Acadine

The Greek historian Diodorus Siculus described in Book 11.89 of his Bibliotheca historica a pool that spouted hot, sulfurous water at the sanctuary of the Palici in Sicily, and said solemn oaths were undertaken there. According to the Aristotelian On Marvellous Things Heard, a sworn statement would be written on a tablet and thrown into the pool. If true it floated, but otherwise it sank to the bottom and the perjuror would be scalded. Renaissance and later authors took up this story, calling it the Acadine fountain, though this name is not attested in ancient sources.