In praise of … The Antikythera clock

Twenty-one centuries after it sank under water, and one after it was brought back to the surface, the secrets of the world's oldest computer have been unlocked by X-ray imaging . Sponge divers off the Greek island of Antikythera found relics from an ancient ship in 1901. Among them was a calcified lump shot through with gearwheels . Erudite guesswork and microscopic inspection identified these as parts of a complex classical clock. The mechanical engineering compared with a good Victorian timepiece. The ambition was on another scale – this device did not just tick down the hours, but modelled the paths of the moon and sun and indeed the timing of the Olympics. A BBC4 programme on Thursday night retold the tale. Peer-reviewed papers have hailed the Antikythera mechanism, but the wonder was better conveyed by the engineer who rebuilt the workings with Lego, and accurately predicted a solar eclipse due on 8 April 2024 .