Jacksonville

The Betz Sphere

On 26 March 1974 the Betz family, walking a burned-over patch of woodland on Fort George Island in Florida, picked up a steel ball some twenty centimetres across. At home it behaved oddly: it rolled about the table, came back to its owner, hummed and made the dog howl. The press announced an alien device. James Randi examined and weighed it and showed that the mystery was an offset centre of gravity and a slightly sloping floor, and that any hollow ball hums. The Navy laboratory at Jacksonville identified the material as 431 stainless steel and concluded it was a ball from a ball mill. The sculptor James Durling-Jones later said he had carried such balls in his van and lost some in exactly that area.