journey. They had been sent into the Arctic to locate a wireless station,
supposed to be placed in the Aleutian Islands; a station run by radical
propagandists, part of a world-federation, which proposed to wreck all
organized society. Had Dave realized that the missions of sub and
airplane were alike he would have been startled. As it was, his face
took on a tense, expectant look, his cheeks burned hot with excitement.

The Doctor was called to the conning-tower. After studying the contour of
the island for some time, he said:

"Their shack, built of rocks and driftwood logs, is at the base of the
cliff. That is good. We will divide into two parties. Four of us will go
up the cliff and get above them, while four others will skirt the cliff
and, under cover, await my signal. Our supporting party will take ropes,
rifles and a machine-gun. I will go with the party to the top of the
cliff. We will carry only rifles and some special instruments of attack
which I have stored in canvas sacks below. Two men must remain on board.
Head in close to those rocks before us. They are out of sight of the
shack and there is ice stranded there--a straggler will scarcely tell our
craft from it. I have no doubt there are a number of them and that they
are hardy ruffians. We must proceed with great care.

"Hark!" He put his hand to his ear. "They are sending messages now.

"In the future," continued the Doctor, as he handed Dave two
strange-looking spheres, the size of a man's head, "the work of sheriffs,
policemen and other officers of the law is not going to be quite so
hazardous. When a criminal runs amuck, he will not kill a half-score of
brave men before he is captured. The officers of the law will do what we
will soon be doing, and a child can do the rest. Only," he continued,