"Here goes then. You remember that I set down my theoretical key-sentence, thus:" W O N F O R T O O F O R A T E "The uncoding went along splendidly for eight places, thus:" W O N F O R T O T H A N E C O U "The rest was gibberish. It follows then that the running off the track must have happened at the ninth substitution and nowhere else." "Obviously." "The very morning that your letter about the library window arrived--that is, on June the twenty-first--I was sitting at my desk; for the ten thousand time, more or less, I printed out those distracting capitals:" W O N F O R T O O F O R A T E "As I looked at the line of letters I suddenly discovered something entirely new: the five end ones formed the perfectly good English word, _Orate_. "There is a game, you know, in which you mix up the letters of a long word, such as _Plenipotentiary_, and then try to recombine them into subsidiary words, the biggest list winning the prize. Perhaps there were other esoteric or inside words in my key-sentence, a still deeper meaning and significance to this apparently haphazard collection of alphabetical symbols. I started experimenting, and almost immediately I did get another word, _Fort_. Now I'll write out the series again, using vertical lines to divide off the word-groups. Here it is:" W O N | F O R T | O O F | O R A T E "The only perplexity was in the third section, for although _OOF_ is a Yiddish slang word for money or cash it isn't much in use in our rural locality; in all probability, old Mr. Thaneford had never even heard of it. All the other words were good English. "What was the ninth letter, the alphabetical rock upon which my fine theory had gone to pieces? Why it was none other than the second O in that very word, _OOF_. Then I saw the solution in a flash. Do you?" I shook my head. "There is another English work which corresponds phonetically to the number 2 or two. Of course it is _TO_. Let us make the substitution, thus:" W O N | F O R T | O F | O R A T E "A complete English sentence, you see. It doesn't make very good sense, but that is of no consequence, since it is merely what Chalmers calls er--er--well, what _do_ you call it, Chalmers?" "Mnemonic guide," smiled Warriner. "An artificial aid to one's memory. It would be somewhat easier to write down the key-letters correctly if this absurd sentence were kept in mind. You have to be absolutely accurate in the coding of a cypher message." "Now then, Hugh, do you see?" demanded my wife. "Of course I do," I answered eagerly. "The extra O in your original key-sentence is not only wrong in itself, but its inclusion in the series throws everything which follows it into hopeless confusion. Let's try it out." Rapidly I wrote down the correct key-letters, and underneath them a score of the cypher symbols, thus: W O N F O R T O F O R A T E W O N F O R T Q W O T T U I J X I S V A Z P I H N X J X