A PHOTOGRAPHIC APPARATUS, HAVING FOR OBJECT TO D MOTION
Year: 1861

page_text: LETTERS PATENT to Henry Du Mont, of the Comptoir des Brevets
d'Invention, No. 150, Rue de Rivoli, in the Empire of France, Engineer,
for the Invention of "A PHOTOGRAPHIC APPARATUS, HAVING FOR OBJECT TO
D
MOTION"
PROVISIONAL SPECIFICATION left by the said Henry Du Mont at the
Office of the Commissioners of Patents, with his Petition, on the 8th
June 1861.
1. HENRY DU MONT, of the Comptoir des Brevets d'Invention. No. 150,
Rue de Rivoli, in the Empire of France, Engineer, do hereby declare the
nature of the said Invention for "A PHOTOGRAPHIC APPARATUS, HAVING FOR
OBJECT TO REPRODUCE THE SUCCESSIVE PHASES AND SHIFTINGS OF A MOTION," to
be as follows:-
In order to obtain the proposed result, I expose to the light a succession of
moving glasses, prepared with sensitive layers in the usual manner, and
succeeding each other at regulated intervals, and before which the luminous
ray is also unmasked at regulated intervals, and in due time, that is to say.
when the plane of the sensitive layer is perpendicular to the axis of the ray.
The mechanism by which I obtain the quick succession of the sensitive layers,
and the unmasking of the ray is as follows: These sensitive layers are either
[Price 8d.]

page_text: fixed separately, or the impression can be obtained on cloth prepared with
collodion in the usual manner; the sensitive layers are placed on a circum-
ference of a cylindrical or prismatic drum or box; a rotary motion given to the
drum makes them succeed each other in the focus of the obscure chamber, and
the moveable drum bearing the sensitive layers is shut in a fixed box, black
inside, in order to prevent the sensitive layers being affected by a prejudicial
luminous ray. The axle of the drum can be either horizontal or vertical.
In order to put the subject to the distinct point of view on the unpolished
glass, it is sufficient to take the drum out of the box and to place before the
obscure chamber a double sash, bearing on one side the unpolished glass, and
on the other the looking glass in which the object is reflected.
Another means of obtaining the quick succession of the sensitive layers is to
place them together side by side on an ordinary sash, but much longer, and
moving intermittently in its-groove, vertically or horizontally.
A third means of obtaining the quick succession of the sensitive layers is to
set them behind each other in a long box with vertical grooves, and moving in
a contrary direction to a similar box situated under it, and intended to receive
the layers impressed by the light. While the upper box is moving towards
the objective, the other is going from it. The approaching box contains the
impressed layers. Each sensitive layer transported by the motion of a cog
wheel catching in a ratchet reaches the focus of the objective, receives the
impression during the unmasking of the luminous ray, then instantly falls to
the bottom of the box or the board bearing it, leaves it because this board is
rolled round the axle of the cog wheel, and the impressed layer falls into a
compartment of the lower box, going in a contrary direction, a second layer
succeeds to it, and so on; when all the layers are down a cover is put on the
lower box, and it can be immediately removed. I obtain the unmasking of
the luminous ray in due time, that is to say, when the ray falls on the sensitive
layer nearly perpendicularly to its plane by different means, which I will
enumerate. The luminous ray penetrating from the objective into the obscure
chamber through an orifice (or two orifices of the stereoscopic apparatus has
or contains two objectives) before reaching the sensitive layers meets a black
moveable screen, the regulated motions of which are connected with the
motions of the system bearing the sensitive layers. The motion of the screen
may be oscillating; in such a case it should be connected with the system
bearing the sensitive layers by means of a lever; instead of being single it
may be double. The screen may have a rotary motion, whether set perpen-
dicularly to a cylinder turning on its axis in the obscure chamber, or whether it
is a portion of the surface of a cylinder or of a sloped prism, turning also on

page_text: its axis in the obscure chamber. In either case the motion of the axle of the
screen will be connected with the motion of the axle of the drum (if a
drum is used to bear the sensitive layers) by a ratchet or an endless screw
or a rag chain and wheel. If a drum is not used, but the moveable boxes.
the motion of the axle of the screen will be derived from the cog wheel
situated between the two boxes. If a long sash is used, the motion of the
axle of the screen will be derived from the cog wheel through a ratchet fixed
along the sash. In every case, and by a proper choice of the diameter of the
wheels and of the cogs, the apparitions and disappearances of the screen are
regulated once for all in such a way that the apparition and disappearance of the
luminous ray takes place in due time according to the position of the sensitive
layers. By the above-described apparatus I propose to reproduce objects
and persons in motion, and in every successive phase and shifting of their
motion.
:
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Du Mont in the Great Seal Patent Office on the 30th
November 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I. HENRY
DU MONT, of the Comptoir des Brevets d'Invention, No. 150, Rue de Rivoli.
in the Empire of France, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of June, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fourth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Henry Du Mont, Her special licence that I, the said Henry Du Mont.
my executors, administrators. and assigns, or such others as I, the said
Henry Du Mont, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "A PHOTOGRAPHIC
APPARATUS, HAVING FOR OBJECT TO REPRODUCE THE SUCCESSIVE PHASES AND SHIFTINGS
OF A MOTION," upon the condition (amongst others) that I, the said Henry Du
Mont, my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great

