IMPROVEMENTS IN ADDADA ZAVER 717 QASEI
Year: 1881

page_text: LETTERS PATENT to George Henry Stephens, at present of Upper Baker
Street, in the County of Middlesex, and Horace Wilmer, of the Great Eastern
Railway, Liverpool Street, also in the County of Middlesex, Associates of the
Institution of Civil Engineers, for an Invention of "IMPROVEMENTS IN
ADDADA ZAVER 717 QASEI
PROVISIONAL SPECIFICATION left by the said George Henry Stephens
and Horace Wilmer at the Office of the Commissioners of Patents on the
4th October 1881.
-
GEORGE HENRY STEPHENS, at present of Upper Baker Street, in the County
of Middlesex, and HORACE WILMER, of the Great Eastern Railway, Liverpool
Street, also in the County of Middlesex, Associates of the Institution of Civil
Engineers. "IMPROVEMENTS IN APPARATUS EMPLOYED IN SURVEYING."
Our Invention, relating to apparatus employed in surveying, has for its object
the production of an instrument which shall be capable of determining the length
of a line, its magnetic course, and its inclination.
In carrying out our Invention in order to effect these objects we employ a
telescope mounted upon a tripod or other suitable stand by means of a ball and
socket joint, so as as enable it to be moved into any position in which it may be
retained by a screw or otherwise. In the diaphragm of the telescope are fixed
two horizontal hairs and one vertical hair, for tho purpose of ascertaining the
length of the line, by observing the length subtended by means of the horizontal
hairs on an ordinary level staff held vertically at the end of the line to be measured,
the distance between the cross hairs being capable of adjustment.
The magnetic course of the line is determined by means of a prismatic compass
hinged over the centre line of the telescope, and the compass is levelled partly by
turning the telescope about its horizontal axis in a suitable collar, and partly by
means of a slotted or segmental bar and thumb screw.
The inclination of the line is ascertained by means of a segmentul or semicircular
bar or frame fixed to the underside of the telescope, from the centre of which bar
or frame is suspended a weighted pointer, so that the angle of inclination may be
read off.

page_text: SPECIFICATION in pursuance of the conditions of tho Letters Patent filed by
the said George Henry Stephens and Horace Wilmer in the Great Seal
Patent Office on the 4th April 1882.
GEORGE HENRY STEPHENS, at present of Upper Baker Street, in the County
of Middlesex, and HORACE WILMER, of the Great Eastern Railway, Liverpool
Street, also in the County of Middlesex, Associates of the Institution of Civil
Engineers. "IMPROVEMENTS IN APPARATUS EMPLOYED IN SURVEYING."
Our Invention relates to apparatus to be employed in surveying, and has for its
object to provide an instrument which shall be capable of use for determining the
length of a line, its magnetic course, and its inclination.
And in order that our said Invention may be fully understood we shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of the accompanying Drawings represents in side elevation, Figure 2 in
end elevation, and Figure 3 in plan, an instrument constructed according to our
Invention.
A telescope A is mounted upon a tripod or other convenient stand B by means
of a ball and socket joint a, and is fixable in the position to which it has been
brought by pinching screws b, b.
In the diaphragm c of the telescope A are fixed two parallel horizontal hairs d, d,
for the purpose of ascertaining the length of the line by observing the length
subtended by means of the said horizontal hairs on an ordinary levelling staff held
vertically at the end of the line to be measured.
The distance apart of the hairs will bear the same proportion to the focal length
of the objective lens that the divisions of the staff subtended by the hairs is
required to bear to the total length of the line measured; thus if the divisions
observed on the staff are required to be one hundredth part of the length of the
line, then the distance between the cross hairs shall be one hundredth part of the
focal length of the objective lens. The exact distance apart of the hairs is
obtained by means of adjusting screws h, which raise or lower in guides the two
halves of the diapliragm c.
A vertical hair is or may be used in combination with the horizontal hairs, in
order to enable the said hairs to be readily brought into a truly horizontal
position.
E
The magnetic course of the line is determined by means of a prismatic compass
hinged at e to the telescope A over the centre line thereof. The said compass is
levelled by turning it in one direction upon its joint at e, and in the other direction
by turning the telescope about its horizontal axis, which may be effected by making
the connection of the said telescope with the ball and socket joint of the stand by
means of a hinged collar f, in which the said telescope can be rotated. The said
compass is fixed in its adjusted position in the one direction by the pinching
screw and segmental bar e, and in the other direction by pinching the collar f
upon the telescope by means of the binding screw ƒ³.
The inclination of the line is ascertained by means of a segmental or semicircular
har or frame constituting a clinometer, and fixed to the underside of the telescope A.
Froin the centre of this bar or frame or from the telescope a pointer g is suspended,
so weighted that it is plumb or points in a vertical direction. By means of this
pointer and the divisions of the clinometer the inclination of the telescope and
consequently of the line being measured may be ascertained.
Having now described and particularly ascertained the nature of our said

page_text: Invention, and the manner in which the same is or may be used or carried into
effect, we would observe in conclusion that what we consider to be novel and original,
and therefore claim as the Invention secured to us by the hereinbefore in part
recited Lotters Patent is,-
First. The apparatus or instrument for use in surveying, the same consisting of
means for determining the length of a line, its magnetic course and its inclination
combined, in one instrument, substantially as hereinbefore described and illustrated
in the accompanying Drawings.
Second. In apparatus or instruments for surveying, the employment of horizontal
hairs, the distance apart of which bears the same proportion to the focal length of
the objective lens that the divisions of the staff subtended by the hairs bear to the
total length of the lino or actual measurement, as herein before described with
reference to the accompanying Drawings.
In witness whereof, I, the said Horace Wilmer, for myself and the said George
Henry Stephens, have to this our Specification set my hand and scal, the
Third day of April, One thousand eight hundred and eighty two.
HORACE WTT MED