“The chief feature,” said Alexis Didier, “of the somnambulistic lucidity is its variability. While the conjurer or juggler, at all moments in the day and before all spectators, will invariably succeed, the somnambulist, endowed with the marvellous power of clairvoyance, will not be lucid with all interviewers and at all moments of the day; for the faculty of lucidity being a crisis painful and abnormal, there may be atmospheric influences or invincible antipathies at work opposing its production, and which seem to paralyse all supersensual manifestation. Intuition, clairvoyance, lucidity, are faculties which the somnambulist gets from the nature of his temperament, and which are rarely developed in force.” Further, he adds, “the somnambulistic lucidity varies in a way to make one despair; success is continually followed by failure; in a word, error succeeds a truth; but when one analyses the causes of this no right-minded person will bring up the charge of Charlatanism, since the faculty is subject to influences independent of the will and the consciousness of the clairvoyant.” Alexis Didier, like his brother Adolphe, was a natural clairvoyant, and excelled in direct and objective clairvoyance, phases of the most striking and convincing character. Clairvoyance can be cultivated by the aid of mesmerism and by the introspection process. By the first, the sensitive can be materially assisted by the experience and help of the operator. By the second, something like natural clairvoyance can be induced. Either processes are more or less suitable to subdue the activity of the senses, and give greater range to the psychic powers. General instructions are of little use. Personal advice is best. The operator then knows with whom he has to do, their special temperament and character, what are the best processes to adopt to cultivate their gift, and how far such sensitives and students are themselves likely to be suitable for clairvoyant experiments. I have found the “Mirror Disc” useful in inducing favourable conditions in the normal state for the development of clairvoyance, and recommend its use. CHAPTER IV. Psychometry. [Illustration: J. RHODES BUCHANAN, M.D.] What is psychometry? Dr. George Wyld esteems psychometry a phase of clairvoyance--“the knowledge the psychic obtains by a _clue_, such as a lock of the hair of some absent person, or some portion of a distant object.” Mr. Stead calls it (_Review of Reviews_, p. 221, September, 1892) “the strange new science of psychometry.” In this he pardonably errs. Psychometry may be strange, but _it_ is _not_ new. We may not recognise the name as old, but the class of phenomena it specialises is as old as clairvoyance and mind-reading.