IMPROVEMENTS IN APPARATUS FOR TAKING MINUTE PHOTOGRAPHIC PICTURES AND MAGNIFIED PICTURES OF MICROSCOPIC OBJECTS
Year: 1862

page_text: LETTERS PATENT to Alfred Frederick Eden, of Threadneedle Street, in
the City of London, Optician, for the Invention of "IMPROVEMENTS IN
APPARATUS FOR TAKING MINUTE PHOTOGRAPHIC PICTURES AND MAGNIFIED
PICTURES OF MICROSCOPIC OBJECTS."
Sealed the 3rd February 1863, and dated the 3rd December 1862.
PROVISIONAL SPECIFICATION left by the said Alfred Frederick Eden
at the Office of the Commissioners of Patents, with his Petition, on the
3rd December 1862.
I, ALFRED FREDERICK EDEN, of Threadneedle Street, in the City of London,
Optician, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN APPARATUS FOR TAKING MINUTE PHOTOGRAPHIC PICTURES AND MAGNIFIED
PICTURES OF MICROSCOPIC OBJECTS," to be as follows:-
My Invention of improvements in apparatus for taking minute photographic
pictures and magnified pictures of microscopic objects, consists,, first,. in
adapting to the object end of the camera a small box or dark chamber, in
which is placed the glass plate with the sensitive surface when it is desired to
obtain a minute photographic picture.. In order to obtain an enlarged or
magnified picture of a microscopic object the latter is placed in the chamber,
and light is admitted through a proper aperture through the object, and an
arrangement of lenses which will throw the magnified image on to:a_sensitive.
surface placed at the proper. focal length behind. It will be seen, therefore,.
that this box or dark chamber performs a double office, depending upon. the
nature of the operation that, is to be performed. To facilitate the operations
of the photographer, this box.or.dark chamber is, made to work in guides or

page_text: dovetailed grooves so that it may be easily removed from the camera and
replaced when required.
Another improvement consists in placing a small stop behind the lens and
in front of the negative.
Another improvement consists in adapting to the object end of the camera 5
a focussing lens, which is screwed on to the metal plate of the camera, and is
adjusted by means of a sliding tube. This focussing lens also serves as a con-
densing lens for throwing light on the object when the apparatus is employed
for taking photographic pictures of microscopic objects.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alfred. Frederick Eden in the Great Seal Patent Office on
the 3rd June 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
FREDERICK EDEN, of 45, Threadneedle Street, in the City of London, Optician,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of December, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Alfred Frederick Eden, Her special license, that I, the said Alfred
Frederick Eden, my executors, administrators, and assigns, or such others
as I, the said Alfred Frederick Eden, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time and
at all times thereafter during the term therein expressed; 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 APPARATUS FOR TAKING MINUTE PHOTOGRAPHIC PICTURES AND
MAGNIFIED PICTURES OF MICROSCOPIC OBJECTS," upon the condition (amongst
others) that I, the said Alfred Frederick Eden, by an instrument in writing
under my hand and seal, should 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 Alfred Frederick Eden, do hereby declare
the nature of my said Invention, and in what manner the same is to be

