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The weekly Lost Knowledge column explores the possible technology of the future in the forgotten ideas of the past (and those slightly off to the side). Each Tuesday, we look at retro-tech, "lost" technology, and the make-do, improvised "street tech" of village artisans and tradespeople from around the globe. "Lost Knowledge" is also the theme of MAKE Volume 17 (due on newsstands March 10, 2009)

In this week's column, we look at the Antikythera mechanism, the over 2,000 year old "computer" found off the coast of a Greek island at the turn on the 20th century. In Volume 17 of MAKE, it is extraordinarily fitting that Bruce Sterling should write about this ancient mechanical computer in his "Hands On" column. It was Bruce, and fellow cyberpunk sci-fi godfather William Gibson, who fully pressurized the boilers on the steampunk movement with the publication of their 1990 book The Difference Engine. It provided the conceptual yeast which gave rise to the steampunk literary genre, and by extension, the steampunk makers movement. The idea was this: What would have happened to the future if British mathematician Charles Babbage had been successful in building his analytical engine, and the computer revolution had arrived a hundred years earlier?

So, now imagine if the Antikythera Device had been a common appliance of the time around 100 B.C. (assuming that it wasn't), and the computer revolution had arrived several thousand years earlier. Here's the beginning of Bruce's column:

Hands On: The Kosmos in a Box

Bruce Sterling

We call it the Antikythera Device, or sometimes "the world's oldest computer." That's not what the machine's maker called his box. He would never have wanted it lost in a Roman shipwreck, near the obscure, rocky island of Antikythera.

If that maker saw his high-tech gizmo now, boy, what a comedown. It sank to the bottom of the Mediterranean under a tonnage of pottery, statues, and furniture. It was smashed to pieces. Its stout wooden frame flaked away like wet paper. It was also severely corroded. Fossil dinosaurs have been found in better shape.

Once, there was room to claim that modern ideas about this machine's complex functions might be far-fetched. However, in 2005 the machine's fragments were digitally CAT-scanned, revealing that the Greek maker carved specific instructions inside.
Those scales and labels eliminate any doubt: we've got a crank-driven, precisely geared bronze orrery.

The Antikythera Device predicts the position of the sun and the phases of the moon, and it probably tracks all five visible planets. It also predicts eclipses, and, as a final throw-in bloatware feature, it will tell you whenever the Greek Olympic games occur. All this in a single mechanism from 85 B.C., or very near it.

To understand the huge extent of the lost knowledge here, we need to grasp what this lost object once meant -- not to us who found it, because for us it's mind-blowing -- but within the context of its own time and place. All we've got is a few hints. We'll have to blue-sky it a little.

Bruce goes on to weave a fun speculative tale of a student from the Rhodes Academy who's built this device as his graduate project. It's a "pocket universe from a university," it encodes the students education, the box *is* "his working diploma, a physical proof of the
ordeal he had been through."

Read the rest of the piece in MAKE Volume 17. If you're already a subscriber, but haven't received your issue yet, you can read the Digital Edition here.

Wikipedia has an excellent entry on the Device. Here's an excerpt, on the function of the mechanism:

Function

The device is remarkable for the level of miniaturization and for the complexity of its parts, which is comparable to that of 18th century clocks. It has over 30 gears, although Michael Wright (see below) has suggested as many as 72 gears, with teeth formed through equilateral triangles. When a date was entered via a crank (now lost), the mechanism calculated the position of the Sun, Moon, or other astronomical information such as the location of other planets. Since the purpose was to position astronomical bodies with respect to the celestial sphere, with reference to the observer's position on the surface of the earth, the device was based on the geocentric model.^[10]

The mechanism has three main dials, one on the front, and two on the back. The front dial has two concentric scales. The outer ring is marked off with the days of the 365-day Egyptian calendar, or the Sothic year, based on the Sothic cycle. Inside this, there is a second dial marked with the Greek signs of the Zodiac and divided into degrees. The calendar dial can be moved to compensate for the effect of the extra quarter day in the year (there are 365.2422 days per year) by turning the scale backwards one day every four years. Note that the Julian calendar, the first calendar of the region to contain leap years, was not introduced until about 46 BC, up to a century after the device was said to have been built (and the leap year was implemented with errors until the early first century).

The front dial probably carried at least three hands, one showing the date, and two others showing the positions of the Sun and the Moon. The Moon indicator is adjusted to show the first anomaly of the Moon's orbit. It is reasonable to suppose the Sun indicator had a similar adjustment, but any gearing for this mechanism (if it existed) has been lost. The front dial also includes a second mechanism with a spherical model of the Moon that displays the lunar phase.

There is reference in the inscriptions for the planets Mars and Venus, and it would have certainly been within the capabilities of the maker of this mechanism to include gearing to show their positions. There is some speculation that the mechanism may have had indicators for all the five planets known to the Greeks. None of the gearing for such planetary mechanisms survives, except for one gear otherwise unaccounted for.

Finally, the front dial includes a parapegma, a precursor to the modern day Almanac, which was used to mark the rising and setting of specific stars. Each star is thought to be identified by Greek characters which cross reference details inscribed on the mechanism.

