Bonhams : A 20th Century Congreve rolling ball clock,
Mid 20th century 'Congreve' rolling ball clock, sloped arch and pierced brass movement, the central Arabic minute chapter ring flanked by hour and seconds dials, twin train driven eight day movement, -
A late 20thC Sir William Congreve rolling ball clock. - Bukowskis
Devon Clocks - Congreve type brass 'Rolling Ball' clock, with Arabic hour, minute and second dials, four turned pillar supports, on mahogany plinth, under glass, designed by Sir William Congreve in 1 -
inclined-plane clock; rolling-ball clock; clock-case | British Museum
20th Century Congreve Rolling Ball Clock at 1stDibs
Congreve rolling ball clock
How To Get Your Own Idle-Tyme. The Original Rolling Ball Clock