Improved Mode and Apparatus for Projecting Images, Characters, or the like on to Distant Bodies.
Year: 1892

page_text: Date of Application, 20th Sept., 1892
Complete Specification Left, 20th June, 1893-Accepted, 2nd Sept., 1893
PROVISIONAL SPECIFICATION.
Improved Mode and Apparatus for Projecting Images, Characters,
or the like on to Distant Bodies.
I, RONALD AUGUSTUS SCOTT, of Acton Hill, Acton in the County of Middlesex,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
According to this invention for the purpose of projecting images characters or
the like on to distant bodies a powerful light projector such as an electric search
light projector is used in conjunction with a mirror and an intermediate holder or
carrier adapted to support at the focus of the mirror the object a representation of
which is to be projected to a distance. This object may resemble a stencil plate
having apertures for light according to the nature of the representation to be
projected or the light may be projected around the edges of the body only, or both;
and in order that the arc may he as near as possible to the focus of the mirror
without injuriously affecting the object the latter is specially constructed to
withstand the heat of the electric arc. For this purpose the object may be
constructed of refractory material such as asbestos.
Dated this 20th day of September 1892.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improved Mode and Apparatus for Projecting Images, Characters,
or the like on to Distant Bodies.
I, RONALD AUGUSTUS SCOTT, of Acton Hill, Acton, in the County of Middlesex,
Electrical Engineer, 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 :-
According to this invention for the purpose of projecting images, characters or
the like on to distant bodies, say at a distance of several hundred yards, so that
they can be clearly distinguished at such distances, a powerful light projector,
such as an electric search light projector, is used in conjunction with a mirror, and
an intermediate holder or carrier adapted to support at the focus of the mirror the
object a representation of which is to be projected to a distance. The object may
resemble a stencil plate having apertures for light according to the nature of the
representation to be projected; or the light may be projected around the edges of
the body only, or both, and in order that the arc may be as near as possible to the
focus of the mirror without injuriously affecting the object, the latter is specially
constructed to withstand the heat of the electric arc. For this purpose the object
may be constructed of refractory material such as asbestos.
In the accompanying drawings:-
Figs. 1 and 2 are respectively longitudinal and transverse sections of apparatus
constructed according to this invention.
1 is the casing of a powerful light projector mounted to turn about a
horizontal axis within a frame 2 that is capable of turning about a vertical axis as
well understood. This casing is provided at its rear end with a curved mirror 3
and at its front end is provided with means for producing a powerful source of
light. In the example shown, an electric arc lamp is provided for this purpose.

page_text: The arc or focus of the lamp is at 4 the carbons being carried by carbon holders 5
and 5ª that are simultaneously fed towards each other, at the required rate to keep
the position of the arc constant, by means of an inclined rod 6, which is formed
with right and left handed screw threads 6 and 6b engaging with corresponding
screw threads in the carbon holder, and is operated by a hand wheel 7. 8 is a fixed
rod that serves to guide the carbon holders and prevent them turning with the
rod 6. This rod 8 is fixed to the base plate 9 of the lamp which is arranged to
slide in suitable guides 10 at the lower part of the casing 1. The lamp is placed
in circuit with an electric generator in a manner well understood. To the rod 6
are fixed collars 11, 11ª between which is an external screw threaded sleeve 12
provided with a hand wheel 13 and arranged to work through a correspondingly
screw threaded hole in the lower split end of a bracket 14 carried by the base
plate 9. By these means the rod 6 can be adjusted vertically to vary the position
of the arc to suit requirements, and can be fixed in its adjusted position by
tightening up a screw 15 connecting the divided parts of the bracket.
16 is a holder or carrier fixed to a longitudinally adjustable plate or frame 16"
carried by but insulated from the base plate 9. This holder or carrier is adapted
to support at the required focus of the mirror 3, between the said mirror and the
source of light at 4 the object a representation of which is to be projected to a
distance. This object in the example shown consists of a plate 17 of opaque
material formed with apertures 18 corresponding in outline to the letters, words or
other characters or image which it is desired to project. In the example shown,
the form of the apertures corresponds to the letters R. A. S.
In order that the
electric are may be brought near to the required focus of the mirror, which is
necessary to obtain a satisfactory result, the plate 17 is as hereinbefore stated made
of refractory material such for example as asbestos or of metal plate, such as a
steel plate, having a high melting point.
The size of the object to be projected must be such that light passing there-
through or around it will fall on the mirror. When using a mirror 24 inches in
diameter, I have obtained satisfactory results with an object 2 inches square, the
image thereof being projected on to a body at a distance of about four hundred
yards therefrom.
19 is a shield to protect the rods 6 and 8 from the heat of the arc.
With the arrangement described, when object and lamp have been suitably
abjusted to the body upon which the object is to be thrown, and the lamp is in
action, light will pass through the apertures in the plate 17 and will fall upon the
mirror 3 from which a well defined and greatly enlarged reproduction of the object
will be projected onto the body, for example a cloud, situated at a great distance
from the apparatus.
The focus of the mirror at which the object 17 is placed will vary with the
distance from the mirror of the distant body upon which the image is to be
projected, but should in each case be such that the conjugate focus of the light
passing through or around the object, or both through and around the object will
be on the surface of the body upon which the image is to be thrown. Thus it
will be understood that in all cases the object and the centre of light will be
situated between the centre of curvature of the mirror and the principal focus of
the mirror, the object and the image being at all times at the conjugate foci of the
mirror. This will be readily understood from the diagrammatic view Fig. 3
wherein a is the mirror, 6 the centre of curvature thereof; c the principal focus of
the mirror; d the object an image of which is to be projected and e the electric
arc lamp or other powerful source of light.
With the object and source of light in the position shown an enlarged image of
the object will appear upon a surface at f which will be at the conjugate focus of
the light emanating from the object, whilst the image of the source of light e will
be at g and therefore will not interfere with the projected image. By moving the
object, and source of light nearer to the principal focus c, the image of the object
will recede from the mirror and can be thrown upon a more distant body than

