THE WISDOM OF FATHER BROWN
"Have you noted another thing?" went on Flambeau eagerly, "this Hawker hears his love insulted; but doesn't strike till he's got to the soft sand-hills, where he can be victor in a mere sham-fight. If he'd struck amid rocks and sea, he might have hurt his ally."
"That is true again," said Father Brown, nodding.
"And now, take it from the start. It lies between few people, but at least three. You want one person for suicide; two people for murder; but at least three people for blackmail."
"Why?" asked the priest softly.
"Well, obviously," cried his friend, "there must be one to be exposed; one to threaten exposure; and one at least whom exposure would horrify."
After a long ruminant pause, the priest said, "You miss a logical step. Three persons are needed as ideas. Only two are needed as agents."
"What can you mean?" asked the other.
"Why shouldn't a blackmailer," asked Brown, in a low voice, "threaten his victim with himself? Suppose a wife became a rigid teetotaller in order to frighten her husband into concealing his pub-frequenting, and then wrote him blackmailing letters in another hand, threatening to tell his wife! Why shouldn't it work? Suppose a father
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