IMPROVEMENTS IN SURVEYING INSTRUMENTS
Year: 1860

page_text: LETTERS PATENT to Auguste Armand Trinquier, of Paris, France, Lieu-
tenant in the French Army, for the Invention of "IMPROVEMENTS IN
SURVEYING INSTRUMENTS."
Sealed the 15th March 1861, and dated the 21st September 1860.
PROVISIONAL SPECIFICATION left by the said Auguste Armand
Trinquier at the Office of the Commissioners of Patents, with his
Petition on the 21st September 1860.
I, AUGUSTE ARMAND TRINQUIER, of Paris, France, Lieutenant in the French
Army, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN SURVEYING INSTRUMENTS," to be as follows:-
These improvements relate to instruments for performing surveying opera-
tions, particularly those for military purposes, such, for instance, as measuring
angles, slopes, or levellings, making a rough trigonometrical survey or map of
a small extent of territory, the said instruments giving the greatest facility for
executing these operations and others of the same class, and doing away with
the use of several more or less complicated instruments now in use for such
purposes.
The instruments consist of a rectangular plane or surveyor's table or
drawing board, preferable of wood or of strong pasteboard, on which parallel
to one of its longitudinal sides is fixed a T-rule of brass or other suitable

page_text: material, the long or vertical leg or branch of which is connected to and
allowed to glide over the other, the latter being screwed to the table; a gra-
duated circle or protractor scale of cardboard or other suitable material is
allowed to revolve over the surface of the table on a fulcrum pin fixed in the
upper surface of the moveable leg of the T-rule towards the free end thereof,
while the other end of this latter is provided with a pointer for indicating the
position of the graduated scale or periphery of the protractor circle, the surface
of which circle is divided into suitable squares for indicating certain lengths,
such as steps, metres, yards, or others, according to the nature of the scale
adopted for making the survey.
For using the instruments a piece of transparent drawing paper or drawing
cloth is fixed by pins or other suitable means over the protractor circle, so as to
allow of observing the divisions and graduations of this latter; on this paper or
cloth the map or survey is to be drawn. In the corner of the table a drawing-
board opposite to where the T-rule is situated is fixed to the surface of this
board, by screws or other means, a compass box containing a compass with needle
and graduated circle; to this box is hinged a lid, provision being made for allow-
ing to fix this lid in the lifted position, and also for fixing the magnetic needle,
when required; in the inside of the said lid is made a suitable circular depression
or cavity, the bottom part of which presents a graduated periphery, and suitable
divisions for measuring slopes and giving other indications; and in the centre of
this circular cavity a weighted graduated semicircle or quadrant of brass or
other suitable metal or material provided with a hand or pointer and two pinules
is allowed to rock on a pin inserted in the centre of the cavity, so as to cause
this semicircle to form a pendulum level, provision being made for allowing the
same to stop in any desired position when required. Proper openings or sights
are provided in the sides of the lid for allowing to mark the direction of the
pinules and sight vanes, or alhidades are fixed to the outside of the lid for
observing in any required direction.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of September, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her
reign did, for Herself, Her heirs and successors, give and grant unto me, the
said Auguste Armand Trinquier, Her special licence that I, the said Auguste
Armand Trinquier, my executors, administrators, and assigns, or such others.
as I, the said Auguste Armand Trinquier, 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, use, exercise, and vend, within the United King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN SURVEYING INSTRUMENTS," upon the condition
(amongst others) that I, the said Auguste Armand Trinquier, my executors or
administrators, by an instrument in writing under my, or their, or one of
their hands 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 Auguste Armand Trinquier do
hereby declare 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 :-
These improvements relate to instruments for performing surveying
operations, particularly those for military purposes, such, for instance, as
measuring angles, slopes or inclines, for levellings, for making a rough trigono-
metrical survey, laying down a survey on paper, or the mapping of a small
extent of territory; the said instruments allowing to perform those various
operations and others of the same class with the utmost facility and con-
siderable accuracy, and doing away with the use of several more or less
complicated instruments now in use for such purposes.
In the annexed Drawings to which I will refer in this description various
views are given of my improved instruments, and of parts of them.
Fig. 1 is a top view of a surveyor's table or drawing board A, provided with
a moveable graduated circle or protractor scale B, which latter is allowed to
turn on a pin or pivot b fixed in the board B, in order that each of the
divisions of the circumference of this scale may be brought opposite a fixed
hand or pointer C of the board B. A piece of tracing paper or drawing

