Reflect for a moment, and you will fully realise the peril of my position. To me, it seemed quite plain that I had by my readiness to accept Kirk's friendship, given myself entirely into the hands of the conspirators. If Kirk were truly an honest man and not afraid, he certainly would have called in the police. Yet had he not openly admitted his inability to prove an alibi? That afternoon, a damp and dismal one, I had to run out on a car to Tunbridge Wells to see a customer who was purchasing the car which I drove. I took Dick with me, and, the car being a "forty-eight," we sped along pretty swiftly until we halted before the entrance to that old-world promenade, the Pantiles, near which my customer lived. Before we got home again it was near midnight, but on that night drive I resolved that on the morrow I would embark upon the work of amateur detective, and endeavour to discover something on my own account. To solve such a complete enigma as that now presented one must, I realised, begin at the beginning. And that was what I intended to do. Therefore, on the following night, at half-past eleven, I left King's Cross in a sleeping-car for Edinburgh, having first ascertained that the conductor was the same who had travelled by that train on the night of the Professor's alleged journey. He was a tall, lean, fair-whiskered Scot, whose uniform seemed too big for his shrunken frame, but who bustled up and down the corridor as soon as the train had started, inquiring of the passengers at what hour they would like to be called, and whether they would take tea. I waited until he came to my compartment, and then I put to him certain questions regarding his passengers on the night of Sunday, the thirteenth, asking whether he remembered Professor Greer. "Why, yes, sir," was his answer with a strong northern accent. "Another gentleman asked me about the Professor when I got back to King's Cross." "Did you take the Professor up to Edinburgh?" "Certainly, sir. I remember the name. Indeed, here it is in my book," and, turning back a few pages, he showed me the name among those who had secured sleeping berths in advance. "As I told the other gentleman who inquired, he wouldn't have any tea, and told me to call him at Dunbar." "And when you called him did you then see him in his berth?" "Yes, sir, he pulled the door back and inquired what kind of a morning it was." "Where did he alight?" "At Waverley, of course. I handed him out his bags, and one of the porters of the North British Hotel took them." "You're quite certain of that?" "As certain as we're going north to-night, sir," replied the man. Then I drew forth the Professor's photograph from my pocket and showed it to him. "That's the same gentleman, and a very nice gentleman he was, too, sir," he declared, the instant his eyes fell upon it. "But for what reason do you ask this? You're the second person who has made inquiries."