What I regard as the two essentials of magical practices, namely, the use of symbols and the appeal to the supernatural realm, are most obvious in what is called "ceremonial magic". Mediaeval ceremonial magic was subdivided into three chief branches--White Magic, Black Magic, and Necromancy. White magic was concerned with the evocations of angels, spiritual beings supposed to be essentially superior to mankind, concerning which I shall give some further details later--and the spirits of the elements,--which were, as I have mentioned in "Some Characteristics of Mediaeval Thought," personifications of the primeval forces of Nature. As there were supposed to be four elements, fire, air, water, and earth, so there were supposed to be four classes of elementals or spirits of the elements, namely, Salamanders, Sylphs, Undines, and Gnomes, inhabiting these elements respectively, and deriving their characters therefrom. Concerning these curious beings, the inquisitive reader may gain some information from a quaint little book, by the Abbe de MONTFAUCON DE VILLARS, entitled _The Count of Gabalis, or Conferences about Secret Sciences_ (1670), translated into English and published in 1680, which has recently been reprinted. The elementals, we learn therefrom, were, unlike other supernatural beings, thought to be mortal. They could, however, be rendered immortal by means of sexual intercourse with men or women, as the case might be; and it was, we are told, to the noble end of endowing them with this great gift, that the sages devoted themselves. Goety, or black magic, was concerned with the evocation of demons and devils--spirits supposed to be superior to man in certain powers, but utterly depraved. Sorcery may be distinguished from witchcraft, inasmuch as the sorcerer attempted to command evil spirits by the aid of charms, _etc_., whereas the witch or wizard was supposed to have made a pact with the Evil One; though both terms have been rather loosely used, "sorcery" being sometimes employed as a synonym for "necromancy". Necromancy was concerned with the evocation of the spirits of the dead: etymologically, the term stands for the art of foretelling events by means of such evocations, though it is frequently employed in the wider sense. It would be unnecessary and tedious to give any detailed account of the methods employed in these magical arts beyond some general remarks. Mr A. E. WAITE gives full particulars of the various rituals in his _Book of Ceremonial Magic_ (1911), to which the curious reader may be referred. The following will, in brief terms, convey a general idea of a magical evocation:--