What is the name of those clocks with the glass dome type covers?

Question

usually has like 4 balls spinning at the bottom and is covered with a glass or plastic clear cover that is round on top.. what is the name of that kind of clock?

Answer 1

Anniversary Clock

Answer 2

This is a torsion pendulum clock. The "pendulum" rotates back and forth, instead of from side to side like a regular pendulum.