A rare French portable pillar sundial Henry Robert, Paris, early 19th century With turned plunger concealing a hinged metal gnomon over cylindrical shaft applied with printed paper scale annotated with divisions for the calendar to upper edge and months annotated in French beneath, the single projected hour scale set-up for 49 degrees of latitude and delineated with hour scale annotated with two opposing Arabic numeral scales 6-1.1/2 and 6-10.1/2 printed to the margin alongside signature A PARIS. HENRY ROBERT, HORLOGER, AU PALAIS ROYAL. No. 164 , 12.5cm (5ins) high. Provenance: The beneficiaries of the Estate of an Italian connoisseur collector of horological artefacts and works of art. Henri Robert is recorded in Baillie, G. H. Watchmakers & Clockmakers of the World as 'an eminent maker' born in 1794 who published L'Art de connaitre les pendules et les montres in 1841 and Etudes sur diverses questions d'horlogerie in 1852 as well as many articles in Revue Chronometrique ; he died in 1874. The current lot is designed to operate at 49 degrees latitude and is used by first removing the plunger to fold-out the metal gnomon. The cap then needs to be re-inserted ensuring that the gnomon lines up with the relevant date printed to the lower margin of the shaft. The instrument then needs to be placed in sunlight and aligned so that the shadow of the gnomon falls vertically down the column, the time will then be indicated at the point where the shadow terminates on the projected hour scale printed beneath. As the sundial relies on the altitude of the sun to provide a reading the hour scales are annotated with two opposing sets of numbers - these allow the time to be ascertained both in the morning or afternoon and converge at six o'clock.