IMPROVEMENTS IN MAGIC LANTERNS
Year: 1879

page_text: LETTERS PATENT to Henri Lefèvre, of Paris, 110, Avenue de Villiers,
Engineer, for the Invention of "IMPROVEMENTS IN MAGIC LANTERNS."
PROVISIONAL SPECIFICATION left by the said Henri Lefèvre at the Office
of the Commissioners of Patents on the 5th April 1879.
HENRI LEFEVRE, of Paris, 110, Avenue de Villiers, Engineer.
MENTS IN MAGIC LANTERNS."
"IMPROVE-
My Invention relates to improvements in magic lanterns, and is carried into
practice as follows, that is to say :-
I provide an opaque box or case the lower and upper faces of which are provided
with orifices which allow it to be placed upon two lamps of any kind, the globe-
holders of which are of the same height. The dimensions of the said box or case
and the arrangements of the orifices allow this apparatus to be applied to all lamps
whatever may be the height of the wick above the globe-holder and the dimensions
or shapes of the lamp glasses themselves. In the interior of the said box a system
of reflectors throws the light of the two lamps upon the posterior wall of the
apparatus, where may be placed the opaque objects or pictures, which are thus
greatly illuminated. The anterior wall bears in front of the illuminated object &
system of converging lenses projecting upon an exterior screen the image more or
less enlarged of the illuminated object.
The same apparatus may be adapted to be used as a magic lantern or a lampa-
scope in the following manner:-
The opaque object is replaced by a system of reflecting mirrors which throw the
light (direct or reflected) of the lamps in the direction of the orifice of the anterior
wall. At this orifice the optical device of the magic lantern is fitted with its groove
for the transparent images. By means of my apparatus and of its two transforma-
tions images or pictures blackened or colored, opaque or transparent, the effects of
the phenakistoscope and of the kaleidoscope, moving images are projected more or
less enlarged upon the exterior screen.
I adopt by preference two arrangements the principal difference of which consists
only in the nature of the materials employed and their exterior form. One of these

page_text: is the ordinary apparatus, generally made in cardboard; the second is richer and of
more solid construction, and preferably made of metal.
The ordinary apparatus made in cardboard is composed of an elongated box
having a portion of its walls inclined on both sides and at each end at an angle of
45 degrees; it is placed upon the globe-holders of two lamps of any kind regulated to
the same light. The luminous rays emitted by these lamps are reflected by mirrors of
an elliptic, parabolic, or other form placed upon two of the inclined faces of the wall
of the box to the opaque body which it is necessary to illuminate in order to
enlarge the image. By reason of the arrangement of the object glass the image of
the object is shewn enlarged upon a white screen arranged upon the wall opposite.
The object glass is solely formed of a convexo-convex lens arranged at the forward
part of a tube which slides frictionally in another tube upon a plate which is placed
in a groove provided in a piece on the box or case. Upon the face opposite to that
of the object glass is a sliding frame; another groove serves to receive a black screen
which prevents the luminous rays from passing outside; the opaque object to be
illuminated is introduced into another groove.
In order to convert the apparatus into a magic latern there is arranged in the
said black screen groove a mirror formed of two plane surfaces inclined at 22° 5 to
the plate which supports them. The luminous rays are then thrown by the first
named mirrors upon the last named mirrors, and the latter reflect them upon the
transparent image in the groove of the frame which carries the object glass. In
order to put into position the image projected upon the screen it is only necessary
to push forward or backward the aforesaid sliding tube of the lens within the tube
in which it slides.
The luminous focus of the lamps is generally from 7 to 8 centimetres above the
globe holder; therefore I give to my apparatus a height of 15 centimetres, so that
the centres of the reflectors and of the object glass are 7 centimetres from one base
and 8 centimetres from the other base, therefore according to the height of the wick
of the lamps employed the apparatus may be placed upon one or the other of these
bases in such manner that this luminous focus is always sensibly within the optical
axis of the reflectors.
In order to prevent the deposit of vapor on the lens when the apparatus is placed
upon the lamps, I provide a certain space between the box or case and the aforesaid
plate of the lunette with the object of directing a current of air which carries off the
vapours which might be condensed upon this lens; in case of need air-holes are
made in the pipe which carries the lens. The grooves allow currents of air to cir-
culate, which cool the images and the apparatus; the durability of the latter is.
thus assured whatever may be the material of which it is made. The chimneys
with metal cowls assure the draught of air and the ventilation of the interior of the
apparatus.
In order to prevent the oxidation of the reflectors when the apparatus is not
being used the apertures of the box may be closed. At the back is the screen;
in the front the object glass is turned round, and it is held by a plate in one of the
grooves. Finally, the cowls. of the chimneys having been withdrawn the latter on
being turned back close two by two the four apertures of the upper and lower
bases.
When the said apparatus is made in metal it is constructed as follows, that is to
say, it is of an elliptical form, and at the back is a moveable frame in which there
are grooves to receive the opaque object to be projected. Movable cheeks are pro-
vided to prevent the light from passing out; all the apertures are closed by means
of small hinged doors. The first named reflectors can slide vertically into the box
or case by means of rods which project outside. The apparatus constructed as last
described cannot be used as a magic lantern, but it will be understood that according
to the principles previously explained it can be adapted for this purpose.
It will be seen that in my apparatus I dispense with the costly half sphere of
the ordinary magic lanterns. I can also considerably reduce the size of the
apparatus.

