Ar IMPROVED PLUME RULE AND LEVEL
Year: 1872

page_text: LETTERS PATENT to Sarah Johnson and Alfred Johnson, both of
Leicester, in the County of Leicester, for the Invention of "Ar
IMPROVED PLUME RULE AND LEVEL."
Sealed the 23rd July 1872, and dated the 22nd April 1872.
PROVISIONAL SPECIFICATION left by the said Sarah Johnson and
Alfred Johnson at the Office of the Commissioners of Patents, with
their Petition, on the 22nd April 1872.
We, SARAH JOHNSON and ALFRED JOHNSON, both of Leicester, in the
County of Leicester, do hereby declare the nature of the said Invention
for "AN IMPROVED PLUMS RULE AND LEVEL," to be as follows :—
This Invention consists in the construction of a combined plumb rule
and level for the use of builders and for other purposes, by means of
which the necessity of having two distinct instruments is obviated. The
rule, which consists of a straight piece of wood, has a rectangular hole

page_text: '
cut in its centre, at the back of which hole a plate of brass or other
metal is fastened. In the centre of the rectangular hole, and in front of
the back plate, a perforated dial divided into degrees for the purpose
of giving the plumb line and level, and pitch of gables, is inserted.
In the centre of the perforated dial a crescent-shaped pendulum,
provided with two or four needles or pointers, is suspended upon a
spindle, provided with very fine points which rest in finely punched holes
in the centres of the back plate and of the perforated plate herein-after
mentioned, thus allowing the pendulum to revolve freely with very little
friction. A plate of brass or other suitable metal, perforated so as to
allow the face of the dial to be seen, but having a bearing in its centre
in which the point of the pendulum spindle can work as herein-before
mentioned, is then fastened in the rectangular hole for the purpose of
keeping the dial and pendulum in the requisite position. In front of the
last-mentioned perforated plate a sheet of plate glass may be inserted for
the purpose of keeping the mechanism free from dust and dirt, and
which sheet of glass can be kept in its position and protected by means
of a brass or other metallic plate, or by any other suitable contrivance.
The action of the apparatus, which will be readily understood by
persons conversant with the use of such instruments, is as follows:-
When the rule is held perfectly upright, the crescent-shaped pendulum,
together with its two needles or pointers, hangs parallel to the two sides
of the rule, the needles or pointers pointing to 90 degrees on the dial,
and when the rule is held at an angle of 45 degrees the pendulum falls
and the needles point to the same number of degrees on the dial.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Sarah Johnson and Alfred Johnson in the Great
Seal Patent Office on the 22nd October 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, SARAH
JOHNSON and ALFRED JOHNSON, both of Leicester, in the County of 3
Leicester, send greeting.
J

page_text: '
'
year of our Lord One thousand eight hundred and seventy-two, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and · suc-
cessors, give and grant unto us, the said Sarah Johnson and Alfred
Johnson, Her special licence that we, the said Sarah Johnson and
Alfred Johnson, our executors, administrators, and assigns, or such
others as we, the said Sarah Johnson and Alfred Johnson, our 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
PLUMB RULE AND LEVEL," upon the condition (amongst others) that we;
the said Sarah Johnson and Alfred Johnson, our executors or adminis-
trators, by an instrument in writing under our, 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 per-
formed, 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 we, the said Sarah Johnson and Alfred
Johnson, do hereby declare the nature of our 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
Drawing, (that is to say) :-
Our Invention relates to improvements in the construction of levels
for the use of builders and for other purposes; and it relates especially
to that kind of level which may also be used as a plumb rule for the
purpose of ascertaining and fixing not only a horizontal; line (in the
method in which levels are usually employed), but also a vertical line
) as well as a line at any angle between the two.
Also to additional improvements in such combined levels and plumb
rules, by which improvements any required angle may be determined
and fixed between any two lines, whether one of such lines be a vertical
or horizontal one or not.
In order to carry our Invention into effect we take a piece of wood

page_text: straight in order to form the level or plumb rule. In this rule or level
we make a hole or recess which we prefer to make at or near the centre
of the length of the rule, but which may be in any convenient position.
This hole or recess may be of any suitable form, and is sufficiently
large to allow a needle turning upon centres to revolve within it (in the 5
plane of the rule), in the manner herein-after described. At the back
of the hole or recess described we fix a plate of metal, glass, or other
suitable substance, in front of which but within the recess we fix a cir-
cular dial open at its centre and divided into degrees or other divisions, as
may be required. In front of the hole or recess we fix another plate 10
of metal or other suitable material having openings through which the
divisions upon the circular dial may be readily seen.
In the plate last described, and in the plate at the back of the hole
or recess, we form centres or bearings in which is fitted, so as easily to
revolve, an axle carrying onė or more needles or pointers, the points 16
of which as they revolve indicate the divisions upon the circular dial
described.
One of the needles has attached to it a weight (preferably crescent
shaped) so that the needle always hangs with its upper extremity pointing
vertically upwards, and the divisions upon the dial are so marked that 20
when the level or rule has its edge in a truly horizontal position, the
needle first described will point to the mark 0°. If the level or rule
be then turned until its edge is in a truly vertical position, the needlo
being retained by the weight in its original position will indicate a
point upon the dial ninety degrees from the mark 0°, and this point is 24
accordingly marked 90°, and the intermediate part of the dial is marked
with the intermediate angles. The remainder of the dial is also marked
in a similar way, as required.
The front of the hole or recess described may be closed with a plate
of glass, so that the indications of the dial may be seen whilst the 30
needle and its bearings are kept free from dust.
11

