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CHINA to modernize it. Annals recount how he abol- ished the feudal system, built roads to China’s Archaeologists Seek New Clues to the far corners, and standardized weights, meas- ures, and handwriting. During his reign, hun- Riddle of Emperor Qin’s Terra-Cotta Army dreds of thousands of laborers erected much of the Great Wall and scores of palaces. Legend XI’AN, CHINA—In life, he subdued China’s war- has it that in his 40s, the emperor grew obsessed ring states and became the country’s first Searching for answers. with death and searched for an elixir of immor- emperor. In death, he brought an army to Xu Weihong hopes to tality. But he failed to even attain old age: Qin unearth artifacts heaven to perpetuate his rule. Since the stun- more illuminating died when he was 50. In the power vacuum that ning discovery of Emperor Qin Shihuang’s than yet more followed, rival armies vied for control of the tombs 35 years ago, archaeologists have soldiers. empire. The victor was Liu Bang, founder of unearthed about 1300 life-size terra-cotta sol- the Han Dynasty. diers and horses and a wealth of other artifacts Soon after Qin took power, he began prepar- that illuminate the brief but world-changing ing for the afterlife. Construction of his mau- Qin Dynasty 2200 years ago. Last month at the soleum at Mount Li, 35 kilometers east of renowned site, archaeologists began the latest Xi’an, took 38 years. The mausoleum, once round of excavation in a pit untouched for evidence is not decisive. “The larger question crowned with pavilions, was never a secret, and 2 decades. They hope to penetrate lingering of the significance and purpose of burying even today it is visible as a kilometer-long puzzles about the Qin Dynasty, and they will life-size replicas of Qin soldiers remains, in my wooded mound that rises a gentle 75 meters test a new method of preserving the terra-cotta opinion, largely unanswered,” says Jeffrey above the surrounding land. warriors’exquisitely perishable hues. Riegel, an East Asia scholar at the University Nearby, one of ’s greatest sur- Perhaps the biggest mystery is why Qin led of Sydney in Australia. prises lay hidden for centuries. In March 1974, an army into the afterlife. “We’ve never found Contemporary accounts paint a broad- farmers digging a well discovered pottery frag- anything like it in the tombs of earlier kings,” brush view of Qin Shihuang’s life. Born in ments about 1.5 kilometers east of the mau- on August 2, 2010 says the excavation’s executive director, 259 B.C.E., the future emperor, Ying Zheng, soleum. Excavations revealed the smashed-up archaeologist Xu Weihong of the Museum of ascended to the throne of Qin State when he remains of Qin’s terra-cotta army—8000 clay the Terracotta Warriors and Horses of Emperor was 13. Nine years later a regent ceded him soldiers and horses, researchers estimate— Qin Shihuang here. There are several theories, power, and the young monarch was soon tested arrayed in three vast pits. including a popular one that Qin believed his by internal revolt. Ying pacified Qin and then Over the centuries, fire and floods bled army would awaken and empower him in the proceeded to conquer China’s other six states. many warriors of their original colors. Past spirit world. Supporting that idea, archaeolo- He proclaimed himself emperor and took the excavations unearthed some figures with intact

gists have uncovered only real weapons—no name Qin Shihuang in 221 B.C.E. paint, but within minutes after exposure to air, www.sciencemag.org facsimiles—interred with the soldiers. But the After unifying China, Qin Shihuang set out the paint would peel off and reveal the dull-gray

PALEOANTHROPOLOGY “I strongly support new excavations,” says paleoanthropologist Russell L. Ciochon of Still Seeking the University of Iowa in Iowa City. “For too many years, has been treated ZHOUKOUDIAN, CHINA—On a sweltering late (IVPP) in Beijing who more as a shrine rather than a valuable paleo- Downloaded from June day, Zhang Xiaoling hunches under a just earned her Ph.D., is grinning from ear to anthropological site.” makeshift canvas roof over one of Asia’s most ear. “I think we’ll find something soon,” she Peking Man (now called Beijing Man in famous Stone Age sites. It’s roasting in the says. “I’m so excited.” Chinese) has a storied history. European sci- shelter, but Zhang, a stone-tools specialist at Last week, work commenced on a new entists discovered a few ancient teeth here at the Institute of Vertebrate Paleontology and excavation here in the cave-riddled hills of Dragon Bone Hill in the 1920s before archae- Zhoukoudian, 50 kilometers ologist Pei Wenzhong made a stunning find in southwest of Beijing, where 1929: a nearly complete skull. Up until the early last century scientists dis- Japanese invasion in 1937, Pei and others covered Peking Man: a trove of unearthed some 200 bones, including five Homo erectus fossils as well as more partial skulls—all of which vanished rudimentary tools and the bones during World War II—and thousands of of woolly rhinos and other Ice pieces of worked stone. In a paper last March Age fauna. The new dig aims to in Nature, IVPP Vice-Director Gao Xing and both stabilize the iconic site and colleagues used the ratio of aluminum-26 and unearth evidence that could beryllium-10 in quartz crystals to date the influence simmering debates, Peking Man strata to 680,000 to 780,000 Perilous perch. The excavation such as whether Peking Man years old, about 200,000 years older than pre- will take place at the edge of an was a hunter or a scavenger and viously thought.

