The heliotrope or bloodstone was supposed to impart a reddish hue to the water in which it was placed, so
that
when the rays of the sun fell upon the water they gave forth red
reflections. From this fancy was developed the strange exaggeration
that this stone had the power to turn the sun itself a blood-red, and
to cause thunder,
lightning, rain, and tempest. The old treatise of Dami-geron relates
this of the bloodstone, adding that it announced future events by
producing rain and by "audible
oracles. ' ' Probably the conjurors, before proceeding to use the
stone for their incantations, watched the heavens and waited until
they noticed the signs of an approaching storm. They then interpreted
