a rod M¹ which is capable of sliding
longitudinally within brackets M² mounted upon the forward ends of the lens
tubes E¹.
The plates hang down a little in advance of the tubes E¹, with the points of their
teeth m facing in opposite directions. The plates are placed at such a distance apart
that, as the teeth of one plate are drawn, points foremost, over the adjacent lens to
gradually shut off the light issuing therefrom, the teeth of the other plate are with-
drawn, roots foremost, from the corresponding lens, so that the light is, in a similar
manner, permitted to issue therefrom with a gradually increasing intensity. The
"dissolving" effect is thus produced on the screen. The rod M may be made
telescopic between the plates M, so that the latter may be readily adjusted in their
distance apart.
By my invention, the operator is enabled to manipulate the lantern entirely from
the rear of the instrument, and at the same time to have a full view of the screen.
The slides are inserted at D, the foci of the objective lenses are adjusted at e, and the
light regulated at K and inspected through the windows k, which are provided with
sliding shutters . The two optical systems may be adjusted at g¹ and the dissolving
device actuated by a button M. The lamp casing is mounted in slides L, and it may

page_text: be drawn out bodily from the lantern by simply depressing the spring catch L', and
turning back the curved flanges h¹ which are, for this purpose, hinged to their casing,
as shown in Figure 2.
Instead of adjusting the wicks B by the milled buttons K located at the side of the
lamp, they may be adjusted by similar buttons placed at the rear of the lamp and
connected, by cross shafts and small bevel wheels, with the wick-adjusting shafts K'.
It will be obvious that the two optical systems above mentioned need not necessarily
be arranged in a horizontal plane. They may be arranged in a plane lying at any
suitable angle to the horizontal, or they may even, in some cases, be placed vertically
one above the other with the source of light (as for instance an incandescent electric
light) intermediate thereto.
It is not absolutely necessary that both optical systems should be adjustable. I
prefer, however, to have them both adjustable, as the lantern is thereby rendered more
symmetrical, and its adjustment with respect to the screen may be made rather more
readily.
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. A bi-unial or dissolving-view lantern, having a pair of light condensers located
one at each side of a common source of light with their axes passing through the
same, two sets of objective lenses having their axes intersecting those of their respec-
tive condensers, two reflectors each located at the point of intersection of the axes of
its condenser and lenses and adapted to reflect the light forward through.said lenses,
and means for adjusting some or all of the above parts in such manner that two
coincident discs of light may be thrown upon the screen at varying distances of the
lantern therefrom, substantially as described.
2. In a bi-unial or dissolving-view lantern, provided with two sets of objective
lenses having axes that can be made to converge, a pair of plain mirrors so arranged
one on each side of a common source of light that the lateral rays therefrom are
reflected forward through said lenses, substantially as described.
3. A bi-unial or dissolving-view lantern, in which two optical systems such as
described are arranged one on each side of a common, source of light and are mounted
upon suitable frames, one or both of which is or are adjustable about an axis passing
through such source and perpendicular to the axial plane of said systems, substantially
as and for the purpose described.
4. The alternative arrangement for adjusting the aforesaid optical systems con-
structed as a whole substantially as described and as illustrated in Figure 3.
5. The improvements in bi-unial or dissolving-view lanterns, taken as a whole
substantially a
as described, whereby the user is enabled to perform all the necessary
operations and adjustments from the rear of the lantern and in full view of the screen.
Dated this 23rd day of July, 1800.
WM. I. THOMPSON & CO.,
Of Liverpool, Manchester, and London, Patent Agents.