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Tenth Instrument.
The Magic Lantern (Laterna Magica) is an instrument that use convex
lenses to create an enlarged image from either, translucent figures
painted on glass or opaque objects. In general it serve the need for
recreation and pastime, and consist of a square box (plate 34,
fig.1) wich can be closed lighttight. In the upper part, rooftop
shaped, a bended tube is mounted to enable the escape of smoke,
originated from the illuminant – placed inside the box.
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plate
34 fig.1 ©
The
Hauchs' physiske cabinet in Denmark
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In the frontside a tube (HI) is attached made of
several parts that can move in and outside each
other by the aid of a crank & toothed wheel (K)
connected with the piece of the tube nearest to
the frontside of the box.
A toothed bar grasped by the wheel (k) is attached
to the adjustable farest part of the tube (I).
When turning the crank, either left or right, it
is possible to lengthen or shorten the tube (HI).
Besides, this tube got near L a square shaped
widen part, open at both ends, to shove in various
pieces of glass depicting objects painted with
translucent colors. Prior to this place one find,
inside the fixed part of this tube, a convex glass
(M) as seen in the profile of the tube depicted in
plate 34 fig.2.
In the farest part of the tube (I) there is as
well a convex glass (N), placed in such a way that
the glass N is always situated in the focus range
of the glass M; even when the tube is at his
maximum length.
So, both convex glasses are working as one single
lens with changeable focal distance according to
the length (shorter or longer) of the tube.
Besides, inside the box an Argandlamp is placed
provided with a concave mirror, parabolical
polisched.
Such a mirror reflects all rays, leaving the focal
point, parallel with the axle of the parabole.
Click image to see more fantascope
prints |
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The positioning of the lamp need to be donne in such a way
that the flame is situated in the axle of the tube HI.
This lamp is a very important accessorie because it’s
neccassary to illuminate the drawnings and objects as strong
as possible. For this reason a transsection of the lamp is
illustrated in plate 35 fig.2. One places the lamp in the
above described way inside the box and close the door. In the
square opening near L a piece of glass is slipped-in, for
example depicting a man but the background filled up by using
opaque black paint - in such a way that his head is downwards
and his legs upwards.
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In this case the lamp will send parrallel rays
through the tube HI - according to the previous
explained property of the parabolic mirror - wich
cause a strong illumination on the figure placed
in the opening F.
These rays will now go through the glasses M&N and
cause a refraction of light in such a way that a
reversed image of the upside down placed figure is
created, thus an upright image will arise
sommewhere in the extension of the axle after
going through the tube.
This (upright) image is situated nearer or further
away the instrument according to the position of
the tube I, in or outside H. (variable length)
This will bring the figure / object nearer or
further away the focus of the glasses |
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plate
34 fig.2 ©
The
Hauchs' physiske cabinet in Denmark
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plate
35 fig.2 ©
The
Hauchs' physiske cabinet in Denmark
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When a screen is placed on the spot where the
image is build up, the figure will appear
there-upon in the same colours as seen on the
painted glass but much bigger - depending on the
distance of the image to the instrument. The
bigger this distance The bigger the image will be.
Because the illumination of the image is
diminishing due to the increase of the distance
quadrates, one will understand that the enlarging
possibilitys of the image is limited between well
defined boundaries.
(Plate 34)-When some parts of the figure are made
movable and connected with each other in a
suitable way with the aid of steel-wire, it
becomes possible to change the position of the
figure placed in the instrument. This will give
the performance a more lifelike character.
Fig.4&5 (plate 34) are depicting two suchlike
designed figures. When pin T is shoven, to and
fro, the characters in fig.4 will rock and the man
depicted in fig.5 will move his arms.
Because the enlargement of the image depends on
the distance to the instrument, one will
understand, one can- by use of the instrument –
which has the purpose, as seen in the illustration
is equipped of 4 wheels- can be pushed nearer or
further away the screen – the image will be
enlarged or diminished in size when simultaneously
the position of the glasses is changed to give the
image constantly the same clearness (sharpness).
If the image is received, instead of a white
opaque, on special prepared translucent exquisite
muslin (as seen in fig.3) these kinds of
performances are known by the name
Phantasmagorie.
Because the image, when the instrument is moved
for and backwards, is diminishing in size or
growing, the onlooker (observer) situated on the
other side of the screen, will experience this as
if the objects (figure) are approaching or moving
away.
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It is however
important to emphasise that the image, when reducing
in size, will gain more brightness although it
should normally loose clarity when situated further
away. The latter effect (loose of clarity) is
obtainable when a frame is mounted in front of
the tube I. In this frame a moveable strip of
glass is placed showing increasing opaque qualities
from one side to the other. (This create the
same effect as the better known cat-eye, |
Obviously
the theme of Ghosts is also most popular among children
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When this kind of phantasmagoria performances are
intended for (such as theatre performance) public
performance, all the three movements need to be
done very accurate and at the same time.
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Movement of the carriage,
for and backwards.
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Movement of the tubes in and
out. (Focusing).
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Movement of the glass-strip
- in front of I
{with changing
(increasing or decreasing) opaque qualities}
To do so, a special designed machinery is
connected and synchronised with the glasses
(lenses) to move the latter in a correct way
depending what direction the carriage is being
pushed
Translucent figures painted on glass are not the
only kind of images that can be showed enlarged
with the aid of a Magic Lantern.
Opaque objects can be persuaded in such a way to
depict themselves in the in the same manner. The
following instrument introduces a Magic Lantern
modified for this purpose. |
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plate
35 fig.3 ©
The
Hauchs' physiske cabinet in Denmark
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