“Yes, that’s true. Still, it’s only a subsidiary point. Let’s see . . . the sleeper had originally been dated for the Thursday, hadn’t it; and then Thursday had been scratched out and Wednesday put instead?”
“Yes, but it was no good supposing that was a fraud. Because Thursday wouldn’t be any more probable than Wednesday,—in fact, less.”
“Yes; it’s confoundedly queer. I suppose he couldn’t possibly—Gordon, what date was the Wednesday?”
“The 17th.”
“It was? Then the Tuesday would be the 16th, and the Thursday the 18th.”
“My dear Reeves! How on earth . . .”
“Child’s play, my dear Gordon. No, but look here, it’s serious. Don’t you see that if there’s one day of the week whose name can be easily changed to another it’s Tuesday, which you can always change to Thursday? And that if there’s one number which can be easily changed it’s 6, which you can always change to 8?”
“Yes, but this wasn’t a change of . . .”
“Oh, don’t you see? The sleeper was for Tuesday the 16th, the day of the murder. Brotherhood meant to go straight from Binver. The murderer found this sleeper-coupon in his pocket, and saw a golden opportunity of clinching his faked evidence about the trains. He could have destroyed the document, of course,—it was dangerous to him, because it proved that Brotherhood was really on the fast train. But he could do better by faking that too; changing Tuesday into Thursday and 16 into 18. Look here, how easy it is to do . . . There! Very little risk of detection there. But there was just a slight risk of detection, and this man wasn’t taking any risks, So, having changed Tuesday the 16th into Thursday the 18th, he deliberately crossed out Thursday the 18th, and wrote in ‘Wednesday’ the ‘17th.’ Double bluff, that is. People don’t look for two corrections where they can see that there’s one.”
“I say, this murderer is some fellow!”