t Mollie.
But they tried to conceal their growing uneasiness from Grace and Amy.

Suddenly there came a sharp report, louder than any that had gone
before, and, involuntarily, Mollie raised the spiked wheel. The ice boat
slowly lost headway.

"Don't stop! Don't stop!" cried Betty. "Keep on!"

"But it may be dangerous!"

"It will be more dangerous to stand still! Don't you know that a moving
body has a better chance over thin ice than one standing still? Keep
going, Mollie, and head for shore!"

"Oh, I'm sure something is going to happen!" cried Amy.

"Nonsense, be quiet!" urged Betty. "Grace, give her a chocolate! Mollie,
lower that wheel again."

Again the "propeller" engaged the ice, and the _Spider_ forged ahead.
Grace looked back, and saw where a big crack had appeared. It was
constantly widening.

Then came a thunderous report. The girls screamed, and Betty almost let
go of the tiller. Then she grasped it more tightly, for she saw, with a
shudder of fear, that black water was now all around them.

"Stop! Stop!" cried Betty to Mollie. "Stop the boat! We're on a big cake
of ice and we're floating away! Stop it!"

In an instant Mollie had lifted the wheel, and in the next she had shut
of the motor. The _Spider_ with the girl passengers was indeed marooned
on an immense cake of ice, while all about were other cakes, grinding
and smashing over one another. The river was breaking up fast.

CHAPTER XX

TO THE RESCUE

"Oh--oh!" gasped Grace, when she saw the dark and seething water all
around them. "Oh, we're--afloat!"

"And it's a good thing, too!" exclaimed Betty quickly, as she squared
the rudder-runner. "If we weren't afloat we'd be sinking, and I don't
want to do that--it's too cold!"

Thus spoke the practical Little Captain, for she realized that now was
the time to gain control over the nerves of her chums. Once they became
hysterical there would be no managing them. And, as she spoke she
glanced sharply at Mollie, who had opened her mouth to say something,
but had thought better of it.

"But we're on a cake of--ice!" cried Amy.

"And, as the old wolf said to Little Red Riding Hood, so much the better
to keep afloat with, my dear!" went on Betty gaily, a condition which
she was far from feeling.

[Illustration: "WE ARE ON A CAKE OF ICE, AND WE ARE FLOATING AWAY!"

_The Outdoor Girls in a Winter Camp._ _Page 160._]

"Yes, it's a nice big cake, too!" declared Mollie, recognizing that