Now, setting a booby-trap for a respectable citizen like a head master (even of an inferior school to your own) is not a matter to be approached lightly and without careful preparation. I don't suppose I've ever selected a lunch with more thought than I did that day. And after a nicely balanced meal, preceded by a couple of dry Martinis, washed down with half a bot. of a nice, dry champagne, and followed by a spot of brandy, I could have set a booby-trap for a bishop.