a needle in a haystack," Jack called to Frank.

"That fellow can't be up to any good," declared Frank. "He showed no
light and was going in a terrible hurry. There's something up."

"Does seem that way," agreed Jack.

"Say! Is this as fast as this thing can go?" demanded Frank. "We won't
ever get any place this way. Let her out a bit."

Jack did so and the little boat seemed literally to fly over the dark
water. This terrific speed Jack kept up for some time and then slowed
down.

"We'll bump into something at this rate," he said; "and that would
settle the whole business. We must be cautious."

"Cautious!" repeated Frank. "We won't find that German being cautious."

"If we weren't cautious, it wouldn't do us any good if we did find him,"
argued Jack. "First thing you know we would be at the bottom."

Frank considered this point a moment.

"Guess you're right," he said at last.

"Swish!" went something at this moment, and, turning quickly, Frank saw
a dark shape speeding away up the river.

"Hey! There went one the other way," he cried to Jack.

"That so?" replied Jack anxiously. "There is something up here, and I'm
going to find out what it is."

He slowed down even more, and, striking a match, lighted the
searchlight, which, until this moment, he had not deemed advisable.

As the light flashed over the water, the lad made out another small
motorboat dead ahead, upon which signs of life became apparent. Jack saw
figures gesticulating violently; then the boat headed directly for the
one occupied by the two boys.

"Guns, Frank!" said Jack quietly. "They are coming at us."

"Leave it to me," replied Frank. "You run the boat. I'll do the rest."

"Don't shoot unless you have to," warned Jack.

Frank made no reply.

Jack kept the light full upon the approaching boat. He could see several
oilskin-clad figures and that was all; and then came a hail from the
oncoming boat.

"What do you want here?"

The query was in English. Jack answered the hail.

"What are you doing here yourself?" he demanded. "We are British
officers. I command you to surrender."

"More likely German officers," was the response. "Heave to now. I'm
coming aboard you."

"If you do you'll get a warm welcome," replied Jack.

He stopped the boat and drew his own revolvers.

"Stand back!" he cried, as the other boat came closer.

In the glint of the searchlight the men aboard the other boat made out
the boys' uniforms. The boat