"The search-light is ready, whenever you want it, Lieutenant," remarked the youthful motor boat skipper.
"The use of the light might save the fellows on the other craft some guessing," smiled Lieutenant Hal. "I want to keep 'em guessing as long as possible."
"I'll kick on more speed," proposed Hank, reaching for the deck controls.
"Wait until you get orders," interposed Skipper Tom Halstead. "This is government business, Hank, and we're not government officers, so we'll act only under orders."
It was evident that those aboard the craft upstream had made out the pursuing motor boat. The unknown craft was now heading straight across the stream, and kicking on some speed.
"How fast is the stranger going?" asked Lieutenant Overton.
"Twenty miles an hour, as nearly as I can guess," replied Skipper Tom.
"How fast can you go?"
"Twenty-six to twenty-eight miles."
"Crowd it about all on, then. I don't want to have that other craft get too close to Mexico before we push up alongside."