page_text: cloth D (represented in the Drawing as partly cut off), sufficiently transparent
for allowing to perceive through it the divisions of the scale underneath, is
fixed in such manner over this latter as to permit of freely moving the circle
on the pivot. The board A is made by preference of wood or pasteboard, and
the graduated protractor circle B of cardboard, but any other suitable material
or metal might be used; the surface of the circle B is divided by means of
suitable vertical and horizontal lines into equidistant squares, according to any
suitable scale, viz., inches for yards, steps, or other measure; the divisions. of
the circumference are likewise made to any suitable scale. The survey is laid
down on the tracing paper, the graduations of the circle serving for indicating
the linear distances measured, while the divisions of the circumference of this
circle serve for mapping the angular distances. In one of the corners of the
board A is fixed a compass box E (either single or double) with magnet
needle and graduated scale, as shown in perspective view in Fig. 2, for a
double box, the north-south line of this box being situated parallel to the line
drawn from the pointer C to the centre of the protractor circle. To the
box E, Fig. 2, is hinged a corresponding lid F, which, when opened, as
represented in Fig. 2, is fixed at right angles with the box by a hook, clasp,
hinge, or any other suitable means; either the box or the lid, or both, are
provided with a pair of sight vanes or albidades G1, G2; in the inner surface
of the lid is a depression or circular cavity H, against the bottom of which is
fixed concentrically a graduated circle I, shown on a larger scale in Fig. 5,
with proper divisions, hatchings, or other indications, in front of which circle
a semicircle J of brass, or other suitable metal, and which, by means of a
counterpoise weight j, forms a pendulum with hand j', is allowed to rock con-
centrically with the graduated circle I on a pivot fixed in the centre of the
cavity H, so as to form a levelling pendulum for measuring inclines, for which
purpose both ends h and h' of the diameter of the pendulum circle are each of
them provided with a pinule i situated just opposite two corresponding holes k
in the sides of the lid F, the angle of inclination may thus be read on the
circumference of the graduated scale I; if required the back of the lid may be
provided with a telescope, to be fixed together with a graduated scale I to the
pivot, on which turns the pendulum circle J, as shown in Fig. 3º. Provision
is made for allowing to fix the pendulum J while reading the angle on the
graduated scale I, which may be done by a pin and slide, to be pushed against
the pendulum, when this latter is momentarily to be fixed. The compass, from
what has been said; consequently forms an entire clinometer or levelling
compass. As may be observed from what has been described, the object of

page_text: the protractor scale and clinometer compass is to offer an easy means for
ascertaining the amount of slope of any incline, and for afterwards putting this
degree of slope as well as the measured distance on paper; this clinometer
consequently allows of at once measuring in a graphical manner any incline,
solely by taking sight at them with the instrument, and recording the
indications observed, and thus obtaining also the graphical distance of any
number of curves situated on the same level, carrying back to the horizontal
line the measured lengths and the difference in level by the intersection of
equidistant horizontal lines with a line forming with them, while taking sight,
the same angle as the incline does with the horizon; whereas, the pointer j¹ of
the levelling pendulum gives by its intersection with an equilateral hyperbola
of the formula x, y=z, the hatching corresponding with the degree of incline.
The principle according to which the protractor scale is constructed is that of
carrying the board A and the said scale B in such relative positions that the
north-south line of the sheet of mapping paper D be brought opposite that
graduation of the said scale as corresponds with the observed compass decli-
nation, in such manner as to cause the north-south line of the scale form with
the north-south line of the paper an angle equal to that of the said declination,.
by which means it will consequently be required only to draw through the
point observed, and which is to be mapped, a line parallel with the north-
south line of the protractor scale; in the modified protractor scale, represented
in plan view in Fig. 6, this parallel line is obtained by a moveable T-square
M, shown in this Figure, by drawing on the transparent mapping paper that
parallel marked on the scale underneath, that passes through the above said
observed point.
In Fig. 6, A¹ is the drawing board, which is allowed to revolve underneath
the mapping paper to be fixed to the lower board B', over the board A¹,,
which latter, of a square form, turns on a central pivot in a corresponding
cavity in the lower board B', in such manner that the upper surface of A¹ is
situated at the same level with that of the side parts C' of the board B'; part
of the circumference of the cavity b¹, b, b, b, is provided with a division scale,
whereas the adjoining angles a¹ and a² of the board A have each of them a
small graduated arc, the divisions of which form vernier with those of the
scales 62, 63, and 63, 64; the opposite angles a³ and a of the board A¹ are
provided with pointers d.
Fig. 6 represents a longitudinal sectional view taken over the line x, y,,
of Fig. 6, and Fig. 6b, a view from underneath of the board A', showing the
manner in which this latter turns on a pivot a³, and the means for momentarily,

