The History of Spiritualism, Volume I

It is impossible to record the many mediums of various shades of power, and occasionally of honesty, who have demonstrated the effects which outside intelligences can produce when the material conditions are such as to enable them to manifest upon this plane. There are a few, however, who have been so pre-eminent and so involved in public polemics that no history of the movement can disregard them, even if their careers have not been in all ways above suspicion. We shall deal in this chapter with the histories of Slade and Monck, both of whom played a prominent part in their days.

Henry Slade, the celebrated slate-writing medium, had been before the public in America for fifteen years before he arrived in London on July 13, 1876. Colonel H. S. Olcott, a former president of the Theosophical Society, states that he and Madame Blavatsky were responsible for Slade's visit to England. It appears that the Grand Duke Constantine of Russia, desiring to make a scientific investigation of Spiritualism, a committee of professors of the Imperial University of St. Petersburg requested Colonel Olcott and Madame Blavatsky to select out of the best American mediums one whom they could recommend for tests.