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Page 2
The next step leads us much further. In the fall of 1832 Stampfer in
Germany and Plateau in France, independent of each other, at the same
time designed a device by which pictures of objects in various phases of
movement give the impression of continued motion. Both secured the
effect by cutting fine slits in a black disk in the direction of the
radius. When the disk is revolved around its center, these slits pass
the eye of the observer. If he holds it before a mirror and on the rear
side of the disk pictures are drawn corresponding to the various slits,
the eye will see one picture after another in rapid succession at the
same place. If these little pictures give us the various stages of a
movement, for instance a wheel with its spokes in different positions,
the whole series of impressions will be combined into the perception of
a revolving wheel. Stampfer called them the stroboscopic disks, Plateau
the phenakistoscope. The smaller the slits, the sharper the pictures.
Uchatius in Vienna constructed an apparatus as early as 1853 to throw
these pictures of the stroboscopic disks on the wall. Horner followed
with the daedaleum, in which the disk was replaced by a hollow cylinder
which had the pictures on the inside and holes to watch them from
without while the cylinder was in rotation. From this was developed the
popular toy which as the zo�trope or bioscope became familiar
everywhere. It was a revolving black cylinder with vertical slits, on
the inside of which paper strips with pictures of moving objects in
successive phases were placed. The clowns sprang through the hoop and
repeated this whole movement with every new revolution of the cylinder.
In more complex instruments three sets of slits were arranged above one
another. One set corresponded exactly to the distances of the pictures
and the result was that the moving object appeared to remain on the
same spot. The second brought the slits nearer together; then the
pictures necessarily produced an effect as if the man were really moving
forward while he performed his tricks. In the third set the slits were
further distant from one another than the pictures, and the result was
that the picture moved backward.
The scientific principle which controls the moving picture world of
today was established with these early devices. Isolated pictures
presented to the eye in rapid succession but separated by interruptions
are perceived not as single impressions of different positions, but as a
continuous movement. But the pictures of movements used so far were
drawn by the pen of the artist. Life showed to him everywhere continuous
movements; his imagination had to resolve them into various
instantaneous positions. He drew the horse race for the zo�trope, but
while the horses moved forward, nobody was able to say whether the
various pictures of their legs really corresponded to the stages of the
actual movements. Thus a true development of the stroboscopic effects
appeared dependent upon the fixation of the successive stages. This was
secured in the early seventies, but to make this progress possible the
whole wonderful unfolding of the photographer's art was needed, from the
early daguerreotype, which presupposed hours of exposure, to the
instantaneous photograph which fixes the picture of the outer world in a
small fraction of a second. We are not concerned here with this
technical advance, with the perfection of the sensitive surface of the
photographic plate. In 1872 the photographer's camera had reached a
stage at which it was possible to take snapshot pictures. But this alone
would not have allowed the photographing of a real movement with one
camera, as the plates could not have been exchanged quickly enough to
catch the various phases of a short motion.
Here the work of Muybridge sets in. He had a black horse trot or gallop
or walk before a white wall, passing twenty-four cameras. On the path of
the horse were twenty-four threads which the horse broke one after
another and each one released the spring which opened the shutter of an
instrument. The movement of the horse was thus analyzed into twenty-four
pictures of successive phases; and for the first time the human eye saw
the actual positions of a horse's legs during the gallop or trot. It is
not surprising that these pictures of Muybridge interested the French
painters when he came to Paris, but fascinated still more the great
student of animal movements, the physiologist Marey. He had contributed
to science many an intricate apparatus for the registration of movement
processes. "Marey's tambour" is still the most useful instrument in
every physiological and psychological laboratory, whenever slight
delicate movements are to be recorded. The movement of a bird's wings
interested him especially, and at his suggestion Muybridge turned to the
study of the flight of birds. Flying pigeons were photographed in
different positions, each picture taken in a five-hundredth part of a
second.
But Marey himself improved the method. He made use of an idea which the
astronomer Jannsen had applied to the photographing of astronomical
processes. Jannsen photographed, for instance, the transit of the planet
Venus across the sun in December, 1874, on a circular sensitized plate
which revolved in the camera. The plate moved forward a few degrees
every minute. There was room in this way to have eighteen pictures of
different phases of the transit on the marginal part of the one plate.
Marey constructed the apparatus for the revolving disk so that the
intervals instead of a full minute became only one-twelfth of a second.
On the one revolving disk twenty-five views of the bird in motion could
be taken. This brings us to the time of the early eighties. Marey
remained indefatigable in improving the means for quick successive
snapshots with the same camera. Human beings were photographed by him in
white clothes on a black background. When ten pictures were taken in a
second the subtlest motions in their jumping or running could be
disentangled. The leading aim was still decidedly a scientific
understanding of the motions, and the combination of the pictures into a
unified impression of movement was not the purpose. Least of all was
mere amusement intended.
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