And yet he had a thomb of gold parde.

– Geoffrey Chaucer

The Canterbury Tales, General Prologue. Here Chaucer is referencing the old proverb, "Every honest miller has a golden thumb". The saying can mean honest millers are as rare as men with gold thumbs, or successful millers have their thumb on the scales to cheat. The Miller in this case grinds grain at the mill for flour and meal, and he is dishonest. He puts a thumb on the scales to cheat his customers, taking more money from them and enriching himself.