An unusual late 18th Century Swiss cylinder with visible balance in a gem set gold brooch watch. Small rectangular full plate gilt movement with canted corners. Keywound and set from the back with resting barrel. Decorative four arm diamond set balance visible through an aperture in the dial. Blue steel spiral hairspring hidden below the polished steel plate which acts a background to the balance. White enamel dial with Arabic numerals in a chapter set under the balance, blue steel Breguet hands. Rectangular gold case with canted corners, plain gold back with apertures for wind, set and regulation. A foliate pierced gold frame surrounds the watch set with rubies, emeralds and diamonds. Small diamond set finial and loop to suspend the watch.