Strange artefacts of times gone by

Businesses used to have special clocks to keep a check on hours logged at work by their employees. One of the prominent British manufacturers for this was National Time Recorder, which was based at Mary Cray in Orpington, Kent after WWII. There must have been such a clock on campus at Merchiston at some point in the past, as this remnant of it remains on a corridor wall near my office. To find out more about NTR, go here.