Improvements in Mathematical Instruments
Year: 1892

page_text: Date of Application, 9th Feb., 1892
Complete Specification Left, 19th Oct., 1892-Accepted, 19th Nov., 1892
PROVISIONAL SPECIFICATION.
Improvements in Mathematical Instruments,
I ROBERT MAYON ROBSON of Hilliary Place Leeds in the County of York,.
Architect do hereby declare the nature of this invention to be as follows:-
My invention relates to improvements in set squares used by architects, engineers,
and draughtsmen, and has for its object to enable such set squares to be employed
for marking or setting off other angles besides the usual ones of 90, 60, 45
and 30 degrees as at present.
My invention consists in marking off on one or both of the vertical or rect-
angular sides, and close to the edge of the same, short lines, which when. produced
to the corner of the opposite base angle, are inclined to the base at angles of 5,
10, 15 degrees, and so on; and if desired the intervals may be still further divided
by shorter lines to mark off divisions of one degree or even of one half degree.
In order to be able to set-off' inclined lines with such set squares, with a great
degree of exactitude and facility, I mark at the base angle part of the circum-
ference of a circle, with lines from the corner of this angle to the circumference,
inclined at angles of 5 10, 15 degrees, etc., to the base line.
This my invention is applicable to either ebonite, wood, skeleton, or transparent.
set squares.
In the case of ebonite set squares, the angle marks are inlaid in white.
Dated this 8th day of February 1892.
J. CLARK JEFFERSON,
2, East Parade, Leeds, Agent for Applicant.
COMPLETE SPECIFICATION.
Improvements in Mathematical Instruments.
I ROBERT MAYON ROBSON of Hilliary Place Leeds in the County of York,
Architect do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement :-
My invention relates to set squares used by architects, engineers and draughtsmen,
and has for its object to enable such set squares to be employed for marking or
setting off other angles besides the usual ones of 90, 60, 45 and 30 degrees as at
present.
My invention consists in marking off on one or both of the vertical or rectangular
sides, or on the inclined side and close to the edge of the same, short lines, which
when produced to the corner of the opposite angle, are inclined to the side used as
the base at angles of 5, 10, 15 and 20 degrees and so on, and still further divided
by shorter lines to mark off all the intermediate angles.
This invention is applicable to ebonite, wood, brass, skeleton and transparent
set squares. In the case of ebonite set squares the marks are inlaid in white,
preferably on both sides, the marks going through. Other set squares may have
the divisions scratched on in the usual manner.
The accompanying drawing, which is added to more clearly illustrate my inven-
tion represents one of my improved set squares with the angle marks on the
inclined side.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
Set squares provided with short lines along their edges, such that by joining a
point opposite one or other of these lines with the corner of the opposite angle,
lines at any determined inclination to the side used as the base line can be set off
and drawn.
Dated this 17th day of October 1892
J. CLARK JEFFERSON,
2, East Parade, Leeds, Agent for Applicant.