IMPROVEMENTS IN STEREOSCOPES, STEREOSCOPIC PIC- TURES, AND CAMERAS FOR TAKING THE SAME.”
Year: 1860

page_text: LETTERS PATENT to Henry Swan, of 5, Bishopsgate Street Without,,
for the Invention of "IMPROVEMENTS IN STEREOSCOPES, STEREOSCOPIC PIC-
TURES, AND CAMERAS FOR TAKING THE SAME.”
TURES, AND CAMERAS FOR TAKING THE SAME."
PROVISIONAL SPECIFICATION left by the said Henry Swan at the
Office of the Commissioners of Patents, with his Petition, on the 29th
February 1860.
I, HENRY SWAN, of 5, Bishopsgate Street Without, do hereby declare the
nature of my Invention for "IMPROVEMENTS IN STEREOSCOPES, STEREOSCOPIC
PICTURES, AND CAMERAS FOR TAKING THE SAME," to be as follows:-
This Invention has for its object improvements in stereoscopes, stereoscopic
pictures, and cameras for taking the same. Heretofore it has been usual, in
the construction of stereoscopes, to employ prisms or lenses of the same
magnifying power opposite each of the eyes, and to use them in conjunction
with pictures in which the two views forming the stereoscopic combination aro
of equal size. Now, according to my Invention, I construct stereoscopes with
prisms or lenses of different magnifying powers, that is to say, the prism or
lens opposite one eye exceeds in magnifying power the prism or lens opposite
the other eye, and I use such instruments in conjunction with pictures in
which the two views forming the stereoscopic combination are of different
sizes, and corresponding with the different powers of the prisms or lenses

page_text: opposite the two eyes; and these pictures, according to my Invention, I
connect together by attaching them both in suitable positions to the same
mounting. In this manner, by the use of one large picture only, I am
enabled to obtain stereoscopic effect combined with minuteness of detail, such
as a large picture alone can give, and am also enabled to arrange the instru-
ment in a form which is much more convenient than that of the instruments
heretofore employed for viewing large pictures.
In some cases I construct instruments having one prism or lens only, the
large picture being then seen without the aid of a prism or lens. Magni-
fying mirrors may be employed in place of prisms and lenses, but not so
advantageously.
My improvement in cameras has for its object the so arranging the same,
that a large and a small picture forming a stereoscopic combination, as above
explained, may be taken at the same time, and on the same plate or surface.
For this purpose the camera is fitted with two lenses, the focal length of the
lenses for taking the larger picture being greater than that of the lens for
taking the smaller picture. These lenses are so placed as to focus on the same
plane or flat surface, and are furnished with separate adjusting screws or means
of adjustment.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Swan in the Great Seal Patent Office on the
29th August 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
SWAN, of 5, Bishopsgate Street Without, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of February, in the year of our
Lord One thousand eight hundred and sixty, in the twenty-third year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Henry Swan, Her special licence that I, the said Henry Swan,
my executors, administrators, and assigns, or such others as I, the said. Henry
Swan, 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 "IMPROVEMENTS IN
STEREOSCOPES, STEREOSCOPIC PICTURES, AND CAMERAS FOR TAKING THE SAME,"

page_text: upon the condition (amongst others) that I, the said Henry Swan, 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 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 Swan, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
This Invention has for its object improvements in stereoscopes, stereoscopic
pictures, and cameras for taking the same. Heretofore it bas been usual, in
the construction of stereoscopes, to employ prisms or lenses of the same
magnifying power opposite each of the eyes, and to use them in conjunction
with pictures in which the two views forming the stereoscopic combination are
of equal size. Now, according to my Invention, I construct stereoscopes with
prisms or lenses of different magnifying powers, that is to say, the prism or
lens opposite one eye exceeds in magnifying power the prism or lens opposite
the other eye, and I use such instruments in conjunction with pictures in
which the two views forming the stereoscopic combination are of different
sizes, corresponding with the different powers of the prisms or lenses opposite
the two eyes, and these pictures, according to my Invention, I connect
together by attaching them both in suitable positions to the same mounting.
In this manner, by the use of one large picture only, I am enabled to obtain
stereoscopic effect, combined with minuteness of detail, such as a large picture
alone can give, and am also enabled to arrange the instrument in a form
which is much more convenient than that of the instrument heretofore
employed for viewing large pictures.
The most convenient sizes for the two pictures of a stereoscopic combination
I believe to be four and a half inches square for the larger picture, and one
and a half for the smaller; I shall therefore describe the apparatus necessary
for taking and viewing pictures of these proportions. I would remark,
however, that by increasing the size of tho larger picture greater minuteness
of detail may be obtained, but it is not convenient to increase the width of the
smaller picture. If the size of the larger picture be increased, the apparatus
required for taking and viewing it will be more expensive and larger, and the
cost also of the picture itself will be greater. The two pictures of a
stereoscopic combination I prefer to mount in the following manner :-I take

