A New Aid to Model Drawing.
Year: 1898

page_text: Date of Application, 22nd July, 1898
Complete Specification Left, 13th Apr., 1899-Accepted, 13th May, 1899
A New Aid to Model Drawing.
I, WILLIAM BARRODALE, 302, Hagley Road, Birmingham, Government Certifi-
cated Schoolmaster, do hereby declare the nature of this invention to be as
follows:.
1.
This instrument is intended for the use of students learning model or object
drawing and enables them to ascertain the apparent proportions of the parts
of a model and the vanishing angles at which the edges appear to recede. It
consists of a thin plate or sheet of metal, wood, cardboard, or other stout sub-
stance, with a square or rectangular hole in it, large enough for the object or
group to be viewed through, when the plate is held in the hand at arm's length,
and along each edge of this hole, on one or both faces of the plate, is marked a
series of equal divisions as quarter inches. A second plate preferably of the
same shane and size as the hole in the first-mentioned plate is marked along its
edges with divisions similar to those around the edges of the hole in the first
plate. When the first plate is held in the hand at arm's length and a model
is viewed through the hole in it, the divisions along the edges of the hole serve
as a means of ascertaining the apparent length and width of each part of the
model, and by noting at which divisions the edges of the model appear to touch
the sides of the hole, the exact vanishing angle of each receding line may be
correctly observed and set down. By means of the second plate, the hole in
the first plate may be gradually decreased in size, and the apparent proportions
of small parts may be correctly observed, as any one of the divided edges of
the second plate appears to travel, in a horizontal or vertical direction, over
the surface of the model.
WILLIAM BARRODALE.
A New Aid to Model Drawing.
I, WILLIAM BARRodale, 302, Hagley Road, Birmingham, Government Certifi-
cated Schoolmaster, 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:-
This instrument or apparatus is intended for the use of students of model or
object drawing to enable them to judge and ascertain the apparent proportions
of the parts of a model and the vanishing angles at which the edges of the
model annear to recede.

page_text: Its principal feature consists of a thin plate or sheet with a square or rect-
angular aperture in it, marked with a series of equal divisions, or scales of linear
measurements, along two or more edges of the aperture.
This principal -plate is made of some stout substance, such as metal, wood, or
cardboard, and is either formed of parts framed together, or consists of one part
or sheet with the aperture cut out of it. The said aperture is made sufficiently
large to admit of the whole of an object, or group of objects, being viewed
through it, when the plate is held in the hand at arm's length, or fixed at some
other suitable distance from the eye of the spectator.
For the purpose of diminishing the size of the aperture in the principal plate
above described and for various other purposes, a secondary plate is used. This
secondary plate, which is preferably of the same size and shape as the said aper-
ture in the principal plate, is marked along one or more of its exterior edges
with a series of equal divisions of the same size as the said divisions along the
marked edges of the said aperture in the principal plate. This secondary plate
does not necessarily contain an aperture in it. The said principal and secondary
plates are each marked with the said series of equal divisions on one or both
sides of the said plates but preferably on one side only. When used to diminish
the size of the said aperture in the principal plate, the said secondary plate is
moved along between two opposite edges of the said aperture, or it slides in
grooves which are formed by turning over the edges of the principal plate or
affixed to the principal plate. When a model is viewed through the aperture
in the principal plate, the division marks along the edges of the said aperture
serve as a means of ascertaining the apparent length and width or height of
each part of the model, and the vanishing angle of each receding line. By
means of the secondary plate the apparent proportions of small parts may be
correctly observed as any one of its marked edges appears to travel in a horizontal
or vertical direction over the surface of the model.
When one side only of each of the said plates is marked with the said series
of equal divisions, a model may first be viewed with the unmarked side of the
plates towards the spectator, and the apparent proportions of parts and the vanish-
ing angles of receding lines be judged and drawn and then accurately ascertained
and the drawing tested.
I will now explain the accompanying drawings.
Figure 1 is a drawing of the front face of the principal plate, showing a
rectangular aperture marked with a scale of linear measurements along the four
edges of the aperture.
Figure 2 is a drawing of the front face of the secondary plate. It is of the
same shape and size as the aperture in the principal plate, and, its edges are
similarly marked.
Figure 3 is a drawing of the front of both plates, showing the size of the
aperture in the principal plate diminished by means of the secondary plate.
The secondary plate is behind the principal plate, the dotted lines indicating
the hidden parts.
Figure 4 is a drawing of the back of the plates in the position shown in
Figure 3. The secondary plate slides along the parallel grooves A A, B B, which
are formed by turning over two opposite edges of the principal plate.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to he performed, I declare that what
I claim is:-
1. The construction of an apparatus, for use in model drawing, consisting of
two plates, one of which contains a square or rectangular aperture having a series
of equal divisions marked on two or more of the edges of the said aperture, the
other plate being similarly marked along one or more of its exterior edges,
substantially as described.
2. The marking of a plate having a square or rectangular aperture in it with

page_text: a series of equal divisions along two or more edges of the said aperture, for
the purpose and substantially as described.
3. The construction of an apparatus, for use in model drawing, consisting of
two square or rectangular plates, one of which contains a square or rectangular
aperture and has two of its opposite edges turned over so as to form parallel
grooves in which the other plate slides.
Dated this 19th day of Auril 1900