This ivory folding compass and sundial is inscribed 'Fait par Gabriel Bloud A Dieppe', 'Made by Gabriel Bloud in Dieppe'. It is made in about 1650-1680. It has an hour dial, an equatorial dial and a polar dial. Bloud was one of a family of ivory sundial makers active in Dieppe in the seventeenth and early eighteenth centuries. Other works by him and by his relative, Jean Bloud, are in the Château-Musée de Dieppe. The collection of scientific instruments, while never the result of a deliberate policy, is indebted to the Museum's founding mission to promote the industrial arts.
These objects were portable and essential for accurate time-keeping, and would have been used by merchants, sea captains, travellers, and indeed anyone who wished to know the time, in the days before accurate pocket watches or of course wrist watches. They relied on measuring the sun’s changing direction in the sky, indicating the hour of the day through the angle of the shadow cast by the gnomon, which was the string in the hinged portable sundials. In order to work correctly the direction dials had to be properly aligned, and for this reason such portable sundials needed to incorporate magnetic compasses.
Ivory was a suitable material for a number of reasons: it was not heavy, did not warp as easily as wood, and its light colour and relative softness meant that it was easy to inscribe. Such objects were produced from the fifteenth century up to the early twentieth.