An Apparatus for Drawing, without any Knowledge of Perspective, any Object or Combination of Objects from Nature.
Year: 1892

page_text: Date of Application, 15th Sept., 1892
Complete Specification Left, 14th June, 1893-Accepted, 29th July, 1893
PROVISIONAL SPECIFICATION.
An Apparatus for Drawing, without any Knowledge of Perspective,
any Object or Combination of Objects from Nature.
I, KARL GENGNAGEL, Ph.D., M.A., of Halle-Wittemberg University, Private
Tutor, residing at Glen View, Southwater Villas, St. Leonards-on-Sea, in the
County of Sussex, do hereby declare the nature of this invention to be as
follows:-
The stereograph consists of a board similar to a drawing board along the top
edge of which a tube is fixed with a longitudinal slot in it, about the length of the
board itself. A light carriage on wheels (or in its absence a smooth piece of metal
or other substance) runs inside along this tube in either direction and is connected
at right angles through the slot to a frame outside the tube. This frame consisting
of one or more (paralle!) tubes or rods extends right across the board to its lower
edge and, with the carriage inside the tube, presents the shape of the letter T, at
the lower end of which a small wheel is fixed to reduce its friction and to support
it. A sliding piece for holding or guiding the pencil is fitted on, between, or
under the frame in such a manner as to allow it to slide freely along the entire
length of the frame to and from the slotted tube, outside of which, at the point
where the frame is joined to the carriage, another tube is fixed perpendicularly to
the frame and fitted at its top with a centrally perforated cap through which a
thin rod guided by a disc round its lower end moves perpendicularly up and down
from within the tube. A small cord is attached to the said disc which passes up
inside the tube over a pulley fitted to the top of the tube, then round a pulley at
the lower end of the tube outside, then along the entire frame over another pulley
fixed to the frame at the further end from the slotted tube where it is attached to
the sliding piece moving along the frame. It will thus be seen that the thin rod
inside the perpendicular tube is regulated in its up and down motion by the sliding
piece so that it rises out and above the tube when the sliding piece is pushed up
towards the slotted tube and descends, by its own weight, back into the tube on the
sliding piece being moved towards the lower edge of the board. The perpendicular
tube being fixed on, and supported by, the frame must of necessity move along with
it in a direction parallel to the slotted tube. It is evident, therefore, that the rod
as well as all its parts must describe before the eye, in a perpendicular plane, the
same outlines which by the pencil in the sliding piece are traced horizontally on
'the board.
A convenient frame is provided-supported from the board-to fix the point of
observation for the eye during the act of drawing.
Dated this 15th day of September 1892.
KARL GENGNAGEL, Ph.D., M.A.
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COMPLETE SPECIFICATION.
An Apparatus for Drawing, without any Knowledge of Perspective,
any Object or Combination of Objects from Nature.
I, KARL GENGNAGEL Ph.D., M.A., of Halle University, Private Tutor, residing
at 45 Southwater Road, St. Leonards-on-Sea, in the County of Sussex do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
Fig. 1 represents a plan and Fig. 2 a side elevation of the apparatus. A is the

page_text: drawing board having a V-groove B near the upper edge extending from left to
right. In this groove a carriage moves consisting of a square tube C having at both
ends fixed on it a short piece of tube D and D which are used as bearings for
4 wheels E E E E
These wheels are provided with separate axles fixed to the wheels and running
in separate hearings the object being to prevent any side shake of the tube C while
moving along the groove B.
On the square tube C a saddle piece F is fitted which can be slid along the tube
between the two sets of wheels E E and E" E. To the upper side of the saddle
.piece Fa frame G is attached by the piece H, so as to stand at right angles to the
groove B and in the same plane as the surface of the board A. The frame G has
a wheel G' fixed to its end nearest the operator so that being supported by the
saddle piece F on the tube C at one end and the wheel G' at the other end it will
move always at right angles to the groove B from left to right or right to left
across the board A.
On the top side of the frame G a slide I is fitted which may be moved backward
or forward towards or away from the groove B. On the upper side of the slide [
a square tube or pillar I is fitted in a perpendicular position over which a short
piece of concentric tube K slides freely up and down which has on one side a
small boss or projection L with a small detachable pin M fitted into it. The short
tube K has also, on its opposite side, a small hook N attached to it.
Near the top
of the pillar on one side is a small V pulley O and at its base another V pulley O¹.
The frame G has also a V pulley O" fixed to it near the wheel G'. A plate or
sliding piece P carrying a pencil P' moveable in the socket Q controls the move-
ments of the frame G by guiding it at the sides, towards the left or right, by means
of 4 projecting pieces R R R R A light cord, string, or chain S is attached
to the hook T on plate P which passes under and over pulley O" under
pulley O¹over pulley O and is attached to hook N on the short tube K.
A steadying rest U is provided which fixes the point of observation. It is shown
as a chin rest in the drawing and may be fixed to the board A or on a separate
base such as a disc of wood. It consists of two concentric tubes the inner one of
which supports the rest W and is adjustable by means of the screw X.
Modifications. The pillar may be made as shown in the drawing Fig. 3, viz., a
circular tube Z having a rod Z₁ moving up and down inside it the lower end of
which is attached to the cord S, the latter passing over the pulleys O and O
(and O as shown in Fig. 2) to be fastened to the sliding plate P (Fig. 2 & 3)
carrying the pencil P¹.
Another modification of the pillar I' is to make it jointed at its junction with the
slide by means of a thumb screw Y so as to allow its inclination towards the
board to be regulated at will (Fig. 3).
Instead of the V-groove B a circular tube B, Fig. 4, may be used with a
longitudinal slot on its upper side to allow the carriage (consisting of the square
tube C (Fig. 2, Fig. 3) and its wheels E E E E to move in it across
the board.
The apparatus (to be called the stereograph) is used as follows. The move-
ments of the pin M being entirely regulated by the sliding plate P, the operator
manipulates the pencil P₁ inserted in the socket Q in such a way as will make the
pin M follow the outlines of the object or objects to be drawn taking care to steady
his head by resting it on the chin piece W.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is :-
First. A small carriage supported by self adjusting wheels running in a groove
or slotted tube from right to left across the board, as described and shown in the
drawing.
Second. The slide 1 with the pillar I¹ and short sliding tube K carrying

page_text: detachable pin M, with the pulleys O, O', O" and cord S arranged as described
and shown in the drawing.
Third. The two sliding pieces P and K connected with each other by means of
a string, cord, or chain in such a way as will make the pillar sliding piece K in its
up and down movements entirely dependent on the sliding piece P and the pencil P¹
inserted into it, as described and shown in the drawing.
Fourth. A drawing apparatus the moveable parts of which are set in motion and
worked from one central point, viz., the sliding piece P connected with the
frame G.
Fifth. The modifications of the apparatus as described and shown in the drawing
Fig. 3 and Fig. 4.
Sixth. The combination of all the parts described, in the manner described, as a
means of simultaneously tracing, by only one series of movements along the board,
two distinct but perfectly equal outlines of which that described by the pillar
sliding piece K in a perpendicular plane not only faithfully represents the action
of the operator on the board but also supplies his eye with a guidance both corrective
and continuous during the act of drawing.
KARL GENGNAGEL, Ph.D., M.A.