IMPROVEMENTS IN PHOTO- GRAPHIC APPARATUS.
Year: 1864

page_text: LETTERS PATENT to Henri Adrien Bonneville, Patent Agent, of the
British and Foreign Patent Offices, 24, Rue du Mont Thabor, Paris,
in the Empire of France, and 38, Porchester Terrace, Bayswater, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN PHOTO-
GRAPHIC APPARATUS.-A communication from Doctor Desiré Charles
Emmanuel Van Monckhoven, residing at Ghent, in the Kingdom of
Belgium.
Sealed the 13th October 1864, and dated the 21st April 1864.
PROVISIONAL SPECIFICATION left by the said Henri Adrien Bonneville
at the Office of the Commissioners of Patents, with his Petition, on
the 21st April 1864.
I, HENRI ADRIEN BONNEVILLE, Patent Agent, of the British and Foreign
Patent Offices, 24, Rue de Mont Thabor, Paris, in the Empire of France,
and 38, Porchester Terrace, Bayswater, in the County of Middlesex, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
PHOTOGRAPHIC APPARATUS," communicated to me by Doctor Desiré. Charles
Emmanuel Van Monckhoven, a person residing at Ghent, in the Kingdom of
Belgium, to be as follows:-

page_text: This apparatus is a solar microscope, which projects in an enlarged
form on a sensitized surface the image previously formed known as a glass
negative.
The apparatus is composed of two distinct systems or series, which are,
firstly, the system of lenses which "lights" the glass negative; secondly, the
objective enlarging system.
7
The first or lighting system is composed of a large short focussed
lens which is lighted by a mirror or heliostate, and of a divergent lens
which corrects the distortions which would otherwise result from the sperical
convexity of the first lens; both these lenses are mounted in a frame or
box.
The second or "enlarging" system is composed of an ordinary objective and
of a negative achromatic lens which corrects the distortions, lengthens the
focus of the oblique rays, and gives an image similar to the plate in every
respect except size.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henri Adrien Bonneville in the Great Seal Patent Office
, on the 19th October 1864.
TO. ALL TO WHOM THESE PRESENTS SHALL COME, I,, HENRI
ADRIEN BONNEVILLE, Patent Agent, of the British and Foreign Patent Offices,
24, Rue du Mont Thabor, Paris, in the. Empire of France, and 38, Por-
chester Terrace, Bayswater, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Royal
Letters Patent, bearing date the Twenty-first day of April in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-seventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Henri Adrien Bonneville, Her special licence that I, the said
Henri Adrien Bonneville, my executors, administrators, and assigns, or such
others as I,,the said Henri Adrien Bonneville, 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 King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of Man,
an Invention for "IMPROVEMENTS IN PHOTOGRAPHIC. APPARATUS," communi-

page_text: cated to me by Doctor Desiré Charles Emmanuel Van Monckhoven, a person'
residing at Ghent, in the Kingdom of Belgium, upon the condition, amongst
others, that I, the said Henri Adrien Bonneville, 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 per-
formed, 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.
NÓW KNOW YE, that I, the said Henri Adrien Bonneville, 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:-
"
This "apparatus is a solar microscope, which serves to project upon a
sensi-
tized surface the enlarged image of a photographic negative on glass. The
illumination employed being obtained from the rays of the sun, these rays
must be directed into the apparatus either by means of a reflector moved by:
the band, or by a heliostat, precisely as with an ordinary solar microscope; or
the whole of the apparatus, including the franie upon which the enlarged'
image is produced, may be mounted on a stand and pointed directly to the sun,
as is done with a telescope.
1 :
This apparatus is composed of two distinct parts, viz.,' 1°, the condenser,
2°, the enlarging objective..
1°. The condenser.-Theory and practice both prove the necessity of a'
powerful condenser without spherical aberration; chromatic aberration is of
no moment, as photographic surfaces, unlike the human eye, are influenced
only by blue and violet rays.
t
The manner in which this has been. attained is as follows:-A (Fig. 1) is
a lens of crown glass having a very large ratio of diameter to its focal length,
ánd upon
the outer surface of which the polar rays fall perpendicularly. The
convex curves of both its surfaces are such that the spherical aberration is
reduced to a minimum. Exactly midway between the lens' A and its focal
point is placed a second lens B, slightly diverging, which completely corrects
the spherical aberration of the condenser. At the back of the latter lens, at
C, is placed the photographic negative through which the solar rays pass, as
shewn in Figure 1, which also exhibits the numerical data of the arrangement.
It will be seen that any point whatever of the negative to be enlarged will
only be traversed by one single luminous ray, coming from the condenser, and

