IMPROVEMENTS IN THE CONSTRUCTION OF STEREOSCOPES
Year: 1859

page_text: LETTERS PATENT to Charles Fréderic Vasserot, of 45, Essex Street,
Strand, London, Patent Agent, for the Invention of "IMPROVEMENTS IN
THE CONSTRUCTION OF STEREOSCOPES."-A communication from Henry
Adolphe Corbin, residing in Paris, in the Empire of France.
Sealed the 13th December 1859, and dated the 17th June 1859.
PROVISIONAL SPECIFICATION left by the said Charles Frederic Vasserot
at the Office of the Commissioners of Patents, with his Petition, on
the 17th June 1859.
J, CHARLES FREDERIC VASSEROT, of 45, Essex Street, Strand, London,
Patent Agent, do hereby declare the nature of the said Invention for "Im-
PROVEMENTS IN THE CONSTRUCTION OF STEREOSCOPES," a communication from
Henry Adolphe Corbin, residing in Paris, in the Empire of France, to be
as follows:-
The object of this new system of stereoscopes is to give the power of seeing
in relief pictures, much more enlarged or amplified than can be effected by the
present system.
My system consists in combining the present form of lenticular or prismatic
stereoscope with an improved form of reflecting stereoscope, that is to say, by
a combination of reflecting medii and transmitting medii.
To explain my mode of constructing more easily, I have appended the

page_text: accompanying Diagram, where S, A, and S, B', are lines representing the
projection on the horizontal plane of two reflecting mirrors S, A, and S, B¹.
A, B, and A', B₁, are similar projections of two pictures in the ordinary
stereoscope condition, and so placed that their reflexions upon the mirrors
shall be in a plane, represented by the line A, B1, which is perpendicular to
the line bisecting the angle A, S, B', formed by the planes of the mirrors. It
will be easily seen, that for all suitable values of the angle A, S, B¹, or all
suitable positions of the pictures A', B', and A, B, I am enabled to obtain
such a partial superposition of A, B, and A", E₁, by reflexion as I wish, that
is, I can regulate the size B", B¹, at will. I now place two ordinary lenses
o, o', as shewn, in a plane at right angles to the line bisecting the angle
A, S, B', and I arrange my mirrors or my pictures so that B, B', shall be
equal to the distance between the two lenses. On looking now through the
lenses o, o', the pictures A, B, and A', B', will be seen exactly superimposed,
and much larger than if I employed the lenses alone.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Frédéric Vasserot in the Great Seal Patent Office
on the 17th December 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
FREDERIC VASSEROT, of 45, Essex Street, Strand, London, Patent Agent, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of June, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Charles Fréderic Vasserot, Her special licence that I, the said Charles
Fréderic Vasserot, my executors, administrators, and assigns, or such others
as I, the said Charles Fréderic Vasserot, 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 Inven-
tion for "IMPROVEMENTS IN THE CONSTRUCTION OF STEREOSCOPES," a communication
from Henry Adolphe Corbin, residing in Paris, in the Empire of France, upon
the condition (amongst others) that I, the said Charles Fréderic Vasserot,
my executors or administrators, by an instrument in writing under my, or

page_text: 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 Charles Fréderic Vasserot, 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 :-
of
The object of this Invention is to give the power of seeing in relief pictures
size (according to the proportions of the apparatus) much more enlarged
or amplified than can be effected by the present system of stereoscopes.
any
In the annexed Drawing the Figs. 1, 2, 3, 4, & 5, exhibit the principle of
the Invention; Figs. 6, 7, 8, & 9, show different ways of applying this
principle. In Fig. 1, A, B, A¹, B', are two ordinary stereoscopic pictures;
0, 0¹, the lenses of the stereoscope; and c, c¹, the centre of the pictures. The
width A, B, or C, C', the distance between the centres of the pictures is equal
to the distance o, o', of the lenses.
In Fig. 2 I obtain the angle of vision A, O, B, more considerable than it
is possible with the ordinary system. A, B, is one of the pictures, and A', B',
is the other, taken in reference to A, B, under the required stereoscopic angle,
but similar to A, B, and making a certain angle with A, B. I place a mirror
B, D, in the plane of the line bisecting the angle A, B, A'; if then the eyes
are placed at o & o', the two pictures A, B, A', B', will be seen superimposed,
and the sensation of the relief will be produced. Let us suppose now that the
points B&B' instead of coinciding are set apart of a distance B, B', equal
to o, o¹, distance of the two eyes.
In Fig. 3 lenses are placed at o, o¹, at the ordinary distance between them,
and at the usual distance c, o, from the pictures. B', A', is the reflection
of A, B, in the mirror D, B'. Supposing that the centre of the lens o
corresponds with c, the centre of A, B, and the centre of o¹ with c', the centre
of B', A', it is clear that by looking through o & o' the two pictures A, B,
& B¹, A³, will be seen perfectly superposed, and much larger than the ordinary
pictures, although placed at the same distance from the eye. For obtaining
the maximum size of the proofs which it is desired to superpose; the part B' is
moved from the mirror, and the picture B³, A, is prolonged as much as it is
not concealed by the observator looking through o & o. It will then be easy
to find out the angle A, B, A', which is the most suitable for the longest sight
and how far the proof B', A', may be prolonged. This disposition is perfectly

