This dishonoured science has some right to be mentioned in a "Treatise on Demonology," because the earlier astrologers, though denying the use of all necromancy--that is, unlawful or black magic--pretended always to a correspondence with the various spirits of the elements, on the principles of the Rosicrucian philosophy. They affirmed they could bind to their service, and imprison in a ring, a mirror, or a stone, some fairy, sylph, or salamander, and compel it to appear when called, and render answers to such questions as the viewer should propose. It is remarkable that the sage himself did not pretend to see the spirit; but the task of viewer, or reader, was entrusted to a third party, a boy or girl usually under the years of puberty. Dr. Dee, an excellent mathematician, had a stone of this kind, and is said to have been imposed upon concerning the spirits attached to it, their actions and answers, by the report of one Kelly who acted as his viewer. The unfortunate Dee was ruined by his associates both in fortune and reputation. His show-stone or mirror is still preserved among other curiosities in the British Museum. Some superstition of the same kind was introduced by the celebrated Count Cagliostro, during the course of the intrigue respecting the diamond necklace in which the late Marie Antoinette was so unfortunately implicated. Dismissing this general class of impostors, who are now seldom heard of, we come now briefly to mention some leading superstitions once, perhaps, common to all the countries of Europe, but now restricted to those which continue to be inhabited by an undisturbed and native race. Of these, one of the most beautiful is the Irish fiction which assigns to certain families of ancient descent and distinguished rank the privilege of a Banshie, as she is called, or household fairy, whose office it is to appear, seemingly mourning, while she announces the approaching death of some one of the destined race. The subject has been so lately and beautifully investigated and illustrated by Mr. Crofton Croker and others, that I may dispense with being very particular regarding it. If I am rightly informed, the distinction of a banshie is only allowed to families of the pure Milesian stock, and is never ascribed to any descendant of the proudest Norman or boldest Saxon who followed the banner of Earl Strongbow, much less to adventurers of later date who have obtained settlements in the Green Isle.