Patent Eight-Day, Visible Escapement, Switzerland

The Hebdomas movement was one of the most distinctive achievements of Swiss watchmaking around the turn of the twentieth century: an 8-day movement, roughly eight times the running time of an ordinary watch, that also exposed part of its balance and escapement through an aperture in the dial so the watch could be seen working. The calibre was patented in 1889 by Irenee Aubry and developed commercially by Arthur Graizely, and went on to win medals at exhibitions across Europe and America.

This example is signed "Hebdomas Patent, 8 Days, Swiss Made" on a white enamel dial, with the hour numerals set on individual deep red enamel roundels, flanked by gilt engraved foliate sprays either side of the visible escapement window. Two regulator index marks sit either side of the aperture. Inside, the case back is engraved "Ancre... Qualite Superieure Garantie" together with three applied gold medal roundels, matching the documented Hebdomas exhibition wins at Geneva 1896, Paris 1900, Chicago 1902 and Brussels 1910. Since a Brussels 1910 medal is included, this case was finished no earlier than 1910. The case is open-face, nickel or white metal, and measures 47mm across.

Sold via Chrono24 to a buyer in Utrecht before The Estate Collection's current cataloguing process was completed, so no detailed condition grading exists for this piece.