"Not hard to say," replied the stranger.  "Every hundred years a little blue bird passes by, flying between them and the globe, and as it passes it touches the stone with the tip of its wing.  On the last day of the hundredth year the people gather and watch with eager eyes all day for the passing of the bird, and while they watch they do not suffer.  Now this is the last hour of the last day of the hundredth year, and you see how they gaze."