page_text: Sometimes we do not use a perforated plate in the front part of the
hole or recess in the rule or level, but we make the point of the axis or
spindle revolve in a hole or recess drilled or made in the glass plate
which covers the apparatus, as described.
Sometimes we make the axis or spindle pass completely through the
front plate, and we attach an indicating needle to such axis after it has
passed through the plate.
And sometimes we make the axis or spindle fixed instead of revolving
in bearings, and we attach to the weighted needle a short tube or
bearings, which may revolve upon the fixed axis or spindle.
By the arrangement described the points of the needle will indicate
upon the dial the precise position of the edge of the rule whether
horizontal, vertical, or at any angle between the two.
. Another part of our Invention consists in adding a supplementary
straight edge or rule to the level or plumb rule described. For this
purpose we take an ordinary straight edge or rule, which may have
suitable divisions marked upon it when required, and at or near one
of its extremities we form a centre upon which it may turn. This
centre is attached to the side of the plumb rule or level, already
described, in such a manner that the supplementary rule may lie
parallel with and upon the former, or it may be turned round so as to
project at any required angle from the plumb rule.
We form a short index or pointer upon the supplementary rule pro-
jecting beyond the centre described, and upon the side of the level or
plumb rule we make or attach a segmental dial marked with divisions to
which the index points. By this means the supplementary rule may be
adjusted so as to project at any required angle from the edge of the
plumb rule or level, and in order to fix it in the required position we
form a nut or thumbscrew upon the centre upon which it turns, by
which it can be tightened and held at the required angle. And in order
to adjust it as required with greater facility we prefer to make a small
hole at each of the divisions upon the segmental dial described, and to
form underneath the index a pin or projection which may fit into one or
other of these holes according to the angle desired. When the nut or
thumbscrew is sufficiently loosened the supplementary rule can be raised

page_text: until the pin is withdrawn from the hole in which it has been adjusted,
and can then be turned round into any required position and again
fixed.
Sometimes we arrange a spring between the centre of the supple-
mentary rule and the level or plumb rule to facilitate the withdrawal of 5
the pin from the holes.
By means of this arrangement the apparatus can be used as an
ordinary square, or for measuring any angle in buildings or other work
(As for instance, by fixing the supplementary rule at an angle of 90°
with the level, and placing the latter upon a wall, the supplementary 1
rule hanging down the face of the wall will shew whether the work is to
the proper guage or not). And such angles when observed may be
noted and reproduced when required. By inserting a "slide rule" into
the supplementary rule described, ordinary centres may be struck out in
building in the way well understood and practised, or by attaching a 1
moveable point to such "slide rule" it can be used as a "protractor
for fixing the angles of distant points.
"
The accompanying Drawing is an illustration of our Invention.
Figure 1 is an elevation, and Figure 2 a plan (partly in section) of
a combined level and plumb rule, constructed according to our In- 2
vention.
A is the level or rule (shewn made of wood) having its edges B and C
perfectly straight; D is a plate covering the back of a hole made through
the level A. A circular dial plate E divided into degrees is fixed in
front of the back plate D. The front of the hole is closed by the plate 2
of glass F, which is held in position by the open covering plate G. An
indicating needle H is fixed to an axis I, the back point of which
revolves in a recess in the back plate D, and the front point revolves in
a similar recess in the plate K, which is made open, as shewn, so that
the marks upon the dial plate E may be scen. The needle II is kept in 3
a constantly vertical position by means of the weight L attached to its
lower end. A is a supplementary rule turning upon a centre N and
having the pointer O attached to it; P is a circular dial plate divided
into degrees, which the pointer O indicates. A pin underneath the
pointer O fits into holes which are made at the divisions of the dial
plate P, as shewn. A thumb-screw R, when loosened, allows the sup-

page_text: plementary rule M to be raised sufficiently to release the pin from the
hole, and the rule M to be turned so as to form any desired angle with
the edgo of the level or rule A (as shewn by the dotted lines) when it is
again tightened up. A spring may be fitted between the level A and
the rule M for the purpose already described.
In witness whereof, we, the said Sarah Johnson and Alfred John-
son, have hereunto set our hands and seals, this 17th day of
October, in the year of our Lord One thousand eight hundred
and seventy-two.