83. Of all spirit-manifestations, the simplest and most frequent are those which
are made audibly, by raps, or by other noises; and here it is that illusion is most to be
feared, for a vast number of natural causes may produce such sounds: the action of the
wind, an object that we may move ourselves without perceiving it, an animal not seen by us, an insect, etc.; not to mention silly tricks played off by foolish persons. Spirit-
sounds, however, are usually of a peculiar character; they have an intensity and a
character of their own, which, notwithstanding their great variety, can hardly be
mistaken, so that they are not easily confounded with common noises, such as the
creaking of wood, the crackling of a fire, or the ticking of a clock; spirit-raps are clear
and sharp, sometimes soft and light, sometimes loud and distinct, sometimes even
noisy; changing their place, and recurring, without any mechanical regularity. The best
means of ascertaining the nature of any unusual sounds, so as to leave no doubt about
their origin, is to satisfy oneself as to their obedience to the will. If the raps make
themselves heard in the place we designate, if they answer to our thought by their
number or character, we cannot doubt that an intelligence is at work; although it must
be remarked that failure to obey our will is not always a proof of the absence of such an
intelligence.
