"Besides," continued Sturgis, thoughtfully, "the letter itself bears evidence, on its face, that it could not have been written by Arbogast. Your bookkeeper was of a weak, nervous, excitable temperament, as all his actions plainly show. Before such a man is brought to the point of taking his own life, he must have passed through a more or less protracted period of agonizing nervous tension, of which you and I can hardly form any adequate conception. Under the circumstances, if he loved his wife, conscious that by his guilt he was about to plunge her into the depths of grief and shame, he might have written her an incoherent and hysterical letter, or a tender and repentant letter, but never this frigid matter-of-fact statement of a supreme decision. This letter is the work of a cold and calculating nature, incapable of ordinary human feeling. The man who wrote it would not have written to his wife at all, or would have written only to serve some selfish purpose. From what I know of Arbogast, I do not believe he was capable of composing these lines." "You think, then, that the letter was written by Chatham," said Dunlap. "But what object could Chatham have for writing such a letter?" "No," answered Sturgis, "I do not think that Chatham wrote this letter. That is the curious part of it. I cannot believe that if Chatham had been aware of the important nature of its contents, he could have been willing to leave it for an instant within Arbogast's reach." "But who, then, could have been its author, and why should he have intrusted the letter to Chatham?"