Mag Ruith, who made a magic fire, and flying upwards towards it, turned it upon the enemy, whose Druid in vain tried to divert it.1049 When the Druids of Cormac dried up all the waters in the land, another Druid shot an arrow, and where it fell there issued a torrent of water.1050 The Druid Mathgen boasted of being able to throw mountains on the enemy, and frequently Druids made trees or stones appear as armed men, dismaying the opposing host in this way. They could also fill the air with the clash of battle, or with the dread cries of eldritch things.1051 Similar powers are ascribed to other persons. The daughters of Calatin raised themselves aloft on an enchanted wind, and discovered Cúchulainn when he was hidden away by Cathbad. Later they produced a magic mist to discomfit the hero.1052 Such mists occur frequently in the sagas, and in one of them the Tuatha Dé Danann arrived in Ireland. The priestesses of Sena could rouse sea and wind by their enchantments, and, later, Celtic witches have claimed the same power.
In folk-survivals the practice of rain-making is connected with sacred springs, and even now in rural France processions to shrines, usually connected with a holy well, are common in time of drought. Thus people and priest go to the fountain of Baranton in procession, singing hymns, and there pray for rain. The priest then dips his foot in the water, or throws some of it on the rocks.1053 In other cases the image of a saint is carried to a well and asperged, as divine images formerly were, or the waters are beaten or thrown into the air.1054 Another custom was that a virgin should clean out a sacred well, and formerly she had to be nude.1055 Nudity also forms part of an old ritual used in Gaul. In time of drought the girls of the village followed the youngest virgin in a state of nudity to seek the herb belinuntia. This she uprooted, and was then led to a river and there asperged by the others. In this case the asperging imitated the falling rain, and was meant to produce it automatically. While some of these rites suggest the use of magic by the folk themselves, in others the presence of the Christian priest points to the fact that, formerly, a Druid was necessary as the rain producer. In some cases the priest has inherited through long ages the rain-making or tempest-quelling powers of the pagan priesthood, and is often besought to exercise them.1056
Causing invisibility by means of a spell called feth fiada, which made a person unseen or hid him in a magic mist, was also used by the Druids as well as by Christian saints. S. Patrick's hymn, called Fâed Fiada, was sung by him when his enemies lay in wait, and caused a glamour in them. The incantation itself, fith-fath, is still remembered in Highland glens.1057 In the case of S. Patrick he and his followers appeared as deer, and this power of shape-shifting was wielded both by Druids and women. The Druid Fer Fidail carried off a maiden by taking the form of a woman, and another Druid deceived Cúchulainn by taking the form of the fair Niamh.1058 Other Druids are said to have been able to take any shape that pleased them.1059 These powers were reflected back upon the gods and mythical personages like Taliesin or Amairgen, who appear in many forms. The priestesses of Sena could assume the form of animals, and an Irish Circe in the Rennes Dindsenchas called Dalb the Rough changed three men and their wives into swine by her spells.1060 This power of transforming others is often described in the sagas. The children of Lir were changed to swans by their cruel stepmother; Saar, the mother of Oisin, became a fawn through the power of the Druid Fear Doirche when she rejected his love; and similarly Tuirrenn, mother of Oisin's hounds, was transformed into a stag-hound by the fairy mistress of her husband Iollann.1061 In other instances in the sagas, women appear as birds.1062 These transformation tales may be connected with totemism, for when this institution is decaying the current belief in shape-shifting is often made use of to explain descent from animals or the tabu against eating certain animals. In some of these Irish shape-shifting tales we find this tabu referred to. Thus, when the children of Lir were turned into swans, it was proclaimed that no one should kill a swan. The reason of an existing tabu seemed to be sufficiently explained when it was told that certain human beings had become swans. It is not impossible that the Druids made use of hypnotic suggestion to persuade others that they had assumed another form, as Red Indian shamans have been known to do, or even hallucinated others into the belief that their own form had been changed.
By a "drink of oblivion" Druids and other persons could make one forget even the most dearly beloved. Thus Cúchulainn was made to forget Fand, and his wife Emer to forget her jealousy.1063 This is a reminiscence of potent drinks brewed from herbs which caused hallucinations, e.g. that of the change of shape. In other cases they were of a narcotic nature and caused a deep sleep, an instance being the draught given by Grainne to Fionn and his men.1064 Again, the "Druidic sleep" is suggestive of hypnotism, practised in distant ages and also by present-day savages. When Bodb suspected his daughter of lying he cast her into a "Druidic sleep," in which she revealed her wickedness.1065 In other cases spells are cast upon persons so that they are hallucinated, or are rendered motionless, or, "by the sleight of hand of soothsayers," maidens lose their chastity without knowing it.1066 These point to knowledge of hypnotic methods of suggestion. Or, again, a spectral army is opposed to an enemy's force to whom it is an hallucinatory appearance—perhaps an exaggeration of natural hypnotic powers.1067
Druids also made a "hedge," the airbe druad, round an army, perhaps circumambulating it and saying spells so that the attacking force might not break through. If any one could leap this "hedge," the spell was broken, but he lost his life. This was done at the battle of Cul Dremne, at which S. Columba was present and aided the heroic leaper with his prayers.1068
A primitive piece of sympathetic magic used still by savages is recorded in the Rennes Dindsenchas. In this story one man says spells over his spear and hurls it into his opponent's shadow, so that he falls dead.1069 Equally primitive is the Druidic "sending" a wisp of straw over which the Druid sang spells and flung it into his victim's face, so that he became mad. A similar method is used by the Eskimo angekok. All madness was generally ascribed to such a "sending."
Several of these instances have shown the use of spells, and the Druid was believed to possess powerful incantations to discomfit an enemy or to produce other magical results. A special posture was adopted—standing on one leg, with one arm outstretched and one eye closed, perhaps to concentrate the force of the spell,1070 but the power lay mainly in the spoken words, as we have seen in discussing Celtic formulæ of prayer. Such spells were also used by the Filid, or poets, since most primitive poetry has a magical aspect. Part of the training of the bard consisted in learning traditional incantations, which, used with due ritual, produced the magic result.1071