"There is no question that Mr. Portman left the house," I said.
"Oh, no. Isaacson was quite definite, but I am trying to fit facts to my theory. I said we should be back in two hours, so we have about two hours to wait."
There was plenty of room behind the screen, but those two hours went slowly. I could not decide what theory the professor had got in his mind, but concluded that he was not so satisfied with the honesty of Mrs. Eccles and the cadaverous youth as I was. He had looked at his watch when we went behind the screen, and he allowed a full two hours to elapse before he would leave our hiding-place.
He walked straight to the chest and opened it. It was empty. All the papers had gone.
"Well, Wigan?"
I stared into the chest and did not answer.
"It looks like another way into this room, doesn't it"—and then he started—"or out of it. I hadn't thought of that. Wait."
He took an old envelope from his pocket, dropped it into the chest, and locked it. He waited a moment, then opened the chest again. The envelope had gone.
"I confess, Wigan, that this is a surprise," said Quarles. "I must go home and think. I believe—yes, I believe we have the clew. You must search Portman's papers for some reference to a business acquaintance, probably a foreigner. Perhaps Portman knows Italy—Florence. It might very likely be Florence. I fancy this chest had its home there. If you find any reference to a friend who is a Florentine, and can lay hands on him, you might question him closely about his movements on the day of Portman's disappearance."
"The first thing is to get this chest moved," I said.