ne either."

The German aeroplane was gaining steadily.

"He can outrun us," said Frank, quietly. "There is only one, thank
goodness. You'll have to bring him down, Jack."

"I'll try," was Jack's reply. "If I had a rifle I might be able to pick
him off now."

"Well, he won't hardly have any the best of it," said Frank. "The
chances are he has no rifle either."

Frank was correct in this surmise.

Rapidly the German aircraft gained.

"Crack!" the German had fired the first shot.

It went wild. Jack fired, but with no better result.

"Hit anything?" asked Frank, without turning his head.

"No," said Jack, "but neither did the other fellow."

"Try it again," said Frank.

Jack did so; but again the bullet went wild. All this time the two
craft were flying straight out to sea.

Once more the German fired and Jack felt something whizz overhead.

"This is getting too close," the lad muttered to himself. Then he
called to Frank.

"Slow down, quick!"

Frank had no means of telling what plan Jack had in mind, but he did
not hesitate. The hydroplane slowed down with a jerk.

The pilot of the German craft was caught off his guard. He dashed upon
the hydroplane. But as he neared it he swerved to the left to avoid a
collision. It was what Jack had expected. Standing up in his precarious
position, Jack took a snap shot at the pilot as the German craft swept
by.

At that close distance, in spite of the rate of speed at which the
enemy was travelling, a miss was practically impossible.

The German machine swayed crazily from one side to the other; then
dived.

"I got him, Frank!" shouted Jack.

Both lads gazed over the side at the falling enemy.

Suddenly the machine righted and descended more slowly.

"By Jove! a cool customer," said Frank. "He's regained control of the
plane. He'll be up again in a moment."

Again they watched the foe carefully.

"No, he won't," said Jack, "he's still going down."

"Then we may as well be moving," said Frank.

"Hold on!" shouted Jack. "We can't leave those fellows there. They may
get to shore or be picked up. Then they would give the warning and all
our efforts would be for naught."

"Right," said Frank. "We'll go down after them."

The hydroplane descended slowly.

CHAPTER X

THE FIGHT ON THE WATER

Below, the fallen aeroplane rested upon the surface of the sea. In the
darkness, it was hard for the lads to tell just how badly the craft was
damaged and