IMPROVEMENTS IN THEODOLITES, LEVELS, AND OTHER INSTRUMENTS, WHICH IMPROVEMENTS ARE MORE ESPECIALLY APPLI- CABLE TO SETTING OUT SURFACE WIDTHS OF RAILWAY SLOPES OR OTHER INCLINED PLANES
Year: 1864

page_text: LETTERS PATENT to James Lister, of Clare, in the County of Suffolk,
Civil Engineer, for the Invention of "IMPROVEMENTS IN THEODOLITES, LEVELS,
AND OTHER INSTRUMENTS, WHICH IMPROVEMENTS ARE MORE ESPECIALLY APPLI-
CABLE TO SETTING OUT SURFACE WIDTHS OF RAILWAY SLOPES OR OTHER INCLINED
PLANES."
Sealed the 24th March 1865, and dated the 28th September 1864.
PROVISIONAL SPECIFICATION left by the said James Lister at the Office
of the Commissioners of Patents, with his Petition; on the 28th September
1864.
I, JAMES LISTER, of Clare, in the County of Suffolk, Civil Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
THEODOLITES, LEVELS, AND OTHER INSTRUMENTS, WHICH IMPROVEMENTS ARE MORE
ESPECIALLY APPLICABLE TO SETTING OUT SURFACE WIDTHS OF RAILWAY SLOPES OR
OTHER INCLINED PLANES," to be as follows:-
My Invention, as applicable to the instruments known as the theodolite and
level, consists in the introduction of a movement by which the telescope.thereof
may be caused to revolve in a plane at any angle with the horizon, and also as
regards the theodolite of certain scales or graduations on the vertical arc.
In the accompanying Sheet of Drawings A, Fig. 1, is the axis or spindle of
the vertical arc, the bearings of which a, a, Fig. 2, work on the standards of
the ordinary theodolite.
V is the vertical are with the ordinary adjustment (but which adjustment is

page_text: not shewn in the Drawing) on which the scale for the angles or inclinations
are graduated. T is the telescope revolving on an axis in the spindle of the
vertical are as shewn by the dotted lines so that when the vertical arc is fixed
at any angle or inclination the telescope shall revolve in the plane of such
inclination or at a right angle to the arc; S is a spring fixed. at e, which on
pressing the small cam c into the jaw d secures the telescope in place when
not required to revolve horizontally; by pressing the spring the telescope is set
at liberty so as to revolve horizontally when required; B is a bubble fixed on
the instrument in the ordinary manner.
My improvement in the level consists in the addition of a clinometer to the
telescope, or an additional plate, and graduated vertical are, or any other modi-
fication by which the beforc-mentioned purpose can be accomplished, viz. the
enabling the telescope to revolve in a plane at any angle with the horizon.
My Invention is more particularly designed (but not exclusively-so) to
facilitate the operation of setting out the surface widths of slopes or battee pegs
required in the execution of railway, canal, and other earthworks. The telescope
of my improved instruments being made. to turn upon an axis at a right angle
to the plane of the slope or inclination to be set out, and the focal axis of the
telescope being in the plane of that slope, any number of points required
within the range of the instrument can be determined by the intersection of
the cross wire with the surface by one operation; whereas to accomplish the
same amount of work with the ordinary instrument, ten, twenty, or more
operations, as the case might be, would.be required.
I claim as my Invention,
First, the telescope of the instrument being enabled to move or revolve in a
plane at any angle with the horizon.
Second, the introduction of certain scales or graduations on the vertical arc
for determining the angle of the slope or inclined plane at any given point or
distance from the instrument.
vrarer 805.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
LISTER, of Clare, in the County of Suffolk, Civil Engineer, send greeting...
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters 3
Patent, bearing date the Twenty-eighth day of September, in the year of our

