CANNONBALLS from centuries-old shipwrecks are wreaking havoc—by exploding on archaeologists’ desks.
Ancient lumps of metal rust quickly once they’re pulled up from the bottom of the sea. The combination of oxygen and sea salt causes the rapid oxidation that can crumble valuable artefacts to bits. But Robert Child from the National Museums and Galleries of Wales in Cardiff has noticed another frightening effect.
Back in the 1970s, Child helped to retrieve some small cannon shot 6 centimetres in diameter from the 1691 wreck of the HMS Coronation in 12 metres of water off Plymouth Sound. Back in the lab,…
