but the
building continued to tremble, and the great wheel to creak.

"What a donkey the man was to let them cut his door right behind the
arms," exclaimed Frankie.

"And with no proper means of stopping the sails from inside, once the
wind began to blow," added Percy.

"No. That's my fault," admitted Ferdinand. "I broke the gear some way."

"Well, if we only had an axe," said one of the other boys, "we might cut
our way out of the building on the side opposite the door."

But Dave had already searched the mill for tools. There wasn't even a
rope. Had there been, they could have let themselves down from the high
window to the ground.

"It should be against the law to build windmills without proper
fire-escapes," declared Frank, trying to laugh.

But it was hard to joke about the matter. It looked altogether too
serious.

The wind continued to blow steadily--a little harder, indeed, as time
passed; but the sun grew hotter. It came noon, and they knew that those
at Green Knoll Camp had long since expected them back.

Finally a figure appeared upon the path far down the hill. They
recognized Tubby Blaisdell trudging painfully up the slope in the hot
sun, evidently an unwilling messenger from Mrs. Havel and Professor
Skillings.

They began to shout to Tubby, although they knew very well it was
useless. He couldn't have heard their voices down there, even if the
windmill hadn't made so much noise.

But the girls fluttered their hats from the window and, bye and bye, the
stolid fat youth, glancing up while he mopped his brow, caught sight of
the signals. He halted, glared up at the window from under his hand, and
then hurried his steps.

"Oh, you Tubby!" shouted Frank, at last, thrusting her tousled curls out
of the window. "Can't you help us?"

He heard these words, and looked more bewildered than ever.

"Say! what do you want?" he bellowed up at them. "Don't ask me to climb
up those ladders, for I can't. And Mrs. Havel and the prof. say for you
to come back to camp. They think a storm is coming. Besides--aren't you
hungry?"

"Hungry! why, Tub," yelled down Ferd, "if we could only get at you, we'd
eat you alive!"

Tubby looked more than a little startled, and glanced behind him to see
that the way of retreat was clear.

"Well, why don't you come down and get your lunch, then?" demanded young
Blaisdell.

"We can't," said Wyn, and she explained their predicament.

"Can't stop those sails?" gasped Tub