"What! for God's sake!" cried Harren hoarsely.
"I don't know yet. Wait; let me study it."
"Can you not see her face, her eyes? Don't you see that exquisite slim figure standing there by the curtain?" demanded Harren, laying his shaking finger on the photograph. "Why, man, it is as clear, as clean cut, as distinct as though the picture had been taken in sunlight! Do you mean to say that there is nothing there—that I am crazy?"
"No. Wait."
"Wait! How can I wait when you sit staring at her picture and telling me that you can't see it, but that it is doubtless there? Are you deceiving me, Mr. Keen? Are you trying to humor me, trying to be kind to me, knowing all the while that I'm crazy—"
"Wait, man! You are no more crazy than I am. I tell you that I can see something on the window pane—"
He suddenly sprang up and walked to the window, leaning close and examining the glass. Harren followed and laid his hand lightly over the pane.
"Do you see any marks on the glass?" demanded Keen.
Harren shook his head.
"Have you a magnifying glass?" asked the Tracer.