5308086 A dome supported on columns.; (add.info.: Engraving depicting a dome supported on columns, standing on a base. Wound round four columns are two parallel inclined rails down which a ball rolls. When it reaches the bottom it is guided into an Archimedean screw which raises it to the top of its run again. In the base is the clock driving mechanism that turns the Archimedean screw and operated dials. Dated 18th century.); Universal History Archive/UIG.