At the completion of the tale of Saint Cecilia, a Canon, riding a dilapidated old hack, and his Yeoman, on an even worse hack, ride up to the pilgrims. The Host welcomes them and asks whether either has a tale to tell. The Yeoman answers immediately that his master knows much about mirth and jollity, and then he begins to tell the secrets of their trade and all he knows about alchemy. Seeing that the Yeoman plans to tell everything, the Canon slips away in shame.
The first part of the Yeoman's tale is autobiographical: He explains that once he had good clothes and a comfortable living, that he and the Canon are alchemists, and that he is so in debt because their attempts at alchemy always fail. He then tries to explain their occupation, their failed attempts at alchemy, and their elusive search for the Philosopher's Stone. The tale itself comprises the second part of The Canon's Yeoman's Tale.
A canon who practices alchemy borrows a mark from a priest. In three days time, the canon returns the mark and offers to reveal a couple of his discoveries. He sends for some quick silver and, by tricks, makes the priest believe that he turned the quick silver into real silver. Unaware of the trick, the priest is very pleased. Three times the canon tricks the priest, each time "turning" a less valuable object (quick silver, chalk, and then a twig) into silver. The beguiled priest buys the secret from the canon for 40 pounds, and the canon promptly disappears. The Yeoman ends his tale with a broadside attack on the subject of alchemy and a conglomeration of all the ridiculous terms used by alchemists.
