IMPROVEMENTS IN APPARATUS FOR TAKING
Year: 1862

page_text: LETTERS PATENT to John Robert Johnson, of Stanbrook Cottage,
Hammersmith, in the County of Middlesex, and John Ashworth
Harrison, of 25, St. Andrew's Road, Southwark, in the County of
Surrey, for the Invention of "IMPROVEMENTS IN APPARATUS FOR TAKING
Sealed the 3rd March 1863, and dated the 5th September 1862.
PROVISIONAL SPECIFICATION left by the said John Robert Johnson and
John Ashworth Harrison at the Office of the Commissioners of Patents,
with their Petition, on the 5th September 1862.
We, JOHN ROBERT JOHNSON, of Stanbrook Cottage, Hammersmith, in the
County of Middlesex, and Joux ASHWORTH HARRISON, of 25, St. Andrew's
Road, Southwark, in the County of Surrey, do hereby declare the nature of
the Invention for "IMPROVEMENTS IN APPARATUS FOR TAKING PHOTOGRAPHIC
PANORAMIC PICTURES," to be as follows:-
Our Invention consists of certain improvements in the apparatus for taking
panoramic pictures. It is well known that if a photographic lens be mounted
vertically upon a pivot, the centre of which coincides with a vertical line
drawn through the true centre of the lens, and if such lens be made to turn
upon the pivot, the images of the objects which are brought in succession in
front of the lens during its revolution may be projected upon a screen placed
behind the lens, and if such screen be part of a cylinder, the radius of which

page_text: is equal to the focal length of the lens for the images so projected, and the
centre of which coincides with the centre upon which the lens turns, such
images are true representations of the objects, and remain stationary upon the
screen, notwithstanding the motion of the lens; cameras thus constructed
have been used for producing panoramic pictures upon curved daguerreotype
plates. It is also known that if instead of the curved plate for receiving the
images a flat plate be employed, and if while the lens and the base upon
which it is mounted and which carries the plate revolve, the plate be made to
traverse in the opposite direction, with due relation to the rotation of the lens,
the images projected upon the plate are likewise stationary; cameras formed
upon this principle have been suggested for the production of panoramic views,
but so far as we are informed have not come into practical use. Now, the
object of our Invention is to render both the above-mentioned forinsofcamera
fit for use with the modern process of photography.
Our improvements consist, 1st, of an improved construction and arrange-
ment of the parts of the flat plate camera, so that their motions are smooth,
equable, and free from vibration, and so that the whole apparatus is rendered
more compact and portable.
2nd, of a new mode or modes of obtaining the relative motions of the lens
and sensitive plate, such motion being obtained directly by mechanical means,
instead of forming "guide curves" by trial, as has before been proposed to
be done.
3rd, of an improvement in the geering when working both forms of camera.
4th, of the application of a spring or falling weight to give the motion to
such cameras, and of means for regulating the motion both at variable and
invariable rates.
5th, of an expanding diaphragm to regulate the exposure in cameras
moving at an invariable rate.
6th, of an expanding diaphragm to be placed between the lens and picture,
by means of which sky and cloud effects may be obtained.
In effecting our first improvement we render the camera symmetrical and
duly balanced by placing the lens in its centre instead of at one side, and
placing the rollers or other support upon which it rotates at equal distances
on each side of the centre, and upon the circumference of a circle whose
centre coincides with the centre of the pivot upon which the apparatus turns,
so that the space travelled over by each roller is equal, and the resistance
consequently equal. The plate holder slides within the camera instead of
through its side.
In its simplest but least compact form, the camera is an oblong box placed

page_text: upon a plate or bed upon which the rollers revolve, as shewn in the Diagram
No. 1, in which the dotted lines indicate the plate holder and its line of
motion, and also the motion of the rollers upon the bed. It will be seen,
therefore, that the whole apparatus has a motion of rotation round the pivot
placed under the centre of the lens, while the plate holder has a motion of
translation from one end of the camera to the other. We render the camera
light and more compact by dispensing with the vacant space, as shewn in the
Diagram No. 2, the dotted lines indicating the condensed form. The camera
proper then assumes very small dimensions, the necessary length for the
traverse of the plate being obtained by a tube or narrow box attached to the
back of the small camera; the weight may be still further reduced by sub-
stituting a plate or thin board for the tube just described. The plate holder
slides upon the plate, which acts at the same time as a dark slide, see Diag.
No. 5. We can still further limit the dimensions of the apparatus by
shortening this plate, and letting the plate holder overhang or extend beyond
the back plate at each end, in which case provision must be made for shutting
out the light, which may be effected by a strip of india-rubber cloth or oiled
silk passing over rollers, see Diag. No. 4, placed at each end of the plate
holder.
2nd, we obtain the relative longitudinal motion of the plate to the rotary
motion of the lens and camera, when a flat plate is used, by a toothed wheel
fixed on the bed or plate, upon which the camera turns, gearing into a rack
attached to the plate holder; but to obtain this effectually, the wheel must be
wholly or partially within the camera, or the plate holder must slide outside,
as in that form of camera previously described and shewn by Diagrams 3
and 4. By this modification of the apparatus the motion is obtained in a
direct manner, and the necessity for the trials or experiments to form the
guide curves is dispensed with, as is also a large amount of friction from the
rollers which act upon the curves. We find, however, that a much smoother
and more equable motion is obtained by employing a fixed disc or pulley
instead of a toothed wheel; a cord or strap is attached at one end to the disc,
and at the other to the plate holder. As the camera revolves, the cord or
strap winds upon
the edge of the disc, drawing forward the plate holder for a
distance equal to the segment of the arc of the circular edge of the disc upon
which the cord or strap has wound itself. Or the cord or strap may be
attached at each end to the disc respectively, and be passed over from rollers,
as shewn in the Diagram No. 5. The plate holder is fastened to the cord or
strap, and slides backward or forward according to the direction in which the
camera carrying the rollers rotates.

