Wednesday, 21 May 2014

New technology unwraps mummies’ secrets


“The public see ancient Egyptian mummies as Hollywood horror villains,” says John H Taylor, a curator at the British Museum specialising in ancient Egyptian funerary archaeology. “But we want to move away from [the notion of] the macabre ‘horror mummy’, to get back to the idea that these were once real, living people.”
Taylor and his colleague Daniel Antoine, the museum’s curator of physical anthropology, are standing in the middle of Ancient Lives, New Discoveries, a new exhibition that they have orchestrated together. Focusing on eight mummies from the museum’s collection, the exhibition employs cutting-edge technology to present fresh insights into what it would have been like to live and die beside the River Nile in ancient times. “From doing this,” Taylor says with a proud smile, “we have got to know these mummies more as individuals.”
To modern eyes, the statuary and funerary art of the ancient Egyptians can seem stiff and formal. “So we wanted to go behind the mask and discover more about the real Egyptians,” Antoine tells me. But seeing beyond the gilded faces of the anthropoid coffins presented the curators with tricky practical problems.
During the 19th Century, when ‘Egyptomania’ electrified Europe, mummies started to be considered less as grisly curiosities and more as important artefacts worthy of study. It became common practice to open their cases and unwrap them, sometimes in front of fee-paying audiences. Unfortunately  this had irreversible consequences, damaging the mummies for ever. So the British Museum took the decision not to unwrap mummies in the future. But without unwrapping or dissecting mummies, how could archaeologists ascertain what lay inside?
What lies beneath
In the 20th Century, the use of X-rays revealed new information about what the mummies contained – but the picture of what was hidden beneath the wrappings remained hazy and indistinct. Over the past two decades, archaeologists have brought the contents of mummies into crisper focus by using computerised tomography (CT) scanning.

Researchers at the British Museum use the latest technology to see beneath the mummies' wrapped exterior (British Museum)

But it is only in the last few years, with the advent of the latest generation of ‘dual-energy’ CT scanners, that they have been able to ‘visualise’ the interiors of mummies – virtually peeling away layers of wrappings, without causing any damage to the surface, to reveal the skull (and much else) beneath the skin. The results of this latest research, which also facilitates the careful dating of mummies for the first time, can be startling – as I discovered when I visited the British Museum.
“A CT scanner is a rotating X-ray machine that usually bombards one X-ray wavelength,” Antoine explains. “For three of the mummies [in the exhibition], we used a dual-energy CT scanner, which can be set at two different wavelengths. That allows you to capture in great detail both the thicker parts as well as very thin parts such as bandages, skin and soft tissue. As a result, we are seeing things now that even three years ago we wouldn’t have been able to see.”
A good example of this is the mummy of Tamut, a high-ranking priest’s daughter who lived in the early part of the 22nd Dynasty, perhaps about 900 BC. The mummy, which was discovered during the 19th Century, has been in the collection of the British Museum since 1891. Until now, though, nobody has been able to ‘see’ inside its elaborately painted case made of cartonnage (layers of linen soaked in glue), which contains Tamut’s mummified remains.
By subjecting the case to a dual-energy CT scan, Antoine and Taylor discovered various things about Tamut and how she was embalmed. For one,her hair was cut short, which suggests she wore a wig. For another, the arteries in her inner thighs were coated with fatty plaque deposits – a sign, perhaps, that she enjoyed a cholesterol-rich diet, and was thus at risk of cardiovascular disease. This is surprising, since we think of cardiovascular disease as a modern phenomenon. Moreover, like the other adult mummies in the exhibition, Tamut also suffered from terrible dental health. 
No-brainer
During the mummification process, her brain was extracted through her right nostril. Her fingernails and toenails were both covered with metal, perhaps gold leaf: “We weren’t expecting to find that,” Taylor says. “It links to an ancient Egyptian text that says you should put electrum [an alloy of silver and gold] on fingernails and toenails to convey new life, but that’s the first time I’ve actually seen it on a mummy.”
In addition, using sophisticated software that can visualise the data gathered by powerful CT scanners, it is possible to see a number of the magical objects that the embalmers placed on Tamut’s skin and inside her torso. These include artificial eyes, amulets, and four figurines of the so-called Sons of Horus, who were placed within the chest cavity in separate bundles containing parts of her internal organs.

The scans reveal keepsakes and trinkets wrapped up with the corpse (British Museum)

The data from the CT scan is so sensitive that it is possible to measure the density of these objects and make an informed guess about their composition. The figurines of the Sons of Horus, for example, were probably made of beeswax.
The mummy of Tamut is an exquisite example of the embalmer’s art. (It is arresting to reflect that by the time of the 22nd Dynasty, mummification had been common practice for thousands of years.) But the exhibition at the British Museum suggests that things did not always go according to plan. Inside the half-empty skull of the mummy of an anonymous man from Thebes who probably lived during the 26th Dynasty, around 600 BC, Antoine and Taylor discovered an unusual, thin implement, not unlike part of a flattened straw. This was a rare example of an embalmer’s tool.
“It seems that there was an accident during mummification,” Taylor explains. “They were using this probe up his nose to extract his brain, and apparently it snapped off and landed in the back of his skull, and they couldn’t retrieve it. They would have used a metal rod initially to break through the bones to get inside. But then they needed something more flexible. The CT scanner tells us that this object is less dense than wood, but denser than straw – probably something like a reed.” “Very few tools like this have been discovered archaeologically,” Antoine adds, “so it’s quite an insight to see how one of them would have been used.”
In order to remove the brain, Egyptian embalmers had to make a tiny hole in the skull, which they often reached via the nose. “In all of the embalmed mummies [in the exhibition], the hole is 2cm by 2cm, and the small, delicate bones inside the nasal cavity are intact,” Antoine explains. “So the embalmers were very precise: their knowledge of human anatomy was great.” He pauses. “Imagine the conditions they were working in. They didn’t have air-conditioned rooms, so they probably worked very rapidly to remove all these organs before the bodies started decaying.”
Walking through the British Museum, it is clear that technology has the potential to transform Egyptology. Take Tamut’s amulets: these remain intact and in situ, wrapped up inside her mummy. Yet thanks to advanced, non-invasive scientific approaches, their properties and placement can be explored and understood. “Amulets tend to be studied individually,” explains Taylor, “but nobody examines how they form a complete system or armoury around the body – that hasn’t been looked at before.”
“Without the science, we wouldn’t see anything that you see here,” adds Antoine, with conviction. “The museum hasn’t unwrapped mummies for more than 200 years, so the science is key to being able to discover more about them. Without it, we would just be left studying the bandages and cartonnage from the outside.

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