unstable 40-meter-high cliff. whether the hominin tamed fire. The new excavation is in a 20-square- CREDITS: R. STONE/ SCIENCE

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Everlasting army. Pieced-together terra-cotta warriors on display at Pit 1.

have evaporated out, and a poly- methacrylate dispersion helps keep the lacquer adhered to the clay. In a second technique, a compound called Plex 6801-3, a sealant for sewage pipes contain- ing 2-hydroxy ethyl methacrylate, works its way into the lacquer and is hardened by electron beam irra- diation. But preventing the terra- cotta warriors’colors from fading remains a major challenge, inde- pendent experts say. After reviewing the new methodology, the State Adminis- fired clay. The loss was more than aesthetic. For and malachite, for the pigments. The much- tration of Cultural Heritage certified the example, one warrior’s face was different from admired “Han purple,” they found, is a mixture museum to resume excavations. The museum the rest: Instead of the usual cream-colored pig- of barium copper silicate and a dash of is going it alone, having ditched its earlier ments, it was painted a garish green. “We think cinnabar. Pigments were applied after fired fig- partner, the Shaanxi Institute of Archaeology. he was a kind of wizard meant to terrify the ures were glazed with two layers of qi lacquer. (A Qin expert formerly with the institute enemy,” says Rong Bo, an analytical chemist The collaborators also figured out why the war- declined to speak with Science.) The new dig and conservation scientist at the museum. riors have a bad case of peeling: Xi’an’s bone- at the UNESCO World Heritage site is attract- on August 2, 2010 Because such tantalizing clues flaked off dry air shrinks the lacquer. ing intense scrutiny from authorities and the before their eyes, archaeologists sharply lim- Hoping to prevent shrinkage, scientists tried public. “We feel a heavy responsibility on our ited further excavations. every off-the-shelf adhesive they could lay their shoulders,” says Xu. In the meantime, Rong and others set out to hands on. Nothing worked. “It was so frustrat- Work is now under way at Pit 1, the biggest crack the riddle of the brittle pigments. Work- ing,” says Rong. Finally, they hit upon two solu- of the three and until last month undisturbed ing with experts from the Bavarian State Con- tions. One employs polyethylene glycol (PEG), (apart from hosting millions of tourists) since servation Office in Germany, the museum used in everything from laxatives to skin 1986. By the end of the year, 200 square meters

researchers determined that Qin artisans creams. Short-chain PEGs penetrate the lac- will be excavated; the plan is to complete 2000 www.sciencemag.org ground up semiprecious stones, such as azurite quer’s tiny pores, replacing water that would square meters in 5 years. Workers frequently sprinkle water on the soil to protect relics. Xu’s aim is not to raise the tally of disinterred war- meter section of the western end of Site 1, fashioning tools. Researchers also hope to riors but to find artifacts that could help where remains of some 40 H. erectus individ- examine stone tools in situ. A better under- researchers understand Qin funerary practices. uals have been unearthed. One objective is to standing of the timeline of hominin occupa- “Digging up more soldiers is not in the least bit stabilize the site, perched on tion “may be more impor- interesting,” she insists. “They really provide the edge of a cliff and at risk of tant than the discovery of little information about that time.” Downloaded from collapse, says Gao, the project isolated fossils,” Gao says. Soon after the Qin Dynasty fell, annals say, leader. The first 2 months will Excavations will con- the king of Chu State raided the tombs and be spent removing a hazardous tinue through October. torched their wooden rafters. His forces also outcropping. Team members Outside the glare of that razed the palaces and pavilions around the will be roped like mountain spotlight, Gao and others mausoleum but evidently failed to penetrate climbers. “It’s very dangerous are planning field surveys the mausoleum’s inner sanctums. Annals tell to work here,” Gao says. and excavations at localities of treasures there that would make King Gao is downplaying expec- across China under a 5-year, Tutankhamen look like a pauper, including a tations of what he describes as $2 million project funded by ceiling studded with jewels representing celes- a salvage archaeology opera- the science ministry. Gao is tial bodies and flowing “rivers of mercury” rep- tion. The biggest prize, he Under no illusions. Finding a eyeing one site in particular: resenting China’s great rivers. Archaeologists says, would be a skull: It would skull would be sheer luck, says a cave in Jianshi in central have peered inside with equipment such as be “sheer luck” to find one, he Gao Xing. China’s Hubei Province, ground-penetrating radar and have measured says. Only casts remain of the dating to more 1 million intriguingly high mercury levels in the soil. But missing skulls. Gao says he would be happy years ago. “It has great potential” to yield the heritage administration forbids any digging with a jawbone, which could clarify evolu- H. erectus fossils, he says. Of course, they at the mausoleum, and Xu insists she’s not curi- tionary relationships with other hominin would have to be especially dazzling to ous. “Not in 100 years will it be opened,” she subspecies, or finger bones, which could nudge Zhoukoudian and Peking Man off says. Rong, looking on, smiles. “I’m curious,”

CREDITS: R. STONE/ SCIENCE shed light on Peking Man’s dexterity for center stage. –RICHARD STONE he says. “But we have to leave something for future generations.” –RICHARD STONE

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