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Mapping the Treasures
by Colin Clement
For many years, tales were told in Alexandria of fabulous statues and
engraved blocks that were littered across the seafloor just outside the
eastern harbor, but the area was a military zone—off-limits to
scientific investigation. All that changed in the fall of 1994, when a team
of archaeologists started to explore the area in earnest. (To learn more
about what has been found, watch the NOVA program "Treasures of the Sunken
City" or read our interview with archaeologist Jean Yves
Empereur.)
As with any archaeological site, the plotting of a detailed and accurate
map of the mass of ruins is a necessary first step to figuring out what one
has actually found. And in this case, the very nature of the underwater
site precluded the possibility of returning day after day in whatever
| Diver attaching lead line to corner of block.
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weather to have a look at the site. The map making has been a major
undertaking, for two main reasons. First, the field of ruins under
examination extends over 5.5 acres, making it one of the largest
underwater archaeological sites in the Mediterranean. To further complicate
matters, the pieces often lie on top of each other; in some areas there
were veritable hillocks of blocks. In order to map the site effectively,
the team set about to create a giant and detailed database, the likes of
which has never been used in archaeology before.
The team began by establishing a fixed position Electronic Distance
Measurement station (EDM)—effectively, an electronic theodolite—on
the shore. This is used to "spot" the underwater blocks, which are
indicated by a reflector mounted upon a floating mast. The mast is
connected to a lead line that in turn is placed against the four corners of
the submerged block and held in position by a diver. Another diver, on the
surface, ensures that the correct tension is maintained and that the
floating mast doesn't move too much. This technique was accurate to between 4 and 12 inches, depending on sea conditions, and was the sole option given
the need to relate the underwater site to other archaeological sites on land in
Alexandria.
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Diver holding mapping line steady at surface.
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At the end of each day's dive, the information stored in the memory of the
EDM is imported into computers by means of a specialist topography
software, called Caltop, which was designed in France. This permits the
plotting of the general map of the site, and it also means that partial
charts can be given to the divers the following day to help orientate them
underwater and to allow the divers to plot and sketch complementary
features of the blocks. (The divers are able to draw underwater using
synthetic calque paper and plastic lead pencils.)
This rapid, 24-hour turnaround in what began as an experimental
method has contributed enormously to the progress of the excavation. It
also seems clear that this technique can now be applied to other underwater
sites around the world. In theory, it doesn't matter how far underwater the
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Diver stretching measuring tape across block
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archaeological site is, as long as calm conditions prevail. The only
constraint is the distance of the site from the shore, because the EDM has
an effective radius of about one and a quarter miles. However, the majority of
underwater archaeological sites are usually within this distance.
Two other methods are used to map the site: triangulation, using several
permanently fixed underwater reference markers; and the Global Positioning
System (GPS). The expedition was fortunate enough to be loaned a
state-of-the-art GPS (accurate to within one centimeter, or 0.4 inches) by the Swiss
company Leica. When this GPS device is mounted on a rubber dinghy and
combined with a sonar device, it gives an exact reading of the contours of
the seabed. This information is particularly relevant in analyzing the
formation of the site, given the strong possibility that part of what is
now the seabed was dry land in antiquity.
The mass of data accumulated over almost ten months of diving has all gone
into a giant computerized database. Three types of information on each
registered block—written, drawn, photo and/or film—has been recorded
and can be combined to produce either on-screen or hard copy identification
sheets. The addition of extensive photography and video film, which can be
paused and rewound, makes the site much easier to study, since the blocks
themselves are underwater. Furthermore, a simple click on any individual
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Divers record the position and size of blocks, columns, and statues.
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element on the map can bring up the relevant block identification sheet.
The system can also respond to specific demands to plot only those blocks
corresponding to certain criteria (form, volume, orientation, material,
etc.). For example, at the push of a button, the computer will bring on
screen a map of only those blocks identified as columns, or statuary, or
those over a certain weight.
The creation of the block identification sheets has made it possible to
define the type of blocks discovered and to develop a terminology. In
architecture, terminology is linked to the function of a block in the
construction—a lintel is only so-called because it serves as a lintel—but here we are dealing with an essentially unknown construction or
constructions and the majority of elements are lying completely out of
context. The new terminology that is being established must ignore the idea
of function and look, instead, at four criteria: form, dimension, volume,
and decoration. Obviously, this very activity brings blocks together into
identifiable groups and is the first step on the road to interpretation.
What the database has already made clear is that the site is made up mostly
of materials that have been recycled or pillaged, in the time-honored
Egyptian fashion, from pre-existing structures in the Nile Delta and at
Heliopolis. There are clear signs of the application of Graeco-Macedonian
technological savoir faire to thoroughly Egyptian architectural materials
(more than 90 percent of the blocks are of granite), and this juxtaposition,
in itself, will throw light upon the style and method of construction of
the Pharos lighthouse. In other words, it is likely that the Pharos was not
built in purely Greek style, because the Greeks had no experience of
building with granite and would have had to use local labor. On the other
hand, the Pharos would not have been purely Egyptian, because the Greeks
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Block with compass rose and identification number scratched by divers in algae covering.
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commissioned it. In addition, the significant amount of statuary discovered
and the evidence of other complete structures underwater could lead to a
new notion of the Pharos as part of a greater complex, and spur
interpretations as to its civic and or religious function.
Clearly, the architectural analysis of the Pharos site is still in its
infancy and presents a formidable challenge. The only blocks that can be
dated even approximately are those bearing decoration—moldings,
inscriptions, statuary, etc.—and there are relatively few of these. The
fact that the majority of the material has been recycled also presents a
challenge. Any masons' marks or traces of construction techniques could
either be from the original structure or from the building of the Pharos
itself.
In fact, before any architectural analysis can be definitively broached,
the long, painstaking, and at times tedious accumulation of data must be
completed. The 2,110 blocks recorded as of the end of June 1997 may comprise
the totality of the upper layers, but until access can be gained to what
lies beneath, the study of the site will not be complete. (It is anyone's
guess how many more artifacts have yet to be uncovered.) At the same time,
there is a need to polish and fine-tune the established database.
However, the aim of the game remains to produce hand-drawn and
computer-generated reconstitutions of architectural elements that now lie
in pieces on the bed of the Mediterranean Sea and to advance a clear
hypothesis as to the spatial arrangement of the site. Given enough time and
resources, this is indeed possible.
Colin Clement, originally from Edinburgh, Scotland, is a writer and
translator who has lived in Alexandria for the past eight years. Since 1994
he has been working closely with the Centre d'Etudes Alexandrines (Center
for Alexandrian Studies) researching, compiling and editing reports and
closely following the various archaeological excavations of the Centre.
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