efore I had the notion
of building a submarine. Yes, I am afraid we'll have trouble getting
away from them."

"I can't understand this phosphorescent glow keeping up so long,"
remarked Captain Weston. "I've seen it in this locality several times,
but it never covered such an extent of the ocean in my time. There
must be changed conditions here now."

For an hour or more the race was kept up, and the two submarines forged
ahead through the glowing sea. The Wonder remained slightly above and
to the rear of the other, the better to keep sight of her, and though
the Advance was run to her limit of speed, her rival could not be
shaken off. Clearly the Wonder was a speedy craft.

"It's too bad that we've got to fight them, as well as run the risk of
lots of other troubles which are always present when sailing under
water," observed Mr Damon, who wandered about the submarine like the
nervous person he was. "Bless my shirt-studs! Can't we blow them up, or
cripple them in some way? They have no right to go after our treasure."

"Well, I guess they've got as much right as we have," declared Tom. "It
goes to whoever reaches the wreck first. But what I don't like is
their mean, sneaking way of doing it. If they went off on their own
hook and looked for it I wouldn't say a word. But they expect us to
lead them to the wreck, and then they'll rob us if they can. That's not
fair."

"Indeed, it isn't," agreed Captain Weston, "if I may be allowed the
expression. We ought to find some way of stopping them. But, if I'm not
mistaken," he added quickly, looking from one of the port bull's-eyes,
"the phosphorescent glow is lessening. I believe we are running beyond
that part of the ocean."

There was no doubt of it, the glow was growing less and less, and ten
minutes later the Advance was speeding along through a sea as black as
night. Then, to avoid running into some wreck, it was necessary to turn
on the searchlight.

"Are they still after us?" asked Mr. Swift of his son, as he emerged
from the engine-room, where he had gone to make some adjustments to the
machinery, with the hope of increasing the speed.

"I'll go look," volunteered the lad. He climbed up into the conning
tower again, and for a moment, as he gazed back into the black waters
swirling all about, he hoped that they had lost the Wonder. But a
moment later his heart sank as he caught sight, through the liquid
element, of the flickering gleams of another searchlight