rd the
river, where they all embarked in a small motorboat and headed for the
spot where they had left the submarine.

But there was no submarine to be found. It had disappeared.

Lord Hastings uttered an exclamation of chagrin.

"They've gone," he said. "Edwards, I guess you didn't hurt Davis very
bad. I don't suppose there was a sailor aboard who could navigate the
vessel. Davis probably could."

"I'm sorry, sir," returned Edwards.

"So am I," returned his commander. "We'll have to catch that fellow, and
it is likely to prove a hard job. However, the sooner we get after him
the better."

"And what do you intend to do, sir?" asked Jack.

"We'll take another of these vessels and put to sea again," declared his
commander. "We may come up with him sooner than we expect. But--we'll
take a British crew this time."

It was now after daylight and Lord Hastings set about his preparations
with vigor. Before evening the lads found themselves aboard one of the
German submarines that had been captured and brought to the surface. The
vessel was manned with a full complement of British underwater sailors.
Edwards was among them.

"We'll go down the river immediately," said Lord Hastings, after a tour
of inspection of the vessel, "and when we are at sea we'll fly the
German flag. None of our submarines looks anything like this craft, so
if we come up with the enemy we will be taken for a German. You may
steam at ten knots, Mr. Templeton."

Jack gave the order and the vessel moved down the river.

Shortly after nightfall the submarine, U-6, was proceeding into the
North Sea, for it was there that Lord Hastings believed he would be more
likely to encounter Davis and the U-16.

"Besides," he explained, "our usefulness is not at an end in the matter
of obtaining information from the Germans. We may put into Ostend again
if necessary."

All during the night, although Frank, Jack or Lord Hastings was
continually on the bridge, they did not encounter anything that looked
like an enemy ship, although the U-6 dived several times when it drew
close to a British ship of war--one of the blockading fleet Had the
submarine approached too closely it would have drawn a shot from the
battleship, whose commander could not possibly have known that the
German submersible carried a British crew in the service of King George.

The following afternoon, having traveled far toward the east, they were
to have an adventure.

Moving slowly a