The above definitive explanation of the term clairvoyance agrees with the idea of the best authorities, and distinguishes between the phenomena of clairvoyance and that of telepathy, on the one hand; and between the former and that of seeing apparitions, on the other hand. I, personally, accept this distinction as both scientific in form, and as agreeing with the facts of the case. You will, of course, see that the acceptance of the existence of the astral senses throws light on many obscure points about which the psychic researchers are in doubt, and reconciles many apparently opposing facts. All scientific authorities, as well as the best occultists, divide the phenomena of clairvoyance into several well-distinguished classes. The following classification is simple, and indicates clearly the principal forms of clairvoyant phenomena: (1) Simple Clairvoyance, in which the clairvoyant person merely senses the auric emanations of other persons, such as the auric vibrations, colors, etc.; currents of thought-vibrations, etc.; but does not see events or scenes removed in space or time from the observer. (2) Clairvoyance in Space, in which the clairvoyant person senses scenes and events removed in space from the observer; and, often also is able to sense such things even when they are concealed or obscured by intervening material objects. (3) Clairvoyance in Time, in which the clairvoyant person senses scenes and events which have had their original place in past time; or scenes and events which will have their original place in the future. I shall describe each of these three classes, with their many variations, as we reach them in their proper places in these lessons. Before doing so however, I wish to explain to you the several methods by which clairvoyant vision is usually induced. These methods may be designated as follows: (1) Psychometry, or the method of getting en rapport with the astral plane by means of some physical object connected with the person, thing, or scene about which you desire to be informed. (2) Crystal Gazing, etc., or the method of getting en rapport with the astral plane by means of gazing into a crystal, magic mirror, etc. (3) Clairvoyant Reverie, or the method of getting en rapport with the astral plane by means of psychic states in which the sights, sounds and thoughts of the material and physical plane are shut out of consciousness. I shall now proceed to give the details regarding each one of these three great classes of methods inducing clairvoyant vision, or en rapport conditions with the astral plane. Psychometry. Psychometry is that form of clairvoyant phenomena in which the clairvoyant gets into en rapport relation with the astral plane by means of the connecting link of material objects, such as bit of stone, piece of hair, article of wearing apparel etc., which has had previous associations with the thing, person or scene regarding which clairvoyant vision is required.