Old balls still scorch Pores made shipwrecked cannon balls glow spontaneously. 6 May 2002 DAVID ADAM Cannonball run: iron may heat rapidly in air after years in the ocean. © AP Goodness gracious! Two British chemists believe they have solved the 26-year-old mystery of how shipwrecked cannonballs that were rescued from the deep spontaneously erupted into great balls of fire."They were glowing bright red and you could feel the heat coming off them as the desk began to smoke," recalls Bob Child, now a chemist at the National Museums and Galleries of Wales in Cardiff.It all happened in 1976,...