THE INVISIBLE MAN
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 Scotsman's head; "she thought they were true all right, but they couldn’t be 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?"
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