RADIO-CINEMATOGRAPHY: HOW THE X-RAYS ARE USED IN CONJUNCTION WITH THE
MOVING-PICTURE CAMERA
With the perfection of radio-photography it was not surprising that the
cinematograph investigator pressed this new development into service.
It opened up a wide and fascinating field for moving pictures. When the
Röntgen rays were first introduced there was one serious handicap to
photography by their means--the length of the exposure. But the chemist
and the scientist speedily removed this adverse factor, and now X-ray
photographs can be taken instantaneously--60 per minute.
Long before this achievement Radio-photography had been yoked with the
moving pictures. It was a difficult problem, but it was solved. One
scientific inventor stands out prominently in this connection. This
is Monsieur M. J. Carvallo who, during his position as sub-director
and secretary of the Marey Institute, spared no effort to harness
the X-rays to cinematography. Another illustrious worker is Dr. J.
Comandon, who may be said to be the pioneer of the popularisation of
cinematographic science. It was he who first appealed to the public
with films of this character under the auspices of the well-known firm
of Pathé Frères. He has been responsible for the preparation of many
most interesting films. Both of these workers have shown what can be
achieved in this direction, while the fact that they proceed upon
totally different lines adds value to their work. It enables their
followers to decide for themselves which principle is likely to produce
the most satisfactory result in each case.
Strictly speaking, Monsieur Carvallo's methods would appeal more
strongly to the scientific mind, bent upon the discovery of some
abstruse phenomena, and indifferent to the complicated process
involved. The methods of Dr. Comandon, on the other hand, from their
enhanced simplicity, will attract the average worker. This investigator
makes a special point of accomplishing his end in as simple a manner as
possible.
From this it will be judged that radio-cinematography may be expensive
or inexpensive. This is a correct assumption, but the amateur
investigator need not fear that the deeper researches are beyond his
reach. In justice to Monsieur Carvallo, it must be mentioned that his
experiments were undertaken at a time when radio-photography had not
reached its present stage, and therefore he had to contend with certain
difficulties which no longer exist.
[Illustration:
_By courtesy of the Marey Institute._
A WONDERFUL X-RAY FILM MADE BY M. J. CARVALLO.
The process of digestion in the intestine of a frog after its removal
from the body.]
[Illustration:
_By courtesy of the Marey Institute._
MOVING X-RAY PICTURES OF THE DIGESTION OF A FOWL.
These pictures, taken at five per second by M. J. Carvallo, show the
different phases in a complete cycle of the gizzard, which lasts
exactly five seconds.]
Monsieur Carvallo was probably the first worker to attempt to portray
in movement the elusive and peculiar features revealed by the Röntgen
rays. One or two other scientists had dabbled in the art, but their
achievements were not very convincing for the simple reason that they
did not employ chronophotography. Monsieur Carvallo, however, being
fully aware of the valuable work that had been carried out by Dr. E. J.
Marey, saw the true way of applying radiography to cinematography, and
saw that it could not fail to be of scientific value. He embarked upon
a number of illuminating, though tedious, experiments, in the effort to
combine these two branches of photography.
Carvallo's installation was of a most elaborate character, but he
accomplished some marvellous results, the full significance of which
are appreciated only to-day. The complete apparatus he used in his
experiments is shown in Fig. 9. The source of energy was a small
electric motor, capable of making 2,000 revolutions per minute with a
current of only 50 volts. This motor was extremely sensitive, since it
would make 300 revolutions per minute with a current of 10 volts. The
control of the speed was essential to his work, so he elaborated a
simple and ingenious change-speed gear mechanism, which enabled him to
drive the camera at four different speeds without touching the motor.
The gear mechanism was not dissimilar from that adopted upon a larger
scale in automobiles, lathes, and other machinery where the speed has
to be varied according to the character of the work. The direct drive
was transmitted from the motor-shaft to that of the camera mechanism
through a belt and pulleys so as to secure flexibility and immunity
from shocks. The three lower speeds were transmitted through gear
wheels. These sets of wheels were mounted upon two parallel shafts and
worked upon the sliding principle, which was found to be the simplest
and most effective. In order to reduce the noise arising from the
meshing and working of the gears the smaller wheels were made of fibre.
[Illustration: Fig. 9.--The ingenious radio-cinematographic apparatus
devised by Monsieur M. J. Carvallo.
A.A. Film spools. B. Crookes tube. C. Frog being radiographed. D. Coil.
=F=. Film. F. Clock. G. Exposure interrupter. H. Change-speed
gears.]
By this gearing system it was possible to vary the speed of the camera
from 30 revolutions per second to one turn in 15 seconds. When still
slower speeds were desired, upon the one-turn-one-picture principle,
the motor was cut in and cut out intermittently so that the exposure
could be varied from once in 20 seconds to once in an hour or more.
