This vertical disc dial is very similar to Epact 91925. This example, regilded at the end of the 19th century, is made of three plates, the central of which has a decorated handle. On the external side of one of the plates there is a folding gnomon and hour lines, numbered from 4 to 12 to 8 and divided to the quarter hour, and opposite, the initials of the names of the months. There is a notch, probably for turning the plate, but there are no other notches on its limb, as in Epact 91925. However, the plate can revolve. This plate has been cut from and engraved on the back of an old engraved printing plate, and part of an illustration and some text is still visible.
On the other side are a brass arm and a pierced lunar volvelle showing the age of the moon. The circle around the volvelle, on the brass plate, is divided into 29 lunar days. The plate is numbered on the limb from 1 to 31, and is pierced to adjust the name of the month showing its total days (indicated by 'DIE 12 MONET AVF ALE IAR'), the declination of the sun ('SONEN LAVF') and the length of the day ('TAG LENG') and of the night ('NACT LENG'). These are engraved on circles on the central plate underneath. A brass arm rotates on a scale of 31 days engraved on the rim of the plate. Part of the instrument appears to be missing.
Ilaria Meliconi
