AN IMPROVED METHOD OR AN INSTRUMENT OR INSTRU- MENTS FOR DETERMINING OR ASCERTAINING THE CUBIC CONTENTS OF STANDING TIMBER
Year: 1824

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
ROGERS, of Marlborough, in the County of Wilts, Surveyor, send greeting.
WHEREAS His present Majesty King George the Fourth, by His Letters
Patent under the Great Seal of the United Kingdom of Great Britain and
Ireland, bearing date at Westminster, the Twentieth day of March now last
past, did give and grant unto me, the said James Rogers, His especial
licence, full power, sole privilege and authority, that I, the said James Rogers,
my executors, administrators, and assigns, and such others as I, the said
James Rogers, my executors, administrators, or assigns, should at any time
agree with, and no others, from time to time and at all times thereafter during
the term of years therein expressed, should and lawfully might make, use,
exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, my Invention of "AN IMPROVED METHOD OR AN INSTRUMENT OR INSTRU-
MENTS FOR DETERMINING OR ASCERTAINING THE CUBIC CONTENTS OF STANDING
TIMBER;" in which said Letters Patent there is contained a proviso obliging
me, the said James Rogers, by an instrument in writing under my hand and
seal, particularly to describe and ascertain the nature of my said Invention,
and in what manner the same is to be performed, and to cause the same to
be inrolled in His Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said recited Letters Patent,
as in and by the said recited Letters Patent, reference being thereunto had,
will more fully appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
James Rogers, do hereby declare that the nature of my said Invention, and

page_text: :
the manner in which the same is to be performed, are particularly described
and ascertained in and by the Figures upon the Sheet of Drawings which is
hereunto annexed, and by the following description thereof, that is to say :-
Fig. 1 represents a perspective view of the whole instrument, with part of
the tripod stand upon which it is mounted when in use. Note, all the
Figures upon the Sheet are drawn to a scale of about six inches to a foot, or
one half of the real size of the instrument, and the same characters or letters
of reference are used to denote corresponding parts upon the Figures wherever
they occur. The instruments consists of three metal limbs or arms A, B, and
C, one of which, marked A, is situated in an horizontal position or nearly so,
and is united by a joint a with the two limbs B and C (which, for distinction,
I will denominate the angle limbs). These two limbs are also united by a
joint 6 in such a manner that the angle they form with each other may be
increased or diminished at pleasure by means of the small toothed rack or
sector D and pinion d. The angle which the limbs B and C form with the
horizontal limb A may also be increased or diminished at pleasure by means of
the toothed sector or rack E and pinion e. At the same time they can be
secured at any required angle by the aid of the clamping screw h, which is
adapted to bind upon the side of the sector E. The horizontal limb A has a
piece of metal i proceeding from it, which is united by a strong joint k with a
rod or spindle F. This spindle is fitted through a cylindrical hole in a metal
sphere or nob G, which is formed upon the uppermost end of a short pillar H;
and, as this pillar is attached to the head of the tripod stand I, it serves to
support the whole instrument. The nob G has a clamping screw 9 projecting
in an oblique direction from one of it's sides, for the purpose of binding upon
the spindle F, in order to retain the instrument in any required position.
The instrument may be turned partly round upon the joint k by means of the
toothed sector L and pinion l. At the same time the joint k may be clamped
fast, when required, by the thumb screw M. The horizontal limb A bas a
curved plate of metal or sector N fixed to it, which proceeds from the upper-
most side thereof, being described as an arc of a circle from the centre pin of
the joint a. This sector passes freely through an opening or slit in the angle
limb B, and is graduated on both sides in such manner as to indicate the angle
of elevation of the limbs B and C above the horizontal limb A, as will be
herein-after more particularly described. The angle limb B has also a sector
plate O fixed to it, proceeding from the inner side thereof, being described as
an arc of a circle from the centre pin of the joint b. This sector plate is
adapted to slide freely through an opening or slit formed through the angle
limb C, and it's surface is graduated with several scales, in order to indicate