Of course, in those instances where the exposures only needed to be
made at relatively prolonged intervals, the driving motor was started
up intermittently so as to move the shutter at the required moment. A
pendulum clock was introduced into the electrical circuit, together
with a novel relay. The clock-face was provided with a ring around
the dial, with the hour intervals represented by contacts instead of
figures. The clock was fitted with one hand only. One electrical lead
was connected to the contact ring and the other to the pivoted end of
the clock-hand. When the latter came against one of the contacts the
electrical circuit was completed, the motor was set in motion, and the
camera mechanism was given one turn--sufficient to make an exposure
and to jerk the film forward the desired distance through the gate for
the next exposure. Obviously this clock system is capable of variation
as desired. The contacts may be disposed to coincide with intervals of
a second, a minute, an hour, or more between successive exposures. It
was necessary to ensure that the contact was of sufficient duration
to complete the cycle of camera movements, and, on the other hand,
to prevent the motor movement being so prolonged that more than the
requisite exposure and movement of the film would be made. This was
effected by means of a brake, which arrested the movement of the motor
after the exposure had been completed.
[Illustration:
I. II. III.
_By courtesy of the Marey Institute._
RADIO MOVING-PICTURES OF COLD-BLOODED ANIMALS MADE BY M. J.
CARVALLO.
I. The stomach and the intestine of a trout (one exposure every 20
seconds). II. The digestive organs of the frog (one exposure every
2 seconds). III. Lizard digesting its food (one exposure every 90
seconds).]
[Illustration:
1. 2.
_By permission of Pathé Frères._
TWO OF DR. J. COMANDON'S EARLIEST INVESTIGATIONS IN
RADIO-CINEMATOGRAPHY.
1. X-ray moving-pictures of the bending of the knee, showing muscular
movement. 2. X-ray film of the opening of the hand.]
With this seemingly complicated apparatus it was possible to take any
desired number of successive pictures and at any intervals of time with
unerring precision.
For these particular experiments a special film was prepared, for
the pictures produced by the standard camera were not large enough.
Monsieur Carvallo took pictures of a depth of 2-2/5 inches instead
of the usual 3/4 inch. Special arrangements were made also to secure
extreme sensitiveness of the emulsion so that it might be more
susceptible to the action of the X-rays. The disposition of the film
followed special lines, as may be seen by reference to the diagram
(Fig. 9). The Crookes tube, containing the X-rays, was placed beneath
a table provided with an aperture upon which was laid a transparent
medium, such as glass, to support the subject under investigation.
Above this was placed the gate through which the film was moved
intermittently, the sensitized ribbon travelling in a horizontal
direction from one spool to the other. In the early experiments a
Maltese cross movement was incorporated to provide the requisite
intermittent motion to the film, but subsequently a novel claw motion
devised by Monsieur Noguès, the mechanician to the Marey Institute, was
introduced with far better results.
In carrying out the experiments with different live subjects extreme
ingenuity was used in placing and holding the creature so that the
most perfect images might be obtained. Monsieur Carvallo devoted his
energies largely to radio-cinematographing the functions of digestion,
and selected such subjects as fresh-water fish, toads, frogs, lizards,
birds, and mice. Thus he obtained comparative results from five species
of the animal kingdom. The subjects were fed first with a special diet,
comprising a mixture of flour, sugar, peptone, sub-nitrate of bismuth,
and water or milk. The chemical, sub-nitrate of bismuth, was used in
order to give the alimentary canal the necessary opacity to secure
the best results under the Röntgen rays. In the case of the trout the
chemical was injected into the blood.
In order to obtain sharp, clear, and distinct pictures upon the film,
the subject under study had to be fixed in an immovable position. In
the case of a trout a small celluloid envelope was made, fitted at
each end with a small glass tube through which water necessary to the
fish's existence was passed in a continuous stream. This vessel was
only just large enough to contain the fish, so that movement was quite
impossible. The top of the vessel was closed with a sheet of paraffin
paper, which was placed in front of the aperture of the film gate. It
was a very novel and successful means of radio-cinematographing a fish
under natural conditions. The fish themselves appeared to suffer no
ill-effects from the method adopted to keep them alive, a trout in one
instance being kept in this confined position for two consecutive days.
So long as an adequate supply of fresh water was passed through the
celluloid vessel in which it was encased it experienced no trouble in
respiration.
In the case of the toad and frog the subject was kept in a prone
position by attaching thin ribbons to the legs and extending the latter
to their utmost so that the digestive organs might be radiographed
clearly, distinctly, and without difficulty. The lizard, which is very
difficult to photograph, was secured in a similar manner. The birds
likewise were attached by their legs, and had their wings extended so
that the body came directly in the path of the rays. When young birds
were under investigation it was necessary to maintain a circulation of
warm water around their bodies so that the temperature might remain
constant; otherwise the digestive functions might have been disturbed,
thereby invalidating the value of the pictures. In one investigation a
fowl was placed in a plaster cast so as to hold it perfectly still and
steady.
