neck became of a deep crimson colour.  I was saying to myself that this was a common effect of sudden surprise, when I saw her clutch quickly at the back of her chair, as if to steady herself.  A moment later she sank into her seat.  Her face was now as pale as ashes, and I felt I had good reason to be alarmed.  I think she was conscious of my scrutiny, for she turned her face from me and remained motionless.  The movement told me she was trying to regain command of her faculties and I forbore to interfere in the struggle, though I watched her with some solicitude.  My fears were at once dispelled, however, when Maitland entered, for Gwen was the first to welcome him.  She extended her hand with much of her old impulsiveness, saying:  “I have so much for which to thank you—­” but Maitland interrupted her.  “Indeed, I regret to say,” he rejoined, “that I have been unable thus far to be of any real service to you.  The Ragobah clue was a miserable failure, though we may do ourselves the justice to admit that we had no alternative but to follow it to the end.  I confess I have never been more disappointed than in the outcome of this affair.”  “My dear fellow,” I said, “we all have much to be thankful for in your safe return, let us not forget that.”  Maitland laughed:  “That reminds me,” he said, “of the man who passed the hat at a coloured camp-meeting.  When asked how much he had collected, he replied:  ’I didn’t get no money, but I’se done got de hat back.’  You’ve got your hat back, and that’s about all.  However, with Miss Darrow’s permission, I shall go back to the starting point and begin all over again.”

“You are making me your debtor,” Gwen replied slowly, “beyond my power ever to repay you.”

“It is in the hope that no payment may ever be demanded of you,” he rejoined, “that I am busying myself in your affairs.”  The colour sprang to Gwen’s cheeks, but she only replied by a grateful glance.  I knew what was passing through her mind.  She was thinking of her promise—­of her father’s last words, and of the terrible possibilities thereof from which Maitland was seeking to rescue her.  She felt that she could safely owe him any debt of gratitude, however great, while he, on his part, took what I fancied, both then and afterward, were unnecessary pains to assure her that, in the event of his finding the assassin, she need have no fear of his making any claim whatsoever upon her.  And so the whole affair was dropped for the time being and the rest of the evening devoted to listening to Maitland’s account of his experiences while abroad.

The next morning I called upon our detective at his laboratory and asked him what he intended to do next.  He replied that he had no plans as yet, but that he wished to review with me all the evidence at hand.

“You see,” he said, “the thing that renders the solution of this mystery so difficult is the fact that all our clues, while they would be of the utmost service in the conviction of the assassin had we found him, are almost destitute of any value until he has been located.  Add to this that we are now unable to find any motive for the crime and you can see how slight are our hopes of success.  If ever we chance to find the man,—­for I feel that such a consummation would result more from chance than from anything else,—­I think we can convict him.