Magnetic azimuth dial for latitude 49° North. This is a brass disc dial. On its obverse side is a degree circle, within which is an elliptical hour scale. In the centre is a cross-shaped slit to allow for the adjustment of the brass pin and the whole side is decorated with scrolled floral patterns. On the reverse side is an elliptical date scale, an elliptical zodiac scale and a rotatable circular disc engraved with floral designs and with an arrow-shaped pointer to indicate the date. This is attached to the pin. The main compass-needle gnomon is missing.

This instrument works on the same principles as the Dieppe magnetic azimuth dials. The date scale on the back is set to the correct date and this moves the small pin on the front of the instrument. The dial is then held horizontally and turned until the shadow of the pin lies along the meridian line. A magnetic needle placed on the pin will indicate the time in the hour scale. This plate was probably originally set inside a round box with a glass cover over the compass. A very similar instrument, dated 1604, was included in the sale of the Greppin Collection in 1975 (no. 3014), from which the dating for this entry was suggested.

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