bit of it will grow," said Bob. "But first, come back into our coach with me; I want to tell you about those two men who sat back of you."
"Is that what you were staring about?" demanded Betty, as they found their seats and Bob picked up his camera preparatory to putting in a new roll of film. "I wondered why you persisted in looking over my shoulder so often."
Bob Henderson's boyish face sobered and unconsciously his chin hardened a little, a sure sign that he was a bit worried.
"I don't know whether you noticed them or not," he began. "They went out of the diner a few minutes ahead of us. One is tall with gray hair and wears glasses, and the other is thin, too, but short and has very dark eyes. No glasses. They're both dressed in gray—hats, suits, socks, ties—everything."
"No, I didn't notice them," said Betty dryly. "But you seem to have done so."
"I couldn't help hearing what they said," explained Bob. "I was up early this morning, trying to read, and they were talking in their berths. And when I was getting my shoes shined before breakfast, they were awaiting their turn, and they kept it right up. I suppose because I'm only a boy they think it isn't worth while to be careful."