page_text: performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
My Invention of "Improvements in Apparatus for Taking Minute Photo-
graphic Pictures and Magnified Pictures of Microscopic Objects," consists,
first, in adapting to the object end of the camera a small removeable box or
dark chamber in which is placed the glass plate with the sensitive surface
when it is desired to obtain a minute photographic picture. In order to obtain
an enlarged or magnified picture of a microscopic object the latter is placed
in the small removeable dark chamber, and light is admitted through a proper
aperture and allowed to pass through the object and also through an arrange-
ment of lenses, which will throw the magnified image on to a sensitive surface
placed at the proper focal length behind.
.
From this explanation it will be understood that this small box or dark
chamber performs a double office, depending upon the nature of the operation
that is to be performed: To facilitate the operations of the photographer, this
box or dark chamber is made to work in guides or dovetailed grooves so that
it may be easily removed from the camera and replaced when required.
Another improvement consists in placing behind the lens and in front of
the negative a stop with a very small aperture, in contradistinction to the large
apertures of the ordinary stops.. I find by experience that for producing good
results in making micro-photographs, the aperture of the stop should not
exceed the fiftieth of an inch in diameter, and that in good lights and under
favorable circumstances, a much smaller aperture may be advantageously
employed:
Another improvement consists in adapting to the object end of the camera
a focussing. lens, which is screwed on to the small removeable box or dark
chamber, and is adjusted by means of a sliding tube. This lens is only used
for focussing when it is desired to produce micro-photographs, but it will also
serve as a condensing lens. for throwing light on the object when the apparatus
is employed for taking photographic pictures of microscopic objects.
In the accompanying Drawing Fig. 1 is a side elevation of the apparatus
complete; Fig. 2 is a longitudinal. vertical section, drawn full size, of the
object-glass end of the apparatus, shewing the small box or dark chamber,
which forms an important feature of my Invention; Fig: 3 is a front view of
this box or dark chamber with the door open, so as to shew the internal.
parts.
In Fig. 1, A is the camera box or large dark chamber of the usual con-
struction; it is provided with the ordinary dark box for the glass plates or other

page_text: sensitive surface, and the hinged door at the end carries a silvered glass or
mirror for the purpose of throwing light through the negative and along the
box A on to the focussing glass in the box C of the camera, when it is desired
to produce a micro-photograph; B is the camera head, to which the lenses and
apparatus for adjusting the focus of the object are adapted. A small remove-
able dark chamber or box C to contain the microscopic object to be enlarged,
or the glass slide to receive a micro-photograph, is also adapted to the other
end of the head B. A tube D is also secured to a plate placed at the front
end of the camera, and to this tube D is fitted a sliding tube a, which carries
a mirror or reflector b, for throwing light through the microscopic object c,
Fig. 2, on to the sensitive surface of the plate or slide in the dark plate box at
the other end of the camera. The small removeable dark chamber C, shewn
detached at Fig. 3, is composed of a close box d, d, provided with a hinged
door e, which opens, so as to give access to the interior of the dark box C.
The glass slide c, Figures 2 and 3, represents either a slide to receive a micro-
photograph or the focussing glass for the same, or a microscopic object which
it is desired to enlarge, and project on to a sensitive surface in the plate box
at the large end of the camera. This slide crests upon four pins 1, 1, 1, 1,
and is supported in its place by six other pins 2, 2, 2, 2, 2, 2. Two small flat
springs 3, 3, fixed on the inside of the door e will, when the latter is shut, press
on the glass slide c, and hold it steady. A sliding shutter f is made to slide
up and down in vertical guides, and serves for opening or closing the opening f'
in front of the slide c until everything is prepared ready to take the photo-
graphic picture. A small microscopic tube g provided with suitable lenses is
adapted to the box C for the purpose of enabling the operator to examine the
micro-picture that is thrown on the focussing glass c. The lens of the tube g
may be adjustable to suit various sights, and as it is employed to examine the
detail of the picture that is thrown on the focussing glass of the box C, it is
called the focussing lens. The microscopic tube is removeable and the aper-
ture left may be closed by a cap or cover to exclude the light when the
focussing lens is not in use.
Having explained the construction of the principal parts of my improved
apparatus, I will now proceed to describe, first, the plan of taking magnified
pictures of microscopic objects. For this purpose the small object to be mag-
nified is mounted on a slip of glass three inches by one inch. This slip of
glass with the object thereon is placed in the small box or dark chamber C on
the pins or studs 1, 1, 1, 1, as already explained. The six longer pins which
are placed round the edges of the object or slip of, glass, keep it in its place.
These pins pass through the back of the small mahogany box, and are fastened

