An explosion occurs in a gunpowder factory. Once all the mess has been cleared up, the inquiry begins. One of the few survivors is brought in to make a statement. "Okay Simpson," says the investigator, "you were near the scene, what happened?"

"Well, it's like this. Old Charley Higgins was in the mixing room, and I saw him take a cigarette out of his pocket and light up."

"He was smoking in the mixing room?" the investigator said in stunned horror. "How long had he been with the company?"

"About 20 years, sir."

"Twenty years in the company, then he goes and strikes a match in the mixing room. I'd have thought it would have been the last thing he'd have done."

"Well... it was, sir."