The Nanjing Belt July 9, 2011Posted by Beachcombing in : Ancient, Contemporary , trackback
Beachcombing always comes to China with a certain trepidation. After all, he doesn't have much Mandarin (i.e. absolutely zilch), he has an embarrassingly modest knowledge of Chinese historiography and yet he must admit to having nothing but fascination for the exotic flowers that grow in the swamps of the Chinese past – recent oriental posts have included manned kite flight and (alleged) Roman legionaries in ancient China. The danger, of course, is that the sirens pull you into the mud and before you know it the water’s pouring over the top of your Wellington boots. And how much worse that water feels when ‘China’ combines with another unknown like, say, ‘metallurgy’. Welcome, please, oh reader, the Nanjing Belt.
Beachcombing will quickly get the routine details out of the way. The Nanjing Belt was discovered in a tomb in 1952 around a skeleton. The tomb and the body dated to the Jin Dynasty that brings us back to the early centuries A.D (265-420) and luckily the name of the occupant was established through an inscription. He was one Zhou Chou (obit 297) who died fighting, of all people, the Tibetans.
So far so easy: belts and even britches are common in graves around the world from the mysterious dragon buckles of Late Roman mercenaries to the ceremonial belts of the Lords of the Maya. In fact, the problems only really began when the boffins got the belt off Zhou and back into a laboratory.
The belt included ‘about’ (?) twenty pieces of metal – which had presumably been attached to the now rotted leather – and four of these were made of almost pure aluminium. Aluminium it will be remembered does not appear alone in nature. It took Europeans till the early nineteenth century to understand how to isolate this useful substance and even then the aluminium that issued was far from pure.
Chinese historians were, understandably, bemused and something of a civil war broke out, not helped by the fact that the Cultural Revolution was on the horizon. If there was a resolution though before Mao’s guillotine came down it was that four pieces were, indeed, aluminium. The problem then was not metallurgical but rather archaeological: were they Jin Dynasty relics or had they been placed in the tomb in the nineteenth or twentieth centuries? If genuine, it goes without saying that you would need a merchant cash advance and possibly your life savings multiplied by three to get a sniff at these objects in an auction house.
This question was taken up in the west by three scholars – Butler, Glidewell and Pritchard – at St Andrew’s University who looked at the question in ‘Aluminium Objects from a Jin Dynasty Tomb – Can They Be Authentic?’ Interdisciplinary Science Reviews 11 (1986), 88-94.
The abstract sums up their work nicely:
Pieces of aluminium, supposedly parts of a set of belt ornaments, were found in a Jin dynasty (AD 265–420) tomb during excavations in the 1950s. The authenticity of these finds was questioned at the time in view of the technology required to isolate aluminium from its ore. In this review the archaeological and analytical evidence is reconsidered, but the matter remains unsettled, as it is known, from experimental evidence, that aluminium alloys can be prepared by the carbon reduction of alumina. Examination of the thermodynamic data for this process in terms of Ellingham diagrams demonstrates unequivocally that the temperature required for this process is greatly in excess of that possible with Jin dynasty technology, and so the finds cannot be authentic. However, it is quite possible that metallic objects containing small quantities of aluminium could have been produced in China at that time. The review ends with some speculation on how the pieces of aluminium came to be in the tomb.
Beachcombing need only add that the three end by suggesting that the aluminium had been included with the other belt fragments as a practical joke at the time of excavation, but that the joke got out of hand: memories of Anglo-Saxon Attitudes.
It is a reasonable solution and 'Butler, Glidewell and Pritchard, 1986' is now the conventional answer to the problem of the Nanjing Belt in west and east.
Beachcombing is a natural sceptic where aluminium before its time is on offer. But he is left slightly cold by the methodology in the St Andrews article. After all, the authors seem to go backwards, proving first that something cannot have been done... Still unless there is a way to prove the age of aluminium in the laboratory perhaps they had no other way to approach the problem.
Beach will round off with William R. Corliss on the belt in 2003 for Corliss introduces one later Chinese attempt to explain the belt as a genuine artifact (249): ‘Assuming no hoax, it would appear that the Chinese had somehow isolated aluminum from its ores 1,500 years before the Europeans. Much has been made of the so-called Nanjing belt. No vague tale from antiquity, the tomb and belt were thoroughly studied by modern archaeologist and chemists. The latter vouched for the existence of aluminum. A hoax was deemed highly improbable. Where, then, did the aluminum come from? Two possibilities seem in play: (1) The Chinese metallurgists of the Jin Dynasty, who had high temperature furnaces, accidentally hit upon one of several ways to chemically win aluminum from one of its several ones. (2) Contradicting the encyclopaedias [i.e. aluminium not found in an isolated form], Chinese geologists reported in 1985 that they had found grains of native aluminum in Guizhou Province. Could the Jin Dynasty metallurgists have collected enough of these grains to make the aluminum sections of the Nanjing belt? Did they hammer the grains together or perhaps melt them. The melting point of pure aluminum is only 1220 f. This temperature might not been out of reach 1,500 years ago.’
Beachcombing is always on the look out for wrong time objects: drbeachcombing AT yahoo DOT com
12 July 2011: Marcy writes in to say, 'If temperatures of only 1220 F are required to extract aluminum from soil, then the Chinese should be ruling the world. Their porcelains have been fired to temperatures well over 2500 F for millenia. The "standard" among American potters is currently (2011) called 'cone 6'. Cone six is attained between 2230 and 2250 Fahrenheit. Even in the USA some dedicated potters fire to cone 10 and cone 13. That covers 2380 to 2455 Fahrenheit. There must be a strong interaction between pottery and metallurgy.' Thanks Marcy!