rough the
opening in their fur caps. The snowflakes covered everything and the
airship looked more like a craft bedecked from stem to stern with cotton
batting than anything else. Jack and Mark walked around to the stern.
Suddenly Mark stumbled over something.

"What's this?" he cried.

Jack hurried to his side. As he did so the bundle gave a heave, and,
breaking through the snow blanket, there was displayed the calm features
of Dirola.

"Me sleep!" she announced with a smile.

And that was what she had been doing while the airship was being whirled
around by the strange force! She had braced herself in a corner, pulled
her furs about her face, and slumbered, even when the ship turned over.
So well braced was she that she did not tumble off.

"Well! She's a cool one!" exclaimed Mark.

"I guess you'd be too, if you slept out of doors with the temperature
about seventy below zero," remarked Jack. "But let's go in and tell the
professor Dirola is here. He may be worried about her."

The boys started for the cabin. They had not taken five steps before,
with a sudden lurch, the airship dived like a kite without its tail.
Then the craft turned completely over!

Jack and Mark with the two helpers and Dirola were thrown from the deck,
head first, toward the earth! Down and down they fell, uttering
despairing cries!

CHAPTER XXI

LOST IN THE SNOW

Once more the wind blew with hurricane force. On board the _Monarch_
Washington and Professor Henderson were tossed to the ceiling again.
Then the ship righted herself.

"De boys! De boys!" cried Washington, suddenly thinking of them. "Dey
hab falled off!"

"Great Scott! So they have!" exclaimed the inventor. "That is, unless
they grabbed something as we went over!"

"An de Sesquitomexico woman, too!" cried the colored man, meaning
Dirola.

"I guess she went with the others," said the professor. "We must take a
look as soon as it is safe."

Then came a strong gust of wind that hurled the ship forward. When it
had subsided Washington and the old inventor ventured outside. The boys
were nowhere to be seen.

"They are lost!" cried Andy, who had crawled to the bow of the ship
after the captain and Washington.

For a little while longer the airship sailed along easily, the wind no
more rushing with such force. Then, all at once the craft settled down
until, with a jerk, it came to rest on a big snow bank.

"We's landed!" exclaimed Washington. "We's hit de