杏吧原创

FEDERICO CESI was passionate about nature. Animal, vegetable or
mineral鈥攈e wanted to make sense of the whole of creation. In the early
17th century, this wasn鈥檛 the ideal career for a member of one of Rome鈥檚
aristocratic families with close links to the Church. Cesi鈥檚 father, the Duke of
Acquasparta, was bitterly opposed to it. Cesi carried on regardless. But while
nature was always fascinating, it could also be baffling. As Cesi wandered
around his estates, he was puzzled by one of nature鈥檚 more peculiar products:
the fossilised remains of a forest.

What was he to make of the great 鈥渓ogs鈥� he saw sticking out of the hillside?
Some were massive. Cesi needed eight pairs of oxen to pull one particular
specimen from the ground. But there were smaller pieces too. Some were gnarled
and knotty and looked just like the wood of living trees鈥� except the knots
were filled with metal. And some were clearly stone鈥攂ut with the wavy
growth rings and grain of wood.

Cesi鈥檚 interest in the strange chunks of stony and glittery 鈥渨ood鈥� went
further than simple curiosity. In 1603, when he was just 18, Cesi persuaded a
group of eminent scholars to join him in forming Europe鈥檚 first scientific
society, the Accademia dei Lincei. Cesi and his friends aimed to classify the
natural world. They observed and examined, made notes and commissioned artists
to draw everything they saw. Mythical monsters and fabulous beasts were out:
Cesi and his fellow scholars believed only what they had seen themselves.

But sometimes they saw things that were hard to fathom. Cesi was especially
curious about things that didn鈥檛 fit easily into the usual categories, like the
strange 鈥渨oods鈥� he found on his land. From his letters, it鈥檚 clear that Cesi
entertained the notion that the fossil woods had once been part of living trees.
But the prince died in 1630, aged only 45鈥攁nd before he had the chance to
write up his research.

Seven years later, Cesi鈥檚 friend Francesco Stelluti wrote a short treatise
based on the prince鈥檚 findings. 鈥淭he wood is not generated from the seed or root
of any plant whatsoever, but only from a type of earth, containing much clay,
which is slowly transformed into wood,鈥� he wrote.

Historians have suggested that Stelluti wrote what he thought would be
acceptable to the Church. He made sure that Cesi reached the 鈥渞ight鈥�
conclusion鈥攐ne that wouldn鈥檛 call into question the Bible鈥檚 account of the
Creation. By this time, Galileo, who had joined the Academy in 1611, had been
tried by the Inquisition and found guilty of heresy. The society had to tread
carefully.

According to Stelluti, Cesi reasoned that the great 鈥渓ogs鈥� couldn鈥檛 have come
from trees because such giant trees simply didn鈥檛 exist. Nor did these logs
stand upright like trees, but always lay horizontally. They were so heavy they
could never grow upright. And if all that weren鈥檛 proof enough, there was one
fact that clinched it. When a lump of damp earth was kept in a room at Cesi鈥檚
palace 鈥渋t was found after some months to be wholly converted into wood鈥�. As the
clay dried out, it must have cracked and dropped off, exposing a piece of fossil
wood. Cesi was so amazed by this, wrote Stelluti, that he 鈥渉ad no doubt
whatsoever that the earth is the seed and mother of this wood鈥�.

With Cesi dead and Galileo under house arrest, the academy fizzled out. One
member, Cassiano dal Pozzo, preserved Cesi鈥檚 pictures of fossils as part of his
鈥淧aper Museum鈥�, a vast collection of paintings and drawings of antiquities,
architecture and natural history. Eventually, the collection was broken up. The
fossil drawings found their way to England and into the collections of George
III, and are now in the Royal Library at Windsor.

Almost four centuries after Cesi鈥檚 pioneering study, Andrew Scott, a
palaeobotanist at Royal Holloway, University of London, began to doubt that
Cesi鈥攐r Stelluti鈥攈ad pandered to the Church. They simply got it
wrong鈥攂ecause all the evidence suggested they were right. To find out why
Cesi was fooled by his fossils, Scott needed to see more than just the drawings.
He decided to go to Acquasparta himself to repeat some of Cesi鈥檚 field
studies.

Scott started at Dunarobba, where part of a fossilised forest had been
uncovered in 1980 during excavations for clay. The tree stumps at Dunarobba are
huge鈥攗p to 10 metres tall and 8 metres around鈥攁nd stand upright.
Although Cesi collected fragments of fossil wood at Dunarobba, he had never seen
these stumps or he would almost certainly have made the connection between the
fossils and living trees. Armed with Cesi鈥檚 field sketches, some of his letters
and an old map, Scott identified several other sites where the prince had been
collecting.

The fossils around Acquasparta are confusing even for a modern expert. In
just one small area, Cesi would have found lumps of wood going through a whole
range of fossilisation processes. Scott found specimens that were hardly
altered, while others were perfused with various mineral-rich fluids鈥攊ron
carbonates, pyrites and different-coloured oxides, or sometimes fluids rich in
calcium. Some fossils were completely petrified. Even more confusingly, a few
were woody at one end and stony at the other. If you knew nothing about the
various processes of fossilisation, then you would have a hard time deciding
whether this was wood being turned to stone or stone turning into wood.

Two million years ago, the region around Acquasparta lay at the edge of a
great lake. The climate was semi-tropical and forests fringed the swampy margins
of the lake. Most of the trees were Glyptostrobus, the Chinese swamp
cypress which today grows only in southern China and North Vietnam. When the
water level in the lake rose, the forest drowned.

Some of the trees turned to brown coal, which occasionally caught fire. This
accounts for Cesi鈥檚 reports of underground fires which went on burning for many
years. Many of the trees were fossilised鈥攂ut by so many different
processes, scientists are still trying to unravel what鈥檚 going on. In Cesi鈥檚
day, no one in Europe could have imagined such a landscape existed, with trees
of such huge height and girth, nor that their 鈥渨oods鈥� were millions of years
old. Cesi reached his conclusions for perfectly logical reasons, says Scott.
鈥淏ut it was also extremely convenient. If the evidence had shouted out that
these things had once been living, he would have been in trouble.鈥