page_text: When the opaque object to be illuminated is small I arrange, in the direction of
the rays reflected by the mirrors, converging lenses which concentrate these rays in
a very small focus and strongly illuminate it. The converging lenses project the
image of the object.
In order to enlarge transparent objects a two-faced mirror is provided, and the
lens is turned round in its sheath.
For large apparatuses some modifications may be necessary, which will be readily
understood.
With spherical reflectors a great part of the light is lost at the base of the flame.
I employ parabolic reflectors of a very small focus; upon the edges the curvature is
not parabolic, and it is mixed and studded with points in such manner that the rays
are reflected to the illuminated centre. In this case it will be necessary to cut the
reflector in order to place therein the lamp. An additional support is also required
which can be made to rise or fall at will by turning a nut.
The apparatus in some of these forms when closed may in the daytime be
employed as dark chambers, suitable for photographic purposes. If it is desired to
enlarge objects of small dimensions, a triangular form is given to the apparatus and
the luminous rays are concentrated upon the object by means of two converging
lenses. The object glass with a short focus projects the image outside.
may arrange my apparatus so as to put in movement turning pieces by means
of rods traversing the apparatus and not requiring the complicated, heavy, and
costly gearing of the usual phantasmagoria.

page_text: the centres of the reflectors, and of the object glass are 7 centimetres from one base,
and 8 centimetres from the other base; and according to the height of the lamp-
wicks the apparatus may be placed upon one or the other of these bases in such
manner that the luminous focus is always very perceptibly within the optical axis
5 of the reflectors.
To prevent the deposit of vapour on the lens when the apparatus is placed upon
the lamps I provide a space between the box A and the plate d, with the object of
directing a current of air which carries off any vapours that might be condensed
upon this lens; in case of need air-holes are made in the pipe which carries the
said lens.
The grooves permit the circulation of currents of air, which cool the objects or
images and the apparatus, the durability of the latter is thus ensured whatever
may be the material of which it is formed. The chimneys with metal, cowls
ensure the draught of air, and the ventilation of the interior of the apparatus.
To prevent the oxidation of the reflectors when the apparatus is not being used
the apertures of the box may be closed; the back is provided with the screen, and
at the front the object glass is turned round, and it is held by a plate fitted in the
groove c; finally, the cowls of the chimneys having been withdrawn the latter are
turned back, and close two by two the four apertures of the upper and lower bases.
The reflectors m are held in position by screws v, and pressure is exerted upon the
said reflectors by the springs r. The said screws may be adjusted vertically in the
slots u to permit the position of the reflectors to be regulated.
Figures 5 and 6 represent in side view and in plan the said apparatus constructed
of metal; it is of an elliptical form, and at the back is provided with a moveable
frame i, in which there are grooves to receive the opaque object to be projected;
moveable cheeks are provided to prevent the passing out of the light behind, all
of the apertures are closed by small hinged doors. The reflectors m can be slid
vertically into the box or case A by means of rods k which project outside. The
apparatus constructed as last described cannot be used as an ordinary magic lantern
for projecting transparent images, but it will be understood that as above explained
it can be changed to adapt it for this purpose.
It will be seen that in the above described apparatus I dispense with the costly
half sphere heretofore used in the ordinary magic lanterns; I also considerably
reduce the size of the apparatus.
When an opaque object to be illuminated is small I arrange in the direction of
the rays reflected by the mirrors converging lenses D (see Figure 7), which con-
centrate these rays in a very small focus, and strongly illuminate it. The
converging lenses and l' project the image of the object.
For enlarging transparent objects the double faced mirror g is provided, and the
lens is turned round in its sheath.
For large apparatus I adopt the arrangement shewn in horizontal and vertical
section in Figures 8 and 9. With the spherical reflectors a great part of the light
is lost at the base of the frame. I employ parabolic reflectors m with a very short
focus; upon the edges the curvature is not parabolic; it is formed and arranged in
such manner that the rays are reflected to the illuminated centre C. In this case
it will be necessary to cut away the reflector in order to place the lamp therein.
On the other hand the latter has an additional support which can be made to rise
or fall at will by turning a nut or other suitable device.
When the apparatus represented in Figures 1 to 6 are closed they may in the
day time be utilized as dark chambers suitable for photographic purposes. If it is
desired to enlarge objects of small dimensions a triangular form is given to the
apparatus, as shewn in Figure 10, and the luminous rays are concentrated upon the
object by means of two converging lenses t. The object glass with a short focus
projects the image outside.
I may arrange my apparatus to put in motion turning pieces by means of rods
traversing the said apparatus, and not requiring the complicated, heavy, and costly
gearing of the ordinary phantasmagoria.

page_text: The aforesaid apparatus may be constructed of any desired dimensions, and of
pasteboard, wood, metal, or other suitable materials.
Having thus fully described my said Invention, and the manner of performing
the same, I wish it understood that I claim,―
The improved apparatus herein termed a "lampadorama," the construction of
which is varied as described, according to the nature and dimensions of the object
to be illuminated, magnified, and projected thereby, and which apparatus will
serve to project either opaque or transparent images, substantially as above set
forth.
In witness whereof, I, the said Henri Lefèvre, have hereunto set my hand
and seal, this Eighth day of August, in the year of our Lord One thousand
eight hundred and seventy-nine.
HENRY LEFÈVRE. (L.S.)
JULES ARMENGAUD, Jeune,
"
of Paris,
Witness.
Boulevard de Strasburg, 23,
Civil Engineer.