Vertical disc dial

Vertical disc dial for latitude 47° North. Brass vertical disc dial with a suspension ring attached to the date indicator. On the obverse side are hour-lines for 4 am-8 pm. Various decorative circle arcs are drawn, centred on the hinged brass pin gnomon. It is stamped 'R. I. COI:.'. The reverse side has a date scale divided from solstice to solstice, marked by month. The equinoxes are given at approximately 20 March and 20 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 has a bevelled edge to mark the date in the date scale. The style of the dial suggests a possible Italian origin, but the latitude is that of Switzerland, Austria or mid-France.

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