As a matter of fact, I'd like to make you an offer right now to do some original research with me. I may not be a top-flight genius like Metternick or Dahl, but my reputation does carry some weight with the Board. (_That, Turnbull thought, was a bit of needless modesty; Duckworth wasn't the showman that Metternick was, or the prolific writer that Dahl was, but he had more intelligence and down-right wisdom than either._) So if you could manage to get a few months leave from Columbia, I'd be honored to have your assistance. (_More modesty, thought Turnbull. The honor would be just the other way round._) The problem, in case you're wondering, has to do with the Centaurus Mystery; I think I've uncovered a new approach that will literally kick the supports right out from under every theory that's been evolved for the existence of that city. Sound interesting? I'm mailing this early, so it should reach you in the late afternoon mail. If you'll be at home between 1900 and 2000, I'll call you and give you the details. If you've got a pressing appointment, leave details with the operator. All the best, Jim Duckworth * * * * * Turnbull slid the letter back into its tube and picked up the second letter, dated 22 August 2187, one day later. * * * * * Dear Dave, I called last night, and the operator said your phone has been temporarily disconnected. I presume these letters will be forwarded, so please let me know where you are. I'm usually at home between 1800 and 2300, so call me collect within the next three or four days. All the best, Jim * * * * * The third letter was dated 10 November 2187. Turnbull wondered why it had been sent. Obviously, the manager of the Excelsior had sent Duckworth a notice that Dr. Turnbull was off-planet and could not be reached. He must have received the notice on the afternoon of 22 August. That would account for his having sent a second letter before he got the notice. Then why the third letter? * * * * * Dear Dave, I know you won't be reading this letter for six months or so, but at least it will tell you where I am. I guess I wasn't keeping as close tabs on your work as I thought: otherwise I would have known about the expedition to Lobon. You ought to be able to make enough credit on that trip to bring you to the attention of the Board. And don't feel too bad about missing my first letters or the call. I was off on a wild goose chase that just didn't pan out, so you really didn't miss a devil of a lot. As a matter of fact, it was rather disappointing to me, so I've decided to take a long-needed sabbatical leave and combine it with a little research on the half-intelligent natives of Mendez. I'll see you in a year or so. As ever, Jim Duckworth * * * * *