page_text: Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said Henry Du Mont, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings, that is
to say:-
My Invention consists in a new or improved photographic apparatus for
reproducing the successive phases of a motion. Nowadays, photographers
are enabled to reproduce on surfaces of great sensibility to the light what they
have termed instantaneous images; they photograph a moving object, such as
a running horse, &ca., but have never thought of obtaining but a single image
of the same object, and did not even wish to reproduce several successive ones,
or the successive phases produced by motion.
I thought that among the several images reproducing the successives phases
of a motion some would be found superior to others by the harmony of the
lines, the shades, the naturalness of the attitudes, which are generally affected
when persons are suddenly and abruptly called to sit for a picture, and thought
that such inconvenience might be obviated by an apparatus that would photo-
tograph the successive phases of an object in motion. The difficulty of
reproducing truly the successive phases of a motion at several minutes' interval
(a difficulty which is insurmountable with the known apparatus) led me to
make use of a new photographic apparatus which permits of reproducing the
successive phases of a motion at only a few fractions of second's interval, or the
space of time between such phases. To attain this result, instead of the
common motionless sensitive layer or plate. I substitute, during the exposition
to the light, a series of movable layers in proper succession, that is to say, only
when the plan of the sensitive layer is radial to the axis. I will describe the
mechanism through which I obtain such rapid substitution of the sensitive
layers and the unmasking of the rays.
1. The sensitive layers are fitted either separately, or after being juxtaposed
upon a cloth strip over the periphery of a cylindrical or prismatic drum; a
rotary motion imparted to the latter causes them to come successively into the
focus of the camera obscura, the movable drum which carries the sensitive
layers being itself enclosed in a box previously blackened inside, by which the
said sensitive layers are sheltered against all luminous rays. The axis of the
drum may be either horizontal or vertical.
In order to set at the distinct point on the roughened glass, it suffices to
remove the movable drum from the box which encloses it, and to place before

page_text: the object glasses, a double case, containing on one side the roughened glass and
on the other a mirror. into which are reflected the objects to be reproduced.
A second means of obtaining the rapid substitution of the sensitive layers
consists in fitting them side by side on a common case, but longer, and having
an intermittent motion throughout its plane, either vertically or horizontally.
The duration of such intermissions and the amplitude of the movement suitable
to every one is regulated by a rack and click work. and the driving power
used, which is to be regular, is produced by means of a weight, and is readily
directed by a pulley.
A third means of procuring the substitution of the sensitive layers is to space
them behind one another in a long box with vertical grooves, and moving in
opposite direction to a similar box placed beneath, in order to receive the layers
impressed by the light.
My Invention will be better understood by an inspection of the annexed
Drawing, wherein Fig. 1 shows the dark chamber completely closed, and
Fig. 2 the same dark chamber quite ready for operation. a, a, are the object
glasses of the camera obscura: b. camera obscura; c, upper box containing the
sensitized plates; d, lower box for admitting the impressed plates; e, e, racks
on the two boxes c & d; j. pinion gearing with the racks e, e, and causing the
boxes c&d to pass in or out. It will be easily understood that while the
upon box c advances towards the object glasses a, the other withdraws from it,
the advancing box encloses the sensitive layers, and the withdrawing box the
impressed layers or plates. Each sensitive plate carried by the motion of
pinion, (which motion is imparted to the racks e, e.) reaches the focus of the
object glass, and is impressed during an unmasking of the luminous rays, then
an instant afterwards the bottom of the box which supports it withdraws.
being rolled up round the axis of the pinion, and the impressed plate drops into
a partition of the lower box d, which is carried in an opposite direction, another
plate or layer comes in, and so forth in succession. When all the plates are
thus dropped, a lid is slid over the lower box d, which can be then taken out
immediately and carried away in full sun's light.
II. I obtain the unmasking of the luminous ray in proper time, or when
such ray falls on the sensitive plate almost perpendicularly to the plane of the
said plate by various means, which will be described. The luminous ray or
rays penetrating the object glass a into the camera obscura b, through a
hole (or through more than one hole for a stereoscopic apparatus with two
object glasses), meets before it reaches the sensitive plate a movable blackened
screen, the motions of which are connected with the motions of the sensitive
plate-carrying system. The motion of this screen may be an oscillating motion,

page_text: in which case it will be so connected through the medium of a lever, and it
may be double instead of being single, as is the case for phantasmagoric and
refraction experiments. The screen may also have a rotary motion, whether
it is fitted perpendicular to the surface of a cylinder turning upon its axis in
the camera obscura, or whether it be formed with or make part of the surface
of a cylinder or prism hollowed out, and turning also upon its axis in the said
camera. In both cases the motion of the screen's axis shall be connected with
that of the drums (if a drum is made use of to carry the sensitive plates) through
gear, an endless screw, bevel wheels, or a Vaucanson chain. If, instead of the
drum, movable boxes are made use of, the axis of the screen will derive its
motion from the pinion situated between the two boxes. Where a long frame
is made use of. then the screen would derive its motion from a pinion moved
by a rack fitted lengthwise on the frame.
In all cases, and with a proper diameter of the wheels and pinions, the
coming in and out of the screen is once for all regulated, so that the coming in
and cessation of the luminous ray determined thereby may take place at the
instants required by the position of the sensitive plates.
By means of the apparatus above described I am enabled to reproduce
moving things and persons through all the successive phases of their motions.
And having thus described the nature and particulars of my Invention, I
wish it to be well understood that I do not confine myself to the precise details
herein specified, nor likewise to the strict form of the apparatus, or parts of
the apparatus herein described and shown, as such may be varied or modified
without departing from the principle thereof; but what I claim as new, and as
being of my Invention, is.-
First, the improved apparatus as I have described.
Secondly. utilizing the series of images thus produced, viz.. the series of
motions of a dancer, of one or more soldiers, of a machine, &ca., &ca., both
for the pleasure of the eyes and for other purposes. .
In witness whereof. I, the said Henry Du Mont, have hereunto set my
hand and seal, this Twenty-eighth day of November, in the year of
our Lord One thousand eight hundred and sixty-one.
II. DU MONT. (L.S.)