“De gas machine am gone on a rampage ag’in!”

Then, all at once, the airship began to sink.  All rushed to the engine room.  The gas generator had ceased working and the craft was settling toward the ocean, there being nothing to keep it aloft.

Frantically the professor and Washington worked at the apparatus.  It could not be adjusted.  Despair was on every face.  Faster and faster sunk the Monarch.

“Will we sink?” asked Andy.  “I can’t swim.”

“We may float,” said the professor.  “The bottom part of the ship is water tight.  We may float long enough to fix the machinery.”

Then, with a splash, the Monarch settled into the ocean, the gas bag falling limply on top of the cabins.

“Get out the life preservers!” shouted the professor.  “They are in the forward part.  Put them on, while Washington and I try to fix the gas machine!”

The airship had now become a water ship.  It rose and fell on the waves, rocking from side to side.

“Get ready to jump!” yelled Jack, running in from the conning tower.

“What now?” asked Professor Henderson, “Haven’t we troubles enough?”

“There’s a big whale and he’s headed right this way!” yelled Jack.  “He’s coming on like a locomotive, to ram us!”

Andy caught up his gun and hastened to the tower.  As Jack had said, a big sperm whale, spouting water high in the air from his nostrils, was headed for the Monarch, which, as it lay on the surface, the whale evidently took for a rival.

“I wonder if I can stop him with this rifle,” exclaimed Andy.

“No, but you can with the machine gun!” said Jack.

“Not while it’s in the stern,” replied the old hunter.  “I guess we are done for this time.  I’ll fire a few shots, anyhow, before I die!”

“Wait!” yelled Jack.  “I’ll turn the ship around!”

“Can you do it?”

“I think I can,” was the short reply.

“We cannot use the machinery.”

“I know that, but I can use something else—­that is, I think I can.”

“There is nothing to use.”

“Yes, there is.  See here!”

As the youth spoke he seized a long pole from the deck, and stuck one end of it in a large cake of ice that floated close by.  Slowly, but with the strength of despair he pushed the bow of the airship around so that it was pointed away from the on-coming whale.

“Run to the rear!” the boy cried to Andy.  “And hurry up!”

The hunter did so.  A few seconds later the stern of the ship was toward the ocean monster.  Andy called for some one to bring ammunition and feed the hopper of the machine gun, and Bill responded.

Then, when the whale was within a hundred feet of the Monarch, Andy began turning the crank.  A storm of lead shot out toward the big fish.  The water about was dyed with blood and the spouting streams from the nostrils were changed from white to red.  With a terrible flurry, lashing the waters of the ocean to foam with its broad flukes, the whale died, hundreds of bullets in its head.