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Ancient aluminum? Flexible glass?: looking for the real heart of a legend

Skeptical Inquirer, May-June, 1995 by Gerhard Eggert

The story has hardly been well-enough authenticated to warrant the publicity which it has long received.

Pliny, Natural History, Book 36, para. 195

Do you like strange stories? What about one with ingredients like an inventor of genius, flexible glass, a tyrannical emperor, and a surprising end? The story, so critically commented upon above by the Roman encyclopedist Pliny the Elder (Gaius Plinius Secundus, A.D. 23-79), "who was besides not unduly skeptical" (Trowbridge 1930), has it all. And more: According to the editors of Time-Life Books (1990) in their Feats and Wisdom of the Ancients, the story could be about aluminum. If true, then certainly "the ancient metalsmith was centuries ahead of his time."

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Are you curious about it now? Here is the detailed version given by the contemporary Roman author Petronius in his Satyricon (chap. 50, para. 7, to chap. 51, para. 6), where inserted in a conversation on metal tableware the swank Trimalchio boasts:

Personally I prefer glass; glass at least does not smell. If it were not so breakable I should prefer it to gold; as it is, it is so cheap. But there was once a workman who made a glass cup that was unbreakable. So he was given an audience of the Emperor with his invention; he made Caesar give it back to him and then threw it on the floor. Caesar was as frightened as could be. But the man picked up his cup from the ground: it was dinted like a bronze bowl; then he took a little hammer out of his pocket and made the cup quite sound again without any trouble. After doing this he thought he had himself seated on the throne of Jupiter, especially when Caesar said to him: "Does anyone else know how to blow glass like this?" Just see what happened. He said not, and then Caesar had him beheaded. Why? Because if his invention were generally known we should treat gold like dirt.

Pliny (Nat. Hist., bk. 36, para. 195) relates the story in a matter-of-fact manner:

The tale is told that, during the reign of Tiberius, a glass was devised, so compounded as to be flexible, and that the workshop of the inventor was utterly destroyed, lest there should be a decline in the value of copper, silver, and gold.

The story must be seen in its historical context in the first century A.D. The rather new invention of glass-blowing spread at that time, and glass vessels became readily available, competing economically with luxury metal tableware (Pliny, Nat. Hist., bk. 36, para. 198; Forbes 1957: 170-171). Should the new decolorized glass of crystal-like appearance have had the desired metallic properties (fracture strength, forming by cold work), then the market for metal tableware would have totally broken down.

In the Middle Ages, this fascinating story was often repeated (Trowbridge 1930: 112). Alchemists searched for the secret of malleable and flexible glass in pursuit of perfect matter (Kunckel 1689; Ilg 1873: 133-134).

Ancient Aluminum

Where does the idea that the story is about aluminum come from? Every encyclopedia dates the discovery of aluminum to the nineteenth century, so the existence of Roman aluminum is certainly an extraordinary claim.(*) So, what about the necessary extraordinary proof?. Although Time-Life correctly gives Pliny and Petronius as sources and cites them speaking of glass, its version of the story clearly contains fakes, as is easily revealed by direct comparison. Time-Life calls the craftsman a "metalworker" and says the material of the cup "looked like silver but was much lighter" and "was extracted from clay - just as aluminum is." All these claims are fabrications that have nothing to do with the original story. Based on these and not, as it falsely claims, on Petronius's and Pliny's descriptions, the Time-Life book says, ". . . however, modern experts have speculated that it [the cup] might have been fashioned from aluminum." Invent citations and you certainly have a lot to speculate about!

Of course the Time-Life editors did not do it themselves; they got their version thirdhand. By a search in libraries, I traced this account back to Henri Sainte-Claire Deville (1818-1881), the founder of the industrial production of aluminum. His "silver from clay" was shown at the World Exhibition in Paris in 1855. In 1864, during an evening lecture at the Sorbonne, he told his audience that he had had a Roman predecessor. He cited a General de Beville verbatim, who had "discovered it in many latin texts" (Menault 1864). From this quotation, de Beville's intentions are obvious. He did not only try to flatter the modern aluminum producer for reviving an ancient Roman tradition. He also contrasted the tyrannical ancient Roman emperor Tiberius, who suppressed the invention, with the modern French emperor Napoleon III, who acted as a patron of the technical innovation.

De Beville's idea to relate the story to the production of aluminum might come from a misinterpretation of Petronius's expression aurum pro luto habere (literally: to have gold as dirt). The Latin word lutum, which means either dirt or clay, is here (and in other passages of the Satyricon) used in a comparison as an example of something totally valueless. De Beville possibly interpreted the word as indicating that the vessel itself was made from clay. In his mind, what else could the material of the vessel be? It behaves like a metal and competes with gold and silver, as "silver from clay," i.e., aluminum? A nice anecdote, indeed, perhaps intended to cause a smile and not be taken seriously. Later readers apparently did not understand that - and so the story of Roman aluminum was born. And there is one lesson of experience with such stories: Once promulgated, they never go away.

Ancient aluminum? Flexible glass?: looking for the real heart of a legend

Skeptical Inquirer, May-June, 1995 by Gerhard Eggert

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