Dora. Sam said something, too, to Grace about a ring, at
which she laughed merrily and slapped his face. But when the boys were
in the biplane and ready to sail away, and he held up a finger with a
ring on it and looked at her questioningly--and longingly--she gave a
quick little nod of her curly head.

[Illustration: "OH, DICK, A DIAMOND RING!" SHE CRIED.--_Page_ 161.]

"All ready?" asked Dick, at last.

"All ready!" replied his brothers.

"Then start her up!" cried the oldest Rover boy, and the others gave a
turn to the propellers. Bang! bang! bang! went the engine, and Sam and
Tom rushed to their seats.

"Come again soon!" cried the girls.

"Just as soon as we can!" was the answer.

"Be careful!" pleaded Dora. "Please, please be careful!"

"We'll look out--don't worry," answered Dick. He had to shout, to make
himself heard above the noise of the motor. Then came the usual whizz
and rush, and a few seconds later the Rover boys were once more in the
air and bound for Brill.

Dick would have been pleased could he have allowed his mind to linger on
the conversation he had had with Dora, but he soon found this out of the
question. The wind had come up again, and was now blowing as strongly as
ever, and he had all he could do to manage the _Dartaway_. Soon the big
biplane commenced to pitch and toss like a small boat on the bosom of an
angry ocean.

"Say, this is getting something fierce!" was Sam's comment, after a
particularly thrilling dip. "I thought we were going right down that
time."

"You hold tight!" yelled Dick. "Don't let go for an instant."

"I'm as tight as glue," was the reply.

"Hadn't you better go up a bit, Dick?" came from Tom.

"Just what I thought of doing," was the answer.

The rudders were shifted, and swiftly the biplane mounted through space.
It was now growing dark, and presently the panorama that had been below
them, vanished from view.

"Huh! This won't do!" cried Dick. "I can't see how to steer."

"Steer by the wind for awhile," suggested Sam.

A minute later came a fierce gust of wind, followed by a second and then
a third. Around spun the biplane and then tilted up as if about to go
over. Then came an unexpected ripping and tearing sound.

"It's the left plane--it's torn loose!" yelled Sam. "Let her down, Dick,
before it is too late! If you don't, we'll drop to our death!"

CHAPTER XVII

CAUGHT IN A HAILSTORM

All of the Rover boys realized their extreme per