Improvements in Optical Lanterns.
Year: 1890

page_text: Date of Application, 27th Sept., 1890
Complete Specification Left, 18th June, 1891-Accepted, 19th Sept., 1991
PROVISIONAL SPECIFICATION.
Improvements in Optical Lanterns.
WILLIAM STROUD, Professor of Physics, Yorkshire College, Leeds, JAMES
ROBSON RENDELL, Whinside, Accrington, Minister of Religion, do hereby declare
the nature of this invention to be as follows:-
In connection with the projection of images on a screen by means of an
optical lantern our improvements consist (1) in the provision of means for
illuminating objects in a horizontal or vertical plane without shifting the source
of light (2) in the provision of means for accurately adjusting the position of
the burner.
The first improvement consists in attaching a mirror to an axis so as to be
capable of being introduced between two of the lenses of a condenser in such a
manner that it may be removed altogether from the path of the rays when the
object to be illuminated is in a vertical plane but when introduced between the
two lenses at an angle of forty five degrees or thereabouts with the axis of
the instrument it may reflect the approximately parallel beam in a direction at
right angles to the original direction so that the rays afterwards pass through
a converging lens before they illuminate the object to be exhibited.
The second improvement consists in attaching the burner to a stout triangular
tube which can move up and down on a triangular rod and can be fixed to the
rod in any position by means of a thumb screw. Attached to the rod are arms
against which screws passing through studs attached to the base of the instrument
press. The rod has a circular hole in the direction of its length through which
an upright rod fixed in the base passes. The arrangement provides for steady
motion in both horizontal and vertical planes.
Dated this Twenty-sixth day of September 1890.
WILLIAM STROUD.
JAMES ROBSON RENDELL.
COMPLETE SPECIFICATION.
Improvements in Optical Lanterns.
WILLIAM STROUD, Professor of Physics, Yorkshire College, Leeds, JAMES
ROBSON RENDELL, Minister of Religion, Whinside, Whalley Road, Accrington,
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 connexion with the projection of images on a screen by means of an optical
lantern our improvements consist :
1. In the provision of means for illuminating objects in a horizontal or vertical
plane without shifting the source of light.
2. In the provision of means for accurately adjusting and fixing the relative
positions of the burner and condensing lens.
The arrangements for illuminating objects in a horizontal or vertical plane at will
are shewn on Sheets 1, 2, 3.
Sheet 1 shews a general view of the apparatus. Forming a portion of the lantern
in front there is a box in which a mirror is shewn at an angle of 45° with the
vertical. The light through the condensing lens is thrown vertically upwards
through a converging lens upon which the object or slide to be projected is laid.
An objective lens and mirror or rectangular prism are carried on an upright rod or
[Price 6d.]

page_text: tube fixed on the top of the lantern as seen on Sheet 1. Another objective
placed in front of the lantern.
Details are shewn on Sheet 2. Lis the lime or other source of light. The
lens B and either G or H according as a direct or reflected beam is required form
the condensing apparatus, so arranged that the beam_emerging from B is slightly
divergent as shewn by the straight dotted lines. D is a mirror attached to a
hinge. E is a stud fixed to the mirror which passes through a curved slot in
the side of the box. In the position shewn in the drawing the light would
pass through the lens H. If the mirror were shifted along the dotted curve by
raising the stud outside the lantern, the light would pass through G as shewn
on Sheet 3. There is a spring catch T-Sheets 2 and 3-which serves to retain
the mirror in its horizontal position.
In the case where the burner is fixed in position in the instrument the lens B
is adjusted by means of slides. Sheet 3 shows the details. The condenser B is
attached to a short pillar and is so arranged that it can be raised or lowered
by a screw and spring.
C1 is a round rod of metal, as shewn, the upper part of which is screwed.
A circular milled nut E turns upon this screw. An arm projects from the
pillar as shewn and presses as a spring A upon the upper side of the nut. The
lower part C fits a hole in the pillar.
In C there is a slot lengthway and a pin N through the pillar goes into this
slot. The pin prevents any rotation of the screw. Turning the nut E will
therefore raise or lower B without causing its rotation.
The pillar is attached to a slide K which moves at right angles to the length
of the instrument. The guides P P. of this slide are attached to a second
slide M which can be moved along the instrument. The condensing lens B by
these movements can be accurately adjusted to the right position.
The upper
The arrangements for fixing the burner are shewn on Sheet
drawing shews the apparatus as seen from the open end of the lantern, the
lower drawing as seen from above. Hand O are the tubes carrying the
hydrogen and oxygen. These together with a metal rod R, S, are fixed to a
triangular tube X which can move up and down on a triangular rod T. Tubes H
and O, rod R, S and the tube X can be fixed so far as vertical motion is
concerned by a set-screw M. Through the rod T a circular hole is bored
through which a rod passes. This rod is fixed to the base on which the burner
is carried. The burner thus revolves horizontally about this rod as axis.
and Qare set-screws passing through plates fixed in the base and pressing
upon R and S as shewn. By means of the screw M the burner can be fixed
so far as vertical motion is concerned. P and Q adjust the horizontal motion.
Thus the burner can be easily adjusted and fixed.
P
4
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The use of a reflecting mirror supported so as to be capable of being
readily introduced by means of a rotary arrangement such as a hinge, between
the convex lenses forming the lantern condenser.
2. The arrangement of two slides at right angles to each other for the adjustment
of the lens nearest the source of light.
3. The arrangement of the burner on a triangular tube and the movement of it
by projecting arms through the agency of a screw or screws.
Dated this 16th day of June 1891.
WILLIAM STROUD.
JAMES ROBSON RENDELL.