Balance wheel
Balance wheel ({not transcribed})
1.
(a) (Horology) A wheel which regulates the beats or pulses of a watch or chronometer, answering to the pendulum of a clock; -- often called simply a balance.
(b)
(Horology) A ratchet-shaped scape wheel, which in some watches is acted upon by the axis of the balance wheel proper (in those watches called a balance).
2.
(Machinery) A wheel which imparts regularity to the movements of any engine or machine; a fly wheel.