The mechanism of this captivating Congreve-type rolling ball timepiece is considered the most frustrating, yet fascinating of timekeeping instruments. The widely recognized design was patented by Sir William Congreve in 1808, and reflects the aspiration of clockmakers to find an alternative to the pendulum as the escapement regulator. In this interpretation of Congreve's ingenious design, crafted by renowned clock makers French of the Royal Exchange, a steel ball takes 30 seconds to run down the inclined zig-zag track where it trips the escapement, reversing the angle of the tray and causing the clock hands to move forward correspondingly. Three silver plated dials shows the hours, minutes and seconds separately, while a sliding bar hidden in the ball arches indicates every other second. Neoclassical brass columns provide the structure to the timepiece as it rests on a black marble and red velvet platform. A brass-lined perspex cover protects the eight-day single wire fusée movement and ball bearing instrument. Similar designs are featured in Mystery, Novelty & Fantasy Clocks by Derek Roberts.