November's Object - John Evan's Rolling Ball Clock

Noel Poirier

NAWCC Member
Jul 30, 2007
171
54
28
Country
Region
Shelf Clock, c. 1885, John Evans. Two-day brass and steel time only movement. Fusee driven. Inclined brass plane underneath the movement has track for steel ball. As plane tips, escape wheel is released. Made by John Evans after the design of its inventor, Sir William Congreve. Three dials. Hours represented on left most dial, and seconds on the right. Central dial indicates minutes and is printed, "Sir William Congrieve [sic]. Inventor." Engraved on signature plate, "89 Mount St, J. Evans, Grosvenor Sq. W." Brass movement is mounted on square wood base with velvet-upholstered top. Glass cover over movement.

See this clock in operation on Youtube
 

Attachments

MartyR

Registered User
Dec 16, 2008
11,072
346
83
UK
Country
One thing that always surprised me about these clocks is that the ball and the grooves in which it ran withstood the ravages of friction sufficiently to maintain (presumably) some acceptable level of accuracy over many years.

Is there any measure of the degradation of accuracy over time, and what material did the ball/grooves need to be made of?
 

Forum statistics

Threads
177,524
Messages
1,555,851
Members
53,604
Latest member
Pocwat
Encyclopedia Pages
909
Total wiki contributions
3,054
Last edit
Illinois Watch Company by Kent