"Because if it was any other coloured sack, the case must begin over again," said Father Brown; "but if it was a light brown sack, why, the case is finished.""I am pleased to hear it," said Angus with hearty irony. "It hasn't begun, so far as I am concerned.""You must tell us all about it," said Flambeau with a strange heavy simplicity, like a child.
Unconsciously they were walking with quickening steps down the long sweep of road on the other side of the high crescent, Father Brown leading briskly, though in silence. At last he said with an almost touching vagueness, "Well, I'm afraid you'll think it so prosy. We always begin at the abstract end of things, and you can't begin this story anywhere else.
"Have you ever noticed this--that people never answer what you say? They answer what you mean--or what they think you mean. Suppose one lady says to another in a country house, `Is anybody staying with you?' the lady doesn't answer `Yes; the butler, the three footmen, the parlourmaid, and so on,' though the parlourmaid may be in the room, or the butler behind her chair.
She says `There is nobody staying with us,' meaning nobody of the sort you mean. But suppose a doctor inquiring into an epidemic asks, `Who is staying in the house?' then the lady will remember the butler, the parlourmaid, and the rest. All language is used like that; you never get a question answered literally, even when you get it answered truly. When those four quite honest men said that no man had gone into the Mansions, they did not really mean that no man had gone into them. They meant no man whom they could suspect of being your man. A man did go into the house, and did come out of it, but they never noticed him.""An invisible man?" inquired Angus, raising his red eyebrows.
"A mentally invisible man," said Father Brown.
A minute or two after he resumed in the same unassuming voice, like a man thinking his way. "Of course you can't think of such a man, until you do think of him. That's where his cleverness comes in. But I came to think of him through two or three little things in the tale Mr. Angus told us. First, there was the fact that this Welkin went for long walks. And then there was the vast lot of stamp paper on the window. And then, most of all, there were the two things the young lady said--things that couldn't be true.
Don't get annoyed," he added hastily, noting a sudden movement of the Scotchman's head; "she thought they were true. A person can't be quite alone in a street a second before she receives a letter.
She can't be quite alone in a street when she starts reading a letter just received. There must be somebody pretty near her; he must be mentally invisible.""Why must there be somebody near her?" asked Angus.
"Because," said Father Brown, "barring carrier-pigeons, somebody must have brought her the letter.""Do you really mean to say," asked Flambeau, with energy, "that Welkin carried his rival's letters to his lady?""Yes," said the priest. "Welkin carried his rival's letters to his lady. You see, he had to.""Oh, I can't stand much more of this," exploded Flambeau.
"Who is this fellow? What does he look like? What is the usual get-up of a mentally invisible man?""He is dressed rather handsomely in red, blue and gold,"replied the priest promptly with precision, "and in this striking, and even showy, costume he entered Himylaya Mansions under eight human eyes; he killed Smythe in cold blood, and came down into the street again carrying the dead body in his arms--""Reverend sir," cried Angus, standing still, "are you raving mad, or am I?""You are not mad," said Brown, "only a little unobservant.
You have not noticed such a man as this, for example."He took three quick strides forward, and put his hand on the shoulder of an ordinary passing postman who had bustled by them unnoticed under the shade of the trees.
"Nobody ever notices postmen somehow," he said thoughtfully;"yet they have passions like other men, and even carry large bags where a small corpse can be stowed quite easily."The postman, instead of turning naturally, had ducked and tumbled against the garden fence. He was a lean fair-bearded man of very ordinary appearance, but as he turned an alarmed face over his shoulder, all three men were fixed with an almost fiendish squint.
* * * * * *
Flambeau went back to his sabres, purple rugs and Persian cat, having many things to attend to. John Turnbull Angus went back to the lady at the shop, with whom that imprudent young man contrives to be extremely comfortable. But Father Brown walked those snow-covered hills under the stars for many hours with a murderer, and what they said to each other will never be known.
