Among other charms practised was Dactylomancy, which was performed by means of a ring suspended by a thread in the centre of an earthenware or metal pitcher. The ring, which was supposed to have been made under the influence of a certain constellation, was swung from side to side of the vessel, and the sounds it made on touching were taken as predictions and oracles. The art of divination by fire was called Pyromancy, and was performed by allowing a certain body to burn, the smoke from which, by its density and colour, forecast the future. A favourite medium for consulting this oracle was a donkey’s head roasted on hot coals. Popular belief in mediæval times attributed anything unusual or beyond its understanding, to magic; so most of the early alchemists were believed to be magicians. Both Albertus Magnus and Roger Bacon were accused of dealing in the black arts, one having to resign his bishopric of Cologne and retire to a monastery, and the other to the Franciscan cells in Paris, to free themselves from the charges of their accusers. CHAPTER X. BLACK MAGIC. Geber, an alchemist of great repute in Arabia, was believed to possess the power of creating gold by magic. He was a man of undoubted learning and a skilful practitioner of his time, yet he was dubbed a sorcerer. He was said to possess all kinds of extraordinary implements; among others, a book of black magic which gave him full power over demons, and a brass idol which spoke oracles. On the day of his death, in 1003, the Evil One is supposed to have carried him off. James Iodoc, an Englishman, achieved considerable notoriety by claiming that he had succeeded in setting the demon in a magic ring. These men should not be confounded with the host of impostors and charlatans who simply preyed on the credulity of the people, but in those days all were judged alike. Most of the great mediæval alchemists dabbled in magic, and all agreed that to obtain the intervention of Satan in human affairs it was necessary to enter into a pact with him. Those who went to this length and became exponents of demonology, or the black art, were initiated with much solemnity. TAKING THE OATH. The oath to the demon had to be pronounced in the centre of a circle traced upon the ground, accompanied by the offer of some pledge, such as a garment of the noviciate. The edge of the circle was supposed to establish a mark which the demon could not cross. Heavy perfumes such as vervain, with burning incense and lighted tapers, always formed part of the ceremonial. The smoking brazier, which entered largely into the ritual, was believed to act upon the demons, and was constantly fed with all kinds of mysterious vegetable and animal substances, those that would produce most smoke being preferred. It is said that belladonna and opium were always used as ingredients in the incense, in order to produce a state of semi-stupor and influence the imagination.