Ah...Calcium Carbide, the stuff they used to use to light bicycle lamps etc with. You could easily buy that stuff when I was a kid and one thing we used to do, as horrible children (and I make no apologies for being a child of 6 or 7 at the time), was to go down to the beach near where I lived with a little tin full of calcium carbide and a loaf of stale bread. We'd wrap a small bit of carbide into a piece of bread then throw it up to the seagulls who would catch it mid air and continue flying, then a few seconds later they would explode!!! I know, it wasn't a nice thing to do, and I certainly wouldn't do it now, but at the time all us snotty nosed little monsters thought it was FUNNY!!!