A contoured base with foliate and strapwork decoration has a slot to receive a detachable sight and clinometer and a scale 6 to [0] to 6, divided to 1, subdivided to 1/2, numbered by 1 with '12' at the zero point; an index moves over this scale as the sight is adjusted transversely in the slot. The base also carries a glazed magnetic compass and a volvelle. Two upright columns are joined by a cross-piece at the top, to form a slot on which a rod can slide. Scales on either upright are 0 to 15, divided to 1, subdivided to 1/4, numbered by 1, and 0 to 15, divided to 3, subdivided to 1. The sliding rod has a double index (for both scales) and a pinhole sight. A shaped, pierced and decorated semicircular scale is attached to one upright, with a scale 6 to [0] to 6, divided to 1, subdivided to 1/4, numbered by 1 with '12' at the zero point. Signed: 'IOSVA HABERMEL'
