the big hammer. It looks like a Rhinds boast that they are to do big
things on this lightning cruise."

"Yes; Thor was an old Norse god," muttered Captain Jack. "And the early
Norsemen were very largely pirates. Perhaps we are to take the signal
on the 'Thor' as an intimation that Rhinds is out to play pirate in
earnest on this cruise."

As Benson uttered these words he felt an odd little shiver run over him.
Yet he gave it no more thought. Little idea had he, at that moment, how
prophetic his words were likely to be!

In half an hour, as planned, the "Oakland," after firing a warning gun,
steamed away from her moorings. Gradually the gunboat's speed
increased, until the full sixteen miles were being made--miles, instead
of knots, since gasoline boats, like these submarines, are usually rated
by miles instead of by the longer "knot."

It was a rattling rate of speed to exact from these little craft, when
it was considered that the gait would have to be continued, without
break, for at least twenty-four hours.

Eph was at the wheel, at the start, and Jack standing back by the
conning tower. Mr. Farnum had gone below, for a nap, as he intended to
relieve Hal in the engine room after a few hours.

"Benson," remarked Danvers, approaching the submarine boy, "I guess your
remark of a few minutes ago exactly defines this trip."

"What remark?" asked Jack.

"You spoke of it as a lightning cruise. It is going to be one, indeed,
for these little submarine craft."

"Our boat can stand it, I think," smiled the submarine skipper.

"And so can the Rhinds boat, probably. But some of the others will find
themselves sorely put to to keep up the speed for twenty-four hours."

"And, if they don't?" queried Jack.

Danvers shrugged his shoulders.

"Then I guess they'll have to be satisfied with being left far behind,
unless they signal that they're in actual distress."

"This speed," mused Captain Jack, "must be part of the government's
plans for another test. The Navy Department must have planned to see
whether any of these boats could stand such a gait for twenty-four long
hours."

"I couldn't tell you if I knew," remarked Lieutenant Danvers, with a
quizzical look, then turned and strolled away.

"And I guess," muttered the submarine boy to himself, "that that's about
as near as a fellow can go to giving a tip, once he has had the Navy
muzzle padlocked to his jaws."

Some of the submarines in this long race