This rings a bell

"Run like the clappers.." apparently means 'flee in haste'. (I saw it in a Guardian story on volcanic lightning.) But for us old US sorts, what does 'the clappers' mean?

It has to do with the ringing of a bell.
Definition:
clapper - noun [C]
a piece of metal which hangs inside a bell and makes the bell ring when it hits the sides
(from Cambridge Advanced Learner's Dictionary)
SR

For more information, search the archives under "clappers."

In West Virginia, if someone was running fast, he was "splitting the mud."