ok out! Yell at the man in the ice-boat!"

It did indeed seem a time of danger, for a swift ice-boat--one with big
white sails and runners, like large skates under it, was skimming over the
frozen lake straight for the smaller twins.

CHAPTER II

BUILDING THE "BIRD"

Flossie and Freddie, anxious to win the skating race, were bending over
with heads down, as all skaters do who wish to go fast and keep the wind
from blowing on them too hard. So they did not see the ice-boat coming
toward them, for the craft, blown by the wind, made hardly any noise, and
what little it did make was taken up by the clicking of the skates of the
smaller twins.

"Oh, Bert! Do something!" cried Nan.

"Yes, yes! I will--of course!"

Bert shook off Nan's hand, for it was still on his arm, and started to
skate toward the twins as fast as he could. He hoped to reach them in time
to stop them from skating right into the path of the oncoming ice-boat.

But he soon saw that he was not going to be able to do this. The ice-boat
was coming toward the small twins faster than Bert could ever hope to
skate and reach them.

"Yell at them!" shouted Nan. "That's the only way to stop them! Yell and
tell them to look out!"

Bert himself had decided this was the best thing to do. He stopped skating
and, making a sort of funnel, or megaphone, of his hands, he cried out:

"Flossie! Freddie! Look out! Danger--the ice-boat!"

Just at this moment, whether it was because of Bert's shouts or because
they were tired of going so fast and wanted a rest, the two children
leading the skating race stood up straight and looked back. They saw Bert
pointing toward them and then they glanced at the ice-boat. It was very
close, and Flossie screamed.

At the same time the man who was steering the boat saw the children. With
a shout that echoed the one given by Bert, and the screams of Nan and
Flossie, the man steered his boat to one side. But he made such a sudden
change that, though he steered out of the way of Flossie and Freddie, he
nearly ran into Tommy Todd. That small boy, however, was a good skater
and stopped just in time, for he had seen the ice-boat coming.

Then with a whizz and a clink of ice, as the runners of the boat scraped
big chips from the frozen lake, the skimming boat shot past Nan and Bert,
not doing a bit of harm, but scaring all five children very much.

"Sorry! Didn't see you! Next time----"

This was what the man in the ice-boat