A few hours later found them aboard the snug, shapely hull of U boat N.
12 of the U.S.A. submarine fleet. The sub was a small one, patterned
after the most recent British model, known as the "K" class. Fleet as a
flying-fish, she made twenty-two knots on the surface and ten knots when
submerged. She presented a rather odd appearance, having a short, square
funnel, which was swung over into a recess in the deck when the craft
submerged.

Her gun and torpedoes had been removed. The weight of those had been
replaced by an additional supply of oil and by quantities of provisions.
The provisions, together with bales of skin clothing, were packed into
every available space.

She made splendid progress as she left the harbor and wound her way in
and out among the islands of Puget Sound, to emerge finally round Cape
Flattery and strike away into the open sea.

It became evident at once that this was no coastwise journey. Further
than that, not even Ensign Blake knew its purpose.

The sub was registered at the Navy-yard as "off on detached duty." The
crew of ten men were all volunteers for the trip. The expedition was
under the direction of a doctor. A man past middle age, he sat in a
wicker chair below, smoking innumerable cigars and saying nothing.

"Far's I can dope it out," Blake said to Dave, "the old fellow did some
good service for the Government during the war. He's had plenty of
experience in the North; has some theories he wants to work out about
subs and the Arctic. The Government has some little trick they want
pulled off up in that North country. The Doctor volunteers to lead the