Applicable also for Laying Down Coast Lines.
Year: 1886

page_text: Applicable also for Laying Down Coast Lines.
I GEORGE FREDERICK REDFERN, of the General Patent Office, N° 4 South Street,
Finsbury, in the county of Middlesex Patent Agent do hereby declare the nature
of this invention (a communication from abroad by Hans George Jakob Stang of
Christiania in the Kingdom of Norway, Lieutenant) and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement :—
The object of this improved instrument is to enable a person from a station, the
height of which above the level of an adjacent tract of water is known, to transfer
directly onto a map placed under the instrument the movement of an object on
the surface of the water or a point or line upon the same, the instrument being
also applicable for laying down coast lines.
The instrument can be thus employed for the purposes of warfare by following
from a station the notion of a vessel by means of a telescope, whereby cro-sed
wires with which the apparatus is provided will indicate the movement of a vessel
on the map on which the positions of mines are marked out.
For laying down coast lines the apparatus is used so that the telescope is
directed along the outline or configuration of the coast, when a drawing pen in
the instrument will trace it upon the map on a scale to which the instrument is
adjusted.
In order to enable the invention to be fully understood I will describe the same
by reference to the accompanying drawing in which figure 1 represents a side
elevation of the apparatus mounted on a table, upon which the map is placed;
figure 2 is a plan of the apparatus; figure 3, is an end view of the upper part of
the apparatus drawn to a larger scale and seen from the eye glass end of the
telescope. Similar letters in all the figures represent similar parts.
B, is a table or board upon which the map is placed in front of the apparatus ;
m, is the platform of the apparatus, turning on a pivot P, by means of which the
whole apparatus is secured to the table. At the ends of the platform m, are small

page_text: rollers to allow of the apparatus being easily turned round on the pivot P, whilst
at the same time it is rendered steady. On the platform an upright or standard S,
is secured supporting a cradle U, pivotted at O. The telescope K, is by means of
pivots R, secured at the fore part of the cradle. At the eye glass end of the
telescope in the cradle U, is a screw W, supporting the telescope. On the
platform m, are further secured a guide plate D, and a bar V, serving as a stay to
the former and supporting in bearings the axes of two pinions t and t¹ gearing
with each other. The lower of these pinions t¹, also gears with a toothed rack T,
secured to the cradle U.
In the fore part of the platform m is a slide bar in which a slide E, can move.
This slide is provided with an opening of considerable size above which two
crossed wires are stretched.
The slide E, is connected by means of a joint to a link or bar c, which is con-
nected in a similar manner to the bar a, passing through and sliding in a socket
secured to the axis of the pinion t.
In the guide plate D, is a curve or groove b, b, b, b, of suitable depth and at the
joint, between the bars c and a, is a handle C provided with a pin, which latter can
by means of the handle be caused to follow the curve b, b..
The screw W, is provided with divisions or a scale to allow of the telescope K,
being properly adjusted with relation to the cradle U. The bar c, is made so that
it can be lengthened or shortened, whereby the wire cross can be adjusted with
relation to the commencement of the curve b, b, above the pivot P.
i The operation of the instrument is as follows:
When the apparatus has been secured in position the back part of the same is
taken hold of "with one hand in order to turn the apparatus horizontally. The
handle C, is held with the other hand and moved so, that the point of the handle
follows the curve b, b. The bar a, being turned in this manner, turns the pinion t,
gearing with the pinion t¹, which in its turn gears with the toothed rack T. By
.this means the inclination of the telescope K, is changed, so that by turning the
instrument and following by means of the handle C, the curve b, b, the motion of an
object on the water can be followed by means of the telescope. As will be easily
seen by the construction of the instrument, the crossed wires E, will simultaneously
with the motions of the tube partly pivot on the pivot P, and partly approach or
withdraw from the same. The table B, of the instrument is adjusted horizontally
and the map placed in front of the instrument, so that the situation on the map of
the place of observation coincides with the fulcrum P, of the instrument and the
points indicating the various places or positions on the map correspond with the
real ones.
When the movement of an object upon the water is followed by
the telescope, the motion of the telescope will consist of a horizontal and a vertical
inotion. It will therefore be obvious that the longitudinal wire of the wire cross
on the slide E, of the instrument, when following the movement of the object with
the telescope, will always be placed on the map in the same direction as the object.
The motion of the telescope in a vertical direction is determined by the increase or
decrease of the distance of the object a certain distance corresponding with a certain
angle of the optical axis of the telescope to the vertical line. When the pin or
handle C, as indicated in the drawing, is at the lowest point of the curve b, b, the
wire cross is occupying its most distant position on the map and the telescope will
then make a corresponding angle with the vertical line. This position varies
according to the height occupied by the instrument above the water level, the
instrument must therefore previous to its use be carefully adjusted by means of the
screw W, and by regulating the length of the bar c. The shape of the curve b, b,
will also vary with the varying height of the instrument, but it is possible by
adjusting the parts of the instrument to cause three points of the different curves
to coincide, and as the shape of the curves is not varied very much, there is no
ineed to substitute other curves except when the water level has fallen or risen one
meter. The curves for this substitution may be engraved on separate plates, which
· can easily be secured to or removed from the plate D.

page_text: The rectilinear part of the groove b, b, would if extended pass as will be seen,
through the shaft of the pinion t, thus the telescope will not change its position, if
the pin at the end of the bar a, be removed from one end to the other of this
rectilinear part. Further the position of the wire cross will be the same if the
pin or handle C be at the upper or at the lower part of the said rectilinear part of
the groove.
If the instrument is to be used for laying down a coast line there will usually
be no fixed point to depart from. Therefore the telescope must by means of the
screw W, be first adjusted for a height of 0 meter. The optical axis is then
adjusted horizontally by means of a water level on the telescope, the telescope and
the bar c, are then placed in positions in accordance with the actual height of the
instrument, which is then ready for use.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
An instrument for determining upon a map the motion of an object on a
horizontal surface and for laying down coast lines, the said instrument being
provided with a telescope and cross wires moveable along a rule and so combined,
that when the optical axis of the telescope by following, (by the point on the end
of a bar the angular motion of which is by means of gearing communicated to the
telescope) a curve of the instrument and by turning the instrument is caused to
follow the movement of an object on the surface of water the crossed wires shall
simultaneously be caused to follow the same course of movement upon a map placed
upon the instrument.