"Just so. The consequence is that you get a very unsatisfactory affair that has no special interest to an amateur and is only baffling because it is--well----" "Well, baffling?" "Exactly, Max. Your would-be jest has discovered the proverbial truth. I need hardly tell you that it is only the insoluble that is finally baffling and this is very probably insoluble. You remember the awful smash on the Central and Suburban at Knight's Cross Station a few weeks ago?" "Yes," replied Carrados, with interest. "I read the whole ghastly details at the time." "You read?" exclaimed his friend suspiciously. "I still use the familiar phrases," explained Carrados, with a smile. "As a matter of fact, my secretary reads to me. I mark what I want to hear and when he comes at ten o'clock we clear off the morning papers in no time." "And how do you know what to mark?" demanded Mr Carlyle cunningly. Carrados's right hand, lying idly on the table, moved to a newspaper near. He ran his finger along a column heading, his eyes still turned towards his visitor. "'The Money Market. Continued from page 2. British Railways,'" he announced. "Extraordinary," murmured Carlyle. "Not very," said Carrados. "If someone dipped a stick in treacle and wrote 'Rats' across a marble slab you would probably be able to distinguish what was there, blindfold." "Probably," admitted Mr Carlyle. "At all events we will not test the experiment." "The difference to you of treacle on a marble background is scarcely greater than that of printers' ink on newspaper to me. But anything smaller than pica I do not read with comfort, and below long primer I cannot read at all. Hence the secretary. Now the accident, Louis." "The accident: well, you remember all about that. An ordinary Central and Suburban passenger train, non-stop at Knight's Cross, ran past the signal and crashed into a crowded electric train that was just beginning to move out. It was like sending a garden roller down a row of handlights. Two carriages of the electric train were flattened out of existence; the next two were broken up. For the first time on an English railway there was a good stand-up smash between a heavy steam-engine and a train of light cars, and it was 'bad for the coo.'" "Twenty-seven killed, forty something injured, eight died since," commented Carrados. "That was bad for the Co.," said Carlyle. "Well, the main fact was plain enough. The heavy train was in the wrong. But was the engine-driver responsible? He claimed, and he claimed vehemently from the first and he never varied one iota, that he had a 'clear' signal--that is to say, the green light, it being dark. The signalman concerned was equally dogged that he never pulled off the signal--that it was at 'danger' when the accident happened and that it had been for five minutes before. Obviously, they could not both be right." "Why, Louis?" asked Mr Carrados smoothly. "The signal must either have been up or down--red or green."