This circular astronomical compendium consists of a nocturnal for different latitudes, a converter for solar and lunar time, an equatorial pin gnomon dial, a magnetic compass with the main directions and corresponding weather indications and a list of latitudes. The outside of the lid is laid out as a NOCTURNAL with a volvelle rotating over a fixed disc and a hinged index arm rotating over both. The scales on the disc and the volvelle correspond to each other. The disc is inscribed with a calendrical scale with the abbreviated names of the months in Latin and the corresponding numbers of days. The nocturnal can be set for the right time of the year with the help of a small pointer on the volvelle. One inscription on the volvelle gives instruction on its use; a second tells the user how to align the pointer with the index stars in the Great Bear. The pointer itself is a hinged arm, labelled in the centre, with stars on the foldable part; its tip is broken off and a letter is missing from its inscription. The outside ring of the volvelle is marked as an hour scale 3 to 12 to 9, with small pins on the outside. This hour scale is continued for latitudes 44, 47, 50 and 53 on the fixed disc and can be seen through two apertures in the volvelle. The inside of the lid contains a LUNAR VOLVELLE for converting solar time into lunar time and vice versa. Three concentric rings of scales are shown: 1) an hour scale twice I to XII, 2) the age of the moon 0 to 29 1/2; 3) a second hour scale on the volvelle 3 to 12 to 9. The scales are labelled on a fourth, innermost ring. An aperture in the volvelle reveals the phases of the moon on the disc underneath. An aspectarium is inscribed in the centre of the volvelle. Hinged between the lid and the bottom of the box is an EQUATORIAL DIAL consisting of a double hour ring and a foldable pin gnomon. The outer, movable ring bears an hour scale 1 to 24. The inner, fixed ring is marked twice 1 to 12. By turning the outer ring against the inner ring common hours can be converted into Italian or Babylonian hours. The signature of the maker and the date are given on the reverse of the ring. The dial can be set to the appropriate latitude with the help of a foldable DEGREE ARC hinged to the bottom section, which has a scale from 16 to 90 and is labelled on the reverse. The eight main directions and the corresponding weather conditions are inscribed on the inside of the bottom element. In the centre, around an inset MAGNETIC COMPASS, is a degree scale for the magnetic variation, marked 0 to 90, 0 to 90. The compass is marked for North and South and a deviation of 10°W of N. The underside of this section has a circular list of 30 European cities with their latitudes. The outside of the box is decorated with foliate scrollwork.
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