page_text: the angle subtended between the limbs B and C, as will be herein-after more
particularly described. P represents a small spirit level, which is adapted to
hang upon eyes or staples in the under side of the limb A, it's use being to
adjust the limb A into the horizontal position previous to making observations
with the instrument. The centre pins of the joints a and b are perforated to
receive small plates of metal (as seen separately at R and S upon the
Drawing, having very minute apertures through them to serve as sights for
viewing the object which is to be measured, for which purpose the extremities
of the limbs A, B, and C are furnished with small elevated points or sights
marked s, s, t, and v, to direct the line of vision.
Fig. 2, upon the Sheet of Drawings, represents a side elevation of the
upper part of the instrument; Fig. 3 shews a plan of the angle limbs B and
C detached from the rest of the instrument; Fig. 4 shews a plan of the hori-
zontal limb A, with it's appendages, which are situated beneath. Note, the
letters of reference, which are placed upon the various parts of these Figures,
being similar to those marked upon the Fig. 1, will serve to explain them
without entering into a further description thereof.
I will now describe the mode of graduating the arc or sectors N and O, as
above mentioned, beginning with the arc N, which is for determining
elevations. The instrument is intended to be placed at a distance of twenty-
four feet from the base or foot of the tree in measuring small or moderate-
sized timber, and at forty-eight feet distance from the base or foot of the tree
when employed in measuring large and lofty trees. For this purpose the
sector N has two distinct scales graduated upon it, corresponding with those
distances. For instance, that part of the scale which is to be used for
measuring altitudes when the centre a of the instrument is placed at a distance
of twenty-four feet from the base of the tree is marked with the right sines of
the angles at every three inclies in height measure upon a base of twenty-four
feet; and, in like manner, the other part of the arc is graduated upon a base
line of forty-eight feet. This mode of laying down the scales will be easily
understood by persons conversant with the dividing of mathematical instru-
ments; but, in order to render it as clear as the subject will admit of, I will
describe the process which I have adopted practically in laying down the
divisions upon the instrument above described. I draw a right line upon a
true and smooth piece of board, and mark a centre point upon one end of the
line; then, at the distance of three feet from the said centre point I erect a
perpendicular upon the line, and divide the perpendicular into equal spaces of
one inch and an half, which is to serve for the scale, with a base of twenty-four
feet; and I likewise divide the perpendicular into equal spaces of three

page_text: quarters of an inch for the scale, with a base line of forty-eight fect, after
which I divide each of these spaces into four parts. This being done, I place
the metal sector N upon the board in such a position that the centre from
which the sector was described will correspond with the centre point marked
upon the board; then, with a straight-edge or ruler laid so as to pass through
the centre point, I transfer the lines from the perpendicular, and mark them
upon the proper arcs on the sector, as will appear evident from inspection of
the red lines marked upon the Fig. 1 of the annexed Drawing. The sextor
plate O has several arcs of divisions marked upon it, which arcs are intended
to be employed in measuring the diameters of trees at different parts of their
height. These divisions are laid down in the following manner :-When the
angle limbs B and C of the instrument are brought down into an horizontal
position, the distance or base being twenty-four feet, and the largest arc upon
the sector O being twelve inches radius, the divisions will be half an inch to a
foot. Thus, if the inner edges of the angle limbs were extended to half an
inch distance at the rdius of the largest arc upon the sector O, and the instru-
ment was placed at twenty-four feet distance from the root or base of a tree,
the eye, on being applied to the sight R and points s, s, upon the upper side of
the angle limbs, would appear to embrace the tree, and include a diameter of
twelve inches. The divisions upon the second arc of the sector O are intended
to be used at an elevation of eight feet up the tree from the horizontal point;
consequently, the divisions upon the arc will be laid down by using the hypo-
thenuse of the angle for a base, and marking the right sines of the angles
upon the sector for every inch in the diameter of the tree. In like manner,
the altitudes proceed four feet at a time up to forty-four feet, with a separate
arc of divisions for each; then four other arcs are marked each for four feet
higher, but with a distance of forty-eight feet.
The method of using the instrument is as follows:-Suppose, for example,
that the cubic contents of a moderate sized tree is required to be ascertained.
The centre a of the instrument is to be set up at a distance of twenty-four feet
(which is determined by previous measurement) from the centre of the tree.
This being being done, the limb A is to be adjusted into a horizontal position
by means of a plumb line, or by observing the bubble of the spirit level P, and
moving the legs of the tripod stand I upon the ground; or, if preferred, the
instrument might be furnished with a joint and clamping screw (similar to the
joints and clamping screws in common use for adjusting the horizontal position
of theodolites and other similar instruments) applied at the bottom of the
short pillar H, which would render it more easy of adjustment. When the
limb A is found by the plumb line or spirit level to be in a horizontal position,