page_text: 3rd. Our third improvement consists in adding a fly wheel or other
regulator to the gearing for working panoramic cameras, by which a greater
uniformity of motion is produced.
4. In order to obtain definite exposure with wet collodion or other quick-
acting processes, especially in obtaining the so-called instantaneous pictures,
we find that the due rapidity and equality of motion cannot be obtained by
hand. We therefore adapt a spring or weight to move the apparatus. With
a weight or spring the rate of motion may be made invariable or variable.
We obtain an invariable motion by a fly wheel escapement, or by any other
mode of obtaining motion at a fixed rate. In this case it is necessary to adjust
the rate of exposure by the amount of light admitted; to effect this we form
an expanding diaphragm by making openings in two plates of metal having
motion in opposite directions by means of a right and left-handed screw, or
otherwise. In one position the openings on the plates coincide, and the full
aperture is obtained; but when moved in opposite directions the resulting
opening becomes reduced, and at last closed. The diaphragh thus formed is
placed within the tube of the lens, and by this means any amount of aperture
within certain limits may be given, and the amount of light adjusted. A
variable notion may be given to the apparatus proportionate to the amount of
exposure required by a fly or vane, the arms of which may be set at a varying
angle, or by other known modes of adjusting of motion; we prefer, however,
for this purpose a tube or small cylinder fitted with a piston, the two ends of
which are in communication by a pipe; the rod of the piston passes through
a stuffing box, so that the tube may be kept full of water, or any other fluid.
A cock or valve is placed within the pipe which joins the two ends of the tube
or cylinder, by adjusting the cock or valve the aperture may be increased or
diminished at will, and thus the rate of the passage of the fluid from one end
of the tube to the other under an equal pressure of the piston, and consequently
the rate of motion of the latter may be regulated; such a regulator may be
attached directly to the string of the falling weight, or by a rack fixed to the
end of the piston gearing into a toothed wheel attached to the pulley over
which the cord passes. Any rate of motion may be thus obtained.
5. We fix a diaphragm between the lens and sensitive plate close to the
latter, as in the curved plate camera. We render this opening of the diaph-
ragm variable by forming it of superposed plates of metal which slide over
each other, so that the form and size of the opening may be changed at will.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Robert Johnson and John Ashworth Harrison in the
Great Seal Patent Office on the 5th March 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
ROBERT JOHNSON, of Stanbrook Cottage, Hammersmith, in the County of
Middlesex, and JOHN ASHWORTH HARRISON, of 25, Saint Andrew's Road,
Southwark, in the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of September, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
us, the said John Robert Johnson and John Ashworth Harrison, Her special
licence that we, the said John Robert Johnson and John Ashworth Harrison,
our executors, administrators, and assigns, or such others as we, the said
John Robert Johnson and John Ashworth Harrison, our executors, adminis-
trators, 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 "IMPROVEMENTS IN APPARATUS FOR TAKING PHOTOGRAPHIC PANO-
RAMIC PICTURES," upon the condition (amongst others) that we, the said John
Robert Johnson and John Ashworth Harrison, our executors or administrators,
by an instrument in writing under our or their hands and seals, or under
the hand and seal of one of us or them, 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 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. John Robert Johnson, on behalf of
myself and the said John Ashworth Harrison, do hereby declare the nature of
the said Invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement
thereof, that is to say :-
Our Invention consists of certain improvements in apparatus for taking
photographic panoramic pictures. It is well known that if a photographic
lens be mounted vertically upon a pivot, the centre of which coincides with a
vertical line passing through the true, that is, the optical centre of the lens,
and if such lens be made to turn upon a pivot, the images of the objects which

page_text: are brought in succession in front of the lens during its revolution may be
projected upon a screen placed behind the lens, and if such screen be part
of a sphere, or (for practical purposes) a cylinder, the radius of which is equal
to the focal length of the lens for the images so projected, and the centre of
which coincides with the centre of the pivot upon which the lens turns, such
images are true representations of the objects, and remain stationary upon the
screen notwithstanding the motion of the lens. Cameras thus constructed
have been used for producing panoramic pictures upon curved daguerreotype
plates. It is also known that if instead of the curved plate for receiving the
images, a flat plate be employed, and if while the lens and the base upon
which it is mounted, and which carries the plate, revolve, the plate be made to
transverse in the opposite direction with due relation to the rotation of the
lens, the images projected upon the plate are likewise stationary, and are for
practical purposes sufficiently sharp and defined, provided that but a narrow
portion of the plate is used at one time, for the true images are projected upon
a curved surface, and the plate is only a tangent to that curve, and cameras
formed upon this principle have been suggested for the production of panoramic
views, but so far as we are informed have not come into practical use. Now,
the object of our Invention is to render both the above-mentioned forms of
camera fit for use with the modern processes of photography.
Our improvements consist, first, of an improved construction and arrange-
ment of the parts of the flat plate camera so that their motions are smooth and
equable, and free from vibration, and so that the whole apparatus is rendered
more compact and portable than those previously suggested.
Second, of a new mode or modes of obtaining the relative motions of the
lens and sensitive plate, such motion being obtained directly by mechanical
means or by appliances constructed mechanically instead of by "guide
curves," or "grooves" formed" by trial" as has heretofore been proposed to
be done.
Third, of an improvement in the gearing when working both forms of
camera.
Fourth, of the application of a spring or weight to give motion to such
cameras, and of means for regulating such motion both at variable and invarible
rates.
16
Fifth, of the application of an expanding diaphragm to regulate the
exposure" in cameras moving at an invariable rate.
Sixth, of an expanding diaphragm to be placed between the lens and the
sensitive plate by means of which "sky and cloud" effects may be obtained
and by which the amount of exposure may also be regulated.

