APPLICATION OF THE STEREOSCOPE TO PURPOSES OF AMUSEMENT.
Every experiment in science, and every instrument depending on
scientific principles, when employed for the purpose of amusement, must
necessarily be instructive. “Philosophy in sport” never fails to become
“Science in earnest.” The toy which amuses the child will instruct
the sage, and many an eminent discoverer and inventor can trace the
pursuits which immortalize them to some experiment or instrument which
amused them at school. The soap bubble, the kite, the balloon, the
water wheel, the sun-dial, the burning-glass, the magnet, &c., have all
been valuable incentives to the study of the sciences.
In a list of about 150 binocular pictures issued by the London
Stereoscopic Company, under the title of “Miscellaneous Subjects of the
‘Wilkie’ character,” there are many of an amusing kind, in which scenes
in common life are admirably represented. Following out the same idea,
the most interesting scenes in our best comedies and tragedies might
be represented with the same distinctness and relief as if the actors
were on the stage. Events and scenes in ancient and modern history
might be similarly exhibited, and in our day, binocular pictures of
trials, congresses, political, legislative, and religious assemblies,
in which the leading actors were represented, might be provided for the
stereoscope.
For the purpose of amusement, the photographer might carry us even
into the regions of the supernatural. His art, as I have elsewhere
shewn, enables him to give a spiritual appearance to one or more of his
figures, and to exhibit them as “thin air” amid the solid realities of
the stereoscopic picture. While a party is engaged with their whist or
their gossip, a female figure appears in the midst of them with all the
attributes of the supernatural. Her form is transparent, every object
or person beyond her being seen in shadowy but distinct outline. She
may occupy more than one place in the scene, and different portions
of the group might be made to gaze upon one or other of the visions
before them. In order to produce such a scene, the parties which are
to compose the group must have their portraits nearly finished in the
binocular camera, in the attitude which they may be supposed to take,
and with the expression which they may be supposed to assume, if the
vision were real. When the party have nearly sat the proper length
of time, the female figure, suitably attired, walks quickly into the
place assigned her, and after standing a few seconds in the proper
attitude, retires quickly, or takes as quickly, a second or even a
third place in the picture if it is required, in each of which she
remains a few seconds, so that her picture in these different positions
may be taken with sufficient distinctness in the negative photograph.
If this operation has been well performed, all the objects immediately
behind the female figure, having been, previous to her introduction,
impressed upon the negative surface, will be seen through her, and
she will have the appearance of an aerial personage, unlike the other
figures in the picture. This experiment may be varied in many ways.
One body may be placed within another, a chicken, for example, within
an egg, and singular effects produced by combining plane pictures
with solid bodies in the arrangement of the persons and things placed
before the binocular camera. Any individual in a group may appear more
than once in the same picture, either in two or more characters, and
no difficulty will be experienced by the ingenious photographer in
giving to these double or triple portraits, when it is required, the
same appearance as that of the other parties who have not changed their
place. In groups of this kind curious effects might be produced by
placing a second binocular slide between the principal slide and the
eye, and giving it a motion within the stereoscope. The figures upon
it must be delineated photographically upon a plate of glass, through
which the figures on the principal slide are seen, and the secondary
slide must be so close to the other that the figures on both may be
distinctly visible, if distinct vision is required for those which are
to move.
Another method of making solid figures transparent in a photograph
has been referred to in the preceding chapter, and may be employed in
producing amusing combinations. The transparency is, in this case,
produced by using a large lens, the margin of which receives the rays
which issue from bodies, or parts of bodies, situated _behind_ other
bodies, or parts of bodies, whose images are given in the photograph.
The body thus rendered transparent must be less in superficial extent
than the lens, and the body seen through it must be so far behind it
that rays emanating from it would fall upon some part of the lens, the
luminosity of this body on the photograph being proportional to the
part of the surface of the lens upon which the rays fall. This will be
readily understood from Figs. 48 and 49, and their description, and
the ingenious photographer will have no difficulty in producing very
curious effects from this property of large object-glasses.
