Bodrum, Turkey: The Marmalade Analogy
Modern Bodrum was ancient Halicarnassus, the place where a man named Mausolus built a great monument to himself, thus giving the ancient world one of its Seven Wonders and the modern world the word mausoleum. After the fall of Constantinople, the Knights of Rhodes captured Bodrum and used the Mausoleum as a quarry when they built what was to be the biggest and best castle ever, with the most up-to-date defences imaginable.
Unfortunately, just as they finished this project, which took decades, Rhodes itself fell to the Ottomans and the knights had to abandon all their holdings in the Eastern Mediterranean and retreat to Malta. So it was the Ottomans, not the Knights of Saint John, who got to make use of the best castle of its time.
Nowadays the Castle of St Peter houses the Bodrum Underwater Archaeological Museum (and the guides will hasten to inform you that the museum itself is not actually underwater although the artifacts it houses used to be). We were given a tour by the Director of the Museum, Tugba, and one of the conservators, Asaf; when they realized both how interested we were and how many scientists we had in our group (a retired chemist, a research biologist and a pathologist), they very kindly invited us back to their lab up on top of the hill after lunch. Tugba confessed that although the new lab facilities were wonderful, she missed one thing about having the conservation lab in the castle: it was no longer possible to run down a long stair to a little stony beach for a swim at lunchtime. The new facility, however, is very nice; there’s a garden in front where we were greeted by friendly stray dogs who had found a home and regular food there, and inside it’s very clean and bright and white, with a cool marble staircase leading down to the labs. As you can imagine, the wooden parts of a ship that went down, say 2600 years ago pose particular problems for conservation; the water preserves wood very well, but when you take it out, it’s more like a sponge than anything else, soggy and fragile.
To explain how you preserve bits of ancient ships, Asaf made one of the best analogies ever (and, as a teacher who often depends on analogies myself to make something alien and complicated seem familiar and simple, I know a good one when I hear one). To make waterlogged wood solid, you have to impregnate it with polyethylene glycol (PEG), which is a sort of water soluble wax. To do this, you put the wood in a vat of water, and you heat it up very slowly. As it heats, you add the PEG gradually. It’s just like making marmelade: the wood is the fruit, the water is the liquid that it cooks in, the PEG is the sugar you add to preserve the fruit. And then simmer. But if it takes half an hour or an hour to preserve your Seville oranges as marmalade, it can take three years to preserve your piece of ancient wood—three years during which that particular laboratory is like a sauna from the steam. Once it is preserved, however, you might be able to reconstruct an entire Bronze Age or Byzantine shipwreck.
And then it was down to the harbour and onto our boat, the heroic Arif Kaptan, where I was more than delighted to find that we had the same cabin as last time. So late in the day, we sailed the seas and came to the ancient city of Kos.