page_text: (1.) In enecting our nrst improvement we render the camera symmetricat
one side,"
and duly balanced by placing the lens in its centre, instead of at ".
and placing the rollers or other supports upon which it rotates at equal
distances on each side of the centre, and upon the circumference of a circle
whose centre coincides with the centre of the pivot, upon which the apparatus
turns so that the space travelled over by the rollers is equal, and the resistance
therefore is equal.
In our simplest but least compact form of camera, the plate holder slides
within the camera instead of through its side. In this form it is an oblong
box somewhat broader than the focal length of the lens and of a length
varying with the angle of the view to be taken. For the whole horizon the
length must be somewhat more than six times the length of the focus of the
lens, for one-third somewhat more than twice that length. It is supported by
a bed or plate upon which the rollers fixed under the camera revolve and in
which the pivot about which it revolves is fixed.
Plate 1, Figure 1 shews the outline in plan of a camera taking a view of
one-third of the horizon in three phases of its course, that is, at the beginning,
middle, and end of its motion. The dotted lines indicate the position of the
plate holder, and the inner circle of dots the space traversed by the rollers
upon the semicircular supporting bed. It will be seen from this diagram
that the whole apparatus has a movement of rotation round the pivot placed
under the centre of the lens upon the fixed bed plate, while the plate holder
has a movement of translation from one end of the camera to the other.
Only the outline of the camera is here shewn. Such a formed camera must
have a narrow tube or box behind the lens within the camera to confiue the
rays of light to but a small part of the plate. Such box must however be
equal to the sensitive plate in height. We render the camera lighter and
inore compact by dispensing with the vacant space as shewn in Figure 2, the
dotted lines indicating the condensed form. The camera proper then assumes
very small dimensions, the necessary length for the traverse of the plate
holder being obtained by a tube or narrow box attached to the back of the
small camera. The tube or box alluded to in describing Figure 1 can then be
dispensed with, the angle at which the lateral rays impinge upon the plate
being determined by the size of the opening in a partition or diaphragm
placed between the camera proper and the tube in which the plate holder
slides. The weight of the instrument may be further reduced by substituting
a plate or thin board for the tube just described. The plate holder slides upon
this plate or board which acts at the same time as a dark_slide, sec Figure 3.
We still further limit the dimensions of the apparatus by shortening the

page_text: plate just described and letting the plate holder overhang or extend beyond
the plate or board forming the back of the camera, when the latter is at each
end of its course, in which case some provision must be made to shut out
the light in addition to the back plate which serves for that purpose in
the form shewn by Figure 3. This may be effected by a strip of india-
rubber cloth, oiled silk, or other flexible opaque material passing over rollers
at each end of the slide. Or an approximation to flexibility may be made by
forming the slide of a rigid material in separate parts joined together by hinges
or their equivalent, see the dotted lines in Figure 3. Or the back board of
the camera may be formed of several parts which are joined together when
the camera is in use, but which are separated when the instrument is packed.
We have shewn the flexible cloth or jointed board applied to shut out the
light upon the dark slide or plate holder itself, but the same effect may be
obtained by passing the flexible cloth over a box in which a dark slide may be
dropped as in an ordinary camera. The cloth and box remain attached to
the camera when the dark slide is removed after exposure. The box fitted
with the flexible cloth or hinged board may be extended in width until it
embrace the camera itself, which may then be a thin tube about an inch
wide and as high as the picture to be taken. This is attached behind the
lens within the box, the lens being fixed to the jointed board in front of the
camera. The lens and board are of course fixed upon the pivot under the
centre of the lens and have a movement of rotation only while the box which
contains the plate holder slides laterally upon the board in front. Figure 6
gives the outline of such an apparatus which is efficient, provided the tube
at the back be not a parallel tube conveying a mere streak of light perpendicular
to the face of the lens, but be of such height that the rays may diverge from
the lens vertically so as to cover the plate, but be confined laterally to fulfil
the conditions of the flat plate camera already described. It is however less
compact and portable than the preceding forms.
(2.) The relative motion of the plate to the rotary motion of the lens and
camera in those forms of our apparatus in which the plate holder is outside, or
in which it is contained in a sliding box, inay be obtained by rollers upon the
end of the plate holderoi bosecting upon properly constructed curves formed
of metal or other resisting material, fixed upon a table or bed plate which
supports the moving parts. Such curves are the volutes of a circle, the
radius of which is equal to the focus of the lens employed, and may be formed
mechanically instead of by trial or experiment; such motion may, however, be
obtained directly and more advantageously from a fixed toothed wheel, the
diameter of which from the centre to the "pitch line" is equal to the focal