One of the most interesting applications of the stereoscope is in
combining binocular pictures, constructed like the plane picture, used
in what has been called the _cosmorama_ for exhibiting dissolving
views. These plane pictures are so constructed, that when we view
them by reflected light, as pictures are generally viewed, we see a
particular scene, such as the Chamber of Deputies in its external
aspect; but when we allow no light to fall upon it, but view it by
transmitted light, we see the interior of the building brilliantly
lighted up, and the deputies listening to the debate. In like
manner, the one picture may represent two armies in battle array,
while the other may represent them in action. A cathedral in all its
architectural beauty may be combined with the same building in the act
of being burned to the ground; or a winter scene covered with snow
may be conjoined with a landscape glowing with the warmth and verdure
of summer. In the cosmorama, the reflected light which falls upon
the front of the one picture is obtained by opening a lid similar to
that of the stereoscope, as shewn at CD, Fig. 14, while another lid
opening behind the picture stops any light which might pass through
it, and prevents the second picture from being seen. If, when the
first picture is visible, we gradually open the lid behind it, and
close the lid CD before it, it gradually disappears, or _dissolves_,
and the second picture gradually appears till the first vanishes and
the second occupies its place. A great deal of ingenuity is displayed
by the Parisian artists in the composition of these pictures, and the
exhibition of them, either in small portable instruments held in the
hand, or placed on the table, or on a great scale, to an audience,
by means of the oxygen and hydrogen light, never fails to excite
admiration.
The pictures thus exhibited, though finely executed, have only that
degree of relief which I have called _monocular_, and which depends
on correct shading and perspective; but when the dissolving views are
obtained from binocular pictures, and have all the high relief given
them by their stereoscopic combination, the effect must be singularly
fine.
Very interesting and amusing effects are produced by interchanging
the right and the left eye pictures in the stereoscope. In general,
what was formerly convex is now concave, what was round is hollow, and
what was near is distant. The effect of this interchange is finely
seen in the symmetrical diagrams, consisting of white lines upon black
ground, such as Nos. 1, 5, 9, 12, 18 and 27 of the Parisian set; but
when the diagrams are not symmetrical, that is, when the one half is
not the reflected image of the other, such as Nos. 26, &c., which are
transparent polygonal solids, formed as it were by white threads or
wires, no effect, beyond a slight fluttering, is perceived. As the
right and left eye pictures are inseparable when on glass or silver
plate, the experiments must be made by cutting in two the slides on
Bristol board. This, however, is unnecessary when we have the power
of uniting the two pictures by the convergency of the optic axes to
a nearer point, as we obtain, in this case, the same effect as if we
had interchanged the pictures. The following are some of the results
obtained in this manner from well-known slides:—
In single portraits no effect is produced by the interchange of the
right and left eye pictures. If any loose part of the dress is in the
foreground it may be carried into the distance, and _vice versa_. In
one portrait, the end of the hat-band, which hung down loosely behind
the party, was made to hang in front of it.
In pictures of streets or valleys, and other objects in which the
foreground is connected with the middle-ground, and the middle-ground
with the distance, without any break, no effect is produced by the
interchange. Sometimes there is a little bulging out of the middle
distance, injurious to the monocular effect.
In the binocular picture of the Bridge of Handeck, the Chalet in the
foreground retires, and the middle distance above it advances.
In the picture of the sacristy of Notre Dame, the sacristy retires
within the cathedral.
In the Maison des Chapiteaux at Pompeii, the picture is completely
inverted, the objects in the distance coming into the foreground.
In the Daguerreotype of the Crystal Palace, the water in the
foreground, with the floating plants, retires and takes an inclined
position below a horizontal plane.
In the binocular picture of the lower glacier of Rosenlaui, the roof of
the ice-cave becomes hollow, and the whole foreground is thrown into a
disordered perspective.
In Copeland’s Venus, the arm holding the bunch of grapes is curiously
bent and thrown behind the head, while the left arm advances before the
child.
In the picture of the Greek Court in the Crystal Palace, the wall
behind the statues and columns advances in front of them.
The singular fallacy in vision which thus takes place is best seen in
a picture where a number of separate articles are placed upon a table,
and in other cases where the judgment of the spectator is not called
upon to resist the optical effect. Although the nose of the human face
should retire behind the ears yet no such effect is produced, as all
the features of the face are connected with each other, but if the nose
and ears had been represented separately in the position which they
occupy in the human head, the nearer features would have retired behind
the more remote ones, like the separate articles on a table.
We shall have occasion to resume this subject in our concluding chapter
on the fallacies which take place in viewing solids, whether raised or
hollow, and whether seen by direct or inverted vision.