In hypnotic clairvoyance the glass ball will be found as useful a "field" as the best rock crystal. Yet it does not follow that because the crystal is highly odylic and glass altogether negative the former will induce clairvoyance. My own first experience with the crystal was entirely disappointing, while very striking results followed immediately upon the use of a black concave mirror.
The mirror is usually circular in shape and about one-quarter-inch curve to a six-inch diameter. This gives a long focus, so that the mirror may be hung upon a wall at about two yards distance from the subject. A greater degree of concavity proportionate to the diameter will produce a focus which allows the mirror to be held in the hand while resting in the lap.
This disposes to a very easy and passive attitude and helps towards results. The base of the mirror may be of tin, wood or other material, and it is usually filled with a composition of a bituminous nature, the glass covering being painted with a preparation of coal-tar on its nether or convex side. The exact focus and consequent size of the mirror employed as most suitable to the individual is a matter of experiment. It is also to be observed that the distance of the mirror, as also the angle of vision, are matters of experiment. Beyond a certain distance it will be found that the mirror has no "draw" on the subject. If brought closer its pull is immediately felt.
It is perhaps too early to theorize upon the modus operandi of the "magic mirror," as it has been called. It appears to induce hypnosis and consequent elevation of nervous activity by refracting and throwing back the rays of magnetic energy which emanate from the subject.
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.
And now a word or two about the disposition and attitude of the subject. The visions do not occur in the crystal itself. They may appear to do so, but this is due, when it occurs, to the projection and visualization of the mental images. The visions are in the mind or soul of the seer and nowhere else. It is a matter of constitutional psychism as to where the sense of clear vision will be located. Personally I find the sense to be located in the frontal coronal region of the brain about 150 to the right of the normal axis of vision, which may be regarded as the meridian of sight. Other instances are before me in which the sense is variously located in the back of the head, the nape of the neck, the pit of the stomach, the summit of the head, above and between the eyes, and in one case near the right shoulder but beyond the periphery of the body. The explanation appears to be that the nervo-vital emanations from the body of the seer act upon the static odyle in the agent, which in turn reacts upon the brain centres by means of the optic nerves. And this appears to be sufficient reason why the crystal or mirror should be kept as free as possible from disturbing elements. Water is extremely odylic and should never come in contact with the agent employed as it effectually carries off all latent or stored imports. I am forced to use a crude terminology in order to convey the idea in my mind, but I recognize that the whole explanation may appear vague and inadequate. It is of course at all times easier to observe effects than to offer a clear explanation of them. Yet some sort of working hypothesis is constructed when we collate our observations, and it is this that I have sought to communicate.
For similar reasons, when in use the crystal or mirror should be shaded and so placed that no direct rays from sun or artificial light may fall upon it. The odyle, as Reichenbach so conclusively proved by his experiments, rapidly responds to surrounding magnetic conditions and to the vibrations of surrounding bodies, and to none more rapidly than the etheric vibrations caused by combustion or light of any kind. There should be no direct rays of light between the agent and the seer.