The Things We Have Already Forgotten How to Make
Companion essay to the third Arcanum World video.
The Things We Have Already Forgotten How to Make
Companion essay to the third Arcanum World video.
In 1900, a Greek sponge diver came up from forty-five metres of cold black water terrified by what he had seen — bronze bodies, he thought, the dead at the bottom of the sea. He had not found bodies. He had found a Roman cargo ship two thousand years on the floor of the Aegean, and the corroded green lump of bronze that arrived in the Athens museum that summer would, a hundred years later, force the scholarly world to admit that some Greek workshop around 150 BCE had built the first computer — fourteen hundred years before anything like it would exist again.
The video this essay accompanies tells that story. This piece is about a different question. What other things have we already forgotten how to make?
The Antikythera Mechanism is the most spectacular case in the historical record. It is not the only one. Lost technologies are everywhere if you look. The pattern of their loss tells us something about how human knowledge actually works that the video could only gesture at.
The Romans built concrete that still stands. Their marine harbours have been underwater since the time of Augustus and are structurally sound. We have studied the material for two centuries. We know what was in it — a particular type of volcanic ash called pozzolana, lime, seawater, and a deliberate amount of tobermorite mineral that grows inside the concrete over the centuries, making the harbour walls stronger the longer they sit in salt water. Modern Portland cement does the opposite. It begins degrading the day it sets. Marie Jackson at Berkeley has now approximated the Roman recipe in the laboratory; we cannot yet make it at industrial scale at competitive cost. Every harbour built since the fall of the Empire has been built out of a worse material than the one the Romans used.
Damascus steel was forged in the Middle East between the third and seventeenth centuries. Crusader knights brought home stories of blades that could cut through European armour and silk scarves in the same swing. The technique died around 1750, partly because the particular ore the smiths used — wootz steel from southern India — became unavailable when the mines were exhausted. Modern metallurgists have spent decades trying to reverse-engineer the result. They have come close. They have not equalled it. The Damascus blades currently in museum collections cannot be made today, with anyone’s tools, by anyone alive.
Greek fire was the fleet-burning naval weapon that kept the Byzantine Empire alive for seven centuries longer than it would otherwise have lasted. The recipe was a state secret entrusted to a single family, the Kallinikoi. When the family died out, the recipe died with them. We do not know what was in it. We have theories — naphtha, quicklime, sulphur, pine resin — but no theory has been able to reproduce the behaviour described in the Byzantine sources, where the substance burned on water and could not be extinguished by sand. We are still guessing.
These are the famous cases. There are many more.
Tyrian purple required a particular sea snail and a particular Phoenician industrial process. When the Phoenician industry collapsed, the dye industry collapsed with it. The exact shade of purple that the Phoenicians produced for two thousand years cannot be made today. The pigment used in some Pompeian frescoes has resisted modern chemical replication for a hundred and fifty years of scholarship. The Stradivarius varnish that gave the eighteenth-century violins their resonance was lost within two generations of Antonio Stradivari’s death, despite his sons and grandsons being violin makers themselves. The construction technique that allowed Justinian’s architects to build the Hagia Sophia dome in five years and have it stand through fifteen centuries of earthquakes that have flattened modern buildings around it is still not fully understood. The Maya Long Count calendar mathematics can be reconstructed from the few codices that survived the Spanish, but the original astronomical observations that fed the calendar — the centuries of patient sky-watching that produced the numbers — are gone.
What these losses share is a particular shape. They were workshop knowledge. They lived in the hands of specific people, in the workspaces of specific cities, in the apprentice chains that connected one generation to the next. They were rarely written down in a form that could be reconstructed without the original masters. The Romans did not publish the recipe for their concrete because everyone in the Roman concrete industry already knew it. The Damascus smiths did not publish their forging technique because it was their livelihood. The Kallinikoi family did not publish the Greek fire recipe because it was the family’s reason for existing.
When the people died and the apprentice chains broke, the knowledge went with them. It did not fade gradually. It vanished in a generation. By the time anyone realised what had been lost, the people who could have rebuilt it were already a hundred years dead.
This is why the Antikythera Mechanism feels so strange when you first see it. You expect ancient technology to be primitive — something we built better versions of. Instead you find the opposite. Someone in a Greek workshop around 150 BCE solved a problem that the rest of human history would not solve for fourteen hundred years. Then they died. And we had to start over.
There is a sentence I keep returning to.
We are not in the third millennium of human progress. We are somewhere in the second great round of it. There were others before us. The strangest thing about what we know is not what we know. It is what we have already, several times, forgotten.
Watch the full video →
Sources
Derek de Solla Price, Gears from the Greeks: The Antikythera Mechanism — A Calendar Computer from ca. 80 B.C. — American Philosophical Society, 1974
Tony Freeth et al., “Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism” — Nature 444 (2006)
Jo Marchant, Decoding the Heavens: A 2,000-Year-Old Computer and the Century-long Search to Discover Its Secrets — Da Capo Press, 2009
Alexander Jones, A Portable Cosmos: Revealing the Antikythera Mechanism, Scientific Wonder of the Ancient World — Oxford University Press, 2017
Marie D. Jackson et al., “Phillipsite and Al-tobermorite mineral cements produced through low-temperature water-rock reactions in Roman marine concrete” — American Mineralogist 102, 1435–1450 (2017)
John D. Verhoeven, Damascus Steel: A Continuing Mystery — Iowa State University Press, 2007
Alex Roland, “Secrecy, Technology, and War: Greek Fire and the Defense of Byzantium” — Technology and Culture 33, 4 (1992)
Inge Boesken Kanold and Roland Haubrichs, “Tyrian Purple Dyeing: An Experimental Approach with Fresh Murex trunculus” — in Dyes in History and Archaeology, 2008
Joseph Nagyvary, Renald N. Guillemette, Clifford H. Spiegelman, “Mineral Preservatives in the Wood of Stradivari and Guarneri” — PLoS ONE 4, 1 (2009)
Rowland Mainstone, Hagia Sophia: Architecture, Structure and Liturgy of Justinian’s Great Church — Thames & Hudson, 1988
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