CONSIDERED to be the voice of the god Apollo, the Oracle at Delphi foretold
the fates of kings and nations. The rulers of Greece, Persia and the Roman
Empire made the arduous journey to the Temple of Apollo, situated above the Gulf
of Corinth, in order to seek divine guidance on everything from wars and
government to their love lives.
But now scientists believe they have unpicked the secret of the Oracle鈥檚
mysterious pronouncements鈥攁nd their explanation threatens to dispel any
spiritual delusions. They say these pilgrims heard nothing more than delirious
ravings from the ancient equivalent of a glue-sniffer. They might just as well
have trawled the local tavernas and sought the wisdom of the drunks of
Delphi.
This news would have come as quite a blow to the ancient world. The area
around Delphi was settled in about 1600 BC, during the Bronze Age, and a shrine
was constructed soon after in the name of the Earth goddess Gaia. According to
legend, Zeus鈥檚 son Apollo took over the shrine when he slew the serpent-god
Python. Apollo then learned the art of prophecy from the wily Pan, and pressed
the shrine鈥檚 priestess鈥攖he Pythoness, or Pythia鈥攊nto his own
service. She became Apollo鈥檚 mouthpiece, and for nearly two thousand years the
site of the Delphic Oracle was a sacred place.
Advertisement
The oracle drew many visitors, who didn鈥檛 always like what they heard. Young
Oedipus was banished with the words: 鈥淎way from the shrine, wretch! You will
kill your father and marry your mother!鈥� And acting on the Oracle鈥檚 advice,
Alcmaeon of Argos murdered his mother, while Thyestes, grandson of Tantalus,
conceived a child by his own daughter. Clearly, the word of Apollo spoke louder
than social convention.
Visitors to the shrine found themselves at an imposing site. The Temple of
Apollo sits on a shelf on the slopes of Mount Parnassus, about half a kilometre
from the city of Delphi
(see Diagram, p 42). The main temple building, a classic
rectangular structure with a colonnade, occupies the centre of a walled
sanctuary. But perhaps the most crucial part of the temple lies hidden below the
floor.
Here there is a small, unpaved chamber called the adytum. To commune with the
god, the Pythia entered the adytum and fell into a trance-like state. The
ancient Greek writers were quite explicit about what this entailed. The Pythia
sat on a tripod and inhaled the fumes, or 鈥減neuma鈥�, coming either from a crack
in the ground鈥攆irst mentioned in 458 BC by the Athenian playwright
Aeschylus鈥攐r from the waters of a natural spring. By the time she left the
adytum, the Pythia was often semi-delirious, only just able to understand and
answer the questions of her visitors.
The Greek writer Plutarch, a long-serving priest of Apollo at Delphi,
believed that the vapours inhaled by the Pythia were a geological phenomenon,
coming from deep within the ground. This seems to make sense, since the Gulf of
Corinth is riddled with faults. Yet when the temple was excavated by French
archaeologists in the late 19th century, they found no sign of any 鈥渟acred
chasm鈥�, or of gases emanating from the Earth. They concluded that accounts like
Plutarch鈥檚 were based on nothing more than myth.
鈥淓ver since 1904, when an English scholar A. E. Opp茅 published an
influential article, opinion has been that the ancient tradition was either a
myth, a mistake or a deliberate fraud,鈥� says archaeologist John Hale of the
University of Louisville, Kentucky.
Many people came to believe that the gases were instead emitted from a nearby
cleft鈥攏ot actually in the temple鈥攁nd that the phenomenon had become
wrongly associated with the shrine in people鈥檚 minds. Opp茅 believed they
were thinking of the Kastalia gorge to the east, while others proposed the
Corycian cave north of Delphi, or the gorge of the River Pleistos. And last
year, Italian geologist Luigi Piccardi of the department of earth sciences at
the University of Florence proposed that the pneuma might have issued from a
fissure at the Temple of Athena, about half a kilometre west of the Temple of
Apollo.