page_text: Lord One thousand eight hundred and sixty-four, in the twenty-eighth year
of Her reign, did, for Herself, Her heirs and successors; give and grant
unto me, the said James Lister, Her special licence-that I, the said James
Lister, my executors, administrators, and assigns, or such others as I, the said
James Lister, 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, usė;
exercise; and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THEODOLITES, LEVELS, AND OTHER INSTRUMENTS, WHICH IMPROVEMENTS ARE MADE
ESPECIALLY APPLICABLE TO SETTING OUT SURFACE WIDTHS OF RAILWAY SLOPES OR
OTHER INCLINED PLANES," upon the condition (amongst others) that I,; the
said James Lister, my executors or administrators, by an instrument in writing
under my, or their, or, one of their bands and seals, should particularly
describe and ascertain the nature of the said Invention, and in. what manner
the same was to be performed, 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.
NOW KNOW YE, that I, the said James Lister, do hereby declaro
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 and accompanying Drawings, that is to say:-.
My Invention consists primarily of a combination of the theodolite and level,
which while serving all the ordinary purposes of the two instruments is
specially adapted to setting out mechanically, without recourse to calculation,
the surface widths or slope pegs, for denoting the top of slope on cuttings, and
the foot of slope in embankment, required in the execution of railway, canal,
and other earthworks.
The ordinary method of setting out surface widths hitherto, practised is the t
generally described in works treating of the subject which involves the use of
the level, and a distinct operation with considerable calculation, for each half
width separately, and which in rough and sidelong ground requires to be
frequently repeated in each case before the required front is found, thus
rendering the operation not only tedious, but very liable to error.
By the following explanation of the instrument and its application, and the
accompanying Drawings, it will be readily understood; that the whole operation
being simply mechanical, little or no calculation being required (not any, if
tables be used), the liability to error is reduced to a minimum, and the mani-
pulation of the instrument is rendered simple and expeditious.

page_text: My Invention, as applicable to the instruments known as the theodolite and
level, consists in the introduction of a movement by which the telescope thereof
may be caused to revolve in a plane at any angle with the horizon, and also as
regards the theodolite of certain scales or graduations on the vertical arc.
In the accompanying Sheet of Drawings A, Fig. 1, is the axis or spindle of
the vertical arc, the bearings of which a, a, Fig. 2 work on the standards of
the ordinary theodolite.
V is the vertical arc with the ordinary adjustment (but which adjustment is
not shewn on-the Drawing) on which the scales for the angles or incli-
nations are graduated; T is the telescope revolving on an axis in the spindle
of the vertical arc as shewn by the dotted lines, so that when the vertical arc
is fixed at any angle or inclination the telescope shall revolve in the plane of
such inclination, or at a right angle to the arc; S-is a spring fixed at e, which on
pressing the small cam c into the jaw d, secures the telescope in place; when
not required to revolve horizontally, by pressing the spring, the telescope is set
at liberty, so as to revolve horizontally when required; B is a bubble fixed on
the instrument in the ordinary manner..
My improvement in the level consists in the addition of a clinometer to the
telescope, or an additional plate, and graduated vertical arc or any other modi-
fication by which the before-mentioned purpose can be accomplished viz. the
enabling the telescope to revolve in a plane at any angle with the horizon.
.
My Invention is more particularly designed (but not exclusively so) to
facilitate the operation of setting out the surface widths of slopes or batter pegs
required in the execution of railway, canal, and other earthworks. The tele-
scope of my improved instrunient being made to turn upon an axis at a right
angle to the plane of the slope or inclination to be set out, and the focal axis
of the telescope being in the plane of that slope, any number of points required
within the range of the instrument can be determined by the intersection of
the cross wires with the surface by one operation; whereas to accomplish the
same amount of work with the ordinary instrument, ten, twenty, or more
operations as the case' might be, would be required.
To express more in detail the nature of my Invention, I wish it to be under-
stood that the main feature or novelty of the instrument consists in a modifi-
cation of the ordinary-theodolite, by giving to the telescope a horizontal action
on the spindle or axis of the vertical arc, instead of being fixed to it, so that
when clamped by the vertical' are to the angle or inclination of the slope
required to be set out, and fixed in this plane at any point, the telescope
will revolve in the plane. It will thus be readily seen, that the telescope re
volving in the plane of the slope, apy point in the surface on that plane, whep

page_text: the line is straight will be cut by the cross wire of the telescope as before
described, and thus the widths, at the several chainages, or at any intermediate
point where the nature of the ground would necessitate a width being put out
within the range of the telescope, would be at once determined on either side
of the instrument to the next change of gradient. When the line is on a curve,
each point is determined' by tangential angles, the method of procedure being
precisely the same as setting out an ordinary curve on the centre line, with this
addition, that the telescope must be depressed to the vertical angle which
the slope line assumes to the chord at each point, or as seen from the in-
strument: This anglè varies from the angle of inclination at the tangent
point, ie, at the instrument, to zerv, or a vertical line when the chord is at
a right angle to the tangent, or when the curve has been traced round to one
half its circumference, and may be found for any point from the following
equation:
cos. tangential angle,
55
tang. of vertical angler X
being the ratio of slope, 1, 1, &c. But this calculation is obviated by
the use of certain scales of tangents graduated on the vertical arc of the in-
strument for the several ratios of. slope, as shewn upon the accompanying
Drawing, it being only necessary to clamp the vertical arc. to the tangential
angle for each point-respectively..
The only calculations required in the operation are those for the tangential
angles which are readily formed by dividing constant 1719 by the radius of the
curve in chains, which gives the angle in minutes for the first chain in the curve.
The angle for any other point is found by multiplying this angle by the distance
in chains or by D. 1719, D being the distance in chains, but the use of tables, par-
ticularly those by Kennedy and Hackwood, who gives the angle for every
chain up to 20 for any curve, obviate any calculation whatever. Thus the
widths on a curve may be almost as readily set out as those on straight, as the
manipulation of the instrument is easily performed during the time the assistant
is driving the peg, and walking from one point to another. In curves of large
radii, the variation of the vertical angle for some distance from the instrument
is so slight that the depression of the telescope is practically immaterial; but in
curves of smaller radii, and in those of larger radii when the widths to be set
out are at a considerable distance from the instrument, it is necessary that
the variation be attended to.
:.
The instrument is perfectly adapted to all other purposes to which the theo-
dolite or level is applied. It is a transit, but is simply reversed by releasing
the telescope from its securing cam, and turning it horizontally on its axis till
the opposite cam is in place.
:
.:

