seem to waver.

"Wow, Peg!" he cried, "that puff didn't even bother Fan Harding's craft.
It was uncanny to see her weather it."

"There's something uncanny about it altogether," sniffed Peggy; "it's a
regular phantom airship."

"That's just what it is," agreed Roy, "but I'm afraid it is a substantial
enough phantom to carry off that $5,000 prize."

Another puff prevented Peggy from replying just then. Once more the
Golden Butterfly careened violently, and then, under Peggy's skillful
handling, righted herself. But this time the puff was followed by a
steady rush of wind.

"Better turn, Peg, before it gets any worse," advised Roy; "we're off our
course now."

"I--I tried to," exclaimed Peggy, desperately, "but the wind won't let
me. I don't dare to."

"We must," exclaimed Roy, with a serious note in his voice; "if this wind
freshens much more we won't be able to turn at all."

He leaned forward and took the wheel from his sister. But the instant he
tried to steer the aeroplane round, the wind, rising under one wing tip,
careened her to a perilous angle.

"No go," he said; "we've got to keep on going."

"But where can we land?" asked Peggy, a little catch in her voice.

"We'll have to take chances on that," decided Roy. "It would be suicidal
to try to buck this wind."

The breeze had now freshened till it was singing an Aeolian song in every
wire and brace of the Golden Butterfly. Brother and sister could feel the
stout fabric vibrate under the strain of the blast.

The aeroplane was moving swiftly now. But it was the toy of the wind,
which grew stronger every minute. The dark landscape beneath fairly flew
by under them. Neither of them thought to look back at the red and green
lights in the sky behind them.

All at once, Roy, who had leaned over his sister's shoulder and glanced
at the compass, gave a sharp cry.

"We've got to turn, sis," he said, in a tense, sharp voice.

"What do you mean, Roy? Are we in any very serious danger?"

The girl's voice shook nervously in response to the anxiety expressed in
her brother's tone.

"Danger!" echoed Roy. "Girlie, we are being blown out to sea!"

Blown out to sea! The words held a real poignant terror for Peggy.

"Oh, Roy, we must do something!" she cried, helplessly.

"Yes, but what? We can't, we daren't turn about. The machine would tip
like a bucket. No, we must keep on and trust to luck."

Peggy shuddered. Hurtled along in the wind-driven darkness,