tense effort. If a murder has been committed, part one of the story ends with the mystery apparently insoluble but with curiosity projected over to part two in which there is a progressive and satisfying solution. If a buried treasure or a stolen letter is sought, part one ends with its finding; part two tells how it was found. You may bend back the second part over the first part and the two will be found to corrëspond in structure about as an itemized letter of inquiry corresponds to the similarly itemized reply. Stories of this kind are longer than those of the A type because there are two processes, tying and untying, complication and explication, enciphering and deciphering. If the A type is more artistic in the accepted sense, the second type is more ingenious, more intellectual, appealing as it does to the puzzle-solving instinct that every reader has to a degree. Poe called the second type "Tales of Ratiocination" (see page 240) and from them sprang the modern detective story. The first masterpiece of this type, The Murders in the Rue Morgue, was written in 1841; the last The Purloined Letter, in 1845. If we call the first type cuneiform, we may call this type insectiform, because, as in insects, there is an apparent cut or dip inward near the middle of the body. But if A represent the structure of the first type, B may well represent the structure of the second type, the two semicircles of the letter picturing the two movements of the story toward its preordained conclusion. The meeting of the two semicircles is where complication ends and explication begins. The poems, by the way, belong prevailingly to the A type, The Haunted Palace alone suggesting the B type.
