Improvement of Compass Cards for use on Board Ship.
Year: 1889

page_text: Date of Application, 21st Mar., 1889
Complete Specification Left, 20th Dec., 1889-Accepted, 25th Jan., 1890
PROVISIONAL SPECIFICATION.
Improvement of Compass Cards for use on Board Ship.
I, Sir WILLIAM THOMSON, Knight, of Glasgow College, Professor of Natural
Philosophy in the University and College of Glasgow, in the County of Lanark,
North Britian do hereby declare the nature of my invention for "IMPROVEMENT OF
COMPASS CARDS FOR USE ON BOARD SHIP " to be as follows:
--
-
The object aimed at in this Invention is to prevent disturbance of the compass
by the engines, or by the firing of guns.
The compass card is an improvement of that described in my Patents Nos. 1339
A.D. 1876 and No. 679 A.D. 1879.
The improvement consists of the addition of a rigid or approximately rigid con-
nection between the magnetic needles of the compass card while leaving the
flexible or springy connection between the rim and needles. This may be accom-
plished in several ways. I prefer to do it by connecting the magnets near their
ends by two fine platinoid or other non-magnetic metallic wires or by stiffening
the silk threads connecting the magnets by means of shellac or otherwise.
Dated this 20th day of March 1889.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Petitioner's Agents.
COMPLETE SPECIFICATION (AMENDED).
Improvement of Compass Cards for use on Board Ship.
I, Sir WILLIAM THOMSON, Knight, of Glasgow College, Professor of Natural
Philosophy in the University and College of Glasgow, in the County of Lanark,
North Britain, do hereby declaro 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 :—
•
The object aimed at in this Invention is to prevent disturbance of the compass
by the engines, or by the firing of guns.
The compass card is an improvement of that described in my Patents, Nos. 1339,
A.D. 1876, and 679, A.D. 1879.
The improvement consists of the addition of a rigid, or approximately rigid con-
nection between the magnetic needles of the compass card while leaving the
flexible or springy connection between the rim and needles. This may be accom-
plished in several ways. I prefer to do it by connecting the magnets near their
ends by two fine platinoid, or other non-magnetic metallic wires, or by stiffening
the silk threads connecting the magnets by means of shellac, or otherwise.
In order that my Invention may be properly understood, and readily carried into
effect, I have hereunto appended an explanatory sheet of drawings, in the several
Figures of which corresponding parts are marked with the same letters of reference.
Figure 1 is a plan of my improved compass card.
Figure 2 is an elevation.
The compass card consists of a light metal rim connected to a central boss by means

page_text: of a number of silk spokes. From the rim the magnets aaaaaaaa are supported
by means of a number of silk threads bbbbb. The general construction of the
compass card is fully described in the Specification of my Patent, No. 1339, A.D. 1876,
and my present improvement consists of providing a stiff connection between the ends
of the magnetic needles. I accomplish this by connecting the ends of the needles acc c
with metallic wire or with silk thread stiffened by shellac, wax, or other suitable
substance.
Having now particularly loscribed 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 :-
A The compass card described above having the magnets supported from the frame-
work by means of silk or other flexible connection threads, while the ends of the
magnets are connected by a stiff connection.
Dated this 19th day of December 1889.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.