page_text: PRVATION OF THE INSTRUMENT ON THE GROUND.
When the line is straight.-In proceeding to set out a series of widths when
the line is straight; first set out in the. ordinary way (using the instrument as
a level) a pair of widths as far as possible apart, or at any convenient distance
according to the nature of the ground or where practicable, put out the forma
tion width at the commencement of cutting or.bank, and make this one of the
points established. Then clamp the telescope by means of the vertical arc to
the angle or inclination of 'the slope, and set it at one of the points already
determined, so that the cross wire shall cut the top of the peg, or coincide
with the plane of the slope at that point: Then direct the telescope to the
distant peg, or other point determined, adjusting it by means of the screws on
the horizontal arc, when it will now revolve in the plane of the slope; the cross
wire coinciding with the surface line of that plane throughout the whole
distance to the next change of gradient, which may now be "nicked out," or
the batter pegs be put in on either side of the instrument, as far as the range
of the telescope will admit.. The operation is then repeated for the other side
of the cutting or bank, the two points for a basis being already found by the
¡former operation. ;
When the line is on a curve.-In setting out widths on a curve, first
Jaccurately lay off in the usual way, by means of a cross staff or optical square
<a "square" line, or line at right angles to the tangent of the curve at each
.chainage peg in the centre line. Then set out the pair of widths as a basis,
and fit the instrument at one of them, as described in case of straight. Having
-done this, calculate the tangential angle for the distant peg D. 1719, D being. the
distance in chains, and R the radius of the curve in chains (or refer to the
tables). Clamp the horizontal arc to this angle, and the vertical arc to the
same angle on the graduated scale, and direct the telescope to the peg.; clamp
the lower peg; unclamp the top plate and the telescope when set at zero is now
on the tangent line, and the method of procedure is the same as setting out
an ordinary curve by tangential angles, as before described, that is, doubling
the angle for the first chain, for the second, and adding it again for each chain
forward (or by using the tables) the vertical arc being clamped to the same
tangle for each chain respectively. The intersection of the cross wire of the
telescope with the square line-set off at each peg, determines the square width
-at that point...
The general advantages of the instrument are,-.
First, its simplicity of manipulation.
Second as avoiding tedious calculation and conseguente liabilit

page_text: Third, by its means surface widths are set out much more expeditiously,
as by one set of the instrument (if no obstruction occur) they may be set
out to any distance on either side of the instrument within the range of the
telescope.
Fourth, on sidelong ground which presents no increased difficulty. Indeed
the real utility and advantage of the instrument can only be fully appreciated
in rough and mountainous districts where the ordinary methods become totally
impracticable.
Lastly, as combining in itself both the theodolite and level. The telescope
freely revolving horizontally as in the common level, independently of the other
parts of the instrument, renders it perfectly adapted for levelling, and thus pre-
cludes the necessity of possessing both instruments, an important advantage
in a pecuniary point of view.
Having now fully described the nature of my Invention, the method of its
application or use, and its general advantages, I wish it to be understood that
what I claim as my Invention is,―
First, the telescope of the instrument being enabled to move or revolve in
a plane at any angle with the horizon.
Second, the introduction of certain scales or graduations on the vertical
arc, for determining the angle of the slope or inclined plane at any given point
or distance from the instrument.
In witness whereof, I, the said James Lister, have hereunto set my
hand and seal, this Twenty-eighth day of March, in the year of our
Lord One thousand eight hundred and sixty-five.
Witness,
RICHARD SILVESTER.
JAMES LISTER. (L.S.)