A tinner by the name of Barker from Towednack used to scoff at the power of the knockers, believing they were figments of the imagination.
An idle fellow, Barker told his workmates he would go to a local mine reputed to be alive with knockers and sit in the sunshine to watch for them.
His lazy day in the sun was interrupted by voices from within the mine. He heard the knockers chattering about where they might hide their tools and determined to steal them, but unfortunately for Barker the knockers didn't like being spied on.
One of them told his fellows," I shall leave mine on Barker's knee!" and instantly the man felt a massive weight smash onto his left knee.
His screams were answered with laughter from within the mine, and the poor man walked with a limp to his dying day.