Everyone's talking about two tombs just discovered in Saqqara, which is just south of Cairo in Egypt. The tombs are about 4300 years old, and date from the time of Unas, who was the last king of the 5th Dynasty. The contents of the tombs have long since been stolen but hieroglyphics at the entrances show that they belonged to two high officials - a woman who was in charge of music and entertainment for the pharaohs, and a man responsible for the quarries that supplied the stone for nearby pyramids.
The BBC has a nice video showing the tombs, with commentary from Zahi Hawass, head of Egypt's antiquities authority. The tombs themselves aren't particularly stunning but archaeologists are excited because they were found in a little-explored area of Saqqara, and their presence suggests that the necropolis there could be much larger than thought.
Meanwhile a fascinating paper to be published in next month's issue of Tunnelling and Underground Space Technology suggests that the ancient Egyptian tomb diggers must have had a sophisticated understanding of natural ventilation techniques. It's by Don Gribble, a student at Carleton University in Ontario, Canada, and he focuses on tombs dug during the New Kingdom (1570-1070 BC) in the Valley of the Kings, which is hidden in the mountains on the west bank of the Nile, 900 km south of Cairo.
Many of these tombs were dug as corridors into the mountain, with only one opening that served as both entrance and exit. The most impressive tomb found so far, called KV5, was built for the sons of Ramses II. It houses up to 150 underground chambers, and stretches more than 200 metres into the mountain. Archaeologist Kent Weeks surveyed it in 2006 as part of the Theban Mapping Project and found something puzzling: part of the floor of the central chamber had been lowered during the tomb's construction, and later raised again to the original level. Why?
Gribble thinks he has the answer. He points out that because the tombs had only one opening, ventilation would have been a huge problem for the tomb builders. He estimates that a medium size tomb of 500 cubic metres would contain enough air to support 35 workers for just eight hours. Unless the air could be refreshed, they would be forced to stop digging... or die of suffocation.
Luckily the conditions in this part of Egypt are just right for natural ventilation. The air temperature drops dramatically at night, causing a draught of cool air to flow into a tomb, flushing out stale air and dust and replacing it with fresh air. Gribble thinks the alterations to the floor of KV5 show that the Egyptians understood this and used it to their advantage.
KV5 is unique because it has two corridors that point backwards under the entrance, as well as areas that progress forwards into the mountain (you can see plans of the tomb plus a video here). With the chamber floor at its original level, cool air would have flowed forward into the tomb each night, but not into the backwards-pointing corridors. By lowering part of the floor, the workers created a wall that would have acted as a barrier and deflected the cool air into this lower part of the tomb. Once they were done with these corridors, they replaced the floor.
It's a lovely theory. At the moment there's no direct evidence for it, but Gribble suggests that archaeologists could analyse other tombs in the valley with this approach in mind. He also wonders whether any words exist in the ancient Egyptian language to describe this nightly airflow - something like "tomb breath", "living (breathing) rock" or "breath of the tomb Gods". Does anyone know?