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Bennett, J. and Johnston, S., The Geometry of War, 1500-1750 (Oxford, 1996)

Although differing in its form from the previous instrument, this combined level and sight also provides direct indications of distance rather than elevation in degrees or points. While its levelling arc looks like many others, its scales are again marked for 'fire bombs' and stone shot. The scales start from opposite ends of the levelling arc and are engraved '2000 STEIN WVRF' (stone throw) and 'FEVER WVRF 1500' (fire throw) for their furthest ranges. The division of the scales has a geometric rather than empirical basis, being calculated as a tangent function (cf. Wunderlich, p. 186). The silvered brass plate for the levelling arc is slightly larger than a quadrant (about 100°) and decorated with foliage and birds.

The sight consists of a sliding plate pierced with holes, moving against a scale of 3 inches divided to quarters. When extended, the sliding plate reveals an extra scale of inches from 4 to 6 so that elevations above 3 inches can be set. The plummet has a central slot so that when the instrument is level the sighting holes are not obscured.

Height (slider not extended): 116 mm

Inventory no. 49,135

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