New Technology May Lead To Light- And Heat-Sensitive Tent

by Sean McLachlan on


The tent we’re all familiar with from camping trips may soon be old tech thanks to a new material designed by a team of Harvard scientists.

Researchers at the Wyss Institute for Biologically Inspired Engineering have announced in a press release that they’ve developed a flexible material that can shed or retain moisture, and turn from opaque to transparent.

You can see how it works in the image below. The material is a liquid-repellent film that coats, and is infused in, an elastic porous backing. Normally the surface is flat and will shed water, but when the backing is stretched it changes the size of the pores, causing the surface to become rough and retain droplets.

In its normal state the material is transparent, but when stretched it becomes opaque. The material could be used to make a tent that blocks light on a dry and sunny day, and becomes transparent and water-repellent on a dim, rainy day.

The material may also be used in products as diverse as contact lenses and water pipes.

Researchers were inspired by the function of tears, which block materials from damaging the eye, and flush out these materials, yet remain transparent. Such inspiration is typical of work at the Wyss Institute, which looks to nature to find solutions to technological problems.

Top image courtesy Krish Dulal. Bottom image courtesy Harvard University.

Egyptian Mummies Weren’t Given Enemas, Study Shows

by Sean McLachlan on


Ancient Egyptian mummies have been an object of fascination. The Greek historian Herodotus, who lived in the fifth century B.C., visited Egypt and wrote a description of the mummification process. Since no ancient Egyptian text survives, his account forms the basis of many descriptions in modern books and museum displays.

Now a new study by two Canadian scientists suggests Herodotus may have gotten it wrong.

Yahoo News reports that two of the key points in Herodotus’ account – that the internal organs were dissolved with cedar oil enemas and the heart was always left in place – don’t stand up to scientific scrutiny. Researchers have examined studies of 150 mummies and put seven through CT scans and found little evidence of cedar oil. Also, in three-quarters of the mummies the heart was missing.

Herodotus also said that the brains were removed with a hook pushed through the nose. The study shows brains in about a fifth of mummies.

So why did Herodotus get it wrong? The study’s coauthor Andrew Wade of the University of Western Ontario says mummification was a lucrative business and its secrets closely guarded. In other words, Herodotus was handed a line. Imagine a bunch of mummy makers drinking wine by the Nile after a busy day at the office and laughing about that clueless Greek who showed up asking questions. “Cedar oil enemas? Yeah, save that for the tourists!”

Another possibility is that the mummy makers cut corners. In many animal mummies, used as offerings to the gods, researchers found only partial skeletons or wrappings that contained nothing. Temples made lots of money selling animal mummies to the faithful, and they created fakes to increase profits.

The Michael C. Carlos Museum at Emory University has a longer account of Herodotus’ writings on mummification here. The study was published in the latest issue of HOMO: The Journal of Comparative Human Biology.

[Photo courtesy Wikimedia Commons]

The ‘Christopher Columbus Of China’ May Have Visited Kenya, A New Find Reveals

by Sean McLachlan on


An explorer from medieval China may have visited an island off the coast of Kenya, archaeologists say.

A joint expedition by The Field Museum and the University of Illinois at Chicago unearthed a 15th-century Chinese coin on the Kenyan island of Manda, according to a Field Museum press release. Starting around 200 A.D., Manda was a trading hub and home to an advanced civilization.

The coin, shown here, is an alloy of copper and silver and was issued by the Ming Emperor Yongle, who reigned from 1403-1425 A.D. The coin bears the emperor’s name.

Emperor Yongle sent Admiral Zheng He, also known as Cheng Ho, on an epic mission of exploration to find new trading partners. He traveled around the coasts of south and southeast Asia, east Africa as far north as Somalia, and the Arabian Peninsula.

“Zheng He was, in many ways, the Christopher Columbus of China,” said Dr. Kusimba, curator of African Anthropology at The Field Museum. “This finding is significant. We know Africa has always been connected to the rest of the world, but this coin opens a discussion about the relationship between China and Indian Ocean nations.”

