Vance had listened with the intensest interest.

“We must go there, Markham. I’ve been rather expecting a call of this kind. It’s possible we may at last find the key to the truth.”

“The truth about what?”

“Pardee’s guilt.”

Markham said no more, and we ate our dinner in silence.

At half past eight we rang the bell of the Dillard house, and were taken by Pyne direct to the library.

The old professor greeted us with nervous reserve.

“It’s good of you to come, Markham,” he said, without rising. “Take a chair and light a cigar. I want to talk to you—and I want to take my time about it. It’s very difficult. . . .” His voice trailed off as he began filling his pipe.

We settled ourselves and waited. A sense of expectancy invaded me for no apparent reason, except perhaps that I caught some of the radiations of the professor’s obviously distraught mood.

“I don’t know just how to broach the subject,” he began; “for it has to do, not with physical facts, but with the invisible human consciousness. I’ve struggled all week with certain vague ideas that have been forcing themselves upon me; and I see no way to rid myself of them but by talking with you. . . .”