The motive-power of a clock is a either a weight, or fusee and
spring which drives a train of wheels.
The fusee is conical-shaped brass drum, with
the gut line from the spring wound round it like a spindle filled with thread,
which controls, by different ratios, the power output of the spring to enable the clock to keep a regular time. Fusees
were used on clock and watches until the late 19th century, not
given up until slimmer Swiss watches became fashionable in early 20th
century.
The escapement is the part
of the clock, watch or timepiece which allows the power driving the mechanism
to escape, and controls the speed at which a clock runs down. The various forms
of escapement release the escape wheel at regular short intervals (giving a
tick-tock sound), allowing the driving force to operate, lock and release
again, in a regulated sequence.
