Compass Card, turning the rose was improved by the materials used, while rocking was reduced by increasing the friction surface of the gem. The rose can be rotated within an outer edge on which a scale in degrees per quadrant is applied, this was to compensate for the magnetic variation (the angle between the actual north and the magnetic north)., J.M. Kleman & Zoon (mentioned on object), Amsterdam, 1825, iron (metal), ruby (mineral), agate (chalcedony), paper, d 21.7 cm
Keywords:
Compass Card, turning, rose, improved, materials, rocking, reduced, increasing, friction surface, gem, rotated within, outer edge, scale, degrees, quadrant, applied, compensate, magnetic variation, angle, actual north, magnetic north, J.M, Kleman & Zoon, mentioned, object, Amsterdam, 1825, iron, metal, ruby, mineral, agate, chalcedony, paper
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