page_text: into a brass plate j, which slides into dovetails, and can be taken in and out of
the box at pleasure. The lid or door of the box C is lined with mahogany,
and the two silver springs 3, 3, are fixed thereto, and therefore, when this lid
is shut down on the object, the latter is securely fastened in its place, the
door e being secured by a small brass hoók, as seen in Fig. 1. On the front
of the lid or door a piece of tube is screwed, into which slides the tube g,
containing a magnifier consisting of two lenses. This magnifier also acts as a
condenser to condense the light reflected from the mirror b, Fig. 1. The pho-
tographic lens used is a microscopic object glass of suitable magnifying power,
and is screwed into the tube h, which is screwed into the head B, and is pro-
vided with a rackwork adjustment for adjusting the lens to the proper focus,
as is well understood. This lens shews a magnified image of the object at c in
the box or. chamber C on the ground glass or large focussing glass at the end
of the large camera. The focus having been adjusted, the ground glass is
removed, and the dark plate box with the sensitive plate therein is substituted
for it in the usual. manner.
In practice it has been found that to obtain a good picture will require
about two minutes exposure if the sun light is reflected from the mirror bat
the object end of the instrument, and ten minutes if an ordinary paraffine lamp
be used. The mirror 6 is adjusted by sliding it on the tube D to or from the
condensing lens, as already explained. When the negative has been obtained
pictures are printed from it in the ordinary manner.
I will now proceed to describe the method of using the instrument for taking
micro-photographs. These are taken from a negative which is fixed in a frame
at the large end of the camera. The mirror b is removed from the small end
of the camera by sliding it off the tube.D. The large flat mirror at the large
end of the camera is fitted in a frame, and is. adjustable to any angle, as shewn
in Fig. 1, for the purpose of throwing the light on the negative; when the
mirror is properly adjusted it is clamped in its place by means of a small
clamping screw i, Fig. 1; a slip of glass three inches by one inch, scratched
with emery paper, is now placed in the box C at the small end of the instru-
ment for the purpose of focussing the picture. The scratched side of the glass
is placed downwards on the four pins 1, 1, 1, 1, previously described, and the
condensing or magnifying lens 6 is adjusted to the proper focus for obser-
vation; the camera lens or object glass must then be adjusted by means of
its rack work, so as to get a sharp image of the scratches on the focussing
glass. While looking through the magnifying or condensing lens (or as it
may now be called the "focussing lens "), make the image of the negative
which is at the other end of the camera coincide with the scratches on the

page_text: focussing glass; and when this is done I remove the small box or dark chamber
C from the dovetails, take it into a dark room, where after closing the shutter
I take away the magnifying or focussing lens, and put in its place a bit of
cork, or otherwise close up the aperture. The slip of glass with the scratches
on is then removed, and another slip of glass with a small drop of collodion
thereon, and prepared in the proper sensitive bath, is substituted for the
scratched glass. The box C is then replaced in the dovetails of the camera
head, and the sensitive surface exposed for about ten seconds; after which I
develop and fix the image in the usual manner. The way to take small full-
length pictures from life is to unclamp the sliding bar which supports the flat
mirror. This latter can then be removed and the negative taken out. The
sitter may then be placed opposite the large end of the camera, and by
manipulating in other respects in the same manner as for obtaining small
micro-photographs from ordinary négatives, micro-photographs may be taken
from the living image.
'
From the above description of the improvements it will be seen that my
apparatus may be used with very little change for taking microphotographs
either from ordinary negatives or from living objects, or it may be employed
for taking magnified representations of microscopic objects.
Having now described my Invention of "Improvements in Apparatus for
Taking Minute Photographic Pictures and Magnified Pictures of Microscopic
Objects," and having explained the manner of carrying the same into effect, I
claim as the Invention secured to me by Letters Patent as aforesaid, the
adapting to photographic cameras of a removable box or dark chamber, as
herein set forth.
Second, I claim the use of stops with small aperture, as herein set forth,
for producing micro-photographs.
Third, I claim the adaptation of a magnifying lens to the object end of
the camera, for the purpose of focussing and condensing, as herein shewn and
described.
: In witness whereof, I, the said Alfred Frederick Eden, have hereunto
set my hand and seal, this First day of June, in the year of our
Lord One thousand eight hundred and sixty-three.
ALFRED FREDERICK EDEN. (L.S.)