The outside of the UPPER LEAF of this brass, spade shaped compendium has a nocturnal with the hinge at about 20th August. The nocturnal arm is now detached; it has an engraved inscription, is lined on the borders and has a Gothic end. The calendar scale on the limb has the names of the months engraved in Latin, sometimes abbreviated, and each month is divided into 10, subdivided in 2, numbered by 10 from 10 to 30 or 31 or 28 as appropriate. The equinoxes are at 10th March and 8th September. The rotating hour ring is engraved with the hours from 6 to 12 to 3, and with small touch pins every hour. Small apertures show the length of the day and of the night, from 8 to 16 to 8, and the times of sunrise and sunset from 4 to 8 to 5. The rest of the space is engraved with strapwork and foliage. The inside of the leaf has a rotating pierced volvelle and aspectarium: the volvelle has an arm for converting lunar hours, engraved 1 to 12 twice, and solar hours engraved I to XII twice. The volvelle is surrounded by the names of the 12 main winds in Latin. The rest of the space is engraved with strapwork. The inside of the central BOX has a compass marked with the cardinal points (abbreviated) and a string gnomon dial with common hours engraved from 7 to 12 to 5, divided to the half hour. The hour lines are engraved on two curved pieces, which can be adjusted for latitude 33°, 36°, 39°, 42°, 45°, 48°, 51°, 54°, 57°. The hour lines 4 and 5 a.m. and 7 and 8 p.m. are engraved on the main box below the sliding arcs. The numbers 6, 12 and 6 corresponding to the hour lines are engraved on the three knobs. The rest of the space is engraved with strapwork and foliage. The other side of the central part, containing the back of the compass and a mechanism for holding the string, is decorated with strapwork and foliage. The inside of the LOWER LEAF has a Rojas projection of the sphere. On the rim is a scale of degrees in four quadrants, divided to 10, subdivided to 2, numbered by 10 with 90 at the top. Eleven main longitudes are engraved and numbered, as are the poles and the zodiacal signs. The alidade is also engraved. The rest of the space is decorated with strapwork and foliage. The outside of that leaf has a volvelle for conversion of planetary hours, engraved from 12 to 6 to 12, into common hours, engraved from VI to XII to (VI), divided to the half hour, subdivided to the quarter hour. On a concentric ring, next to the centre, is an inscription. An eccentric ring has a calendar scale, divided to 10, subdivided to 2, numbered by 10 from 10 to 30 or 31 or 28 as appropriate. The rest of the space is decorated with strapwork and foliage. The instrument rests on three bun feet, and a catch on both lids keeps them closed when not in use. The limb of the compendium is decorated with strapwork and foliate motifs as is the rest of the instrument. On the top is a ring for suspension.
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