Bob well knew that the men up there were keeping the ether humming with reports, messages, orders, between the station and the ships themselves.

What was Payne Bentley thinking up there? Did he see victory or did he fear defeat? Did he, like the ranger who had worked beside him, see the danger in that narrow gully?

He did not have to wait long for an answer to that. As he took a wet sack and threw his dry, scorched one upon the ground he saw that men were being rushed to one point and that point the outermost edge of the blaze where it reached hungry fingers toward the gully. Bob gazed up, almost in awe, at the hovering planes.

“He’ll do it,” he exulted. “He’ll beat that blaze if anybody can.”

It did not take Bob very long to see that he had exulted too soon. Despite the heroic efforts of the men who fought to stem the tide of destruction, the fire crept steadily, relentlessly forward, forcing the workers foot by foot, inch by inch back toward the gully.

Side by side with the men, never faltering, though their lungs felt near to bursting and their smarting eyes tormented them, fought the Radio Boys.

Only once did Jimmy, naturally feeling the strain of it more than the other boys, fall back to get his breath. But not five minutes had passed before he was with them again, gallantly taking up the task where he had left it.

And all for nothing! The fire, feeding on the dry and crackling timber made brittle by weeks of drought, rushed onward like a destroying fiend, seeming to gather headway as it came.

Faster and faster the men retreated before it, back, back, back to the last line of retreat—a deep trench dug at the very mouth of the gully. If they were driven past that——

And they were driven past it, fighting for the last inch, gasping, struggling, sweating—down in the trench—on the other side—hacking frantically at branches, felling them to save them from the worse destruction of the fire.