"Hold on. Don't spoil everything now by betraying our presence. Let him get a little way and we'll follow him."
"But we may lose him in the darkness," objected Merritt.
"I scarcely think so," was the rejoinder; "in fact, I have a pretty good idea where he is bound for."
"And where may that be?"
"The place in which he lay this afternoon to read those signals from the distant island. Depend upon it, he is going to meet the men who manipulated that flag!"
"By hooky! That's so, Rob. What a mind you have for figuring out things! Of course, it's plain enough now that he is betraying Mr. Barr by giving drawings and plans of the submarine to Mr. Barr's enemies, but I didn't think he'd take so bold a method."
"There's nothing very bold about it," retorted Rob. "He is a trusted man, and has been given every opportunity to be dishonest, if it so suits him."
"I guess that's right; but it's our duty to thwart him."
"You just bet it is, and we'll do it, too, if it's possible. See, there he goes over the top of that sand dune. I could see his figure silhouetted against the sky. I reckon it's safe now to take after him."
"All right, you say when."