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  • Flexible Glass in Tiberius’ Rome February 20, 2011

    Author: Beach Combing | in : Ancient , trackback

    Beachcombing has never understood the irrational pleasure of glass. Holding a wine glass in our hands – whatever the content – is surely one of the house’s hidden joys and conversely having a chipped glass or one with any line of imperfection is strangely irritating. It was while contemplating one such imperfect glass yesterday in Beachcombing’s favourite bistro that the desire welled up to tell the story of the accidental if temporary creation of a bizarre form of glass in Tiberius’ Roman Empire.

    The story appears first in Petronius’ Satyricon (51 – early first century AD):

    ‘However, there was an artificer once who made a glass goblet that would not break.  So he was admitted to the Emperor’s presence to offer him his invention; then, on receiving the cup back from the Emperor’s hands, he dashed it down on the floor.  Who so startled as the Emperor? But the man quietly picked up the goblet again, which was dinted as a vessel of bronze might be.  Then taking a little hammer from his pocket, he easily and neatly knocked the goblet into shape again.  This done, the fellow thought he was as good as in heaven already, especially when Emperor said to him, ‘Does anybody else besides yourself understand the manufacture of this glass?’  But, on his replying in the negative, Emperor ordered him to be beheaded, because if once the secret became known, we should think no more of gold than of so much dirt.’

    Of course, it would be easy to disregard this story, for the very fact that it is so pleasing. But then it appears in Cassius Dio (obit after 229) two centuries later:

    About this time one of the largest porticos in Rome began to lean to one side, and was set upright in a remarkable way by an architect whose name no one knows, because Tiberius, jealous of his wonderful achievement, would not permit it to be entered in the records. This architect, then, whatever his name may have been, first strengthened the foundations round about, so that they should not collapse, and wrapped all the rest of the structure in fleeces and thick garments, binding it firmly together on all sides by means of ropes; then with the aid of many men and windlasses he raised it back to its original position. At the time Tiberius both admired and envied him; for the former reason he honoured him with a present of money, and for the latter he expelled him from the city. Later the exile approached him to crave pardon, and while doing so purposely let fall a crystal goblet; and though it was bruised in some way or shattered, yet by passing his hands over it he promptly exhibited it whole once more. For this he hoped to obtain pardon, but instead the emperor put him to death (57,21).

    The story here is attached, rather than to a generic emperor (as in Petronius) to Tiberius (obit 37 AD) and it has also got caught up in a more involved tale about an ingenious architect. Yet again there is the temptation to just disregard this as Imperial metropolitan legend and likewise to write off as a late conflation a seventh-century variant in Isidores, Etymologies (Tiberius again). Smoke does not indisputably mean fire… In fact, in history it rarely does, especially if there is myth in the hearth.

    However, this might just be an exception for Pliny the Elder (obit 79 AD), a near contemporary, reports that in the time of Tiberius, forty years before he brought out his Natural History, a new kind of flexible glass was produced that the Emperor did everything possible to outlaw, even destroying the workshop of the inventor (‘totam officinam artificis eius abolitam’). It then becomes particularly exciting that the Satyricon predates Pliny: at least if that work is truly Neronian as most scholars believe.

    So what was invented in the time of Tiberius? Most scholars shy away from any direct inquiry mumbling about mould blown glass that was making its presence felt at this date. One scholar known to Beachcombing is braver though: ‘The most convincing explanation of what this flexible glass could have been is glass decorated with designs that resembled those commonly embossed in metal’.  It is not clear to Beachcombing with his substandard scientific knowledge why this would make glass bendable, anyone willing to explain please drop a line: drbeachcombing AT yahoo DOT com. The possibility that a Roman had stumbled on the secret of plastic presumably doesn’t bear thinking about?


    23 Feb 2011: Ostrich to the rescue: I tend to wonder if someone hadn’t stumbled on the secret of tempered glass.  In modern times, the Corning corporation patented the stuff in the 1930s,and it was considered quite the marvel in its day, just before plastics came along.  It’s glass that has been formed into shape (e.g., a moulded drinking cup) then slowly heated until it almost melts, then rapidly cooled.  The glass takes on a somewhat plastic-like nature.  It won’t dent, but it will bend quite dramatically then spring back into shape, and is highly resistant to breaking if dropped or struck.  I don’t have any specialized knowledge of Roman glassworking technology, but I’d have to imagine that the heating and cooling cycles were within their abilities, if someone had just thought to experiment. I’m blatantly speculating here, but I wonder if the part about it being dented then hammered out was a fictional enhancement to an otherwise true story?

    2 March 2011: Moonman has an interesting idea here. ‘In Corliss’ Archaeological Anomalies: Small Artifacts: Bone, Stone, Metal Artifacts, Footprints, High Technology, p. 248,  there are two references to the possible production of aluminum in the past.  One is the Tiberius story.  Glass would not dent, but aluminum would.  The other story is about a tomb from the Jin Dynasty which had a belt with four pieces of pure aluminum.  Called the Nanjing belt. Other ‘lost’ methods that are claimed (in the Corliss book) include stone softening in the New World to construct buildings and their parts.  Also, the concrete/mortar used in ancient times seemed to last longer than current products (9000 years for Jericho lime mortar, 4500 years for Great Pyramid cement vs. 50 years for modern cement).  Some speculate about the “pouring” of some Great Pyramid blocks using a geopolymer and crushed limestone.  Also, ancient murrhine vases are speculated to be formed in this way instead of shaping a natural stone (the prior method was mentioned ancient texts of which I do not know the reference but are in The Pyramids, Joseph Davidovits, pp., 76, 113, 158, 166)’. Moonman then sent the relevant documentation and Beach has copied it out for general edification. It seems impossible yet… ‘Although aluminum is the most common metallic element in the earth’s crust, both of the encyclopedias consulted insisted that is never found free in nature. It must be won from its ores by chemical means or, more commonly, by electrochemistry. Accepted history claims that it was not until 1825 that H.C. Oersted finally chemically separated relatively pure aluminum. Consequently it would be highly anomalous, if metical aluminum were found to have been available in ancient times. Nevertheless, two such claims [Tiberius and the Nanjing belt] are herewith catalogued…. [Tiberius story] It is a great story that is perhaps apocryphal but also possibly the first indication of the discovery of a light, silvery metal common in the earth’s crust; i.e. aluminum. In a 1903 number of Knowledge, A. Duboin made the above tale sound more plausible: ‘A few years after the discovery of aluminum, a memorandum from M. Chapelle appeared in the Reports of the Academy of Sciences, tending to prove that by heating a mixture of chloride of sodium, clay, and charcoal, a multitude of metallic globules are obtained, which would be aluminum.’  Duboin also mentioned other chemical methods for winning aluminum from clay. Could the Romans workman have accidentally have hit upon one of these formulas? The Nanjing belt… another post, another day. Thanks, Moonman! BTW Moonman has not been able to track down Duboin.

    30 Dec 2014: Chris S writes, ‘Out of the blue, reading this, I immediately thought of Starlite. It’s a powdery compound that’s flame and heat retardant. Maurice Ward was the genius behind this miracle material, but he was so secretive about its chemistry and production that Starlite died with him in 2011. For a moment, I imagined humanity’s descendents rummaging through the detritus of western 21st century civilization, finding whispers about this singular compound, and possibly twisting it into “… And then Beachcombing the Elder wrote that Maurice Ward was slain by President Barack Thatcher for his creation, for fear of upsetting the order of civilization.” thanks Chris!