n increasing their speed.

"Stop that, Ferd!" shouted Dave again, starting to descend the ladder.

"Isn't that just like a boy?" demanded Bess, in disgust. "He just
_had_ to fool with the machinery."

"What do you suppose the miller will say?" queried Wyn, anxiously.

The roar of the whirling arms almost drowned their voices. The wind had
increased to a brisk breeze. With the sails so well filled the arms
turned at top-notch speed. The tower shook as though it were about to
tumble down.

"Oh, dear me!" moaned Mina, the timid one. "Let us get out of here."

"Why doesn't Dave make him stop it?" shouted Frankie.

"Why doesn't the foolish Ferd stop it himself?" was Wyn's demand.

The other boys were already tumbling down the ladder, and the girls
followed as fast as possible. It was rather dark below, and when they
came to the ground floor, it was full of dancing dust-particles. Dave
and Ferd were busy over the machinery near the door.

"Can't you stop it, Dave?" shrieked Percy.

"The confounded thing is broken!" announced Dave, in disgust.

"Goodness me!" cried Frank. "I want to get out of here."

She started for the door; but Wyn grabbed her just in time. Past the
open door whirled the sails of the mill--one after the other--faster and
faster. And so close were the sails to the doorway that there was not
room for the very smallest of the Go-Ahead girls to get out without
being struck.

Dave stared around at the others. It was almost impossible to hear each
other speak--and what was there to say? Each boy and girl realized the
situation in which Ferd's meddling had placed them.

Until the wind subsided they were prisoners in the tower.

Ferd Roberts subsided into a corner, and hid his face in his hands. He
had done something that scared his inquisitive soul to the very bottom.

He had started the sails, and then, in trying to throw out the clutch,
he had started the millstones as well. _They_ made most of this
noise that almost deafened them.

Finally, however, Dave pushed the power belt from the flywheel, and the
stones stopped turning; but there was no way of stopping the sails. To
step outside the door was to court instant death, and until the wind
stopped blowing it seemed as though there would be no escape.

"And the wind blows sometimes two or three days at a stretch!" cried
Frankie.

"It's lucky Tubby isn't up here with us," Dave said, grimly. "He would
want to cast lots at once to see which on