Wednesday, July 2, 2008

Ancient metallurgy--art

It is the common case when we go to a museum and observe artifacts made of metal that we often don't even consider the science of metallurgy. We love the golden objects but never give a thought about the art of making the objects.

This topic is concentrated on the mining, smelting, and practical production of metallurgy and how the ancients revered and used such metals as copper, iron, silver, gold, tin. National isolation was counter productive and international trade and contact with other cultures enabled the disbursement of not only the refined metals and raw ores but the technology of smelting and combination of many of these metals. A bonus was displayed in the realm of art. Some alloys are simply impossible in certain regions...such as the famous Damascus swords. As usual, much of the finer aspects of ancient metallurgy was directed towards personal adoration objects, embellishing funerary items, religious practices.

One would initially think that ancient Egypt was not much more than a land of limestone and silica, but there were active copper mines to the East and rare deposits of iron; large quantities and objects of iron were imported from the Hittites [era of the Nineteenth Dynasty Rameses II]. Very few of the iron artifacts remain from that period for, yep...good ole oxidation and disintegration. Some weapons have been found and upon chemical analysis suggest quantities of carbon--hence steel. That would maintain a keen edge on the blade. Much better than copper weapons or just pure iron. Tin was essential for it hardened bronze. Cobalt was used for color additions to glass and ceramics. The lead mines at Gebel Rasas was a huge repository of Galena [lead sulfide]. Mercury was abundant. And finally, gold was accumulated via tribute and conquest and such areas like Ikoptos, Ombos, and Apollinopolis Magna East of the Nile River, South into the Sudan, and alluvial reclamation. [Incidentally, the alluvial collection method has a curious connection to an ancient myth from the Greeks. Remember Jason and the Argonauts? The "Golden Fleece" is a reference to gold collection in streams whereby a sheep skin was placed in a stream to catch the minute golden nuggets.] True for Cerro Rico de Potosí in the Bolivian Andes by 11th to15th Century Inca metallurgists where there is evidence of lead [Pb] being used a flux for silver [Ag] extraction and manipulation of antimony [Sb], tin [Sn], and bismuth [Bi]. Lydian Kingdom [western Turkey] of the 6th Century B.C. was known for gold refinement and the origin of the first gold coinage. Here King Croesus's metallurgists refined impure gold from the Pactolus River. The precious gold is long gone but the description of the technology remains. [Wonder where the value of that situation lies?] Consider the Chinese cast iron plow that antedated the European and Chinese production of "pig iron" for in 1078 A.D. North China was producing more than 114,000 tons and in 1788 England's production of "pig iron" was around 50,000 tons. And don't forget those exquisite bronze figures. Athens was founded by the wealth gleaned from Laurian cupellation of argentiferous lead. What all of this means is that the ancients and near ancients certainly had a working knowledge of mining and smelting ores for tools, art, agriculture, and weapons. And all wasn't cut and dry metallurgical science but many times interwoven into mythology and ritual. I well remember the PBS series "The Ascent of Man" broadcast in the early 1970's where the physical efforts to produce a fine steel Japanese Samurai sword was not always the formula found in a book but by oral tradition. "Iron is a later discovery than copper because at every stage it needs more heat--in smelting, working and, naturally, in processing its alloy, steel." The steel billet is heated, hammered, and folded many times--some fifteen times. It is covered with clay and plunged into water. All of this is not done according to a written recipe, for there was none, but to rigid ritual and colorful analogies: The sword is "...heated until it glows to the colour of the morning sun...." Similar practices were done in Europe when it was said that tempered steel was at its maximum when " glowed straw-yellow, or purple, or blue, according to the different use for which it was intended." [The Ascent of Man by Jacob Bronowski.]. Metallurgy not at its most accurate but got the job done nevertheless.

Ancient Metallurgy

Blast furnaces in Song-Yuan China

Technology as seen through the case of ferrous metallurgy in Han China



Institute for Archaeo-Metallurgical Studies


King Croesus' Gold: Excavations at Sardis and the History of Gold Refining


Andrew Ramage and Paul Craddock

ISBN 0-674-50370-8


"Secrets of the Samurai Sword"--transcript

"Secrets of the Samurai Sword"--Home page

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