But new evidence has emerged that seems to prove Plutarch correct after all.
Hale, geologist Jelle de Boer of the Wesleyan University in Connecticut and
geochemist Jeffrey Chanton of Florida State University have been surveying the
area around the temple for the past six years, and have uncovered the first
strong evidence that the pneuma emerged either very close to the Temple of
Apollo, or actually inside it.
It was already known that a fault line, dubbed the Delphi Fault, runs
approximately east-west across the site. Because it has not slipped for a long
time, it is covered over with the detritus of erosion from the mountain slopes.
No wonder early archaeological surveys failed to see it.
But now Hale, de Boer and Chanton have revealed that the sacred site seems to
be picked out on geological maps by an auspicious X, where the Delphi Fault
intersects a second, previously unknown fault running from north to south
(Geology, vol 29, p 707). The team have christened this rift the Kerna Fault
because it crosses the Kerna spring which lies about 60 metres north-west of the
sanctuary. They cannot say exactly where the Kerna and Delphi faults cross one
another, but their projections suggest that they meet right below the Temple of
Apollo.
This intersection probably weakened the mountainside, triggering landslides
that formed the spectacular ledge on which the temple sits, says de Boer. The
faults leave the rocky ground laced with cracks, allowing groundwater to rise up
from below. Only two springs still flow鈥擪erna and Kastalia, which lies 100
metres east of the temple鈥攂ut there is geological and archaeological
evidence for several more. The ancient Greek writer Pausanias, for example,
describes a spring on the slopes near the temple whose waters ran into the inner
sanctum. He claims that the Pythia鈥檚 prophecies were inspired by drinking this
water.
What鈥檚 more, one of the walls around the temple is covered with deposits of
the carbonate mineral travertine, which is formed by hydrothermal activity.
Travertine also coats the Kerna spring. The researchers believe that water from
the ancient springs reached the surface still warm from deep in the Earth鈥檚
crust, and rich in dissolved carbonates from the limestone below.
When the team analysed the spring water and samples of the travertine, they
found traces of methane and ethane, along with other light hydrocarbon gases.
The concentration of dissolved gas seems to be particularly high near the
temple: the Kerna spring releases three times as much methane as the more
distant Kastalia spring.
The team has found one particularly intriguing chemical in the Kerna spring
water: ethylene. This is a gas that affects the human central nervous system and
produces sensations of light-headedness and euphoria. Ethylene was used as an
anaesthetic for surgery in the early 20th century. But Henry Spiller of the
Kentucky Regional Poison Center in Louisville, who is now working with de Boer
and his team, has shown that ethylene can cause more extreme reactions than
anaesthesia, including violent frenzies and delirium. In very high doses it can
be fatal.
All of this seems to fit with accounts of the Pythia鈥檚 behaviour during
pronouncements. Plutarch describes how a prophetess once died, presumably from
an overdose of the intoxicating fumes in the adytum. He also recounts that the
vapours had a sweet smell like perfume鈥攁 smell shared by ethylene.
It is not hard to see how hydrocarbon gases could be emitted from the faults
at Delphi. The limestone of the Pleistos Valley contains several strata that are
rich in deposits of oily bitumen. De Boer and his team say that seismic activity
in the area causes frictional heating of the rocks. This would vaporise the
lighter petrochemicals in the bitumen, and these gases could then escape through
the web of cracks in the rocks above.
If de Boer and his colleagues are right, what does this mean for the Delphic
Oracle? Prophecies and divinations have been made since the beginning of
recorded time, based on everything from the stars to chicken guts. These omens
may not be literally true, but they can mirror the culture鈥檚 undercurrents and
become a ritualistic way of bringing into the open the subconscious fears, hopes
and desires of those who seek such guidance. Who can deny that the Pythia鈥檚
advice was a catalyst for kings and heroes to act on their fantasies and
forebodings? What does it matter if she was high as a kite on natural gas?
