She brought one from her toilet-table and handed it to him in evident astonishment.
"What do you see in the mirror?" he asked, and held a page of the blotting-book at an angle in front of it.
Miss Vaughan uttered an exclamation of surprise, as she read the words reflected there:
MR. FREDERIC SWAIN,
1010 Fifth Avenue,
New York City.
If not at this address,
please try the Calumet Club.
"'Tall oaks from little acorns grow,'" quoted Godfrey, tossing the book back upon the desk. "But for the fact that you blotted the envelope, Miss Vaughan, young Swain would never have been accused of murder."
"I do not understand," she murmured.
"Don't you see," he pointed out, "the one question which we have been unable to answer up to this moment has been this: how did Silva know you were going to meet Swain? He had to know it, and know it several hours before the meeting, in order to have those finger-prints ready. I concluded, at last, that there must be a blotting-book—and there it is."
Miss Vaughan stared at him.
"You seem to be a very wonderful man!" she said.