The 1665 3rd Edition of Reginald Scot's Discoverie of Witchcraft has
Appendices that are not by Scot which were influential on British
magical practice down into the 19th Century. A woodcut shows magicians
in front of a volcano. The image is to be drawn outside the magic circle
in a ceremony to obtain an infernal familiar. Elsewhere there are
references to volcanos near Iceland where fiery and aerial spirits meet
Basically people saw volcanos and thought they were probably looking at
infernal regions touching the material world.
There are also references to the troublesome spirits found in caves and
mines, which were likewise seen as gateways into other realms points of
ingress for denizens of these other realms.
Incidentally I have reprinted these appendices, details can be found on
my website below.
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