page_text: the angle limbs B and C are brought down close upon the limb A by turning
the pinion e. The instrument is then turned round upon the joint k by the
rack and pinion L, 1, until the point s, upon the angle limb B (when viewed
through the sight hole R), is brought to coincide with one side of the trunk of
the tree. The joint k is then clamped fast by it's screw M, and the pinion d is
turned until the point s, upon the angle limb C, when viewed in like manner
through the sight hole R, is brought to coincide with the opposite side of the
trunk of the tree. In this situation the divisions upon the largest arc of the
sector plate O, when read off by the inside edge of the angle limb C, will
indicate or determine the diameter of the tree in feet and inches at the level
of the horizontal line. After this has been done, the angle limbs are to be
elevated by turning the pinion e until the under side of the angle limb B is
brought up to the mark or division of eight fect upon the sector N, at which
elevation the angle limbs may be secured by the clamping screw h; and the
same process may be followed as above described to ascertain the diameter of
the tree at that elevation (viz, eight feet above the former place measured);
observing that the diameter must always be read off from the divisions of that
are of the sector plate O which corresponds with such elevation; and, in like
manner, the diameters may be taken at as many points in the height of the
tree as may be desired; from which data (after making the usual allowance
for the bark) the cubic contents of the tree may be ascertained or reduced by
calculation in the ordinary manner, or by the use of a series of tables adapted
to the purpose. Such process being sufficiently understood by persons con-
versant with the calculations requisite for measuring timber, it will not be
requisite to enter into a description of the mode of performing them in this
Specification. When it is required to ascertain or determine the cubic con-
tents of any large branch or arm which proceeds from a tree, or to determine
the cubic contents of trees which are not perpendicular or nearly so, the
whole instrument may be moved into an oblique position by relieving the
clamping screw 9, and turning the spindle F round in the hole in the nob G
until the instrument is adjusted into an obique position, corresponding with
the obiquity of the tree or the branch to be measured, where it may be
secured by the screw g, after which the measuring of the lengths and diameters
may be proceeded with as before described.
Fig. 5 upon the annexed Drawing represents a small sector or bevel,
furnished with a moving arm. The sector is divided into degrees. Its use is
to ascertain the angle at which any branch proceeds from a tree. This is
done by holding the bevel in the hand, and moving it until the tail or handle
T is brought to correspond with the trunk of the tree; then, by turning the

page_text: arm V round upon its centre until the edge is brought to correspond with the
direction of the branch, the angle may be read off upon the arc of divisions.
I have above described a convenient mode of constructing the said instru-
ment for determining or ascertaining the cubic contents of standing timber
with reference to the annexed Sheet of Drawings, and have described the
method of using it in such manner as to enable persons conversant with
works of a similar nature to practice the Invention; and I hereby declare that
I consider my claim to extend to the manufacturing and using of instruments
for ascertaining the cubic contents of standing timber, constructed according
to the principles of the instrument above described, viz', their being composed
of three or more limbs or arms moving upon centres, being furnished with
sights and graduated scales for the purposes aforesaid, leaving the form and
proportion of their parts to the discretion of the workmen employed in the
manufacture of them; as also the manner of moving the said arms and limbs,
whether by screws, racks, or otherwise. The materials of which the same
may be constructed may also be adapted to the nature of the case without
departing from the object of the Invention, as herein-before described and set
forth.
In witness whereof, I, the said James Rogers, have hereunto set my
hand and cool the Thistinch
JAS STEPHEN.
JAMES ROGERS. (L.S.)
AND BE IT REMEMBERED, that on the same Thirtieth day of August,
in the year above mentioned, the aforesaid James Rogers came before our
Lord the King in His Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained, in form above written. And
also the Specification aforesaid was stamped according to the tenor of the
Statute in that case made and provided.