page_text: length of the lens, and still more advantageously from a smooth edged disc of
the same size. The wheel is fixed upon the bed or table upon which the
camera turns, so that its centre coincides with the centre of the pivot under the
lens, and its pitch line consequently under the sensitive plate upon which the
picture is to be taken. A rack is placed upon the plate holder which gears
into the wheel as the camera revolves; as the wheel is stationary the rack and
plate holder travel forward inadirection opposite to the motion of the camera.
The same means also serve to give motion to the plate holder in those forms
of apparatus in which it slides within the camera or its appended tube or box;
but in this case the fixed wheel or segment of wheel must be wholly or
partially within the camera as is the disc about to be described, as shewn in
Plate 2, Figures 1 and 3, or intermediate wheels must be employed similar to
the arrangement to be referred to subsequently, Plate 1, Figure 13. It will
be obvious to practical men that mechanical equivalents may be substituted
for the wheel, thus it may be of smaller size than that described, and inter-
mediate wheels may give the required motion to the rack. The motion thus
produced is superior to that obtained from the curves, even when these have
been constructed with precision instead of approximatively by trial, and the
apparatus is more compact and portable. The motion is, however, still
smoother and more equable by dispensing with the teeth of the wheel, and
employing in its place a fixed disc or pulley with a smooth edge or surface. A
cord or strap is attached at one end to the disc, and at the other to the plate
holder. As the camera revolves the cord or strap winds upon the edge of the
disc drawing forward the plate holder for a distance equal to the segment of
the arc of the circular edge of the disc upon which the cord or strap has
wound itself. The radius of the disc must therefore be equal to the focal
length of the lens, as has been said. Or the cord or strap may be attached at
each end to the disc respectively, and be passed over four rollers carried by
the rotating camera, as shewn by Figure 5. The plate holder is fastened to
the cord or strap,and slides backward or forward according to the direction in
which the camera carrying the rollers rotates. Motion in both directions may
also be obtained by using two cords or straps attached at each end to the disc
and plate holder respectively, or to the disc and to a rod or bar to which the
plate holder may be fastened, Figure 7. We have described a cord or strap
asforming the connection between the disc and the sliding plate holder, but it
will be obvious to practical men that several mechanical equivalents may be
substituted, some of which with their application will be shown subsequently
after the details of the apparatus have been described.
(3.) Our third improvement consists in adding a fly wheelor other regulator

page_text: to the gearing for working all forms of panoramic cameras by which a much
greater uniformity of motion is obtained.
(4.) We find that the due exposure of the plate when employing wet
collodion or other quick acting processes is obtained with great difficulty by
hand, especially when the so-called instantaneous pictures are required, we
also find the use of hand gearing tiresome and fatiguing when the dry plate or
other slow acting processes are used; we therefore adopt a spring, weight, or
other prime mover to give motion to the apparatus. In this case the motion
may be invariable or variable. An invariable motion may be obtained by a
fly wheel, fly escapement, governor, or other known means of obtaining
motion at fixed rate. We would here remark that such means have already
been suggested for moving panoramic caneras, but are useless unless accom-
panied by some method of adjusting the amount of light with great accuracy,
for as the time of exposure is constant, being determined by the uniform rate
of motion of the apparatus, the amount of light admitted must vary inversely
with its intensity. The ordinary diaphragms are insufficient for the purpose.
We use the sliding diaphragmns to be described subsequently. A variable
motion may be given to the apparatus proportionate to the amount of exposure
required by a fly or vane, the arms of which may be set at a varying angle or
by a pendulum with a shifting bob, or by other known means of adjusting
motion. We prefer for this purpose hydraulic apparatus, which with other
modes will be subsequently described.
(5.) Plate 1, Figure 8, represents the expanding diaphragm which we use
for regulating the amount of light in panoramic cameras moved at an uniform
rate. It consists of two plates of metal a and b moving over each other by
means of a small pinion & placed between them and gearing into two racks
fixed in front of a and behind b. The shaft of the pinion and the plates
are maintained in position by the box c, which can be dropped into a recess in
the lens like that used for Waterhouse's diaphragms. The plates have an
opening in each as shewn in the Drawing, and the size of the opening is
indicated by a scale on the plates projecting above the top of the box. The
width of the diagonal of the opening being measured by the position of the
plate babove the bottom of the scale; or if the size of the pinion be made to
correspond with the size of the opening in each plate, the head of the shaft by
which the pinion is moved may be divided for the purpose of indicating the
amount of aperture. In both cases the amount of light will vary as the square
of the opening indicated.
(6.) Figures 9, 10, 11, shew the parts of the expanding diaghiragin which
we employ between the lens and the sensitive plate, for the purpose of regu-

