ae. There are in
existence works by Tristemius, Francis Barrett, Ebenezer Sibley
and others in which the use of the crystal is made by means of
magical invocations and a variety of ceremonial observances. It
is not within the scope of this treatise to determine the
value of such rites or the desirability of invoking extraneous
intelligences and powers by the use of magical practices; but I
think we may conclude that communion of this order is not
unattended by grave dangers. When the Israelites were ill-content
with the farinaceous manna they invoked Heaven to send them meat. They
got what they wanted, but also the dire penalty which it incurred; and
it is quite likely that in invoking occult forces beyond one's power
to control great evils may ensue. All action and reaction are equal
and opposite. A child can pull a trigger but cannot withstand the
recoil of a gun, or by moving a lever may set machinery in motion
which it can by no means control. Therefore without strength and
knowledge of the right sort it is foolish to meddle with occult
forces; and in the education of the development of the psychic and
spiritual faculties native in us, it is better to encourage their
natural development by legitimate exercise than to invoke the action
of a stimulus which cannot afterwards be controlled. Water will
wear away a rock by continual fretting, though nobody doubts
that water is softer than a rock, and if the barrier between this
and the soul-world be like granite, yet the patient and persistent
action of the determined mind will sooner or later wear it away,
the last thin layer will break and the light of another world will
stream through, dazzling our unaccustomed eyes with its bright
effulgence.

It is my object here to indicate by what means and by what
persons the natural development of the clairvoyant faculty may
be achieved. In regard then to the subject, medium or seer, there
are two distinct temperaments in which the faculty is likely to
be dominant and capable of high and rapid development. The
first is the nervous temperament, characterized by extreme
activity of body and mind, nervous excitability, dark complexion,
prominent features, and wiry frame. Types of this temperament are
to be seen in the descriptions of Dante, Swedenborg, Melancthon,
Edgar A. Poe and others. This type represents the positive seers.

The other temperament is of the passive type and is characterized
by a full lymphatic habit, pale or