There can be little doubt that Dee used more than one crystal in the course of his experiments; that now in the British Museum is of cairngorm, or “smoky-quartz.” This variety of quartz may have been chosen because of the Scotch superstitions regarding its virtues; for, as a rule, charlatans seek to avail themselves of already existing superstitions in order to make their innovations more acceptable. [Illustration: DR. DEE’S SHEW STONE. Natural size. British Museum. This sphere of smoky-quartz came to the British Museum in 1700 with the Cottonian Library, donated at that time by the grandson of the original collector, Sir Robert Bruce Cotton (1571-1631).] [Illustration: OBSIDIAN MIRROR, WITH NATIVE TEXTILE STRING. Used by Aztecs and ancient Mexicans for various purposes. British Museum. Identical in shape and size with that known as “Dr. Dee’s Mirror,” now in the possession of Prince Alexis Soltykoff, of Russia. This was enclosed in a leather-covered case.] To give assurance to those who consulted such crystals that no diabolical agency was involved in the production of the phenomena, it was customary that a child should be the crystal-gazer. In Dr. Dee’s experiments, however, it was usually the notorious Kelley, his _âme damnée_, who undertook this task of interpreting the crystal visions. The description given by Dee of a little girl who frequently acted as the intermediary of the higher powers suggests one of the fanciful creations of our great novelist Hawthorne. Her mystic name was Madimi, and she is depicted as a pretty girl about eight years old, and with long flowing hair. To make her appearance more conspicuous, she was attired in a silk dress with chatoyant effects in red and green. At times, during the séances, this gay little figure could be seen flitting about the study, rendered even more whimsical and strange from its contrast with the piles of dusty old books, the curiosities, and the magical instruments collected there.[289]