Improvements in Topographical Apparatus, which is also applicable to the Measurement of Altitudes.
Year: 1890

page_text: Date of Application, 20th Sept., 1890-Accepted, 10th Jan., 1891
COMPLETE SPECIFICATION.
Improvements in Topographical Apparatus, which is also applicable
to the Measurement of Altitudes.
I, PEDRO GONZALEZ PERERA of Santa Cruz de Teneriffe, Canary Islands in the
Dominion of Spain 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 :-
My invention relates to a topographical apparatus which I entitle "Prophilograph"
or "Outliner" by which one or more profiles in a zone of land intended for a path-
way or a canal may be taken graphically and geometrically from a single point
or station, the said apparatus being also applicable to the measurement of
altitudės.
On cutting one or two sides of a polygonal pyramid through planes parallel to
each other, the resulting sections are similar polygons and the relation between
their corresponding sides is equal to that between the two respective distances from
the said planes to the vertex of the pyramid.
Upon this simple fact is founded the principle upon which the instrument herein
described is constructed. In fact on the axis of the telescope of a theodolite for
surveying the several points of a profile or outline of a piece of land a pyramidal
surface is produced the vertex of which lies in the intersection of the vertical axis of
the instrument with the optic axis of the telescope. Therefore on cutting the surface
by means of a plane parallel to that of the said profile a polygon is obtained similar to
the polygon of the land.
Such a result cannot be obtained in a direct manner, but if another line is drawn
parallel to the axis of the telescope the same principles may be applied to it and like
results will be obtained.
In the accompanying drawing
Figure 1 represents a front and side elevation respectively of the instrument.
Figure 2 represents in detail one of the rods and the head of the piercer or needle
and spiral spring.
Figure 3 is a view of the metallic tube wherein the needle is situated with the spiral
spring.
Figure 4 is a plan of the metallic frame for the board and the bracket connecting
it with the base plate.
Figure 5 is a vertical section through B B of Figure 4.
Figure 6 represents a front view and longitudinal section respectively of the wooden
board with a metallic edge or frame.
In carrying my invention into practice I take two rods of equal length V, V,
Figure 1 equidistant from the central point on which turns the rule QQ supporting
the telescope K as shown in the drawing the said rods being also hinged at their
opposite ends to a metallic tube W W Figure 3 provided with a horizontal axis E E
Figure 3 parallel to that of the telescope supported upon the mounting of the same
and the axis of the said tube intersects the vertical axis of the instrument from which
the said rods must also be equidistant. A needle or piercer situated within this tube
and which is caused to return to the position shown in Figure 1 by means of a spiral
spring N will reproduce the movements of the axis of the telescope.
The plane or board HH Figure 1 is to receive the impression of the needle or
piercer. This board consists of a piece of seasoned wood of any kind edged or framed
with brass inlaid or projecting into the thick portion of the board for the purpose of
strengthening the same and facilitating a better adjustment (Figure 6). The said
board is fixed to a metallic frame M M Figure 5 which in its turn is connected to
the horizontal plate G G and firmly arranged so as to be perpendicular not only to

page_text: the plate itself but also to the vertical plane containing the axis of the telescope
when the azimuthal vernier points to zero. This board should be ordinarily thirty
centimetres long and seventeen wide, being separated ten centimetres from the vertical
axis of the instrument. Figure 4 shows in detail the means of connection of the
metallic frame of the board by means of a bracket R. To ensure an accurate and
positive connection there are three screws T and three pair of guides g. The board
is arranged within its frame so as to allow of its being removed and replaced in a
rapid and convenient manner. Figure 5 shows in detail the means employed for
such purpose. These consist of a longitudinal groove cut out on the outside of the
rectangle which forms the frame and two tongues marked L in the top portion
(Figure 6) which are enclosed by the clamps p (Figure 4) turning on the points o.
Two lines, the one horizontal, and the other vertical, prove the accuracy of the relative
position between the metallic frame and the board. From the brass edge the afore-
said tongues project and on its side is formed the flange or rib lodged in the above
mentioned groove of the frame.
A common sheet of paper cut to the exact size of the board is placed upon the
latter; on both its sides two straight lines are drawn at right angles uniting at the
central point, the said lines being a prolongation of the above mentioned lines of
adjustment.
The point at which both lines intersect each other corresponds with the
geometrical axis of the needle or piercer when the horizontal and vertical plate
points to zero. To ensure adhesion of the paper on the board when the latter is not
in its frame, small sharp pins two millimetres high and slightly conical are placed on
the board about the ends of the lines of adjustment.
The proportions hereinbefore mentioned and represented in the annexed drawings
may be varied without affecting the essential principle of the invention.
Further it should be stated that insomuch as the limbs and verniers indicated in
the drawing are not essential parts of the prophilograph they may be dispensed with,
marking simply lines of adjustment on the two horizontal plates that point to the
position zero. The telescope can also be dispensed with using instead a pinnule-alidade
or sight arm such as used in clinometers. With these simplifications an inexpensive
and efficient model may be obtained practically useful as a prophilograph whilst the
former may be also used as a theodolite.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
First. An apparatus designed for determining graphically and geometrically with
one single station one or more profiles within the zone of land whereon a pathway,
canal or any other work requiring the ground relief to be represented is projected;
substantially as herein described and for the purpose stated with reference to the
annexed drawings.
Second. The combination in an apparatus of the class mentioned, of the two
horizontal plates upon a three screwed platform the upper plate carrying two
mountings on the top portion of which turns a telescope, the two rods suspended
from the telescope and hinged to the supporting rule, the needle or piercer moving
within the metallic tube by means of the rods mentioned, and the board situated
within a metallic frame attached to the base plate and which receives the impression
of the needle or piercer; substantially as and for the purpose herein set forth.
Dated this 20th day of Sentember 1890
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.