IMPROVEMENTS IN APPARATUS FOR EXHIBITING DISSOLVING VIEWS." PROVISIONAL SPFICATION
Year: 1863

page_text: LETTERS PATENT to Peter Hubert Desvignes, of Lewisham, in the County
of Kent, Gentleman, for the Invention of "IMPROVEMENTS IN APPARATUS
FOR EXHIBITING DISSOLVING VIEWS."
PROVISIONAL SPECIFICATION left by the said Peter Hubert Desvignes
at the Office of the Commissioners of Patents, with his Petition, on the
8th December 1863.
I, PETER HUBERT DESVIGNES, of Lewisham, in the County of Kent,
Gentleman, do hereby declare the nature of the said Invention for "Im-
PROVEMENTS IN APPARATUS FOR EXHIBITING DISSOLVING VIEWS," to be as
follows:-
My Invention consists in constructing an apparatus which I may term a
double stereoscope with screens for admitting and excluding light when and
as may be necessary, and with two holders for containing the stereoscopic,
mimoscopic, or other pictures or objects to be viewed. In addition to the
ordinary glasses I employ a diaphanous reflector placed at an angle to those
glasses in such manner that when one screen is raised to admit light, the
picture in a line with the ordinary glasses shall be viewed, then, upon gradually

page_text: closing that screen and opening the other, the picture first seen gradually fades
away or dissolves, while another picture gradually and finally appears entirely
to the view.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Peter Hubert Desvignes in the Great Seal Patent Office on
the 8th June 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PETER
HUBERT DESVIGNES, of Lewisham, in the County of Kent, Gentleman, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of December, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-seventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Peter Hubert Desvignes, Her special licence that I, the said
Peter Hubert Desvignes, my executors, administrators, and assigns, or such
others as I, the said Peter Hubert Desvignes, 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 APPARATUS FOR EXHIBITING DISSOLVING VIEWS," upon the
condition (amongst others) that I, the said Peter Hubert Desvignes, 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 Peter Hubert Desvignes, 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 thereof, reference being had to the Drawings hereunto
annexed, that is to say:-
My Invention consists in constructing an apparatus which I may term a
double stereoscope with screens for admitting and excluding light when and
as may be necessary, and with two holders for containing the stereoscopic or

page_text: other pictures or objects to be viewed. In addition to the ordinary glasses 1
employ a diaphanous reflector placed at an angle to those glasses, in such
manner that when one screen is raised to admit light, the picture in a line
with the ordinary glasses shall be viewed, then, upon gradually closing that
screen and opening the other, the picture first seen gradually fades away or
dissolves, while another picture gradually appears in its place, and so on alter-
nating for any given number.
Figure 1 of the accompanying Drawings is a vertical section, and Figure 2
a plan with the top removed, of an apparatus constructed according to my
Invention. A, A', are two boxes or cases similar to that of an ordinary
stereoscopic; B, B¹, are screens or shutters for admitting and excluding light
when and as required; when the shutter B is open the shutter B¹ inust be
closed, and vice versâ ; C is a cord by which the shutter B may be closed, and
by which the extent to which it is open is regulated; D is a projection fixed
to the shutter B¹ for opening and closing it, or a friction lever may be
employed. In large apparatuses the shutters must be counterpoised and
connected by pulleys and cords within reach of the operator; E, E', are two
holders for containing the stereoscopic or other pictures or objects to be viewed,
which are introduced through openings F, F¹; G, G, are diaphanous reflectors
placed at an angle to the ordinary glasses H, H. I prefer to use as these
reflectors what is known as No. 1 test glass (employed for the coverings of
microscopic test objects), or Muscovy glass, or selenite finely divided, or glass
ground and polished to extreme thinness and perfectly even, or glass of
prismatic or wedge shape. I attach the reflectors G, G, to small frames I, I,
and introduce them into the apparatus at the point J; K is a partition in
front of and between the glasses H, H; L, L', are levers for facilitating the
removal of the views or pictures. In Figure 2 one picture is shewn in its
place, while the other is partly driven forward by the lever L'; M, M', are
buttons on the ends of rods M', jointed to the levers L, L'; by pressing on
these buttons the levers are caused to drive out or remove the views or slides;
springs N return the rods M' and levers L, L', to their original position;
0, 0, are spaces to admit the levers L, L'; and O', projections to steady and
protect the levers; these projections may also be used to hold the apparatus
when no stand is employed. The views or pictures are kept pressed against
the projections Q by springs P; R, R, are cross pieces for confining the rays,
they should be covered with black velvet or other dark material. The inner
surface of the box A', and of the shutters B, B¹, should be coated or covered
with some bright material to concentrate the light; S, S, are diaphragms with
separate openings to confine the rays. I continue the sides of the apparatus

