"Thanks," Dave replied. "We got away with it okay. But I'd hate like heck to have to do it every day. You spotted that mountain peak, didn't you?" "Quite," the English youth murmured. "But I thought it best to keep my mouth shut. Realized that you knew what you were doing. And besides, no sense in--" "No sense in giving this old dodo grey hairs, eh?" Colonel Welsh spoke up with a chuckle. "Well, it was nice of both of you, but I saw it, too. The only reason _I_ didn't speak, though, was because my tongue was frozen stiff. As you say, Dawson, I'd hate to have that sort of thing for a daily diet. Very sweet flying, though, very sweet." "We could have made it sweeter if this plane had been armed," Dave grunted, and stared at the black sky ahead. "That tramp certainly had his nerve jumping on us. Wonder who the heck he could be. Sure you haven't any ideas, Colonel?" There was a long minute of silence while the senior officer seemed to make up his mind. "No, I'm afraid I haven't," he finally said slowly. "As you mentioned awhile back, there are probably plenty of birds who would like to see me out of the way. Somehow, though, I can't see them going about it in this manner. Their style is more along the line of pot shots from dark doorways. Or a bomb in my car, or tossed through my window. Frankly, I can't make head nor tail of this business tonight." "Many chaps know you were headed west, sir?" Freddy Farmer asked quietly. "What do you mean, many?" the Colonel replied sharply. "Did I broadcast it, you mean?" "Hardly that, sir," Freddy chuckled. "I mean, did you tell many people that you were making this trip? Not that any of them are in the pay of Tokio or Berlin, sir, but it's possible that one of them might innocently enough mention the fact to somebody who was. You understand what I mean, sir?" There was another moment of silence while the chief of U. S. Intelligence thought things over. "I see what you mean, Farmer," he grunted presently. "No, I didn't tell anybody who didn't have the right to know. Fact is, the only ones I told were those three officers you met in my office. And if those three aren't one hundred per cent Americans, then I'm Adolf Hitler in the flesh." "What about the other end?" Dawson asked. "What other end?" "San Diego," Dave said. "Is your man in charge there expecting you? Or are you just dropping in on a surprise visit?" "No wonder you chaps always come out on top," Colonel Welsh said in a frank tone. "Once you get your teeth in something you keep at it until there's nothing left. Yes, I did wire my head agent in San Diego that I was coming west tonight. And--" "And my first month's pay as a U. S. Naval Aviation Lieutenant says somebody read that wire!" Dawson cut in quickly.