page_text: of a calculated refrangibility which is here well understood to be blue; where-
as when only one lens is employed for this purpose, as has hitherto been the
case, two rays differing in their obliquity to the axis would pass at one time
hrough any one point of the negative; this is caused by spherical aberration,
and mars the definition of the enlarged image.
2°. The enlarging objective. This objective is free not only from spherical
but also from chromatic aberration (so far as the yellow and indigo rays are
concerned). It is an ordinary photographic lens D, E, (Fig. 1), but as
the image projected on the screen is not only much curved, but also shews
distortion and astigmation, a negative achromatic lens F has been added and
is placed immediately behind the objective, as seen in the Diagram. The
focal length of the oblique rays is thereby increased and the field made flat,
the projected image being (except its enlarged size) absolutely similar to the
negative.
The mounting and working of the complete apparatus may be thus de-
scribed The lenses of the condenser A and B, Fig. 2, are placed in a
cubical box G, H, I, J, made either of wood or of metal. This box is fixed
upon a frame J, K, upon which two vertical frames L, M, and O, P, are made
to travel by means of the rack and pinion motions N and Q, the details of
which are shown in section at the base of Fig. 3; the former receives the
negative C to be enlarged, the latter carries the enlarging objective. Hitherto
in every enlarging apparatus, the photographic negative (which is invariably
on glass) was fitted into a frame and the solar rays traversed its centre only
(the portion to be enlarged, while the margin was always ill defined and
indistinct. Thus the centre of the negative became heated while the sides
remained cold, hence the frequent breakings which occurred. In the above-
described apparatus the negative upon glass is cut to the exact size required,
(that which is to be enlarged) and kept in position by means of four metal.
slides, grooved at their inner edges to support the negative, and slotted to
admit of copying negatives of various sizes. The negative, being thus isolated
from the wooden frame which supports it, is placed in the cone of solar rays
so as to be completely surrounded and equally heated. The enlarging objec-
tive D, E, F, must be moved forward or backward until the image is perfectly
defined on the screen, when the latter must be replaced by the sensitized
surface which is to retain the image.
1.
The whole apparatus is placed in a wooden box from which all external
light is excluded, and works as an ordinary solar microscope.

page_text: Having thus described the nature of the said Invention, and the manner
in which it is to be performed, I claim, the general arrangement of the parts
composing the above-described photographic optical apparatus for enlarging
negative images, substantially as above described and represented in the
annexed Drawings.
In witness whereof, I, the said Henri Adrien Bonneville, have here-
unto set my hand and seal, this Nineteenth day of October, in the
year of our Lord One thousand eight hundred and sixty-four.
composing the above described photographic optical apparatus for enlarging
negative images, substantially as above described and represented in the
annexed Drawings.
In witness whereof, I, the said Henri Adrien Bonneville, have here-
unto set my hand and seal, this Nineteenth day of October, in the
year of our Lord One thousand eight hundred and sixty-four.
In witness whereof, I, the said Henri Adrien Bonneville, have here-
unto set my hand and seal, this Nineteenth day of October, in the
year of our Lord One thousand eight hundred and sixty-four.
H. BONNEVILLE. (L.B.)