page_text: lating the form and dimensions of the aperture by which the light is admitted
to the plate brought gradually past this aperture during the rotation of the
camera. It is well known that much less exposure is necessary for a picture
of the sky in order to mark the delicate gradations of its clouds than for the
foreground of a landscape, and various contrivances have been adopted for
varying the exposure of sky and ground when taking landscapes with the
ordinary camera. Now in our panoramic camera this can be regulated with
great nicety by making the opening of the diaphragm in question opposite to
the images of sky and ground on the plate correspond to the relative amount
of illumination in each, and by making the transition from the one to the
other gradual. As the position of the horizon varies with each landscape, and
the position of the camera, it is necessary for the form as well as the dimensions
of the opening in the diaphragm to vary accordingly; this may be effected by
cutting out a card to be used as a diaphragm for each picture, but we effect
this as follows:-Figure 9 is a front and edge view of a small frame made of
a sheet zinc turned up at the edges, and having an oblong opening in the
middle; Figure 10 are two slips of zinc which slide horizontally between the
edges of Fig. 4,9, their distance asunder determining the ratio of the narrow to
the wide space between them, and consequently the relative amount of
exposure of ground and sky, for as will be obvious the narrow space will be
opposite the image of the sky, and the wide to that of the ground. So
arranged the diaphragm would only serve for pictures in which the horizon
should pass through the curved part of the slips. To extend its use to other
views in which the horizon is lower than this, we use the pieces shewn in
Figure 11. These slide vertically in the grooves formed by the turned-up
edges of 10, and by these the proportion of the height of the narrow space to
that of the broad can be changed at will within certain limits. For views in
which but very little sky is shewn, the diaphragm must be modified, so that
the height of the narrow space on the slips (Figure 10) may be less than that
shewn. Good effects are likewise produced by making the diaphragm of two
slips only with straight edges but inclined to each other, so that the opening at
the top (opposite the foreground of the picture) may be much wider than at
the bottom (opposite the top of the sky). These may be made to move
towards each other by a pinion as in the diaphragm described under head 5,
and will thus serve to regulate the amount of exposure as well as the other.
Having described in general terms our improvements in panoramic cameras,
we now proceed to give detailed instructions for applying the same in practice,
reference being made to the annexed Drawings.
Plate II. represents the detailed construction half size of a camera of the

page_text: form of that shewn in Plate L. Figure 2, fitted with a four-inch lens, and
calculated to take a picture 8 inches long, that is of 115°, or nearly one-third
of the horizon.
Figure 1 is a vertical section of the camera through A, B; Figure 2 is a
section through C, D; Figure 3 a section of the tube and plate holder
through E, F, the rest of the remaining parts being shewn in plan; Figure +
is a partial section through G, H, of the base containing the apparatus for
giving motion to the instrument. a, a, is the lens in its mount, screwed into
the sliding front of the camera proper b, b, in the usual way; c, c, is the tube
or box forming the back of the camera in which the plate & carried by the
plate holder e, e, slides upon the carriage. The whole is mounted upon the
pivot g and the rollers h, h. The latter run on the surface of the segment of
the disci, i. The edge of this disc gives motion to the carriage f,, upou
which is the plate holder e, by means of the cords of gimp or other mate-
rial,. The cords k, k¹, are fixed at one end to the disc i, and at the other
to the carriage, crossing each other at the centre of the disc. The motion
of the carriage is facilitated, and its true position in the tube c determined
by the rollers 1, 2, and the two springs m, m. The plate holder is fixed to
the carriage by means of the pointed piece of brass n, and the bolt o. The
plate holder or dark slide is constructed precisely like those in common use,
with the exception that the shutter which keeps out the light from the plate
in front of the slide has two narrow projecting pieces at its end, shewn by
the dotted linesin Figure 2, which prevents the slide from leaving the groove
in which it runs when it is drawn out to the fullest extent required. When
the shutter is closed, these pieces project beyond the slide as shewn. In the
same Figure two small rollers are placed at the top of the slide, and a spring
at the back of it, to keep it in its position in the tube c. Between the
camera proper as we call b, b, and the tube or box which forms the back of
the camera, the expanding diaphragm shewn by Plate I. Figures 9, 10, 11, is
fixed, sliding through a slot in the top of b, b. The parts just described, the
pivot g, and disc being supported upon a board or plate, constitute all that is
necessary for the working of the instrument, provided that the motion is given
by taking hold of it with the hand, and drawing it round its pivot.
We will therefore proceed to describe the adjustment of the instrument,
and the mode of using it in its simplest form, before noticing the parts for
rendering the notion more uniform and steady. The first step in adjusting
the instrument is to determine the focus of the lens employed for objects at
a distance of about 100 feet, for it will be observed that in this form of the
instrument there is no adjustment for focus. The lens is set to objects in

page_text: tapped into the
Having adjusted
lens, the segment
the middle distance, and when there are many objects in different planes a
small stop is used. Having carefully determined the focus for this distance
in the usual way, which we will assume to be four inches, the camera must
be so constructed that the sensitive plate is placed at that distance. The
last adjustments for this may be effected by adjusting the position of the
rollers in front of the plate holder e and carriage f; these may be more or
less sunk into the holder and carriage so as to bring the former nearer or
further from the lens, the springs m causing both plate holder and carriage
to bear upon the rollers in front, which ride upon the side of the tube c. Or,
the lens may slide in the outer tube, on which it is marked as is usual. The
camera may be made somewhat too short, and the lens be drawn out to the true
focus, at which point it may be fixed by a small screw
outer fixed tube, and entering a hole in the inner one.
the position of the sensitive plate at the true focus of the
of the disc i is turned in a lathe, so that the radius of the disc from the centre
to the edge upon which the cord winds is exactly equal to the focus of the lens
as determined. The next step is to place the camera upon the pivot g, in
such a position that a line drawn through the centre of the pivot, shall pass
through the optical centre of the lens. In order to effect this the brass socket
g' which fits the pivot g, is fixed temporarily under the camera by screws
smaller than the holes in the flanch of the socket, or by any other mode. The
camera is then placed before some well defined object, and its image is pro-
jected upon a ground glass placed behind the lens; the door c' in the tube c
being opened for this purpose. The relative position of the camera and
socket' is shifted until the image of the test object is perfectly stationary,
while the camera is moved upon the pivot. When this is effected, the screws
are fixed, and the socket is prevented from shifting by a steady pin. The
camera is now in its right position, it only remains to fix the disc so that its
centre shall coincide with the centre of the pivot. This is easily effected by
a pair of dividers. The cord is then attached to the disc and carriage in such
a manner that when the camera is in the centre of the disc, the carriage is in
the centre of the tube at the back of the camera in the position shewn in the
Drawings. It is evident from the construction that if the camera be moved
round its centre from right to left, the cord will unwind off the disc, and
the cord & will wind upon the disc, drawing the carriage and plate holder
from left to right, and if the camera be made to rotate from left to right the
cord / winds upon the disc, and the cord ' unwinds, moving the carriage and
plate holder from right to left.

