IMPROVEMENTS IN BINOCULAR AND STEREOSCOPIC MICROSCOPES
Year: 1869

page_text: LETTERS PATENT to Samuel Holmes, of No. 12, Brunswick Terrace,
Lower Road, Rotherhithe, in the County of Surrey, for the In-
vention of "IMPROVEMENTS IN BINOCULAR AND STEREOSCOPIC MICROSCOPES."
Sealed the 22nd October 1869, and dated the 19th June 1869.
PROVISIONAL SPECIFICATION left by the said Samuel. Holmes at
the Office of the Commissioners of Patents, with his Petition, on
the 19th June 1869.
I, SAMUEL HOLMES, of No. 12, Brunswick Terrace, Lower Road,
Rotherhithe, in the County of Surrey, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN BINOCULAR AND STEREOSCOPIO
MICROSCOPES." to be as follows:-
Microscopes are of two kinds, simple and compound, and in their.
general construction but one eye is used. A form of the compound
microscope has also been made in which two eyes can see the object at:
once by deflecting by a reflecting prism a half of the light from the
object glass into a second eye piece.

page_text: My improvements provide for the use of both the eyes during obser-
vation, so as to give a natural stereoscopic view of opaque or transparent
objects, by dividing the object glass through its centre, or making an
object glass in two halves, and causing each half to assume such an
angular position as will direct its light into one of two erecting or inverting
eye pieces, the object being illuminated if opaque by light reflected (in
the case of high powers) from between the space formed by the division
of the object glass when separated for binocular vision, or by two prisms
or a diverging or converging lens placed under the object when that
object is a transparent one. Each eye thus sees through one-half
of the microscope, and the two views seen together give binocular or
stereoscopic relief to the object observed. When the two halves of
the combination are closed the whole can be used as a monocular
instrument.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Samuel Holmes in the Great Seal Patent Office
on the 10th December 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
HOLMES, of No. 12, Brunswick Terrace, Lower Road, Rotherhithe, in
the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of June, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Samuel Holmes, Her special licence that
'I, the said Samuel Holmes, my executors, administrators, and assigns,
or such others as I, the said Samuel Holmes, my executors, adminis-
trators, and assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term therein ex-
pressed, should and lawfully might make, use, exercise, and vend, within
the United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN BINOCULAR AND
STEREOSCOPIO MICROSCOPES," upon the condition (amongst others) that I
the said Samuel Holmes, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals, should

page_text: particularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the same to
be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Samuel Holmes, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement :-
My Invention consists in the use of two object glasses or portions of
two object glasses, or of one object glass divided into two parts, to
supply through two eye pieces a binocular and stereoscopic view of opaque
or transparent microscopic objects while illuminated by reflected.. or
transmitted light, and also in the use of certain mechanical means
herein described, or their equivalents, for securing the motion in required
directions, or rest in necessary positions of the optical parts of such
combinations for obtaining monocular or binocular vision.
The Objective. I take an ordinary object piece, and by a circular
saw divide it along its line of collination, and afterwards rejoin the
halves by screws and steady pins, until as an objective it is in as perfect
a state of adjustment as before division. It is then capable of acting as
an objective for one or two eyes, according to the position assumed
by the two halves under the control of the mechanical part of the
instrument when the direct light is stopped out.
According to another method I work the lenses of
an achromatic
object piece out of divided and rejoined discs of glass, which when
finished and fixed in a divided mounting temporarily held together for
that purpose may be afterwards separated by dissolving out the cement
by which the halves of the discs were originally conjoined.
Or lastly, I make two whole object glasses, and fix one into each half
of a divided mount, cutting away only such portion as will allow of
proper approximation. This method is available for high powers. and
for binocular use only. .
In all cases I cut the usual screw thread on the objectives to aflix
them to the body, and more surely secure their halves in their re-
spective places in the divided body tube of the instrument by two small
milled headed screws.

page_text: The Stand Figures 1, 2, and 3.(sec Drawings annexed,) represent
a front, side, and back view respectively of the mechanical arrangement
of a miscroscope according to my. Invention, and Figure 4 shows a
section of its optical arrangements.
On
A reference to these Drawings will show that two rules or bars are
jointed at one end (like a sector), and this joint is in the plane of
focus of the object glass. The upper ends of the bars are free to
separate a distance equal to the width of the two eyes (about 24 inches)
when operated by the upper millhead and its levers, as shown.
these two bars slide respectively the two halves of the bisected tube
carrying the object glass and eye piece or eye pieces, according as to
whether the body tube is closed for observing with one eye or separated
for binocular use. This sliding motion is given by a crank on the lower
millhead, and serves to make the focus of the object glass coincide with
the centre of motion of the two bars. The central millhead gives a
separate motion of small extent to each of the half body tubes, when
any little inequality of focal length, either of the eyes of the observer
or in the glasses, might make one of the two images indistinct. The
focusing motion is given by the two large millheads moving the stage
to or from the body of the instrument by a rack and pinion.
The
convenient position for observation is secured (as heretofore) by tilting
the whole instrument on the trunnions in the uprights, through which
(in this case) runs the pinion actuated by the two large millheads for
moving the stage.
The Illuminating Lens.-Immediately under the stage is a lens of
large angular aperture, achromatic or not, receiving its illumination
from the usual mirror situated underneath, and by a stop of suitable
form the light from the lens is directed through any transparent object.
It
The Prismatic Illuminator. This is shown at Figure 7 and 8.
is made from a rectangular or isoseles prism of glass by working a
convex or plane face for the incident surface, and cutting the reflecting
surface into two planes at the binocular angle, the emergent surface
being left plane. Its convex surface, when placed at its focal distance
from a flame, renders its light parallel, which the two inclined surfaces
reflect up to the two halves of the separated object glass when the
prism is mounted in an adjustable frame under the stage. If the
incident surface of the prism is plane, the course of the light is un-
altered in its first direction, and therefore not condensed, as in the case

page_text: of the prism having a convex incident surface.
By the use of this
prism the usual mirror is dispensed with altogether, and a far more
brilliant and distinct light secured.
Stops. To prevent false light it is necessary to stop off the central
pencil from the illuminator by a stop of black paper or metal placed
between the halves of the object glass. This stop may or not have a
prolongation, so as to enclose and prevent the entry of light into the
angular space between the separated body tubes, where long draw tubes
are not used for that end. It is unnecessary to use a divided object
glass for monocular vision, as any of the ordinary powers supplied
answer for that purpose, but should the closed divided glass be so
required a narrow stop must be placed so as to prevent the direct light
from coming through the slit.
A reference to Figure 4 will serve to explain the optical arrangement
of this miscroscope, where each half of the object glass occupies an
equally angular position with respect to the object, and is thus capable
of making
a distinct image of the object of the same intensity for each
eye visible through the two eye pieces, as shown, the mirror supplying
through the illuminating lens the light for transparent objects, or the
same may be lighted by the prismatic illuminator without a mirror,
while for opaque objects the light is received from a reflecter above, or
by preference from one side.
Figures 5 and 6 explain themselves, as showing a method of applying
this divided system to microscopes of the usual make wherein the
focusing is done by moving the body of the instrument instead of the
stage as previously described.
The eye pieces most suitable for use with the divided object glass
are of the inverting or erecting kind, according as to whether the
instrument is used as a simple binocular, or as a stereoscopic microscope.
In witness whereof, I, the said Samuel Holmes, have hereunto
set my hand and seal, this Third day of December, in the year
of our Lord One thousand eight hundred and sixty-nine.
SAMUEL HOLMES. (L.S.)