I kept my eyes on the back of Herb's head. You can tell a lot by doing that. At first his head turned this way and that, indicating he was full of curiosity. I was waiting for that telltale sudden tensing, with the head directed at some spot, that would tell of a sudden "memory" stirring in the man's mind.
I almost missed it when it came, because it was between two passages—a blank wall. The briefest pause, then Herb was going on again as though nothing had happened.
But now his head had stopped its curiosity-motivated pivotings. It was the head of a man who was no longer curious—who has made up his mind about something. I didn't like it.
And when the group emerged into open air once more without Herb having tried anything I knew as certainly as I had ever known anything that he intended coming back here, and soon.
In the comfort station before boarding the bus I scrawled a hasty note to the guards to investigate the spot halfway between passageways 14 and 15 on the first level, and slipped it to one of them as I passed him to get on the bus.
We visited four other spots on the tour. When Herb showed no real interest in them it only clinched what I was already sure of, that he planned on returning.
At the Ancient City Hotel once again, I gave the high sign, and shortly Herb and Dotty were being watched by capable men, leaving me free to go to my room.
Once there, I called the dome. They were just getting the X-ray setup in place to explore that wall and promised to call me as soon as they were finished. Next I called C.I. and made my report. I was still making it when the operator broke in.
"Steve Merrit wants to talk to you," she said crisply.