A special class of diviners existed among the Celts, but the Druids practised divination, as did also the unofficial layman.  Classical writers speak of the Celts as of all nations the most devoted to, and the most experienced in, the science of divination.  Divination with a human victim is described by Diodorus.  Libations were poured over him, and he was then slain, auguries being drawn from the method of his fall, the movements of his limbs, and the flowing of his blood.  Divination with the entrails was used in Galatia, Gaul, and Britain.[856] Beasts and birds also provided omens.  The course taken by a hare let loose gave an omen of success to the Britons, and in Ireland divination was used with a sacrificial animal.[857] Among birds the crow was pre-eminent, and two crows are represented speaking into the ears of a man on a bas-relief at Compiegne.  The Celts believed that the crow had shown where towns should be founded, or had furnished a remedy against poison, and it was also an arbiter of disputes.[858] Artemidorus describes how, at a certain place, there were two crows.  Persons having a dispute set out two heaps of sweetmeats, one for each disputant.  The birds swooped down upon them, eating one and dispersing the other.  He whose heap had been scattered won the case.[859] Birds were believed to have guided the migrating Celts, and their flight furnished auguries, because, as Deiotaurus gravely said, birds never lie.  Divination by the voices of birds was used by the Irish Druids.[860]

Omens were drawn from the direction of the smoke and flames of sacred fires and from the condition of the clouds.[861] Wands of yew were carried by Druids—­“the wand of Druidism” of many folk-tales—­and were used perhaps as divining-rods.  Ogams were also engraved on rods of yews, and from these Druids divined hidden things.  By this means the Druid Dalan discovered where Etain had been hidden by the god Mider.  The method used may have been that of drawing one of the rods by lot and then divining from the marks upon it.  A similar method was used to discover the route to be taken by invaders, the result being supposed to depend on divine interposition.[862] The knowledge of astronomy ascribed by Caesar to the Druids was probably of a simple kind, and much mixed with astrology, and though it furnished the data for computing a simple calendar, its use was largely magical.[863] Irish diviners forecast the time to build a house by the stars, and the date at which S. Columba’s education should begin, was similarly discovered.[864]

The Imbas Forosnai, “illumination between the hands,” was used by the File to discover hidden things.  He chewed a piece of raw flesh and placed it as an offering to the images of the gods whom he desired to help him.  If enlightenment did not come by the next day, he pronounced incantations on his palms, which he then placed on his cheeks before falling asleep.  The revelation followed in a dream,