page_text: We will now proceed to shew the manipulation required to take a view
with a camera of this construction in its simplest form. The sensitive plate
having been placed within the dark slide or plate-holder in a dark room or tent,
the camera is placed in the position shewn at a in Figure 1, the doors c¹ & c¹¹
of the tube e are opened, and the plate holder is placed upon the carriage, the
brass piece n entering into a hole in the plate holder, and the bolt o being
shut; the pin is passed through the head or projecting part of the shutter
of the plate holder, and the doors cl and c¹¹ are closed; the camera is then
pushed by hand and made to rotate, the slide making its corresponding motion
in the opposite direction, but its shutter being retained by the pin q remains
stationary, and thus exposes the plated to the rays of light passing through
the lens and the diaphragm p. At half the course to be traversed the relative
position of the plate and camera is that shewn by the Drawings. At the end
of the course the relative position is shewn by Plate 1., Figure 1 c, that is,
the shutter is entirely drawn out with the exception of the narrow projecting
parts shewn by the dotted lines in Plate II., Figure 2. The view is now
taken, and the plate has been removed out of the action of the light from
having passed the opening of the diaphragm p. The lens is then covered by
its cap, and the motion is reversed until the camera is in the position shewn
by Plate I., Figure 1 a. The shutter having been retained in the groove by the
projecting parts has now returned to its original position, the plate-holder or
dark slide is covered and the plate protected from light. The pin is then
withdrawn, the door c" opened, the bolto raised, and the plate-holder with-
drawn in order that the plate d may be carried to the dark room or tent to be
developed. Such is the manipulation required in the simplest form of the
panoramic camera, but it is found in practice that a sufficiently equable
motion cannot be obtained by moving the instrument round its centre by
hand. Instead of a plate or box for supporting the pivot g and the disc i, a
box, 1, is substituted, the pivot g is continued so as to form an arbor or shaft,
the bottom of which is inserted into the plate s. The arbor carries a
wheel t, t, which gears into a screw or spiral (") in connection with the
shaft (v) moved by the winch or handle 2. The spiral (a) is shewn in plan,
Figure 4, but not in Figure 1, to avoid confusion. On turning the handle
the screw (") slowly rotates, drives round the wheel t, and a more uniformn
motion is produced than can be obtained when the camera is inoved directly
by hand.
A still greater uniformity of motion is produced if a fly wheel be
added, moving at a high velocity. This is effected by attaching a cog
wheel (w) to the shaft (v), which gears into the screw or spiral upon the

page_text: vertical shaft (a). On the top of the shaft is placed a fly wheel, which greatly
adds to the uniformity of the motion, and continues it for some seconds after
the hand is withdrawn.
We now proceed to shew several modes of producing the rotation of the
camera by a spring or weight. The Drawings shew the application of the
latter only, but all the arrangements for regulating the motion are applicable
to both. We will first shew means of producing an uniform rate of motion.
A spring may be placed upon the arbor or shaft (g) immediately above the
wheel t, and as only part of a revolution is required, the motion of the spring
is sufficiently regular without a fusee. The screw (u) must be made of such
a pitch that it may be driven by as well as drive the wheel t. If the propor-
tions of the spring be adjusted to the weight of the fly wheel and its speed an
uniform motion is effected by this arrangement alone. Or the fly wheel
may be replaced by a fly, or the shaft may be extended across the box
forming the base, and an escapement with a short pendulum may be fixed
upon
it, which will serve the purpose when the exposure is not too rapid.
We prefer a falling weight for the flat plate camera. This may be applied
conveniently by coiling a string upon the barrels attached to the winch. The
end of the string may be attached to the stud (1), and the falling weight hung
on a pulley under which the string passes, when the pitch of the wheel and
size of the barrel cause the fall of the weight to exceed the height at which
the camera is placed. This is not required with the size of the wheel and
barrel shewn on the Drawings, although the weight or hook to receive it is
shewn so suspended. As has already been said, the uniform rate of motion is
useless unless accompanied by an arrangement for adjusting the amount of
light. The lens must, therefore, have an arrangement like that used for
Waterhouse's diaphragms, into which the expanding diaphragm, Plate 1,
Figure (8), is inserted, and by which the exposure may be regulated with the
greatest accuracy. The speed of the rotation must be sufficiently slow to give
pictures with light of low intensity when using the largest aperture the lens
admits of. Every increase of this intensity will then require the aperture to
be reduced in a corresponding ratio, that is, the rate of motion or time of
exposure is constant, and the aperture, and consequently the amount of light
admitted, varies inversely with its intensity.
We now proceed to shew the mode of producing variable motion with the
apparatus and of adjusting it to the amount of light, the ordinary diaphragms
being used with the lens, i.e., the amount of light admitted is constant, and
the speed, and therefore the time of exposure is inversely proportionate to the
intensity of the light. A spring or weight is used, as before, but the fly

