William Congreve, the son of a British General and more famous
for his invention of the first Rocket in 1795, patented in
1808 a new Principle for the Measurement of Time using a rolling
ball escapement. His original piece was powered by a Cannon
ball although later models were driven by springs.
His resulting clock was far from accurate,
however the mechanism provides a fascinating and hypnotic
spectacle for the viewer. The Sinclair Harding Congreve uniquely
has the track mounted on top of the clock. A ruby ball meanders
along the track triggering the mechanism every 15 seconds
to gently reverse the ball. The skeletonised track also makes
it easy to clean and provides a reasonable degree of timekeeping.
The matching dial is made from brass on to
which is applied a cold enamel of the correct colour. The
quarter hour indicators are then machined through the enamel
before the dial is finally given a coat of clear enamel. The
clock is powered by a spring through a hand made chain, which
drives the movement through a Fusee to ensure the clock mechanism
sees a constant torque. The movement is 8 days and is wound
from the back of the clock on our model with the elliptical
dial or from the front on our model with the circular dial.
At the other end of the train a fly absorbs any shock loads
at each index and prevents the tray indexing mechanism vibrating.