IMPROVEMENTS IN STEREOSCOPES
Year: 1863

page_text: LETTERS PATENT to Victor Julien Cassaignes, of No. 8, Rue des
Fosses, St. Jacques, Paris, in the Empire of France, for the Invention
of "IMPROVEMENTS IN STEREOSCOPES."
Sealed the 2nd October 1863, and dated the 13th May 1863.
PROVISIONAL SPECIFICATION left by the said Victor Julien Cassaignes
at the Office of the Commissioners of Patents, with his Petition, on
the 13th May 1863.
I, VICTOR JULIEN CASSAIGNES, of No. 8, Rue des Fosses, St. Jacques,
Paris, in the Empire of France, do hereby declare the nature of the Invention
for "IMPROVEMENTS IN STEREOSCOPES," to be as follows:-
This Invention consists in coloring the prisms or lenses of stereoscopes
with different colors, or in coloring one portion only of the prisms or lenses,
leaving the other portion uncolored. By these means the stereoscopic picture
when viewed through the instrument may be seen under different aspects,
such, for instance, as the effects of morning, sunshine, or night. The same
result may also be obtained by employing a tinted glass interposed between
the picture and the eye either immediately over or under the prisms or lenses,
the glass being tinted with different colors, or a portion only of the glass being
colored. As in the case of the colored prisms or lenses, the prisms or lenses
or colored glasses may be either fixed or moveable; when moveable, the effects
can be considerably varied.

page_text: The prisms or lenses of a stereoscope may be colored at those parts through
which the foreground of the picture is viewed with a tint suitable for the
foreground, I prefer for this a yellow or golden color; and those parts of the
prisms or lenses through which the background and sky of the picture is
viewed may be colored with a tint suitable for the background and sky; I
prefer blue for these parts. These colors in passing from the bottom to the
top of the prisms or lenses I shade off the one into the other in a regular
gradation of tints. It is not essential that both the bottoms and tops of the
lenses should be tinted, a very good, although not so perfect an effect may be
obtained by tinting either the tops or the bottoms only with a suitable tint,
leaving the bottoms or tops, as the case may be, colorless. This arrangement
also will produce on the stereoscopic image two different tints, that is to say,
that one part of the image will preserve its own proper tint whilst the other
part will take the color given to it. In place of applying the tints to the
lenses, a tinted glass may, as above stated, be interposed between the picture
and the eye either immediately over or under the prisms or lenses, the glass
being, as already described, either colored with two or more different colors,
or a portion only of the glass being colored, the other portion being uncolored.
In place of colored glasses, other transparent colored substances, such as
gelatine, collodion, gum, born, and others, may be employed to produce
analogous effects to those of colored glass.
My Invention consists essentially in producing the coloration of the
stereoscopic image by means of a transparent, colored surface interposed
between the picture and the eye of the observer in such a manner that this
presents two or a greater number of different tints. This improvement can be
applied to all sorts of stereoscopes, and I name chromo-stereoscopes all
stereoscopes provided with it.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Victor Julien Cassaignes in the Great Seal Patent Office
on the 10th November 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, VICTOR
JULIEN CASSAIGNES, of No. 8, Rue des Fosses, St. Jacques, Paris, in the
Empire of France, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of May, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-sixth year of Her

page_text: reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Victor Julien Cassaignes, Her special licence that 1, the said Victor
Julien Cassaignes, my executors, administrators, and assigns, or such others
as I, the said Victor Julien Cassaignes, 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, tho Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN STEREOSCOPES," upon the condition (amongst others) that I,
the said Victor Julien Cassaignes, 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 Victor Julien Cassaignes, 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:-
This Invention has for its object improvements in stereoscopes, and consists in
coloring the prisms or lenses of stereoscopes, so that each prism or lens presents
several different tints or colors, and so that consequently the pictures or images
seen through these glasses will appear under different aspects, giving, for
example, the effects of morning, of sunrise, or of moonlight. Thus, for
example, to have the foreground of a golden color, the distance neutral, and
the sky blue, the upper parts of the prisms or lenses should be colored bluo
and the lower parts yellow, and between the two thero should be a gradual
gradation of the two colors, the one passing into the other. Other colors may
be similarly applied to the prisms or lenses, and thus three or a greater
number of colors may be employed; or a single color may be used, being made
to shade off gradually into the colorless glass; thus blue may be applied to
the upper parts of the prisms or lenses so as to tint the skies of the pictures
seen through them. The same effects can be obtained with the ordinary
uncolored prisms or lenses by placing over or under them a flat glass colored,
as above described, with gradations of colors passing gradually the one into
the other.
In place of glass, other transparent substances capable of being colored may
be employed, such as gelatine and others. These prisms, lenses, and colored
glasses or substances may be either fixed or moveable; by making them move-

page_text: able, so that parts differently colored may in succession be brought opposite to
the oyes, considerable variety of effect may be attained.
The way which I prefer for coloring the prisms, lenses, or glasses is that
for which Provisional Protection has been granted to me, dated October 23rd,
1868, No. 2618, that is to say, I employ plano-convex prisms or lenses, and I
paint on to their flat sides a cement (I prefer a resinous cement) colored with
transparent colors to the tints required, and by means of the cement so
applied I attach to the prism or lens a piece of flat glass which serves to cover
and protect the painted surface.
In case it is desired to employ a flat colored glass placed over or under
uncolored prisms or lenses, I employ similar means for coloring such flat glass
and protecting its colored surface.
I find Canada balsam, prepared in the manner now practiced for cementing
together lenses for optical purposes, a suitable cement to employ. This
improvement can be applied to all descriptions of stereoscopes, and I call
chromo-stereoscopes all stereoscopes so constructed.
In witness whereof, I, the said Victor Julien Cassaignes, have hereunto
set my hand and seal, this Twenty-third day of October, in the year
of our Lord One thousand eight hundred and sixty-three.