Improved Arrangement for Reading the Deflections of Reflecting Instruments.
Year: 1893

page_text: Date of Application, 17th Mar., 1893
Complete Specification Left, 16th Dec., 1893-Accepted, 3rd Feb., 1594
PROVISIONAL SPECIFICATION.
Improved Arrangement for Reading the Deflections of Reflecting
Instruments.
1, WILLIAM THOMSON, Baron Kelvin of Largs, Professor of Natural
Philosophy in the University of Glasgow, do hereby declare the nature of this
invention to be as follows:-
:-
The object of the present invention is improvement in the methods of reading
the deflections of such instruments as the reflecting galvanometer, the reflecting
quadrant electrometer, or reflecting magnetometer.
The improved method of observing the deflections of such instruments consists in
forming an image of the divided scale or of a suitable mark or set of marks, by
means of a good concave or plain mirror with or without the assistance of the
lenticular cover glass used in some of these instruments referred to above, and
observing this image by means of a suitable magnifying eye lens or eye piece, and
a wire, or a scale in the place of the image.
Dated this 14th day of March 1893.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street Glasgow, Applicant's Agents.
COMPLETE SPECIFICATION.
Improved Arrangement for Reading the Deflections of Reflecting
Instruments.
I, WILLIAM THOMSON, Baron Kelvin of Largs, Professor of Natural
Philosophy in the University of Glasgow, 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 :-
The object of the present invention is improvements in the methods of reading
the deflections of such instruments as the reflecting galvanometer, the reflecting
quadrant electrometer, or reflecting magnetometer.
The improved method of observing the deflections of such instruments consists
in forming an image of the divided scale, or of a suitable mark or set of marks by
means of a good plane or concave mirror with or without the assistance of the
lenticular cover glass used in some of these instruments referred to above, and
observing this image by means of a suitable magnifying eye lens or eye piece and
a wire in the place of the image.
In order that my invention may be properly understood and readily carried into
effect I have hereunto appended two explanatory sheets of drawings which I will
now proceed to describe.
Figure 1 is a diagrammatic plan.
Figure 2 is a vertical section.
A is the mirror of a galvanometer or other reflecting instrument; and B is the
scale. Behind the scale is placed an eye piece C consisting of a tube having at one
end a lens c', and at the other end a hole c³, through which the cross wire band
image of the scale reflected in the mirror can be seen and the deflection of the

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: :-
The improved method of observing the deflections of reflecting instruments by
means of an eye piece substantially as described.
Dated this 15th day of December 1893.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.