Never, Ned thought, had he seen a man so slow at getting ready the supply of gasolene. He was to take it out in a wagon, but first he mislaid the funnel, then the straining cloth, and finally he discovered a break in the harness that needed mending.

"I believe he's doing it on purpose to delay us," thought the youth, "but it won't do to say anything. Something is in the wind." He helped the man all he could, and urged him in every way he knew, but the fellow seemed to have grown suddenly stupid, and answered only in French, though previously he had spoken some English.

But at last Ned, by dint of hard work, got him started, and rode on the gasolene wagon with him. Once at the anchored airship, Tom and the others filled the reserve tanks themselves, though the man tried to help. However he did more harm than good, spilling several gallons of the fluid.

"Oh, get away, and let us do it!" cried Tom at last. "I know what you—"

"Easy!" cautioned Mr. Petrofsky, with a warning look, and Tom subsided.

Finally the tanks were full, the man was paid, and he started to drive away.

"Now to make a quick flight!" cried Tom, as he took his place in the pilot house, while Ned went to the engine room. "Full speed, Ned!"

"Yes, and we'll need it, too," said the Russian.

"Why?" asked Tom.

"Look!" was the answer, and Ivan Petrofsky pointed across the field over which, headed toward the airship, came the man who had sought a quarrel with Tom. And with the spy were several policemen in uniform, their short swords dangling at their sides.