65p stamp: Grandfather clock signed by Nicolas Blondel. The clock has a calendar, showing the moon phase, date, time, minutes and seconds, a dial engraved with copper counters for phases of the moon and the date.

£1.20 stamp: No.27, circa 1740, eight-day clock. This long clock has a 12-inch signed square dial with engraved border date aperture and allegorical season spandrels; the rack and bell striking movement is numbered on the backplate.

£2.71 stamp: A typical Normandy clock brought to Guernsey by Mr Blondel's mentor Jean Poppelston.

£4.31 stamp: 1762 Grandfather clock. Before the change from the Julian to the Gregorian calendar which took place in Britain in 1752, the date of Easter was set on a 19-year cycle. The eleven days lost made the change much more difficult, but this was possible to calculate by using the four extra apertures in the dial centre.