page_text: wheel y is replaced by the fly, Plate 1, (Figure 15). The arms of this fly
turn in the boss, and can be fixed at any angle by the set screw, so as to
occupy the position a or b, or any intermediate position. The resistance is,
therefore, variable, and the speed proportionate to that resistance. The range
of variation may be extended by altering the size of the weight, which, for
this purpose, and for the sake of portability, may be an india-rubber bag con-
taining a measured quantity of water, which may, of course, be increased or
diminished to effect the adjustment of the speed. Or, for slower motion, an
escapement, having a pendulum with a shifting bob, may be fixed upon the
end of the shaft (v). A change in the rate of motion is effected by sliding
the bob up or down the stem, which should be properly divided for that pur-
pose. Such an escapement is shewn by Plate 3, Figure 1, (6, 7, 8).
Plate 2, Figure 4, shews a section of the hydraulic apparatus which we also
employ for regulating the motion. 2, 2, is a piece of telescope tube closed at
each end by a screwed plug, and at one end by the disc 3 on which is a hole
fitted with a carefully turned conical valve 4. The stem of the valve is screwed
into the gland 5, and is made tight by packing at the bottom of the gland
constituting a stuffing box, communication is made between the two ends of
the tube by means of the small tube (6) two pistons 7, 7', each formed of a
cup of leather slide within the tube and are joined together by a strip of metal
cut at one side as a rack gearing into the wheel t. The spaces between the
ends of the pistons and the ends of the tube are filled with oil or other fluid
and are in communication with each other by the tube 6. This communi-
cation can be cut off either wholly or partially by means of the discand valve 4.
If a fixed pressure be brought to bear upon one of the pistons by means of
the rack and wheel, then the rate at which the liquid flows from one end to
the other can be regulated by raising or lowering the plug (1) by means of the
screw on its stem, which thus enlarges or contracts the area of the orifice in(3)
and as the wheel (t) is fixed by the arbor of the camera, the motion of the
latter is determined by the rate at which the liquid flows.
Plate 3, Figures 1 and 4, shew another mode of producing variable motion
in the camera with a considerable range. The pivot of the camera has a
toothed wheel fixed upon it which gears into the pinion 2, on the arbor of
which is fixed a light wooden or metal disc 3, fitted accurately so as to turn
truly. A square shaft runs parallel to it, its pivot being fitted at one end
into the step 10 which supports the pivot of the shaft carrying the disc and a
collar at the other end passing through the side of the box supporting the
camera shewn in the Drawing as made of light metal. Upon this shaft the
small pulley is placed which slides to and fro upon the shaft, and can be set

page_text: at any position by means of the rod and guide (9). The shaft being square
and the opening in the pulley also square, the latter is driven by the former,
the velocity being determined by the distance of the pulley from the centre
the disc. If the radius of the disc be accurately divided and set off upon
e rod (9), the velocity may be determined at will. For quick exposures
the end of the shaft 5 is fitted with a fly wheel or a fly with shifting arms
to still further extend the range of speed. For slower speeds the escapement
shown in the Drawing is attached, the rate of the maximum or minimum speed
being determined by the number of teeth on the escapement wheel. This
will of course depend upon the focal length of the lens and the nature of
the process employed. The apparatus shewn in the Drawing is moved by a
weight and string coiled on the edge of the disc 3 passing over a pulley in the
side of the box. Instead of this a coiled spring may be placed upon the
shaft g, and we prefer this arrangement for the circular plate camera. When
the fly wheel is used a small stud upon it serves as a handle to wind up the
apparatus and reverse the motion, but when the escapement is used the
pulley 4 must be pushed off the disc and the camera itself moved round. In
all these arrangements provision must be made to arrest the camera when
wound up, which may be done by a looped string and button, a pin dropping
into a hole in the disc or table, or a latch and pin; the pulley is then placed
upon the disc at the required position, the loop or pin removed, when the
camera will travel at the required rate. To enable the pulley in this and in
the subsequent arrangements for moving the plate holderabout to be described
to bite upon the plate its rim should be formed of leather or india-rubber,
this yields and forms a flattened edge upon the disc and effectually prevents
slipping. Before proceeding to the portable form of panoramic camera shewu
by Plate 3, we will describe some of those other modes of communicating
motion from a disc or pulley to the plate holder to which we have already
alluded (see Plate 1), we find for instance that we may substitute a slip of
india-rubber fixed upon the carriage or plate holder instead of the cord or
strap we have described. Fig. 12 shews this arrangement, i is the disc as in
plate 2, the carriage, and e the plate holder, a strip of india-rubber or
other flexible matter is shewn by the thickened line upon f. This is pressed
upon the edge of the disc by means of the rollers upon the back of the carriage
and it then moves on the rotation of the camera as the rack upon the fixed
toothed wheel.
Figure 13 shews another modification by which the toothed wheel or disc
may be entirely outside the camera, the communication being made by two
pulleys or cogged wheels (accordingly as the disc or wheel is used) to transmit
C