Sadly, later Chinese rulers took a more insular policy and banned foreign expeditions. If they had continued Yongle’s work, the great Age of Exploration may have been more Chinese than European. Manda was mysteriously abandoned around 1430, shortly after Emperor Yongle’s death.

Chinese contact with east Africa has become a hot topic of research in recent years. Back in 2010, we reported that a DNA study found genetic links between China and Africa.

While the focus has been on Kenya, researchers might want to take a look at the city of Harar in Ethiopia, which has been a trading center for centuries. Some Hararis have vaguely Chinese features, and Harari coins have been found in China. When I was doing research there some Hararis told me that the city used to trade with China many centuries ago.

In the nearby early medieval settlement of Harla, which may have been the predecessor to Harar, farmers have uncovered two Chinese coins dated to 1040 and 1080 A.D.

[Photo courtesy John Weinstein/The Field Museum]

London Crossrail Project Unearths Black Death Burial Pit

by Sean McLachlan on

“Bring out your dead!”

If you lived in London in 1348-50, you’d hear that call a lot. All of Europe was swept with the Black Death, a virulent plague that killed an estimated one-third of the population. London, like other congested urban areas, got hit hard.

Now archaeologists working in London have uncovered a mass grave of Black Death victims, a Crossrail press release reports. Digging ahead of the planned London Crossrail transportation project, the team discovered a mass grave of 13 bodies at Charterhouse Square, an area known as a burial ground during the plague. Pottery from the mid-14th century found at the site helps confirm the identification.

The bodies were laid out neatly in rows, hinting that the burial ground was from the early stages of the Black Death. When the plague was going full force, bodies were simply dumped into giant pits.

Now archaeologists are examining the bones to learn more about how the people lived, including diet, physical health and work-related wear and tear on the body. They also hope to find surviving DNA from the plague to give scientists a better idea of how it developed. Researchers stress that the plague bacteria cannot live for long in the soil and the excavation poses no health risk.

This is only the latest in a series of finds by the Crossrail workers. Earlier we reported on their discovery of a 3,500-year-old Bronze Age trackway. The Crossrail project is a high-speed train system that will link 37 stations along 73 miles of track through London. It’s due to open in 2018.

Sadly, the 14th century plague was only the first wave of a persistent contagion. The Black Death returned to London several times, the worst being in 1665-6, when it killed 100,000 Londoners.

[Photo courtesy Wikimedia Commons]

Fabled Sunstone Discovered In English Shipwreck

by Sean McLachlan on


A team of French archaeologists believe they have found a sunstone, a strange crystal that was said to help mariners locate the sun even on overcast days.

Some of the medieval Norse Sagas mention this device. In “Rauðúlfs þáttr,” King Olaf asks the hero Sigurður to point out the sun in the middle of a snowstorm. Sigurður points to where it is behind the gray sky. To test him, the king had a follower “fetch the sunstone and held it up and saw where light radiated from the stone and thus directly verified Sigurður’s prediction.”

One recent study suggests the “sunstone” was a double-refracting crystal, which allows light through when the light is polarized in certain directions. They brighten or darken depending on the polarization of the light behind it. Clouds block the sun’s visible light but let through a concentration of polarized light that can be detected by the crystal as it’s moved around. Double-refracting crystals such as cordierite, tourmaline and calcite are common in Scandinavia.

Some scholars have expressed doubts about the sunstone’s existence because “Rauðúlfs þáttr” is a highly allegorical tale full of magical events.

Now it appears the tale may not be all that fantastic after all. Archaeologists from the University of Rennes have been studying finds from a British ship that sunk in 1592 near the island of Alderney in the English Channel. They found a rectangular block of Iceland spar calcite crystal, a type known for its double-refracting properties. The crystal was found next to a pair of dividers that may have been used for navigation.

The researchers suggest that their discovery shows the use of sunstones lasted well beyond the Viking era.

The team’s results appear in the latest issue of the “Proceedings of the Royal Society.”

[Photo courtesy Alderney Society Museum]