gns of
it now."

He let some gas out of the bag, and the _Monarch_ slowly settled toward
the earth. The inventor opened the trap door that covered the plate
glass in the floor of the cabin, and peered down. When within five
hundred feet of the ground he signaled to stop the descent of the ship.

"Nothing but ice, ice, ice!" he announced. "Big hills and mountains of
it. There is no sign of open water. Well, we are not quite at the pole
yet."

Jack's turn at the wheel came to a close, and Mark relieved him.
Washington, who had been on duty pretty steadily in the engine room,
gave his place up to the inventor, and stretched out to sleep. Bill and
Tom were snoring in their bunks, and Andy was resting easily, the pain
from his wound being relieved by some ointment the professor put on.

The boy in the conning tower kept his eye on the two compasses, the one
telling the direction, the other the nearness to the north pole. The
latter gradually kept inclining more and more toward the earth.

"If we can only make it," thought Mark. "It will be something no one has
ever done before. My! What a story the papers would make of it if they
knew!"

"How is she running?" asked the captain, coming into the tower.

"Very well, indeed, sir."

"You might send her up a little," suggested the professor. "Keep her
about half a mile high, and I'll be with you again before long."

The professor went to his bunk, and Mark was pleased enough to be left
alone in charge of the ship. He held the wheel firmly, and did not
deviate half a point from the northern course.

He had been steering for half an hour when he was suddenly aware of a
dense gloom that settled down all about him. Then there came a great
roaring sound. The air craft rocked violently. The wind whistled shrilly
through the cordage and careened the _Monarch_ to one side.

Then the whole atmosphere grew from a dense black to a strange opaque
whiteness: a whiteness that shut out the view from every side, and
enveloped the ship as if it had fallen into a feather bed. Mark started
back in fright and let go his hold on the steering wheel.

CHAPTER XIX

A BLINDING SNOWSTORM

"Quick! Professor!" cried Mark. "Jack, Washington, everybody! Hurry up!"

"What's the matter?" asked the inventor, running to the conning tower.

In answer Mark pointed outside.

"A snow storm!" exclaimed the captain. "We must expect them up north.
But this is worse than I thought!"

He glan