IMPROVEMENTS IN OXYHYDROGEN & OTHER LANTERN MICROSCOPES
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
We LEWIS WRIGHT, Editor and Author 7 Beaumont Road, Hornsey Rise
Middlesex and HERBERT CHARLES NEWTON Optician 3 Fleet St London EC. do
hereby declare the nature of our invention for IMPROVEMENTS IN OXYHYDROGEN
& OTHER LANTERN MICROSCOPES to be as follows:-
Balsaming a parallellizing lens on the alum trough in order to have a layer of
balsam to stop the balsam-heating rays-& at the same time to save the loss of light
from 2 surfaces.
New objectives specially constructed for producing a flat field with the lantern
microscope while improving the light & definition.
Arrangement of lenses for condensing & parallellizing the light.
The use of a coned or prismatic lens or arrangement of lenses to enable the whole
of the beam to be used with the Lieborkuhn or Spot lens.
The use of a revolving diaphragm as the actual stage in order to bring the object
& the stop close together.
The parallellizing lens is a plano-concave balsamod direct on to the alum trough
to parallellize (or slightly cone according to position of light) the cone of light from
the Lantern condensers.
The new objectives are worked out on the screen with such curves & distances
for the various powers as to produce a flat picture & pass the greatest amount of
light irrespective of their results on the table microscope.
The arrangement of lenses for condensing & parallellizing the light are single,
double & triple combinations of convex lenses to cone down the parallel rays after
passing the alum trough, so as to pass the whole or nearly the whole of the light
through any required size of object according to the power used.
Thus with a 3 objective a single low power secondary condenser is sufficient to
cover a large object while with objective a triple combination is used to pass all
the light through the smaller object & smaller lens.
We propose to use a coned or prismatic lens to split the centre beam from the
condenser in order to make it pass round the opaque portion of Spot lens &c.
The diaphragm plate forms the actual stage the object being placed 'direct on the
diaphragm doing away altogether with any other stage plates.
3001
i
H. C. NEWTON,
p.p. self & Mr. Lewis Wright

page_text: COMPLETE SPECIFICATION.
We LEWIS WRIGHT 7 Beaumont Road Hornsey Rise, Middlesex Gentleman and
HERBERT CHARLES NEWTON, 3 Fleet Street London E.C. Optician, do hereby
declare the nature of our invention for IMPROVEMENTS IN OXYHYDROGEN AND
OTHER LANTERN MICROSCOPES, and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement: E
This invention relates to improvements in that, class of apparatus which is used
for showing microscopic objects on a screen upon an enlarged scale such apparatus
consisting essentially of an Optical Lantern in combination with a microscope and
being known as Lantern Microscopes.
Hitherto microscopes of this description have been very deficient in illuminating
and defining power on account of the reduction in the power of the light in its
passage through the lenses and the great want of definition obtainable from the
objectives.
The object of our invention is to remedy these two difficulties and to produce
a clear and well defined image of the microscopic object on the screen, of a greatly
enlarged size, and also to entirely intercept the heat producing rays proceeding from
the light and prevent their falling on and injuring the object.
In carrying out our invention we collect the light from the "radiant" (the lamp
or other source of light) by means of a condenser formed of three lenses so arranged
as to take up an angle of about 90°.
The light concentrated or coned down, by this condenser passes through a alum
trough which neutralizes the greater part of the heat rays. This trough may be of
any ordinary construction with glass sides.
In this arrangement however the light is brought too soon to a focus and a large
and unequally illuminated.spot is the result so that (particularly with small objects)
a large proportion of the light is lost and the object is not clearly defined.
To obviate this we employ a parallellizing lens which we place in front of the
alum trough.
This lens will have the effect of carrying the light forward in parallel rows but
a loss of light will arise from having two surfaces that is to say the surface of the
glass of the alum trough and that of the lens, and to prevent this loss of light we
place between the trough and the lens, a layer of balsam, or in other words we
balsam the lens (which is plano concave) direct onto the alum trough whereby
while we parallelize (or only slightly cone according to the position of the light)
the concentrated light rays proceeding from the lantern condensers, we form
a continuous lens. This layer of balsam serves also to complete the protection of
the slides from heat by arresting any balsam heating rays which may pass the alum
trough and thus prevent these concentrated heat rays falling upon and injuring
delicate balsam mounted slides.
So perfect is the protection by this method that the most delicate objects may
remain in the Lantern for a long period without the slightest injury.
In order to pass the whole or nearly the whole of the light through any required
size of object, according to the power used the parallel rays of light must be coned