page_text: before, and by moving them away from the principal focus the image can be thrown
upon a nearer body.
As will be obvious any other convenient and powerful source of light, as for
example a magnesium light or a lime light can be used in lieu of the electric
arc.
Also other modes of fixing the focus of the light at the required point may
be used, the arrangement hereinbefore described being given merely as
illustration.
an
Having bow particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The hereinabove described mode of projecting images, characters and the like
on to distant bodies using in the manner set forth a concave mirror, an object
adapted to resist great heat and corresponding in shape to the image to be
projected, and a powerful source of light, such as an electric arc lamp, placed in
close proximity to and at the outer side of said object.
2. In apparatus for projecting images, characters or the like on to distant
bodies, the combination of a casing capable of being moved in horizontal and
vertical planes, a mirror carried by said casing, an electric arc lamp having its
focus in close proximity to the focus of said mirror, a longitudinally adjustable
holder or carrier arranged between the mirror and the said lamp and a plate or
object supported by said holder or carrier and formed to represent the image,
character or the like which it is desired to project substantially as described.
3. The hereinabove described combined apparatus for projecting images,
characters and the like on to distant bodies in the manner set forth with reference
to the drawings.
Dated this 20th day of June 1803
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.

page_text: Date of Application, 20th Sept., 1892
Complete Specification Left, 20th June, 1893-Accepted, 20th Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Projecting Images, Oharacters, or
the like on to Distant Bodies.
I, RONALD AUGUSTUS SCOTT, of Acton Hill, Acton in the County of
Middlesex, Electrical Engineer, do hereby declare the nature of this invention
to be as follows :—
In the Specification of another application for Letters Patent filed by me
dated 20th Sept. 1892 No. 16806 I have described an improved mode of and
apparatus for projecting images characters or the like on to distant bodies
according to which a powerful light projector such as an electric search light
projector is used in conjunction with a mirror and an intermediate holder or carrier
adapted to support at the focus of the mirror the object a representation of which
is to be projected to a distance. The object may resemble a stencil plate having
apertures for light according to the nature of the representation to be projected, or
the light may be projected around the edges of the body only, or both and in order
that the arc may be as near as possible to the focus of the mirror without
injuriously affecting the object the latter is specially constructed to withstand the
heat of the electric arc. For this purpose according to my present invention the
object is made hollow or is formed wholly or partly of tubing wherein water is
caused to circulate so as to keep the object cool.
Dated this 19th day of June 1893
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Projecting Images, Characters, or
the like on to Distant Bodies.
I, RONALD AUGUSTUS SCOTT, of Acton Hill, Acton in the County of
Middlesex, Electrical Engineer, 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 :-
In the Specification of another application for Letters Patent filed by me dated.
the 20th Sep. 1892 No. 16806, have described an improved mode of and
apparatus for projecting images, characters or the like on to distant bodies
according to which a powerful light projector, such as an electric search light
projector, is used in conjunction with a mirror, and an intermediate holder or
carrier adapted to support at the focus of the mirror the object a representation of
which is to be projected to a distance. The object may resemble a stencil plate
having apertures for light according to the nature of the representation to he
projected; or the light may be projected around the edges of the body only, or
both, and in order that the arc may be as near as possible to the focus of the mirror
without injuriously affecting the object, the latter is specially constructed, to
withstand the heat of the electric arc.
The above arrangement of the apparatus forms the subject of the application for
Letters Patent mentioned above, and in itself forms no portion of this my invention
but shall proceed to describe my present invention in connection with such
apparatus in order to fully explain its nature and how it is to be used.
According to my present invention, the object is made hollow, or is formed

