"Ročky" (400-day clock) - battery-operated.
Battery-operated pendulum clock: In the period 1900–1910, this was a technological innovation. Magnetic pendulum - at the bottom of the pendulum there is a curved permanent magnet that moves through a fixed coil (solenoid). This is the heart of the entire system.
In these models, the battery was hidden directly in the wooden base "under the lid."
The body of the clock is made of brass.
The glass lid / cylinder served two purposes in these early electric clocks:
Protection from dust: Electromagnetic contacts were very sensitive to dirt.
Protection from drafts: The pendulums of these clocks were very light and the slightest movement of air would disrupt the accuracy of the movement.
This is a collectors item in very well-preserved, original condition.