page_text: at back in the form of a hood T to exclude false light, and I form the back of
the apparatus as represented at U to fit the contour of the face. The dotted
line U, represents the part for fitting the forehead; V represents the point
of sight, and V₁ another point, assumed equidistant from the centre of the
diaphanous reflector, by which the angle distance and inclination of the
lines V, W, V¹, W¹, are regulated according to the well-known laws of
dioptrics. In the position of the shutters B, B¹, shewn in the Drawings, the
view or picture in the holder E, which is in a line with the glasses H, H, will
be viewed; when, on the contrary, the shutter B is closed and the shutter B¹
opened, the picture in the holder E will no longer be seen, but that in the
holder E¹ will be reflected by the reflectors G, G, and appear to the view.
When it is desired to view those pictures known as transparencies I fit the
shutters as represented by the dotted lines X, X, and connect them by a wire
or cord, so that when one shutter is closed the other is open.
Figure 3 is a perspective view of an apparatus similar to that represented
in Figures 1 and 2, but placed in an inverted or reversed position, similar
letters of reference indicate corresponding parts to those in Figures 1 and 2.
Y is a stop to retain the shutter B¹ in the best position for light, and Z an
inclined plane for closing the shutter B; a is a mill-headed friction pulley for
regulating the position of the shutters. Figure 4 is a view of the opposite
side of the apparatus represented in Figure 3, shewing more clearly the
shutters or screens X, X, used for transparencies drawn in full lines. I regulate
the opening and closing of the shutters by a crank b, c, d, moving on the
centre c; e, e, are rods connected to the shutters in such manner that the
upper shutter remains open while the lower is also opening. Figure 5
represents the manner in which I prefer to hold several views or pictures
which it is desired to exhibit in succession. f is a helical plane or screwed
vane, by turning which one view or picture becomes disengaged and falls into
its place. I form a receptacle for the views at the back of the lower box A³,
Figure 1, from which they fall successively into the holder E¹; the views or
pictures for the upper box A are held in the holder E, and after having been
viewed, fall into a receptacle at g. When the views are large and heavy I
drive them forward at the lower part h, Figure 5, to their proper line by
means of a pulley with a screw. I connect this pulley with the pulley i, and
with others not shewn in the Drawings, so that the hand need not be incon-
veniently extended to reach them. For small views a spring will be sufficient
to keep the lower part in place. For large pictures the views may be
conveniently situated side by side horizontally and at right angles or other
angles, in which case the diaphanous reflectors should be placed vertically.

page_text: And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I do not confine myself to
any particular shape or construction of the apparatus, nor to any particular
method of introducing and removing the views or pictures, or of opening and
closing the screens or shutters, and that I claim as the "Improvements in
Apparatus for Exhibiting Dissolving Views,"
First, the general arrangements of apparatus herein-before described and
illustrated in the accompanying Drawings.
Second, the employment in such apparatus of diaphanous reflectors,
substantially in manner herein-before described.
In witness whereof, I, the said Peter Hubert Desvignes, have hereunto
set my hand and seal, this Eighth day of June, One thousand eight
hundred and sixty-four.
PETER HUBERT DESVIGNES. (L.B.)