page_text: a piece of cardboard, or it may be stiff paper, seven inches wide and fifteen
and a half inches long, and I double it end to end (a cut being made, sup-
posing cardboard to be employed, half through the cardboard from the back, to
cause it to fold readily); another fold parallel to the first is also simi-
larly made at a distance of two and a half inches from one end of the
card or paper, which is then folded to a trough-like form, thus
On the inner side of the larger flap, and in the centre thereof, I mount the
larger picture, the bottom of the same being towards the centre of the
mounting. In the smaller or upper flap I cut a hole two inches square,
the upper edge of the hole comes to within half an inch of the end of the
mounting, and its right or inner edge is a quarter of an inch beyond the
centre line of the mount. On the outer side of the upper flap the smaller
picture is mounted; its top comes to within three-quarters of an inch of the
end of the mount, and its left side is close to the right edge of the hole.
When the pictures are being viewed in a stereoscope, the mounting is folded
as above described, but for packing, the upper flap and centre portion of the
mounting, fold flat, and cover the larger picture. I find that an ordinary
open stereoscope, with the following modifications, is very suitable for viewing
stereoscopic combinations such as above described :-The distance of the stage
of the instrument from the lenses should be seven and a half inches; the
diaphragm separating the two views, or limiting the view of each of the eyes
to the picture intended for it, should not descend more than about two inches
below the lenses. The right eye piece should be mounted with a complete
lens of three inches focal length, and the left eyo piece also with a complete
lens, but of twelve inches focal length.
When the pictures mounted as above described are placed in the instru-
ment, the smaller picture will be so much nearer to the eye than the larger
picture as to appear of the same size as it; the two pictures will also appear
to coincide, and the stereoscopic effect will be produced. In printing the
pictures, care should be taken that the small auxiliary pictures be free as far
as possible from any appearance of grain in the surface, or the effect will be
marred thereby. I prefer to print the auxiliary picture somewhat darker
than the principal picture. It will readily be understood that instruments
may be constructed having one prism or lens only, the large picture being
then seen without the aid of a prism or lens. Magnifying mirrors may be
employed in place of prisms and lenses, but not so advantageously.
My improvement in cameras has for its object the so arranging the same
that a large and a small picture forming a stereoscopic combination, as above

page_text: explained, may be taken at the same time and on the same plate or surface.
For this purpose the camera is fitted with two lenses, the focal length of the
lens for taking the larger picture being greater than that of the lens for
taking the smaller picture; these lenses are so placed as to focus on the same
plane or flat surface, and are furnished with separate adjusting screws or means
of adjustment.
The form of camera which I prefer is that of the ordinary binocular camera
with the following modifications:-The body of the camera to be made very
shallow, say, three inches between front of camera and focussing glass. The
vertical partition or diaphragm used to prevent the two images formed on the
focussing glass from mingling should be placed two inches from the right-
hand side of camera, thus dividing the interior of the body of camera into
two unequal portions, the larger portion being of sufficient size to take the
larger picture. A lens of short focus, mounted with a simple screw adjust-
ment, is placed on the front of the smaller chamber for the purpose of taking
the small picture; for a picture of one and a half inches square the focal
length should be two and a half inches. In order to take the large view on
the same plate, the larger chamber or division of the camera is provided with
a sliding wooden body capable of drawing outwards, and thus extending the
depth of the larger chamber. This sliding body bears on its front the lens of
longest focus, which lens is itself fixed in a brass mount, having two sliding
tubes instead of one only, in order to obtain still further extension, and enable
the lens to be drawn out to the full extent required. The sliding body and
tubes of the larger lens should be so formed as not to interfere with the view
of the smaller lens.
The focal length of the lens to take a picture four and a half inches square
should be seven and a half inches, and the horizontal distance between the
centres of the two lenses is preferred to be two and a quarter inches.
In witness whereof, I, the said Henry Swan, have hereunto set my
hand and seal, this Twenty-ninth day of August, in the year of our
Lord One thousand eight hundred and sixty.
HENRY SWAN. (L.S.)