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.

[Illustration of magic mirror]

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 menta