The Carriage Clock

Invented by Abraham-Louise Breguet for Emperor Napolean Bonapart in 1812 as a reliable, accurate, portable timepiece for use by his officers in the battlefield.
A feature of carriage clocks is the platform escarpment visible through a glazed aperture on the top of the case. Carriage clocks use a balance wheel and balance spring, replacing the larger pendulum mechanism which needed to be kept still and level for accuracy. 
They were originally called Officer's Clocks but developed the later name of Carriage Clock when they became the favoured timepiece of the gentry both in France and England, used hanging from the top handle in their carriages.

Thanks to Laurie54 for hosting an intriguingly inventive month of mono Mondays.