Vertical disc dial for latitude 42° North. This ivory altitude disc dial has a brass suspension ring attached to a brass date indicator. The disc is bowed and the ivory is very discoloured. On its obverse side are hour-lines for 6 am-6 pm. A small, hinged brass pin is attached to act as the gnomon. The reverse side displays a date scale divided from solstice to solstice and marked by month. The equinoxes are at approximately 23 March and 22 September. A brass index arm is held by a central pivot and extends across the whole diameter of the disc; the suspension loop is attached to one end, while the other is shaped and has a bevelled edge to mark the date in the date scale. Although the numerals on the dial are roughly consistent with a German origin, the latitude of the dial is for mid-Italy. It may have been made in Italy or in Germany for sale in Italy.

For more information regarding this dial please refer to the OUP & NMM catalogue, 'Sundials at Greenwich'.