The upper back dial is in the form of a spiral, with 47 divisions per turn, displaying the 235 months of the 19 year Metonic cycle. This cycle is important in fixing calendars.

The lower back dial is also in the form of a spiral, with 225 divisions showing the Saros cycle; it also has a smaller subsidiary dial which displays the 54 year "Triple Saros" or "Exeligmos" cycle. (The Saros cycle, discovered by the Chaldeans, is a period of approximately 18 years 11 days 8 hours -- the length of time between occurrences of a particular eclipse.)

The Antikythera Mechanism Research Project, with experts from Britain, Greece and the United States, detected in July 2008 the word "Olympia" on a bronze dial thought to display the 76 year Callippic cycle, as well as the names of other games in ancient Greece, and probably used to track dates of the ancient Olympic games. According to BBC news:

"The four sectors of the dial are inscribed with a year number and two Panhellenic Games: the 'crown' games of Isthmia, Olympia, Nemea, and Pythia; and two lesser games: Naa (held at Dodona) and a second game which has not yet been deciphered."

In 1900 a group of sponge divers blown off course in the Mediterranean discovered an Ancient Greek shipwreck dating from around 70 BC.

Lying unnoticed for months amongst their hard-won haul was what appeared to be a formless lump of corroded rock. It turned out to be the most stunning scientific artefact we have from antiquity. For more than a century this 'Antikythera mechanism' puzzled academics. It was ancient clockwork, unmatched in complexity for 1000 years - but who could have made it, and what was it for? Now, more than 2000 years after the device was lost at sea, scientists have pieced together its intricate workings and revealed its secrets.

In Decoding the Heavens, Jo Marchant tells the full story of the 100-year quest to understand this ancient computer. Along the way she unearths a diverse cast of remarkable characters - ranging from Archimedes to Jacques Cousteau - and explores the deep roots of modern technology not only in ancient Greece but in the Islamic world and medieval Europe too. At heart an epic adventure story, this is a book that challenges our assumptions about technology transfer over the ages while giving us fresh insights into history itself.

The site offers some brief tidbits from each chapter:

Chapter 7: Mechanic's Workshop

October comes and Wright arrives in Athens with his finished model, grimly triumphant as his competitors complete their imaging. On the day of his talk he demonstrates the workings of his device to a small but captivated audience. He turns the handle on the side like a magician and there's a hush as time passes before everyone's eyes, just a soft clicking sound as the Moon traces undulating circles through a miniature sky, cycling from black to silver as the golden Sun glides slowly round and the planets meander back and forth, their seemingly random paths guided by a hidden clockwork order. Wright sees three decades of his life passing as the heavenly cycles run their course, from the young curator who was once captivated by Price's work and wished it were his own, to the man he is now, standing here with the Antikythera mechanism finally recreated and working again for the first time in 2,000 years.

Chapter 8: The New Boys

There was silence. The surface images from Tom Malzbender's team had been stunning, but everyone knew that for the project to be a success they needed to see inside; they needed to see the internal workings. Andrew Ramsey tapped his computer keyboard to scroll down through the depth of the fragment. At first all they could see was a blur, but then a crackling sharp gearwheel emerged from the fuzz, as if being hauled up out of grey sand. It was better than any of them had dared hope. The letters 'ME' had been scratched into the side of the wheel. It was like a signal from the past, an 'I WOZ ERE' from 2,000 years ago. Suddenly, they felt a direct, almost physical conncection with this ancient machine, and with whoever had carved those letters so long ago. Then Tony Freeth started to laugh. 'Somebody email Mike and tell him we've found a gearwheel with his initials on!

The research team has also deciphered all the months on the Mechanism's 19-year calendar, revealing month names that are of Corinthian origin, probably from a Corinthian colony of the western Hellenic world - overturning the previous idea that the Mechanism was from the eastern part of the Mediterranean. For the first time we have direct evidence of its cultural origins.

Additional research has also transformed our understanding of the Mechanism's sophisticated eclipse prediction dials. These results have extended the previous work of the AMRP on the complex structure of the Mechanism's gears and dials and have added new and intriguing cultural and social dimensions.

More:

• Lost Knowledge: Village tech in West Papua, Indonesia
• Lost Knowledge: Neon lights
• Lost Knowledge: Reanimating Dead Media
• Lost Knowledge: Manual typewriters

From MAKE magazine:

Check out MAKE, Volume 17: The Lost Knowledge issue!

In Volume 17, MAKE goes really old school with the Lost Knowledge issue, featuring projects and articles covering the steampunk scene -- makers creating their own alternative Victorian world through modified computers, phones, cars, costumes, and other fantastic creations. Projects include an elegant Wimshurst Influence Machine (an electrostatic generator built entirely from Home Depot parts), a Florence Siphon coffee brewer, and a teacup-powered Stirling engine. This special section also covers watchmaking, letterpress printing, the early multimedia art of William Blake, and other wondrous and lost (or fading) pre-20th-century technologies.