Signed: Iacobus Lusuerg Mutinensis Faciebat Romae Ao 1677
If Erasmus Habermel's combined quadrant, sight and gauge was devoted to the ostentatious demonstration of aids to gunnery, this quadrant by Lusverg is a model of discreet restraint in comparison. Nevertheless its prospects for active military service were probably no higher.
The upper face of Lusverg's instrument is marked out for a surveyor, with folding sights and a sinical quadrant. However, in the otherwise blank space alongside the ball and socket joint on the under side, there is a circular scale of points marked 'Pro Eleuatione Bombardae'. To measure the elevation of an artillery piece, a plumb bob and line are attached through a hole pierced directly through the plate of the instrument. To forestall any uncertainty, an engraved diagram gives visual instruction on how to use the instrument at the mouth of a gun.
Radius: 157 mm
Inventory no. 48,133