"You don't think that this is very bold of me?" she asked. "I am pretty Bohemian in any case," David laughed, as he looked down fondly into the shy, sweet eyes. "And I'm too overjoyed to see you to think about anything else. I wish my mother was at home. No, I don't, because I have you all to myself." "David! On an occasion like this you ought to be the pink of propriety. Do you know, I believe that I have made a great discovery?" "Indeed, little girl! And what have you found out?" "Well, you must tell me something before my discovery seems valuable. David, you are a close student of human nature. Is it possible for men of phenomenal cunning to make careless mistakes? Do the most clever criminals ever make childish blunders?" "My dear child, if they didn't the police would have very little chance. For instance, I have discovered how those enemies of ours got hold of the notepaper that lured Van Sneck here. They sent a messenger to Carter's, in East Street, presumedly knowing that my dies were there, and ordered a quarter of a ream of paper and envelopes. These were to be sent to an address in East Grinstead in a hurry. Now, that was very clever and smart, but here comes the folly. Those people, in the stress of business, actually forgot to ascertain the cost and pay for the paper, so that it was down yesterday in my last quarter's bill. Oh, yes, I assure you, the most brilliant criminals do the most incredibly foolish things." Ruth looked relieved. Her pretty features relaxed into a smile. "Then I fancy Reginald Henson has done so," she said. "I fancy I have solved the mystery of the cigar-case--I mean, the mystery of the one I bought." "And which was changed for the one purchased at Walen's, hence these tears. But Lockharts say that _our_ case was really purchased by an American." "Yes, I know. And I fancy that the manager honestly thought so. But I think I can explain that." It was David's turn to look up eagerly. "Do you mean it?" he exclaimed. "It will make a wonderful difference if you can. That has been one of the most bewildering knots of the whole puzzle. If we could only trace the numbers of those notes, I suppose changed at the same time as the cigar-case." "Indeed they were not," Ruth cried. "I have ascertained that the case was changed by Henson, as you and I have already decided. Henson made the exchange not at the time we thought." "Not when you left the package on the table for him to see?" "No; at least I can't say. He had the other case then, probably, passed on to him by Van Sneck. Or perhaps he merely ascertained what I had purchased. That was sufficient for his purpose. Of course he must have found out all about our scheme. After I had laid my cigar-case on your doorstep a man quietly changed it for the other purchased at Walen's. But this is the alternate theory only. Any way, I am absolutely certain that you got exactly the same notes that we had placed in the original case."