page_text: the motion from the disc or wheel without to the carriage and india-rubber
slip or rack within, or the wheels may run upon the surface of the disc, the
dimensions of the disc being then determined by the distance at which the
acting part of the pulley, covered as before with leather or india-rubber
placed from the pivot of the camera. This must be determined by trial.
the disc which may then be the top of the supporting box, be large enough,
this arrangement admits of the camera being drawn back for focussing near
objects or to receive a lens of longer focus. This arrangement is shewn in
greater detail in Plate 3, in which Figures 1, 2, 3, 4, are views of the portable
camera, 1 is a vertical section through A, B, 2 an elevation of the back of
the camera, 3 partly a plan partly a section through (E, F,) and 4 a plan of
the supporting box with its lid removed showing the apparatus already
described.
It will be seen that the tube (c) in Plate 2 is replaced by the short frame
or support c of Plate 3, shewn clearly in the section Figure 1, and indicated
by the same letters and curved dotted lines in Figure 2. This frame carries
3 rollers 1, 2, 2, on the bottom, the middle one of which is in communication
with the friction rollerk, deriving motion from the disc, which in this case is the
top of the metal box, the dimensions of the disc, or the length of the course
of the roller being adjusted by the distance of the latter from the pivot under
the centre of the lens.
Another roller m is fixed on the top of the frame by means of two strips of
brass fixed to the frame at one end by a screw upon which the brass roller turns
as upon a centre, and at the other by a pin or thumbscrew, on removing the
pin or thumbscrew the roller can be raised so that the plate holder or dark
slide can be placed upon the lower rollers, when the top roller is lowered, and
the position of the plate holder secured, the rollers fitting into grooves in its
top and bottom, so as to retain it laterally. The length of the dark slide is
extended at each end by wider stiles so that it may be in gear with the rollers
before the plate comes in front of the opening in the camera. It is closed by
a flexible shutter twice the length of the dark slide. Upon the centre of
the shutter a flanch is fixed, which enters into the opening of the
camera when the dark slide is inserted between the rollers. This prevents
the forward motion of the shutter when the camera rotates, the dark slide
alone moving forward, and bringing the plate opposite the flanch, and opening
in the camera.
At the commencement of the operation the flanch is opposite one of the
wide stiles of the dark slide or even somewhat overhanging it. We prefer
to make the inner surface of the flexible shutter of velvet, which effectually

page_text: excludes the light at the ends of the dark slide. The adjustment and
manipulation with this camera are similar to those of the other except as
to the insertion of the slide. We have shewn this camera worked with a
vertical roller on the horizontal surface of a disc, but the other modes of
obtaining the motion of the plate to the rotation of the camera may also be
employed as will be obvious to any workman.
The form of the apparatus may be modified and made to pack into smaller
space by substituting a board for the camera b, b, in which c slides. The
board which is like the base board of an ordinary camera is fixed upon the
pivot in front, and upon a pair of rollers behind. The lens is placed on a
board with a slide, which is clamped by screws in a vertical position over the
pivot, it is joined to the frame, which carries the rollers driving the slide by a
"bellows" or other flexible camera body. The frame is clamped upon the
base board at a suitable distance from the lens according to its focus. On
the clamps being unscrewed, the frame, lens, board, and "bellows body," can
be packed in a very small space. The base board is also the best form of
supporting and giving motion to the camera of form Figure 6, Plate 1. It
must have three rollers on its surface to support the end of the box carrying
the plate, and allow of its motion laterally while the base board rotates.
All the improvements which we have described for giving more uniform
motion to the apparatus, and for regulating the exposure and the amount of
light to different parts of the picture are applicable to the circular plate
camera with a rotating lens as well as to the flat plate camera. The circular
plate or "Martin's" camera is described in several works of photography
usually as applied to be used with curved Daguerreotype plates. This form
may be used for sensitive paper, and other processes on a flexible material as
talc, gutta percha, &c., by using a thin plate of metal having a narrow frame
of metal attached to it by a hinge. The paper or other flexible material is
placed between the plate and frame, and the latter is fastened to the former
retaining the paper &c., straight between them. The whole may then be
treated as a Daguerreotype plate, and bent to the proper curve in the camera,
or the paper or other material may be upon rollers, and be stretched over the
back of a curved frame a portion being brought forward for each view. For
glass plates a dark slide must be attached as in ordinary cameras, but made
of the proper curve. The narrow tube which rotates in this camera, and
limits the angle of the rays acting upon the plate must be fixed upon the pivot
under the lens instead of the camera itself in the flat plate arrangement.
The end of the rotating tube must be fitted with our expanding diaphragm,
and if a fixed rate of motion be employed the lens must have an expanding

page_text: diaphragm in front of it. As the force required to cause the inner tube to
revolve is much less than that required for the various moving parts of the
flat plate camera, a weak spring fixed on the pivot (g) is sufficient to give
the motion.
If the arrangement shewn in Plate 3 be used for giving motion to the tube
provision must be made for rewinding the spring. This should be attached
to the rest of the apparatus by a ratchet so that the spring and shaft alone
move backwards. An arbor or shaft may be fixed upon the board carrying the
lens, and be extended through the top of the fixed camera, and a key or thumb
screw be there applied for winding a spring, and moving back the rotating
tube.
In witness whereof, I, the said John Robert Johnson, have hereunto
set my hand and scal, this 5th day of March, in the year of our Lord
One thousand eight hundred and sixty-three.
JOHN ROBT. JOHNSON. (L.S.)