“That is natural!” I replied, “for the great clock at the end of the corridor was striking twelve as she came back to the bedroom. I thought it never would stop.”

“That tallies also with Miss Cynthia’s testimony. She states that she saw Miss Winnie go to the safe a few minutes before twelve; that she, Miss Cynthia, lay still until the clock struck the quarter, and then examined the safe, finding your money gone.

“Inference (since Miss Winnie apparently noticed nothing out of the way when she looked in): if neither of these young ladies took it, the robbery must have been committed during that fifteen minutes.”

“That seems hardly possible,” I said, “since Cynthia, Winnie, and I were all awake during that time.”

“It is possible, though not probable. Cynthia’s bedroom door, opening into the parlor, was closed. Are you quite certain that you did not fall asleep before the quarter struck. Did you hear it?”

“No, I am not at all certain.”

“Very good. Then if the thief were standing in the studio waiting for his opportunity, he might have slipped in during that time. Is there any way in which we can ascertain whether any one was in the studio between twelve and a quarter past?”

“I know of no way,” I replied. “There was no one in the studio at ten o’clock when I looked in.”

“Very good; the known quantities are being gathered in, the unknown ones defined; the problem becomes simpler. I think we will be able to solve it soon. Meantime, if any new developments appear, be so good as to report them to me.” He rose and bowed stiffly in token of dismissal. I hurried to our rooms and found Adelaide and Winnie.

“Where is Milly?” I cried; “Mr. Mudge wants to see her next.”