Ronnie did not reply. He was seriously contemplating giving up the expedition. The engine trouble was a very serious one. They might last out perhaps another hour, but “The Hornet” could never return to Harbury with the engine in that state. This distressing fact, however, he did not tell her.
“Hark!” cried Beryl suddenly. “Listen! Why, there’s a machine up—over us!”
Ronald hold his breath. Yes, there was the distinct hum of a machine coming up from the east, following the railway from the main line over towards Hawes.
“Oh! do let’s go up. That may be Aylesworth’s friend,” suggested Beryl.
“I expect it is,” replied Ronnie grimly. “But with this engine there is danger—very grave danger—Beryl, dear. Are you quite prepared to risk it?”
“I’ll risk anything with you,” was the girl’s prompt reply. “We’ve risked our lives in the air before, and we’ll do so again to-night. We must not fail now that we’re within an ace of success.”
Her words spurred Ronnie to a supreme effort. With the hum of the mysterious machine in his ears, he set his teeth; then with the spanner in his hand he screwed the nut tightly, and without many further words he told his well-beloved that all was ready. They both got in, and two minutes later they were rising in the air, rapidly overhauling the mysterious machine.
Those moments seemed hours to Beryl. She scarcely dared to breathe. Ronnie had switched on the silencer, and they were now speeding through the air without a sound, save for the shrill whistle of the wind through the planes.
By the hum of the engine of the machine they were following they kept silently in its wake, gradually overhauling it.
Suddenly they saw flashes of white light from it—signals to the traitor Aylesworth in waiting below. Then they knew that they were not mistaken.