The princeps aeris hujus, the “prince of the air” of St. Paul, is not the devil, but the effects of the astral light, as Eliphas Levi correctly explains. The Devil is not “the God of this period,” as he says, for it is the deity of every age and period, since man appeared on earth, and matter, in its countless forms and states, had to fight for its evanescent existence against other disintegrating Forces.