AN IMPROVED CIRCULAR REVOLVING MEASURE
Year: 1881

page_text: LETTERS PATENT to Herbert John Allison, of the Firm of Allison, Brothers,
Patent Agents, of 41, Southampton Buildings, in the County of Middlesex,
for an Invention of "AN IMPROVED CIRCULAR REVOLVING MEASURE."
A communication from abroad by Marie Joseph Mourrier, of Coniza (Aude),
in the Republic of France.
PROVISIONAL SPECIFICATION left by the said Herbert John Allison at
the Office of the Commissioners of Patents on the 7th January 1881.
HERBERT JOHN ALLISON, of the Firm of Allison, Brothers, Patent Agents, of
41, Southampton Buildings, in the County of Middlesex. "AN IMPROVED CIRCULAR
REVOLVING MEASURE" A communication from abroad by Marie Joseph Mourrier,
of Coniza (Aude), in the Republic of France.
This circular measure, which revolves on a central axis, is very simple, and even
more so than an ordinary measure which it may replace.
It consists of a circular metallic piece one metre in circumference, graduated by
centimetres at its outer edge. It revolves round a central axis actuated by a
handle serving to direct the instrument in the direction of the dimensions to be
taken or to be determined.
A small arm or pawl turned at right angles to the handle indicates by its
contact with a starting point adapted to the circular metallic piece the number of
revolutions that the latter makes, and which consequently correspond with the
number of metres measured, so that it is only necessary to direct attention to the
decimal quantity in order to ascertain exactly the development of all circles, or of
all other spherical, cylindrical, or elliptical bodies.
Besides this advantage of precision, which no other instrument possesses, this
instrument has also the not less important advantage of being able to solve
mathematically and without calculations all the principal problems in measuring
circular work and manufacturing different articles and objects ofjart.
For this purpose the circular measure carries also on each face three rows of

page_text: concentric figures, giving the elements hereinafter mentioned, based on the most
needful of known requirements in the art of construction,―
1st. The relation of circumferences with all radii from centimetre to centimetre,
corresponding to the metrical graduations of the instrument to which it is applied.
2nd. The area of circumferences, the section, the cube, or capacity in metres of
cones, cylinders, basins, wells, etc.
3rd. The length of the sides of several inscribed polygons, or of the chords of
circumferences divided in six, seven, or eight equal parts.
4th. The cube in metres of uncleft rough timber, calculated according to the
principal most employed, reducing the trees to the square of quarter of the
circumference.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Herbert John Allison in the Great Seal Patent Office on the
6th July 1881.
HERBERT JOHN ALLISON, of the Firm of Allison, Brothers, Patent Agents, of
41, Southampton Buildings, in the County of Middlesex. "AN IMPROVED CIRCULAR
REVOLVING MEASURE." A communication from abroad by Marie Joseph Mourrier,
of Coniza (Aude), in the Republic of France.
This circular revolving measure is as easy or even easier to use than the ordinary
measure which it may advantageously replace.
Fig. 1 is a view of the front face; Fig. 2 is a vertical section on line X, Y
Fig. 3 is a view of the back face; and Fig. 4 is a horizontal section on line X, Z.
In these four Figures the same letters indicate the same parts.
It consists of a metallic or other suitable disc A, of either 1 or 2 metres in
circumference, and graduated in centimetres on one of its outer edges. It will be
understood that the dimensions of the circumference may be varied indefinitely,
and that it may according to circumstances and requirements be applied to other
measures than those of the metrical system.
This disc revolves round the axis B, and is actuated by the handle B¹, serving
to direct the instrument in the direction of the dimensions to be taken or
determined.
;
A small arm or pawl a is mounted at right angles to the handle, and indicates
by its contact with a tooth or projection b on the disc A the number of revolutions
that the latter makes, and consequently the number of metres measured, so that it
is only necessary to fix the attention on the decimal quantity in order to ascertain
exactly the development of all circles, or of all other spherical, cylindrical, or
elliptical bodies. The arm a is lodged in a recess c made in the bent arm C of the
handle B¹, and has at one end a rectangular hole, through which passes the screw d,
the hole being long enough to allow the arm a to be moved, so as to prevent its
contact with the tooth or projection 6 when desired.
In order to facilitate the reading of the measurement of great distances, and to
avoid all errors, on the axis B is mounted a tooth wheel D having 50 teeth,
numbered from 1 to 50, and which advances one tooth for each revolution of the
arm or pawl a.

