A corroded bronze device recovered from a Roman-era shipwreck in 1901. Upon reconstruction it was identified as a functioning astronomical computer — capable of predicting solar and lunar eclipses, tracking planetary motion, and calculating the Saros cycle with an accuracy not re-achieved until the 17th century AD.

The engineering required to produce this device — miniaturized interlocking gears at tolerances of fractions of a millimeter — did not exist in the ancient world by any known account. No precursor devices have ever been found. No contemporary accounts of its construction exist. It arrived fully formed in the historical record from 機器來源不明.

Researchers have identified a second device in an inscription reference that has never been found. The inscription gives its location as

The gear ratios, when calculated, produce a fundamental frequency of 7.83 Hz. The device would have hummed at this frequency when operational. No ancient text explains why this frequency was chosen.