Betty would need help--"backing-up"--in her efforts to calm the two
more timid girls. "It's a lovely large cake," Mollie added. "The largest
around of any. Just suppose we were on--that?" and she pointed to one
about as large as a "five cent piece the ice man brings in on a hot
day," to quote Betty's later characterization.

"Oh, how can you make fun, when we may--when we may--may slip off any
minute?" protested Grace, half tearfully. "Oh, why did we come out in
this ice boat?"

"Now look here!" and Betty spoke sharply. "Isn't it a good deal better
to be jolly than glum? Of course it is. And we're in no immediate
danger. As Mollie says, we may be thankful we are not on a small cake of
ice. This will hold us nicely."

"But we're floating down the stream," said Amy.

"Of course we are," agreed Betty cheerfully. "A river never stands
still, you know. We are floating down with the rest of the cakes. Pretty
soon there will be an ice jam, and----"

"Oh, don't say that!" begged Grace. "An ice jam! That's one of those
terrible things where so many persons are killed."

"Nonsense! You're thinking of an avalanche!" declared Mollie. "Betty
means that the cakes of ice will all jam together pretty soon, when the
river narrows, and we can walk ashore as nicely as you please, hauling
the ice boat after us."

"Why can't we go ashore in that?" asked Amy, her face brightening.

"Because it will be so--humpy!" explained Betty. "We could not run the
auto ice boat over the bumps. But really it might be worse; I'm not
fooling."

Their situation was indeed peculiarly fortunate considering what had
happened. The warm weather had softened the ice, and the melting of much
snow had caused the river to rise. This had had the effect of cracking
the covering of ice, and it had broken up. The ice boat got on a certain
large section that split off and went floating down stream.

"Well, let's get out and see what we can do," proposed Mollie, as she
left her place near the motor.

"Don't you dare leave this boat!" commanded Betty, a bit sternly.

"Why not?" asked Mollie, curiously.

"I'll tell you why. Though the cake we are on seems solid, there may be
cracks in it, and it might separate if we stepped out on it. You see
our weight would come in a comparatively small space, whereas in the
boat it is distributed over a large surface."

"My? Where did you learn that?" asked Mollie, admiringly.

"In our physics class. It's true, too. We