page_text: down or condensed, and this condensing we effect by means of well known single,
double, and triple combinations of convex lenses according to requirements These
lenses we place in the barrel of the lantern.
In exhibiting opaque objects by means of the Lantern Microscope the central and
brightest portion of the light is lost by falling on the back of the opaque object and
the same loss is experienced when using the Spot lens.
To obviate this we use a coned or prismatic lens or arrangement of lenses in
order to split the central beam and throw the rays outside the opaque object onto
the Luberkuhn reflector which reflects it onto the object and in the case of the
Spot lens, outside the opaque spot onto the lens, thus utilizing a large portion of
the central beam.
Instead of using a stage to carry the object we make use of the stop diaphragm
for that purpose, the slide being secured thereto by adjustable spring fingers
conveniently placed for the purpose or by spring clips or in any other convenient
manner.
The objectives of any ordinary table microscope may be used but with a view to
produce a flat field while improving the light and definition we employ a set of
objectives the curves of which and the distances apart, for the various powers have
been worked out on the screen to produce a flat picture and pass the greatest
amount of light.
In the accompanying drawing we have shown in side elevation partly in section
at Fig 1 a lantern microscope with our improvements adapted thereto Fig: 2 being
a front view of the same with the objective removed.
The
A is the lantern which may be of any suitable construction B represents the
condenser, C is the alum trough and D the plano-concave parallelizing lens which
receives the concentrated cone of light from the condenser This lens is balsamed
to the alum trough, the layer of balsam being shown by the strong line a.
light concentrated onto the parallelizing lens is passed on through the barrel E in
parallel or nearly parallel lines to a second set of condensers F placed in the barrel E
and consisting of one, two, or more convex lenses which are so situated that the
light is concentrated in a greater or less degree of concentration at such a point
that the radiating rays shall be kept within the diameter of the objective. G is
the stop diaphragm which is capable of rotating on the pivot b by which it is secured
to the end of the barrel E. The slide c is held against the diaphragm by spring
fingers & conveniently secured to any suitable part of the apparatus and separate
from the diaphragm or by spring clips or in any other convenient manner.
By thus using the stop diaphragm as the stage, the object and the stop will be
brought close together, a fact which will be duly appreciated by users of this class
of apparatus.
"
His the object glass the position and form of the lenses of which have been
worked out on the screen to produce a flat picture and pass the greatest amount of
light.
I is the coned or prismatic lens or series of lens which are used with opaque
objects as before referred to.
The apparatus will be provided with the usual adjusting racks and screws or
other suitable means for adjusting and regulating the various parts.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that
what we claim is
1. In a lantern microscope the general arrangement of the lenses substantially as
herein shown and described whereby we are enabled to convey nearly the whole of
the light falling from the "radiant" onto the object to be shown.
2. In a lantern microscope, the use in combination with an alum trough, of
a plano concave lens such lens being by preference balsamed to the trough, all
substantially as and for the purpose set forth.

page_text: 3. In a lantern microscope the combination with a stop diaphragm, of spring
fingers or clips or other suitable holding device, whereby the use of a stage for
carrying the object is dispensed with substantially as set forth.
4. In a lantern microscope the use of a coned or prismatic lens or series of lenses I
substantially as and for the purpose set forth.
1