page_text: This wheel gears with the pinion e operated by a small projection on the
disc A.
This arrangement is preferred for transmitting the motion, as being the best
suited to avoid errors, but any other suitable means of transmission may be
employed.
The pinion e is attached to the handle by a nut f. Between the pinion and the
handle is placed a slightly curved spring, the pressure of which prevents the free
movement of the pinion, so that no matter what may be the speed given to the
large disc, the latter will not carry the pinion with it in its course except for the
length of a tooth for each complete revolution.
A small needle or hand g coming in contact with a stop / will indicate the
complete revolution of the toothed wheel D.
By the above description it will be readily understood that in order to read the
distance or length measured it is necessary to look on the tooth wheel D, the needle
or hand g of which marks the number of revolutions made by the disc A, while
the arm a indicates the fraction traversed by the disc.
This new mode of measuring may be advantageously substituted for all those
hitherto employed, principally for the measurement of railroad and of ordinary
roads of but slight gradient, for it incontestably effects an economy of time, and
above all avoids all errors. Supposing a person to employ a disc 2 metres in
circumference he could alone measure, and that without stooping and whilst
running, any flat or nearly flat surface.
Besides the advantages of precision, which no other instrument in use will effect,
this instrument has further the not less important advantage of being able to solve
mathematically and without calculations all the principal problems, including the
measuring of circular works and the manufacture of different articles and objects
of art.
For this purpose the circular measure carries also on each face three rows of
concentric figures, giving the elements hereinafter mentioned, based on the most
needful of known requirements in the art of construction,-
1st. The relation of the circumferences with all the radii from 1 to 100 centimetres,
corresponding to the metrical graduations taken as the base.
2nd. The area of the circumferences or linear measurement of truncated cones,
cylinders, basins, etc., or the cubic contents of barrels, etc.
3rd. The length of the sides of several inscribed polygons, or the chords of
circumferences divided into 6, 7, or 8 equal parts.
4th. The cube per linear metre of uncleft rough timber, calculated according to
the principle most employed, reducing the trees to the square of quarter of the
circumference.
It will be seen by the above description of the instrument that it may be applied
to a great variety of purposes.
It will be useful for builders, locksmiths, hatters, carpenters, wheelwrights, black-
smiths, etc.; in fact to all whose profession or trade necessitates the use of the
metre or of its derivatives, for not only does it indicate linear measurements, but it
is also applicable to the most elementary applications having for object the finding
out of the value of round bodies.

page_text: A, cube of uncleft or rough wood reduced to the square of of its circumference.
A', area or cube per linear metre of cylindrical objects.
A", relation of circumferences to the radii.
Ai, metrical graduation or radius of the circumferences.
Fig. 4, section through X, Z.
Having now described the nature of the said Invention, and the manner of
carrying the same into effect, I wish it to be understood that I claim,-
1st. The construction of the circular measure, as herein described and shown in
the Drawings.
2nd. The manner of graduating the measure, as herein described and shown in
the Drawings..
•
3rd. The employment of an arm to indicate the distance traversed by the disc
taken as the unit, as herein described and shown in the Drawings.
4th. The application and arrangement of the toothed wheel to indicate the
number of revolutions of the disc.
5th. The particular arrangement employed for the transmission of the movement
of this toothed wheel, as herein described and shown in the Drawings.
In witness whereof, I, the said Herbert John Allison, have hereunto set my
hand and seal, this Sixth day of July, in the year of our Lord One
thousand eight hundred and eighty-one.
T