page_text: applicable when the focus c, o, is to be augmented, as it is shown in Fig. 4.
So that c & c', the centres of A, B, & A', B', might well correspond with
o and o', it is necessary that B, B', be equal to o, o'. It is clear that a similar
disposition may be made by diminishing the focus c, o.
In every arrangement founded upon the above combination, it is always
possible to substitute for the picture A, B, a picture A, B, Fig. 5, similar
to A, B, and symetrically placed in reference to A', B', and to A, B, connected
to a mirror D' in the plane of the bisection of the angle B, A, B, so that the
two parts left and right of the apparatus present the same disposition; but
this arrangement would be inferior to the preceding, because, 1stly, it would
be more costly by reason of the mirrors; 2ndly, the pictures seen in a mirror.
are always less clear than those seen directly, and the advantage of seeing
directly the picture A, B, would be lost; and, 3rdly, the proofs A, B, & A¹, B',
could not be transposed, that is to say, placed indifferently one on the right
and the other on the left. In the former arrangement the transposition of the
proofs does not modify the relief.
I shall now describe the construction of the apparatus and the manner of
disposing the pictures, which I suppose to be stereoscopic pictures (Figs. 6, 7,
8, & 9). Let us suppose that I adopt the right angle for the angle of the two
pictures, as well as the focus of about 5 inches, which is usual with the
ordinary stereoscopes. I can give to my apparatus the symetrical shape
shown in Fig. 6; or, if desired, I can leave off the part a, h, e, by closing it,
according to the dotted line 7'. The lenses 1, 1¹, are placed so as to correspond
with the half of the height of the proofs, and the grooves 1, 2, hold the proofs
in their suitable positions. o corresponds to the centre of a, b, & o¹ to the
centre of a', b', by the reflection of the mirror d. This mirror is placed in the
plane of the bisection of the angle a, b', a¹. It is of small thickness, and it is.
fixed to the board d' by means of paper glued on its edges. It can, as well
as the board, be made to slide in grooves, or it may be fixed to the box by any
suitable means. The upper part of the box may be covered with rough glass,
so as to regulate the light, or by any kind of cover.
Fig. 7 is a vertical section taken on the line x, y, of Fig. 6. The apparatus
can have a height of about six inches, more or less, but it must be equal to
the width of the pictures, so as to show square proofs, which will be quadruple
the area of the ordinary proofs. If it is desired to have a focus equal to a¹, b¹,
the width of the pictures, the apparatus must be of the square shape, shown in
Figs. 8 & 9. It is possible to obtain transparent pictures by cutting out the
partitions a, b, and a', 6', and by closing the top of the box by means of an
opaque lid f. The proofs in this case may be on glass or transparent paper.

page_text: It is evident that an analogous disposition is applicable to all the different
shapes which I can give to the apparatus. The photographic proofs to be
seen in this apparatus are to be taken in a peculiar way, which I claim as
part of my Invention. There will be two stations of apparatus, or two
apparatus suitably distanced from each other, as in the ordinary system, by
adopting the disposition of the Fig. 5. The picture taken by the apparatus
corresponding to the left of the operator will be taken on the right as usual,
but the picture of the apparatus on the right will be taken inverted. For
obtaining this inverted view, the prepared glass is turned over so as to turn its
unprepared surface towards the object, or else the picture may be taken in a
looking glass. If I had placed my glass in the plane of the bisection of
e, a, b, Fig. 6, it would be the proof of the left station, which should be
reversed.
I claim besides the apparatus, the combination of proofs entirely new, since
with my system it is necessary for seeing in relief two proofs taken under a
certain angle, one of which is right and the other inverted.
I claim also the disposition allowing to see in relievo pictures of any size,
the several arrangements which the apparatus may receive; the arrangement
of the inside mirror; and, finally, the inversion of one of the two proofs.
In witness whereof, I, the said Charles Fréderic Vasserot, have hereunto
set my hand and seal, this Seventeenth day of December, in the year
of our Lord One thousand eight hundred and fifty-nine.
CH. FRED. VASSEROT. (L.S.)