In the foregoing illustration let A-B be the mirror with F for its focus. Let the subject be stationed at S. Then the rays directed towards the surface of the mirror will be represented by RR-RR. These rays impinge upon a diamagnetic surface which is concave. The rays are therefore bent inwards and thrown back upon the person at S in the form of a cone of energy which has the effect of producing auto-hypnosis. There are other forms of agency, such as the zinc disc with the copper centre as used by Braid to induce the hypnotic sleep, but these appear to depend upon tiring the optic nerves and thus, through their action upon the thalami to produce temporary inhibition of the whole basilar tract of the brain. The mesmerist who throws streams of energy upon the patient would appear to be working on the same principle as that by which the person using the concave mirror induces self-hypnosis. Possibly the latter method may be found to be conducive to the phenomena arising from auto-suggestion, while the conditions induced by the action of the hypnotist may be less liable to the effects of auto-suggestion and more responsive to hypnotic suggestion, _i.e._ the mental action of the hypnotist. These, however, are considerations which need not trouble us overmuch, since by whatever agent the subject is made clairvoyant, the results are equally curious and informing. Auto-suggestion, at least, can hardly be regarded in the category of objections, since we cannot auto-suggest that which does not first of all arise as an image in the mind. It is in the spontaneous and automatic production of auto-suggested impressions that the phenomena of clairvoyance very largely consist; only we have to remember that the suggesting self is a more considerable quantity than the personality to which these suggestions are made, and is in touch with a world immeasurably greater and in every sense less limited than that to which the person is externally related. Looked at from whatever point of view we may choose, the phenomena of clairvoyance cannot be adequately explained without recourse to psychology on the one hand and occultism on the other. Psychology is needed in order to explain the nature and faculty of the human soul, and occultism to define for us the nature of that universal mirror in which the whole category of human events, both past and future, are reflected. Having decided upon a course of experiments with a crystal or mirror, the best of the kind should be obtained. A black velvet covering should be made in which to envelop the crystal when not in use. Mirrors are usually made with a suitable lid or covering. Care should be taken not to scratch the surface, and all cleaning should be done with a dry silk handkerchief kept for the purpose. Exposure to the sun's rays not only scores the surface of a crystal or mirror, but also puts the odylic substance into activity, distributing and dissipating the magnetic power stored up therein.