The photographic speed was varied according to the character of the
investigation and the subject. Thus, in recording the digestion in
the stomach and intestine of the trout, an exposure was made every
twenty seconds. In the case of the toad the speed was one in every ten
seconds, while the chicken required one in every five.
One of the most novel experiments which Monsieur Carvallo carried out
in this particular field was to ascertain the extent to which digestion
will continue in the intestine after it is removed from the animal. The
digestive tube of the frog was selected for this novel investigation
and the photographs taken at the rate of one per second illustrate the
fact that the digestive organ will continue its functions long after
its removal from the body.
Since the year 1900 when Monsieur Carvallo carried out his scientific
researches with the Röntgen rays, radiographic science has made great
strides. Researches of this character no longer require elaborate
and expensive apparatus. This has been shown by Dr. J. Comandon, the
well-known French scientist, who, at the laboratories of Messrs. Pathé
Frères, has prepared some magnificent X-ray films in such a manner as
to make them interesting to the average patron of the picture palace.
Dr. Comandon possesses the unique ability of so treating his subject
as to make it appeal to the unscientific mind.
[Illustration: Fig. 10.--Dr. Comandon's radio-cinematographic
apparatus.]
In his system Dr. Comandon does not radio-cinematograph directly in
the manner of Monsieur Carvallo, but has recourse to the fluorescent
screen, thereby obtaining his results much more simply and easily. By
this means, also, he is able to use the standard cinematograph camera
and film without any modifications, the images upon the sensitized
celluloid ribbon being of the normal size. The general arrangement
of the apparatus used by this investigator is shown in the diagram
(Fig. 10). A room is divided by a partition A. On one side is placed
a camera F of the conventional type. On the other is the necessary
electrical apparatus. An aperture B is provided in the partition,
and this space is filled with a fluorescent screen. On one side of
the partition A centrally in regard to the fluorescent screen, and a
little distance therefrom, is placed the Crookes tube C, the subject
under investigation being placed between the tube and the screen.
Consequently, the radiograph is projected upon the fluorescent screen
and this image is then photographed by the camera. At the normal
photographing speed the exposure is about 1/32 second.
The fluorescent screen employed by Dr. Comandon is of the type known
as "reinforced." It is covered with tungstate of calcium, instead
of barium platino-cyanide. With this screen the Röntgen rays are
intensified, or rather are transformed, the luminous radiation being
rendered more actinic and therefore able to act more quickly upon the
emulsion of bromide of silver with which the film is coated. By using
this fluorescent screen the exposure is reduced to about one-tenth of
what would be required were the subject radiographed direct.
The high tension current is supplied from an apparatus of a special
type E with which a current as high as 100,000 volts can be obtained.
Another prominent feature is the high tension interrupter D, which cuts
the electric circuit of the tube in and out, in synchrony with the
camera mechanism. Thus the Crookes tube is active while the shutter is
open but inactive while it is closed.
This interrupter consists of a small glass vessel, charged with petrol,
and sealed with a cover of insulating material. Within the vessel, and
spaced about 2 inches apart, are two brackets, which extend through
the sides of the receptacle through hermetically sealed joints. To
these brackets the positive and negative wires are coupled. Above
the brackets, and moving within the vessel, is an inverted U-shaped
piece. This slides up and down through apertures provided for the
purpose in the insulated cover. When lowered to its full extent the
arms rest upon the brackets, to which the wires are attached, and
this contact completes the electrical circuit. A pulley wire is fixed
to the centre of the inverted U-piece to allow it to be moved up and
down as required. The up-and-down movement serves as a make-and-break
for the circuit. A lift of a quarter of an inch suffices to break the
circuit, which lift is effected by the mechanism of the camera over a
system of cords and pulleys. Thus, when the camera handle is turned
to open the shutter, the contact piece in the interrupter is lowered,
the circuit is completed, and the Crookes tube is brought into use.
Directly the shutter is closed the contact piece is raised and the tube
is disconnected. This simple control permits the exposure to be varied
from five or six to sixteen exposures per second, while the tube can
be kept continuously at work for as many as fifty-five seconds if
desired.
The camera is fitted with a lens made from quartz, which permits the
maximum quantity of the actinic rays to pass through to the sensitized
film. The film is covered with an exceptionally sensitive emulsion in
order to ensure the best results possible with very short exposures.
In order to protect the spools of film in the camera from the actinic
properties of the rays diffused from the fluorescent screen, the boxes
are covered with sheet lead, while the operator is protected with a
lead apron, such as is used generally in Röntgen ray investigations.
The many interesting films which Dr. Comandon has produced offer
adequate testimony to the practicability and success of the system
which he has evolved. Undoubtedly it is the simplest and most
inexpensive method of "radio-cinematography" which has been brought
into practical operation up to the present, and it is one which may be
followed by the private investigator with such modifications as may
suggest themselves in particular cases.