Improvements in and connected with Photographic Apparatus.for Surveying and Field Sketching Purposes.
Year: 1891

page_text: Date of Application, 22nd Aug., 1891
Complete Specification Left, 21st June, 1892-Accepted, 20th Aug., 1892
PROVISIONAL SPECIFICATION.
Improvements in and connected with Photographic Apparatus.for
Surveying and Field Sketching Purposes.
I, HERBERT WELD-BLUNDELL of the Wellington Club, Grosvenor Place,
London, Gentleman, do hereby declare the nature of this invention to be as
follows:
This invention has for its object to adapt a photographic camera to fulfil the
requirements of surveying and field sketching operations for military and other
purposes, and it relates principally to the combination with a hand or other
portable camera, of means or appliances whereby a record may be easily obtained
of the true relative bearings of the station and sighting points, that is to say, of the
place at which the camera is situated when a photograph is taken and of any distant
object forming a prominent feature in the picture.
For this purpose the screen upon which the picture is focussed or viewed, is
divided and graduated in the manner of a protractor, either by lines upon the glass,
or by a skeleton or wire protractor so applied as to be visible upon or through the
screen. Upon or beneath, or otherwise in proximity to the focussing screen a
magnetic compass having a transparent card is mounted above the optical axis of
the camera whereby orientation of the picture reflected on the screen, and con-
sequently of the landscape or image photographed, is obtained.
Within the camera a fine index wire is mounted perpendicular to the base of the
picture and parallel to the sensitive plate, another wire moving with the first being.
so arranged with regard to the view finder or focussing screen as to cause its.
shadow to be projected thereon, so that upon this index being made to coincide
with the position, with regard to the vertical centre line, of the picture, of the
image of any sighting object therein, there will be produced upon the resulting
negative a fine vertical line corresponding to the image of the sighting object to
serve as a datum line from which to construct the resulting chart.
Within the camera another index parallel and close to the plane of the negative
so as to cause its shadow to be projected thereon, is so mounted as to be adjustable
to any angle through an entire circle, and is operated by gearing connected with
an external index which is set by reference to the magnetic compass and works
over a correspondingly graduated disc in order to produce upon the negative a
graphic record of the orientation or bearing of the camera when the photograph
was taken.
Upon the side of the hood of the focussing or view finder screen a clinometer
may be mounted to enable the elevation or depression of the camera at the moment
when the photograph was taken, to be ascertained. This instrument may be
detachable and marked with radii, formula, measurements and other indications
used in working out calculations.
For accurate observations with a prismatic compass provision may be made for
mounting this instrument upon the camera directly above the optical axis thereof.
Dated this 22nd day of August 1901.
n. WELD
By A. M. & Wm. Clark,
ELL,
53, Chancery Lane, London, Patent Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in and connected with Photographic Apparatus for
Surveying and Field Sketching Purposes.
I, HERBERT WELD-BLUNDELL, of the Wellington Club, Grosvenor Place,
London, Gentleman 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 :-
This invention has for its object to adapt a photographic camera to fulfil the
requirements of surveying and field sketching operations for military and other
purposes, and it relates principally to the combination, with a hand or other
portable camera, of means or appliances whereby a record may be easily obtained
of the true relative bearings of the station and sighting points, that is to say of the
place at which the camera is situated when a photograph is taken and of a distant
object forming the prominent feature in the picture.
The means by which this is accomplished will be described with reference to the
accompanying drawings forming part of this Specification, wherein
Figure 1 is a central longitudinal section of the camera provided with my
improvements, and which is represented as in position for use, and
Figure 2 is a plan thereof.
Figures 3, 4, 5, are detail views of the index for marking on the negative the
object sighted.
Figures 6, 7, 8, 9, and 10, are detail views of the registering device for photo-
graphically numbering the exposures for subsequent identification of the order in
which they were made.
