"Only--well, only because the Professor is a little eccentric," I replied diplomatically, "and we are rather anxious to know of his doings up in Scotland. Nearly all great men of genius," I added, "are slightly eccentric, you know." "Well, he went to the North British," replied the conductor. "They'll be certain to recollect him there." "Do you know the porter who took his bag?" "Yes, it was Walter Macdonald. I'll call him when we get to Waverley in the morning, and you can ask what questions you like." And the man left me and bustled away, while soon afterwards, as the great express began to gather speed towards Hatfield, I turned into the narrow little bed, while we roared along through the dark night. When I drew aside the blind next morning we were skirting the grey misty sea, within sight of the Bass Rock. Therefore I leisurely dressed, and, punctual to time, stepped out upon the long platform at Edinburgh at half-past seven. At a whistle from the conductor, a smartly-uniformed hotel porter stepped up, and I explained, in a few brief words, the object of my visit to Edinburgh. "I remember the gentleman quite well, sir," replied Macdonald, after I had exhibited the photograph. "I took his suit-case and kit-bag and gave them over to the hall-porter. The gentleman did not engage a room, I think. But his first inquiry was for the telegraph-office, and I directed him to the General Post Office, which is almost next door here. That's about all I know of his movements." I gave the man a tip, and, ascending in the hotel lift, passed through the lounge and entered the big coffee-room which overlooks Princes Street, where I breakfasted. Afterwards I lounged about the main hall which opens upon Princes Street--the entrance from the station being from deep below at the back of the premises. I saw that outside the reception office, upon a green baize-covered board and placed beneath tapes, telegrams for visitors were exhibited, and the addressees took them themselves. It would, therefore, be quite easy for anyone not staying in the hotel to have a telegram addressed there, and to receive it in secret. It would also be just as easy for a person to take anybody else's telegram that happened to be there. Two young lady clerks were behind the brass grille, and presently I addressed the elder of the pair, and showed her the photograph. Neither, however, recognised it. I turned up the visitors'-book, and saw that on Monday the fourteenth no person of the name of Greer had registered. "He was a chance customer, evidently," remarked the elder of the girls in neat black. "He arrived, you say, by the morning East Coast express, therefore he may just have had breakfast and gone on. Many people do that, and catch their connections for the North. In such a case we never see them. Both myself and my friend here were on duty all day on Monday." "I certainly have never seen the gentleman to my knowledge!" declared the other.