HF The History of Photography 600pág

The photography of movement 445
Some of Wheatstone's electrical demonstrations proved very popular at the Adelaide
Gallery, but by the time FOX TALBOT applied photography to one of them, they had
apparently been forgotten. This was in June l 85 l at the Royal Institution, London.
Talbot fastened a page of The Times to a wheel which was made to revolve rapidly.
The lights in the lecture room were extinguished, the lens of the camera uncapped,
and an instantaneous exposure was made by the spark from a battery of Leyden jars.
The brilliant flash produced by such a discharge lasts for only 1 00 1 ,000 second or less.
The plate was developed on the spot and showed a clear readable image of the printed
page. The audience was greatly impressed. Everyone imagined that the success of the
experiment depended on the 'highly exalted sensibility' of the albumen plate which
Talbot used. In reality, albumen was the slowest negative material he could possibly
have chosen. But nobody knew it then, for the albumen process was a French invention
hardly known in England. Talbot disclosed his preparation of the platenot
without first having patented it-together with his 'method of obtaining under
certain circumstances the photographic picture of objects which are in rapid motion'.
Nevertheless he seems to have realized that the success of the experiment depended
on the brightness of the flash. 'From this experiment the conclusion is inevitable',
wrote Talbot, 'that it is in our power to obtain pictures of all moving objects, no
matter in how rapid a motion they may be, provided we have the means of sufficiently
illuminating them with a sudden electric flash.' 3 0
Talbot laid the foundation of an entire branch of scientific photography. Before
the century was out, most of Wheatstone's observations had been recorded by
photography, and some others in addition.
In 1887 PROFESSOR ERNST MACH of Prague University and DR P. SAL CHER, professor
at the naval college at Fiume, succeeded in photographing projectiles moving
at approximately 765 miles an hour, and clearly showing the sound waves accompanying
their passage through the atmosphere. The projectile was shot at a glass tube
containing wires and the contact set off a strong electric spark. 31 Mach's photographs,
which are preserved at the Conservatoire des Arts et Metiers, Paris are no bigger
than pictorial postage-stamps. About the same period Ottomar Anschutz took at the
Krupp artillery range near Essen photographs of proj ectiles in flight, the shutters of
the camera being electrically operated by the projectiles as they passed through an
electric circuit. The speed of the projectiles is not known.
PROFESSOR c. v. BOYS, F.R.S., of the Royal College of Science, London, in 1892
extended Mach's experiments with proj ectiles flying at about twice the speed.32 An
interesting sequence of photographs was taken of a bullet piercing a sheet of plateglass.
One photograph showed the bullet just entering the glass plate, throwing a
cloud of glass dust backwards; another was taken after the bullet had passed 5 in.
beyond it, and showed the bullet covered with a thick layer of glass dust. A third
photograph taken after the missile had passed l 5 in. beyond the glass plate showed
the bullet quite clear of. the glass dust, but one large splinter close to it is seen to be
causing air waves on its own account. The remarkable ballistic photographs exhibited
by Professor HUBERT SCHARDlN at the World Exhibition of Photography in
Lucerne, 1952, show the technical advance that has been made in the twentieth
century. It is now possible to take camera photographs of bullets in flight, whereas
Mach and Boys only recorded the shadows of a bullet and sound waves cast by an
electric spark on a photographic plate.
The pioneer work in splash photography of LORD RA YLElGH, F.R.S., PROFESSOR A.
M. WORTHINGTON, F.R.S., and THEODORE LULLIN also seems forgotten, and the credit Pl 254
in this field is given to HAROLD E. EDGERTON and KENNETH J. GERMESHAUSEN of the