Robert Oppenheimer used to tell of the pioneer mysteries of building reliable Geiger counters that had low background noise. Among his friends, he said, there were two schools of thought. One school firmly held that the final step before one sealed off the Geiger tube was to peel a banana and wave the skin three times, sharply to the left.The other school was equally confident that success would follow if one waved the banana peel twice to the left and then, once, smartly to the right. (My counters were unbelievably bad because I didn't use either of these techniques.)