of using the somewhat clumsy paraphrase, "astral or mental matter
ensouled by the monadic essence at the stage of one of the elemental
kingdoms," theosophical writers often, for brevity's sake, call this
quickened matter simply elemental essence; and sometimes they speak of
the thought-form as "an elemental." There may be infinite variety in the
colour and shape of such elementals or thought-forms, for each thought
draws round it the matter which is appropriate for its expression, and
sets that matter into vibration in harmony with its own; so that the
character of the thought decides its colour, and the study of its
variations and combinations is an exceedingly interesting one.

This thought-form may not inaptly be compared to a Leyden jar, the
coating of living essence being symbolised by the jar, and the thought
energy by the charge of electricity. If the man's thought or feeling is
directly connected with someone else, the resultant thought-form moves
towards that person and discharges itself upon his astral and mental
bodies. If the man's thought is about himself, or is based upon a
personal feeling, as the vast majority of thoughts are, it hovers round
its creator and is always ready to react upon him whenever he is for a
moment in a passive condition. For example, a man who yields himself to
thoughts of impurity may forget all about them while he is engaged in
the daily routine of his business, even though the resultant forms are
hanging round him in a heavy cloud, because his attention is otherwise
directed and his astral body is therefore not impressible by any other
rate of vibration than its own. When, however, the marked vibration
slackens and the man rests after his labours and leaves his mind blank
as regards definite thought, he is very likely to feel the vibration of
impurity stealing insidiously upon him. If the consciousness of the man
be to any extent awakened, he may perceive this and cry out that he is
being tempted by the devil; yet the truth is that the temptation is from