For the purpose of my invention the screen A, upon which the picture projected
by a view lens B is reflected from a fixed mirror C, is provided with a protractor D,
as shewn in Figure 2, engraved or otherwise applied upon the screen so as not to
materially obscure the picture focussed thereon. A magnetic compass E, of the
kind known as a trough compass (the bottom of the trough being transparent) is
applied upon the screen, one end of the trough being pivoted about an axis d
coincident with the centre of the protractor, which centre is in the vertical plane of
the optical axis of the camera. The bottom of the trough of the compass may be
graduated to act as a vernier to subdivide the graduations of the protractor. The
one or other end of the trough is pivoted to the protractor centre, according as the
camera is facing a northerly or southerly direction and by adjusting the compass,
after focussing the distant object, until the needle comes to rest freely, the true
orientation of the camera may be ascertained. F is the camera body proper and G
is an ordinary Eastman roller slide containing a continuous sensitized strip, of which
portions are successively exposed in the usual manner.
In order to preserve a graphic record of the particular object sighted (this record
being necessary in the event of there being more than one prominent object in the
picture or to enable the centre of the picture to be readily found should the true
dimensions of the picture not be preserved in cutting up the strip for development)
an index wire H (see Figures 8 and 10) is provided so that its shadow will be
sharply defined on the negative at the vertical centre line of the picture. It is
carried by a lever mounted on the roller slide and is caused by a light spring to
press on the face of the negative during exposure and, to enable the sensitive strip
to be readily shifted for successive exposures, the tail end of lever / is so acted on
by the shutter 1 of the roller slide as to raise the wire from the paper when the
shutter is closed.
For the purpose of photographically recording on the negative a serial number
for subsequent identification, a pair of superposed thin metal dises K K¹ are
mounted to turn on a centre in the frame of the roller slide so as to partly project
in front of the negative, each of sail discs being perforated with a circle of numbers,

page_text: In the
so as to come successively opposite an opening L (Figure 7) which only permits one
pair of numbers to be photographed at a time. Between the numbers of each disc
are gaps to allow the numbers of the other disc to be photographed, the figures of
the disc K representing the units and those of the other disc K₁ the tens. These
discs are operated automatically by a wiper m carried by the paper marker of the
adjacent guide roller M of the roller slide which wiper engages successively with
ten teeth k on the back of the units disc K so as to rotate a tenth of a revolution.
The wiper m being carried by the paper marker will only be in position to operate
on one of the teeth k at the moment when the paper marker is in position to mark
the paper, which happens at, say, every fourth revolution of roller M the paper
marker being operated in the manner usual in the Eastman roller slide.
disc K, opposite the space between the figures 0 and 1, there is a hole k² which at
each complete revolution of disc K allows the wiper m to pass through and engage
with the one of ten holes 3 in the tens disc K' with which hole 2 then coincides,
the wiper then turning both discs simultaneously a tenth of a revolution. It is
about to do this in the position shewn. The accurate register of the figures with
the aperture L (Figure 7) is ensured by spring jumpers kk engaging the toothed
edges of the discs, the jumpers being separated by a stationary plate ko which also
passes between the discs to ensure the alignment of the jumpers with the discs.
N is the tension board over which the paper strip is drawn from the roller M for
the purpose of being exposed.
P is a prismatic compass and clinometer mounted on top of the outer box or case
of the camera with its sights in a fore and aft position in the plane of the optical
axis for making more accurate observations as to orientation than can be made by
means of the ordinary compass E. This prismatic compass is detachable and
provided with the usual foot or straight edge for application to the top of the
camera case when the instrument is used as a clinometer to ascertain the elevation
or depression of the camera at the moment when the photograph was taken.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. The combination, with a photographic camera, of a protractor and magnetic
compass applied to the focussing or view screen, substantially as and for the
purpose specified.
2. The combination, with a photographic camera having a compass and protractor
applied to the view screen, of an index directly in front of the negative, for the
purpose described.
3. The combination, with a photographic roller slide, of automatic mechanism
operating substantially as described for photographically recording serial numbers.
upon successive portions of the paper exposed.
DL: 1 of 1905
H. WELD-BLUNDELL,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.