MAGNETISM
Plate XII. Part of Plate ii in volume iv of George Adams,
Lectures on Natural and Experimental Philosophy, (London, 1794H
A S T R O N O M I C A L M O D E L S
91 TERRESTRIAL GLOBE 1750 (728) Fig. 97, 98, 99
By Gerhard & Leonhard Valk, Amsterdam
HORIZON RING & STAND 1792
By H. van Laun & Zoon, Amsterdam
Globe signed. Gerh. et Leonh. Valk, Amstolaedami, A? 1750, cum Privilegio.
Stand signed on the hour dial: H. van Laun en Zoon fee: Amsterdam.
Globe diameter 153- Base 210 x 160; hour dial diameter 105, horizon ring diameter
4i 5-
The globe is of wood or pasteboard covered with gores printed from engraved plates
and coloured. The base, made of four brass bars, supports an hour dial, divided into
degrees and marked with a double 12-hour set of divisions, set at an angle of 23‘/2° to
the horizontal. There are alternative holes for the rod supporting the globe, one
vertical and the other normal to the plane of the hour dial. This rod provides the
mounting for the globe and the horizon ring, which can be adjusted by an arc
calibrated in degrees. The horizon ring, originally silvered, was plated with nickel in