I've just remembered another one . . . Back in World War II, the Royal Navy realised that torpedoes, which were very expensive bits of kit, could be salvaged if they missed their targets - as they wouldn't explode, and floated to the surface once their internal motors stopped. So the brass-hats in the Admirality put out a reward notice to fisherman, offering to cross their palms with silver if they brought one back. Some time later, a small fishing boat chugged into the Naval dockyard at Devonport, pulled up alongside a destroyer, and the skipper called up to the rating on watch that he he'd found "one o' your torpedoes". The rating called the duty officer, who peered down at the tangle of nets and obscure glimpses of metal . . . and suddenly realised with horror that what he was looking at was NOT a torpedo, but a MINE!! You may have seen pictures of mines of that period; great big steel balls, with spikes sticking out at odd angle - like this: The 'spikes' are, in fact, easily crushed tubes, each one containing a glass phial of sulphuric acid. When a ship nudges the tubes (even gently) the glass breaks, allowing the acid to fall onto two lead plates in the bottom of the tube, which then creates a small lead acid battery. Once the acid makes the circuit complete, the resulting current sets off the detonator, and the mine does this . . . . . . at this point, the duty officer's hair practically stood on end, as he bellowed at the bemused fisherman something on the lines of "Get that (very rude word) thing away from here before it blows us to Hell!! It's not a torpedo, it's (another very rude word) MINE!!" Turning to the equally horrified seaman, he ordered him to call the Captain and let him know what was going on. As the seaman raced off to put the fear of God into the Captain, the duty officer realised the fisherman was calling him again. The sight that met his eyes must have aged him ten years on the spot. There, still right alongside his ship, was the fishing boat . . . with the mine now clearly visible . . . and the skipper dangling a large lump hammer in his hand . . . and a gentle smile on his face as he called up: "Don't worry, boy - Oi've bashed all they triggers off wi' this!" A couple of hundred guardian angels really earnt their pay on that shift . . .