certain places were in direct communication with the lower world. This
was the case at Cumæ where Æneas consulted the Sybil, and at Colonus;
while at Hierapolis in Phrygia there was a famous "Plutonium," which
could only be safely approached by the priests of Cybele.[50] It was
situated under a temple of Apollo, a real entrance to Hades; and it is
doubtless to this that Cicero refers when he speaks of the deadly
"Plutonia" he had seen in Asia.[51] These "Plutonia" or "Charonia" are,
in fact, places where mephitic vapours exist, like the Grotto del Cane
and other spots in the neighbourhood of Naples and Pozzuoli. The priests
must either have become used to the fumes, or have learnt some means of
counteracting them; otherwise their lives can hardly have been more
pleasant than that of the unfortunate dog which used to be exhibited in
the Naples grotto, though the control of these very realistic entrances
to the kingdom of Pluto must have been a very profitable business, well
worth a little personal inconvenience. Others are mentioned by Strabo at
Magnesia and Myus,[52] and there was one at Cyllene, in Arcadia.

In addition to these there were numerous special temples or places where
the souls of the dead, which were universally thought to possess a
knowledge of the future, could be called up and consulted--e.g., the
temple at Phigalia, in Arcadia, used by Pausanias, the Spartan
commander;[53] or the [Greek: nekyomanteion], the oracle of the dead, by
the River Acheron, in Threspotia, to which Periander, the famous tyrant
of Corinth, had recourse;[54] and it was here, according to Pausanias,
that Orpheus went down to the lower world in search of Eurydice.

Lucian[55] tells us that it was only with Pluto's permission that the
dead could return to life, and they were invariably accompanied by
Mercury. Consequently, both these gods were regularly invoked in the
prayers and spells used on such occasions. Only the souls of those