page_text: fixing the board A¹ while reading the angle on the scale and vernier; for
this purpose the under side of the board A¹ is provided with a circular
plate a of brass or any other suitable metal having a circular cavity a7 with
bevelled edge corresponding with that of a wedge a³ fixed to one end of the
rod aº, the other end of which has a screw cut on it; by means of the nut a¹º,
the wedge a³ may be tightly drawn into the bevilled edge of the plate a", and
consequently this latter and the board A¹ fixed thereto, prevented from turning
until the wedge as be withdrawn from the bevelled edge of the plate a". Con-
jointly with this protractor board a T square constructed also on the vernier
principle may be made use of. One of the outer edges C2 of the lower board
B' is provided with a division scale, part of which forms vernier for the divisions
with which the short arms M¹ of the square M are provided; the long arm M²
of the square M is also provided with a similar scale with moveable slide N,
the divisions of the bevelled parts n of which likewise form vernier for the
long arm M³ of the square. Sometimes I apply the venier principle also to
the compass needle S (Fig. 2) by providing both ends of this needle S with a
graduated arcs of very thin brass plate, forming vernier for the divisions of the
scale of the compass.
In the annexed Drawings, Fig. 2 shows a perspective elevation view of a
compass with vernier needle; the graduated pendulum circle J turns on a
central pin or pivot, its diameter arm h, h', to which are fixed the pinules i, is
kept in the horizontal position by the effect of the counterpoise weight j; the
graduated circle I behind the pendulum follows the motion of the alhidade G,
Fig. 2b, in surveying the angle formed by the diameter 1, A, of the circle I and
that h, h', of the pendulum J consequently indicates the angle which the viewed
line forms with the horizon. This circle I has its lower semicircle partly
divided into regular squares by the intersections of a series of horizontal and
vertical lines situated at equal distances apart. The upper semicircle contains the
hatchings drawn according to the principle that their inner extremity be situated
on the incline they represent, and that the distance at which they are set apart
and their breadth is in accordance with the topographical conventions
generally agreed upon.
The Figs. 2b, 3b, 4b, respectively show an elevation view from behind, a side
view when open, and a view from behind when closed, of a clinometer compass
arranged according to my Invention; the back of the lid is provided with an
alhidade G, with two sight vanes G³ and G*.
Fig. 5 shows the graduated circle I, the indications of which may differ
according whether the instrument is to serve for military purposes, for the civil

page_text: engineer, geologist, miner, traveller, and so on. In the present one the
indications are those more particularly required for military purposes.
The Figs. 2, 3, 4", respectively show similar views as those of Fig. 2b 3b, 4b,
of a clinometer compass, the alhidade of which is provided with a télescope.
This clinometer is represented as connected in the usual manner to the top
of a levelling stand or foot W.
Fig. 2° and 3 respectively represent a top and a longitudinal sectional view
of a single clinometer compass in which the graduated circle I, Fig. 5, is
situated in the compass box underneath the magnet needle S.
The above described instruments may be constructed of wood, brass, or any
other suitable metal or material, and they will allow of obtaining the following
results: The compass gives the direction of the viewed lines, the clinometer
indicates their inclination in respect to the horizontal line, while the pro-
tractor scale allows the immediate mapping of these results; the inclination
shown by the clinometer at once gives the graphical distance existing between
any two equidistant curved lines of the survey by the intersection of the
horizontal lines of the clinometer with the diameter of the pendulum.
Further, the difference in level by curves (and consequently in the measure
according to which the divisions of the instrument are made) between any two
points by indicating the number of horizontal lines existing on the clinometer
scale between the real horizontal line and the point of the rule indicating their
distance. The reduction to the horizon of any required length by its projection
on the real horizontal line; the zenithal distances and their inclination on the
horizon; the hatchings corresponding with each degree of slope; the extreme
slopes of the roads, whether accessible to infantry, cavalry, artillery, or other
indications. The protractor scale serves for mapping on paper, in the
topographical mode, the above mentioned results, viz., by drawing inclined and
parallel lines at the required distances apart, and carrying the measured
distances on those lines by bringing the north of the ground opposite the
graduation of the protractor scale (as indicated by the compass) and by drawing
the parallel line passing through the given point, which line is to be seen
through the transparent mapping paper, or by means of the T square. The
distances are to be calculated by the number of lines perpendicular to the
given direction either by the protractor scale or by the T square.
And having now described and particularly ascertained the nature of the
Invention and the manner in which the same is or may be carried into effect,
I would observe in conclusion that I do not confine or restrict myself to the
precise details or arrangements hereabove described, as many variations may

page_text: be made therefrom without deviating from the main features of the said
Invention; but what I claim as the Invention secured to me by the herein-
before in part recited Letters Patent is the general arrangement and mode of
acting of the above described improved surveying instruments.
In witness whereof, I, the said Auguste Armand Trinquier, have hereunto
my hand and seal, this Sixteenth day of March, One thousand eight.
hundred and sixty-one.