John Evans 1838-1905 was a chronometer and watch and clock manufacturer in London. He
apprenticed with Charles Gartner who was listed as a maker to Dent. A tall clock with his
signature on the dial is in the Weatherfield Collection. This clock was originally owned
by Dr. David Hunter and Emma McAlpin, Jr. of Morris Plains, NJ 1862-1934.
The time standard of this clock is provided by the rolling of a steel ball in a zigzag
track on a tilting plate. When the ball reaches the end of the track (every thirty
seconds) the ball hits a lever which reverses the tilt of the plate and releases the
escapement of the spring driven movement.
The unique design of the clock was first created by Sir William Congreve in the early 19th
century. Congreve was not a clockmaker by trade, but today his name is inextricably linked
to the Rolling Ball Clock of his design. The escapement which Congreve termed the
"Extreme Detached Escapement" was patented in 1808. Rather than build the pieces
himself, Congreve hired John Moxon. The first design was weight driven and was presented
by Congreve to the Prince of Wales in 1808. The second design was spring driven and is in
the collection of Buckingham Palace. Since then numerous copies and adaptations have been
made and are still being made today. Each must be evaluated on its own merit. In general,
they are not very accurate timekeepers.
Donated by Elaine T. Grady and Diane T. deSibour
in memory of their mother Elaine McAlpin Tate
and their sister Gay T. Duncan
NAWCC Museum #94.38