page_text: wholly or partly of tubing wherein water is caused to circulate so as to keep the
object cool.
In the accompanying drawings,
Figs. 1 and 2 are respectively longitudinal and transverse sections of apparatus
constructed according to this invention.
1 is the casing of a powerful light projector mounted to turn about a horizontal
axis within a frame 2 that is capable of turning about a vertical axis as well
understood. This casing is provided at its rear end with a curved mirror 3 and at
its front end is provided with means for producing a powerful source of light. In
the example shown, an electric arc lamp is provided for this purpose. The focus
of the lamp is at 4, the carbons being carried by carbon holders 5 and 5ª that are
simultaneously fed towards each other at the required rate to keep the position of
the are constant, by means of an inclined rod 6, which is formed with right and left
handed screw threads 6" and 6 engaging with corresponding screw threads in the
carbon holder, and is operated by a hand wheel 7. 8 is a fixed rod that serves to
guide the carbon holders and prevent them turning with the rod 6. This rod 8 is
fixed to the base plate 9 of the lamp which is arranged to slide in suitable guides 10
at the lower part of the casing 1. The lamp is placed in circuit with an electric
generator in a manner well understood. To rod 6 is fixed collars 11, 11ª between
which is an external screw threaded sleeve 12 provided with a hand wheel 13 and
arranged to work through a correspondingly screw threaded hole in the lower split
end of a bracket 14 carried by the base plate 9. By these means the rod 6 can be
adjusted vertically to vary the position of the arc to suit requirements, and can be
fixed in its adjusted position by tightening up a screw 15 connecting the divided
parts of the bracket.
16 is a holder or carrier fixed to a longitudinally adjustable plate or frame 16ª
carried by but insulated from the base plate 9. This holder or carrier is adapted
to support at the focus of the mirror 3, between the said mirror and the source
of light at 4 the object a representation of which is to be projected to a distance.
This object in the example shown is a plate 17 formed with apertures 18 corre-
sponding in outline to the letters, words or other characters or image which it
is desired to project. In the example shown, the form of the apertures corre-
sponds to the letters R. A. S. In order that the electric arc may be brought
near to the object so that it also may be placed near to the required focus of the
mirror, which is necessary to obtain a satisfactory result, the plate 17 is, as herein-
before mentioned, made hollow, or of tubing with inlet and outlet pipes 17" and 17b
respectively that are connected by flexible tubing at 17° to pipes connected with
a water tank 17d so that water can be caused to circulate through the object
and keep it cool whilst permitting the electric arc to be brought near to the focus
of the mirror.
The size of the object to be projected must be such that light passing there-
through or around it will fall on the mirror. When using a mirror 24 inches
in diameter, I have obtained satisfactory results with an object 2 inches square,
the image thereof being projected on to a body at a distance of about four
hundred yards therefrom.
19 is a shield to protect the rods 6 and 8 from the heat of the arc.
With the arrangement described, when the lamp is in action, light will pass
through the apertures in the plate 17 and will fall upon the mirror 3 from which a
well defined and greatly enlarged reproduction of the object will be projected onto
a body, for example a cloud situated at a great distance from the apparatus.
The focus of the mirror at which the object 17 is placed will vary with the
distance from the mirror of the distant body upon which the image is to be
projected, but should in each case be such that the conjugate focus of the light
passing through or around the object, or both through and around the object will
be on the surface of the body upon which the image is to be thrown. Thus it will
be understood that in all cases the object and the centre of light will be situated
between the centre of curvature of the mirror and the principal focus of the

page_text: mirror, the object and the image being at a 11 times at the conjugate foci of the
mirror. This will be readily understood from the diagrammatic view Fig. 3
wherein a is the mirror, 6 the centre of curvature thereof, c the principal focus of
the mirror, d the object an image of which is to be projected, and e the electric arc
lamp or other powerful source of light. With the object and source of light in the
position shown, an enlarged image of the object will appear upon a surface at f
which will be at the conjugate focus of the light emanating from the object, whilst
the image of the source of light e will be at g, and therefore will not interfere with
the projected image. By moving the object and source of light nearer to the
principal focus c, the image of the object will recede from the mirror and can be
thrown upon a more distant body than before, and by moving them away from the
principal focus the image can be thrown upon a nearer body.
As will be obvious any other convenient and powerful source of light, as for
example a magnesium light or a lime light can be used in lieu of the electric arc.
Other modes of fixing the focus of the light at the required point may be used the
above being given as an illustration.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that
what I claim is :-
1. A projector lamp consisting of a concave mirror arranged at the rearward end
of its casing, an adjustable source of light situated at the forward end of the casing,
and an object holder arranged between the two and adapted to hold the object in
the proper focus of the mirror as herein explained, the object being constructed
hollow or of tubing and arranged for water circulation so as to enable it to
withstand the heat of the lamp which is arranged in close proximity thereto
substantially as herein described.
2. The use in connection with a projector of the kind described in the first claim
of an object constructed with water circulation so as to protect it from the heat
substantially as herein described.
Dated this 20th day of June 1893.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.