“Winwood Reade is good upon the subject,” said Holmes. “He remarks that, while the individual man is an insoluble puzzle, in the aggregate he becomes a mathematical certainty. You can, for example, never foretell what any one man will do, but you can say with precision what an average number will be up to. Individuals vary, but percentages remain constant. So says the statistician. But do I see a handkerchief? Surely there is a white flutter over yonder.”

“Yes, it is your boy,” I cried. “I can see him plainly.”

“And there is the Aurora ,” exclaimed Holmes, “and going like the devil! Full speed ahead, engineer. Make after that launch with the yellow light. By heaven, I shall never forgive myself if she proves to have the heels of us!”