Hitherto we have principally passed such persons in review, as seem
to have been in part at least the victims of their own delusions.
But beside these there has always been a numerous class of men, who,
with minds perfectly disengaged and free, have applied themselves
to concert the means of overreaching the simplicity, or baffling the
penetration, of those who were merely spectators, and uninitiated
in the mystery of the arts that were practised upon them. Such was
no doubt the case with the speaking heads and statues, which were
sometimes exhibited in the ancient oracles. Such was the case with
certain optical delusions, which were practised on the unsuspecting,
and were contrived to produce on them the effect of supernatural
revelations. Such is the story of Bel and the Dragon in the book of
Apocrypha, where the priests daily placed before the idol twelve
measures of flour, and forty sheep, and six vessels of wine,
pretending that the idol consumed all these provisions, when in fact
they entered the temple by night, by a door under the altar, and
removed them.