"I can't make head or tail of them," I said when I had looked carefully at each, and endeavoured to unravel its secret, for obviously it must possess some secret meaning. "What do you make of them, Dick—anything?" "Yes. Look, and I will show you," he answered, going to the writing-table and bringing over pen, ink and paper. "I have always been fond of discovering, or trying to discover, the meanings of these queer cypher messages you see sometimes in some newspapers, and I have become rather good at it—I have a book that explains the way cyphers are usually constructed. I have found out a good many at one time and another, but this one took me rather a long time to disentangle. I can tell you, Mike, that when I found it concerned you I felt frightfully excited." "Concerned me!" I exclaimed. "Oh, nonsense. What is it all about?" "Follow me carefully, and I'll show you. I guessed from the first that it must be one of those cyphers that start their alphabet with some letter other than A, but this one has turned out to be what my book calls a 'complex alphabet' cypher. I tried and tried, all sorts of ways—I began the alphabet by calling 'b' 'a'; then by calling 'c' 'a'; then by calling 'd' 'a,' and so on all the way through, but that was no good. Then I tried the alphabet backwards, calling 'z' 'a'; then 'y' 'a'; right back to 'a,' but that wasn't it either. Then I tried one or two other ways, and at last I started skipping the letters first backwards, and then forwards. Doing it forwards, when I got to 'l' I found I had got something. I called 'l' 'a'; 'n' 'b'; 'p' 'c'; and so on, and made out _bjptnbblx_, the first word in the first cypher, to be the word 'improving,' and the two letters before it in capitals 'R.P.' to be really 'D.C.' The next cypher word, _wamii_, stumped me, as the code didn't make it sense; then it occurred to me to start the alphabet with 'm' instead of 'l,' skipping every alternate letter as before, and I made out _wamii_ to mean 'shall.' The next cypher word, _xvzzjv_, I couldn't get sense out of by starting the alphabet with either 'l' or 'm,' so I tried the next letter, 'n,' skipping alternate letters once more, and that gave me the word 'settle.' I knew then that I had got the key, and I soon had the whole sentence. It ran as follows: "_D.C. improving shall settle all soon.—Dusky Fowl._" "Still, I wasn't much the wiser, and it never for a moment occurred to me that D.C. stood for Dulcie Challoner—" "Good heavens, Dick!" I cried, "you don't mean to tell me that Dulcie—" "Do be patient, brother-in-law, and let me go through the whole thing before you interrupt with your ejaculations," Dick said calmly. "Well, four days went by, and then in the _Morning Post_ of February 7th the second advertisement appeared: "Rlxt. ex. sroehnel. 28. Zcokk. zbpl. qc. Ptfrd. Avnsp. Hvfbl. Ucaqkoggwx.—DUSKY FOWL."