Lactantius,[170] refuting the philosophers Democritus, Epicurus, and Dicearchus, who denied the immortality of the soul, says they would not dare to maintain their opinion before a magician, who, by the power of his art, and by his spells, possessed the secret of bringing souls from Hades, of making them appear, speak, and foretell the future, and give certain signs of their presence. St. Augustine,[171] always circumspect in his decisions, dare not pronounce whether magicians possess the power of evoking the spirits of saints by the might of their enchantments. But Tertullian[172] is bolder, and maintains that no magical art has power to bring the souls of the saints from their rest; but that all the necromancers can do is to call forth some phantoms with a borrowed shape, which fascinate the eyes, and make those who are present believe that to be a reality which is only appearance. In the same place he quotes Heraclius, who says that the Nasamones, people of Africa, pass the night by the tombs of their near relations to receive oracles from the latter; and that the Celts, or Gauls, do the same thing in the mausoleums of great men, as related by Nicander. Lucan says[173] that the magicians, by their spells, cause thunder in the skies unknown to Jupiter; that they tear the moon from her sphere, and precipitate her to earth; that they disturb the course of nature, prolong the nights, and shorten the days; that the universe is obedient to their voice, and that the world is chilled as it were when they speak and command.[174] They were so well persuaded that the magicians possessed power to make the moon come down from the sky, and they so truly believed that she was evoked by magic art whenever she was eclipsed, that they made a great noise by striking on copper vessels, to prevent the voice which pronounced enchantments from reaching her.[175] These popular opinions and poetical fictions deserve no credit, but they show the force of prejudice.[176] It is affirmed that, even at this day, the Persians think they are assisting the moon when eclipsed by striking violently on brazen vessels, and making a great uproar. Ovid[177] attributes to the enchantments of magic the evocation of the infernal powers, and their dismissal back to hell; storms, tempests, and the return of fine weather. They attributed to it the power of changing men into beasts by means of certain herbs, the virtues of which are known to them.[178] Virgil[179] speaks of serpents put to sleep and enchanted by the magicians. And Tibullus says that he has seen the enchantress bring down the stars from heaven, and turn aside the thunderbolt ready to fall upon the earth--and that she has opened the ground and made the dead come forth from their tombs.