AN IMPROVED SURVEYING INSTRUMENT
Year: 1856

page_text: LETTERS PATENT to Charles Barlow, of the Office for Patents, 89,
Chancery Lane, London, for the Invention of "AN IMPROVED SURVEYING
INSTRUMENT."-A communication.
Sealed the 2nd December 1856, and dated the 17th July 1856.
PROVISIONAL SPECIFICATION left by the said Charles Barlow at the
Office of the Commissioners of Patents, with his Petition, on the
17th July 1856.
I, CHARLES BARLOW, of the Office for Patents, 89, Chancery Lane, London,
do hereby declare the nature of the said Invention for "AN IMPROVED
SURVEYING INSTRUMENT," to be as follows:-
This Invention of an improved surveying instrument consists of a box made
of two circular metal plates fitted upon a base or bed plate, the face of which
may be graduated. The circular plates or discs are divided, one into 360
degrees, and the other into corresponding gradients. A wheel having four
points or hands at 90° distance from each other is placed between the circular
metal plates, and hung so as to rotate very easily about the points of support.
One of the points of the wheel is made heavier than the others, by which
means it falls to the lowest point, and in a vertical line with the point above
it. The points of the wheel project a little beyond the circumference of the
metal discs, and serve.to.indicate the difference of level. Sight holes-may be

page_text: made in the base plate, and the whole fitted to a stand to raise it to a con-
venient height. Instead of the wheel with four points, a double-pointed hand
or index may be used, the lower end being made the heaviest to keep it in
a vertical position.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Barlow in the Great Seal Patent Office on the
17th January 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
BARLOW, of the Office for Patents, 89, Chancery Lane, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of July, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Charles Barlow, Her special licence that I, the said Charles. Barlow, my
executors, administrators, and assigns, or such others, as I, the said Charles
Barlow, 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 Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "AN IMPROVED SURVEYING
INSTRUMENT," upon the condition (amongst others) that I, the said Charles
Barlow, 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 Charles Barlow, 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:
This Invention of an improved surveying instrument, which the Inventor
calls a clitometer, from two Greek words. signifying a gradient measurer,
consists of an instrument for ascertaining or measuring horizontal, vertical, or
inclined lines or surfaces, and may be used in lieu of a water or air level,
and as a substitute for the level and plumb line ordinarily used by bricklayers,

page_text: masons, carpenters, and other artizans, as well as for its more legitimate
purpose of surveying and levelling. The instrument consists of two circular
metal plates fitted parallel to each other, and at right angles to the base upon
which they are supported. The face of one of the plates is divided into three
hundred and sixty or four hundred. degrees, and the other into gradients,
showing the inclination per yard or metre. A wheel having four points or
hands, 90° apart, projecting from its periphery, is suspended between the metal
plates. One of the points is made heavier than the others, so that it falls to
the lowest point, and in a vertical line with that above it. The points of the
wheel project a little beyond the circumference of the metal plates or discs,
and serve to indicate the difference of level.
But in order that this Invention may be fully understood and carried into
practical effect,. I will proceed to describe the same in detail, referring to the
Drawing accompanying and forming a part of this Specification, and to the
letters and figures marked thereon.
Fig. 1. is a front elevation of the instrument; Fig. 2 is a perspective. view
of the same, showing the projecting points of the wheel; Fig. 3 is a side
view of the instrument; and Fig. 5, a front view of the wheel detached from
the other parts. A, B, is the base or foot of the instrument, carefully,
adjusted and graduated upon the front, as shewn by Fig. 1; C, C, are the
metal plates or discs. The face of one of these plates is graduated into
degrees, and the other is divided by lines, indicating the inclination per yard,
metre, or other distance. A wheel, shown in front view by Fig. 5, having
four pointers or. indexes a, a, a, a,. placed equidistant, is suspended by its
axle between the plates C, C, so as to move very easily upon its axis. The
lower part of the wheel at P, Fig. 5. is made heavier than the upper part L,
in order that the part P shall always fall to the lowest point, the points a, a,
being in a vertical line, and those marked a', a', in a horizontal line. The
points of the wheel are bifurcated, as seen at Fig. 6, and the one nearest the
graduated circle is made with a small blade on each side, both provided with
a vernier. The point of one of the bands may be fitted with a small clip to
hold letters for weighing. Instead of the wheel, Fig. 5, a double-pointed
hand may be used, as shown by Fig. 6, to the centre of which a rod is to be
fixed, having at the lower end a counterpoise weight, which, acting as a pen-
dulum, serves to keep the hand in a horizontal line. The base A, B, Fig. 1,
is made with sight holes, as shown by Figs. 4 and 4'. Fig. 7 represents the
method of measuring gradients or inclinations either by the yard or metre, as
indicated by the inclined position of the hand, the diagonal lines on the dial
plates-showing-the number of degrees. Fig. 8 represents the upper part of

page_text: a stand of the ordinary kind for supporting the clitometer, the instrument
being held by set screws. When supported by the pointed screws, which are
made to fit the conical holes in the centre of the dial plates, the clitometer
may be used as a water level; where the instrument is required to be used in
lieu of the masons' level, plumb line, or as an air level, it may be made
sufficiently small to be easily carried in the pocket; but for the general
purposes of surveying and levelling it must be made larger, and should be
cased with glass, and mounted on a knee joint, as usual with instruments of
the kind. The instrument may be made of metal or other suitable material,
and its shape and arrangement modified to suit the particular purposes for
which it may be required.
IIaving described the nature of the said Invention, communicated to me,
and the manner of carrying the same into practical effect, I wish it to be
understood that I do not confine myself to the precise arrangement of the
several parts herein-before described and shown, as the same may be varied
without departing from the Invention; but what I claim, and desire to secure
under the herein-before in part recited Letters Patent, is, the construction
and arrangement of a surveying and levelling instrument, as herein-before
described and shown, or any mere modification thereof..
In witness whereof, I, the said Charles Barlow, have hereunto set my
hand and seal, this Seventeenth day of January, A.D. 1857.
CHARLES BARLOW. (L.B.)