AN IMPROVEMENT IN DIAL INSTRUMENTS FOR ASCERTAINING. COMPASS ERRORS COURSES AND BEARINGS
Year: 1884

page_text: I DUNCAN MCGREGOR 72 South Castle Street Liverpool Fellow of the Royal
Geographical Society and Nautical Instrument Maker do hereby declare the nature
of 'my Invention for AN IMPROVEMENT IN DIAL INSTRUMENTS FOR ASCERTAINING.
COMPASS ERRORS COURSES AND BEARINGS to be as follows:-
T
1
Dial instruments for these purposes are commonly known as compass correctors
course indicators azimuth dials some are termed the pelorus others the palinurus,
the compass verifier, the compass error detector and other the like designations.
They are constructed in various ways but generally as circular dials revolving upon
a centre or other bearing and having sight vanes or shadow pins or, threads or
cross-wires and discs for taking bearings of celestial and land objects. Theso
instruments also are often fitted with pendulums which shew upon a side dial the
heel or inclination of the ship from the upright position, this portion of the
instrument being termed the clinometer. These dial instruments have dials circles
and quadrants shewing some of them time, others latitude others declination.
J
My Invention does not deal in any way with the principle of any of these
instruments, it consists simply in the application and use of a substance never so
used before in the construction and manufacture of these dials, circles, arcs or
quadrants. Hitherto these portions of dial instruments have been made. generally
of brass copper or other metal upon which the necessary degrees points figures and
markings have been engraved or cast in relief.
: J
Sometimes these dials are made of wood having the markings engraved upon
them. Sometimes paper properly marked is pasted or fastened to the wood or
metal in some way. Sometimes the markings are painted upon the wood or metal
itself.
2
My Invention consists in the use of vitrified enamel porcelain china or
earthenware in the manufacture of these dials quadrants and circles.
These articles just enumerated will now have the necessary markings transferred
to their surfaces from. engraved plates or they can be painted by hand and then
fixed permanently.

page_text: The enamel porcelain, china or earthenware may be put upon copper brass iron
or other metals used in the manufacture of these instruments. The markings upon
the dials circles, quadrants and arcs are preferably black upon a white ground but
they may be made white upon a black ground or of any other suitable colour.
By the use of this Invention these dials, circles quadrants and arcs are not to any
extent affected by exposure to the weather or the heat of the sun, and will remain
clear distinct and serviceable after being a long time in use.
I DUNCAN MCGREGOR 72 South Castle Street Liverpool Fellow of the Royal
Geographical Society and Nautical Instrument Maker do hereby declare the nature
of my Invention for AN IMPROVEMENT IN DIAL INSTRUMENTS FOR ASCERTAINING
COMPASS ERRORS COURSES AND BEARINGS and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
:
Dial instruments for these purposes are commonly known as compass correctors
course indicators azimuth dials some are termed the pelorus others the palinurus
the compass verifier the compass error detector and other the like designations.
They are constructed in various but generally as circular dials revolving upon a
centre or other bearing or bearings and having sight vanes or shadow pines or
stiles or threads or cross wires and discs for taking bearings of celestial and land
objects. These instruments also are often fitted with pendulumns which shew upon
a side dial the heel or inclination of the ship from the upright position. This
portion of the instrument being termed the clinometer. These dial instruments
have dials circles and quadrants shewing some of them time others latitude, others
declination.
My Invention does not deal in any way with the principle of any of these
instruments. It consists simply in the application and use of a substance nover 80
used before in the construction and manufacture of these dials circles arcs or
quadrants..
Hitherto theso portions of dial instruments have been mado generally of brass,
copper or other metal upon which the necessary degrees points figures and
markings have been engraved or cast in relief. Sometimes these dials are made of
wood having the markings engraved upon them. Sometimes paper properly
marked is pasted or fastened to the wood or metal in some way. Sometimes the
markings are painted upon the wood or metal itself.
My Invention consists in the use of vitrified enamel porcelain china or
earthenware in the manufacture of these dials quadrants and circles.
"
These articles just enumerated will now by my Invention have the necessary
markings transferred to their surfaces from engraved plates or they may be painted
by hand and then fixed permanently. The enamel porcelain china or earthenware

page_text: may be put upon copper, brass iron or other metals, or upon wood or slate or other
the like substances that are or may be used in the manufacture of these
instruments.
The markings upon the dials circles, quadrants, and arcs are preferably black
upon a white ground, but they may be made white upon a black ground or of any
other suitable colour. By the use of this Invention these dials circles quadrants
and arcs are not to any extent affected by exposure to the weather or the heat of
the sun and will remain clear distinct and serviceable after being a long time
in use.
Having now described and ascertained the nature of my said Invention and
in what manner the same is to be performed I declare that what I claim is
1. The use of vitrified enamel porcelain china or earthenware in the manufacture
of these dials quadrants circles and arcs and their application to dial instruments
for ascertaining compass errors courses and bearings.