An extremely rare pre balance spring English silver pair case Astronomical verge watch with year calendar indicating date, month, sign of the Zodiac and time of sunrise with further indications for day of the week, and the age and aspect of the moon, signed “Henricus Harpur / Londini”, circa 1670, 55 mm diam

dial

The watch has a matted gilt brass dial plate with two silver dials and two groups of apertures between them. The surface has been further chased with cherubs pointing to the several apertures.

The upper subsidiary dial is a calendar consisting of a fixed outer date ring enclosing a rotating disc carrying a blued steel pointer to indicate the date on the ring. The center of this disc is engraved with sectors for each month and the corresponding sign of the Zodiac. Each sector also indicates the Julian day of the month on which the Sun enters each sign and, in addition, the average hour of sunrise for each month. To indicate the current month, a blued steel hand moves independently over the disc.

The lower subsidiary hour dial has a roman chapter ring enclosing an engraved scene of a riverbank with a town in the distance. There is a single blued steel hand.

The apertures between the dials reveal: 1. The day of the week and its ruling deity; and 2. The age and aspect of the Moon with a third aperture giving the corresponding phase in twelfths. There are setting squares adjacent the apertures.