The instrument consists of a hinged lid and a box with a suspension ring which also serves as a lock for retaining the lid.
The outer face of the lid carries a 'Tabula latitudinis Regionum' giving the latitudes of 38 places in roughly alphabetical order. The sides of the lid are decorated with oak leaf engraving.
The inside face of the cover has a volvelle for converting equal and Italian hours given the time of sunset in equal hours. The fixed scale of hours runs 1 to 12, 1 to 12, divided to quarters and surrounds a silvered disc with the scale of Italian hours 1 to 24 divided to quarters around its circumference. Inside the scale is the instruction 'HABETVR HORA ITALICA SI 24 PONAS SVPER HORAM OCCASVS'. The central portion of the disc is decorated with a star engraving and the four cardinal directions are marked as 'SEPTENTRIO', 'ORIENS', 'MERIDIES' and 'OCCIDENS'. At the northern end of the plate is the signature '15 [star]V[star]S[star] 85' and at the southern end the title 'VIATORIVM' as the contemporary name of this type of instrument.
The main box carries an inclining string-gnomon dial. There is a folding gnomon support sprung perpendicular to the dial plate whose two parts are decorated as fish. The integral plummet is positioned above a latitude scale from 42 to 52?, with dots every second degree, and the whole plate is pivoted to set the dial for latitude. The hour plate runs from 4 to 12 to 8 with additional lines for the half hours. The string emerges from the plate through the mouth of the sun.
The inset compass is 21 mm in diameter and its silvered bowl has a cross of direction. By reaching under the dial plate it is possible to rotate the compass and to set it for variation against a scale of degrees marked 'GRADVS DECLINACIO MAGNETIS', whose major portion runs 60 to 90 to 30, divided to 10 and 2 and numbered by 10. To facilitate access, the dial plate pivots about points near its southern end rather than in the middle of the plate. is hinged near its base Around the edge of the dial plate is a scale of equal hours 3 to 12 to 9, with the half hours marked by stars.
The sides of the box are decorated with foliage engraving. The base is titled 'IVDITHA' and carries a portrait of a sword-bearing Judith with the head of Holophernes.
Provenance: Lewis Evans Collection G. 386.