ed Nan. "Let us go directly school is out, so as to have some
good, long rides."

Four o'clock in the afternoon found them at the lake shore. It was a
cloudy day with a fair breeze blowing across the lake.

"Now you sit right there," said Bert, as he pointed to a seat in the
back of the boat. "And hold on tight or you'll be thrown overboard."

Nan took the seat mentioned, and her twin brother began to hoist the
mainsail of the _Ice Bird_. It ran up easily, and caught by the wind the
craft began to skim over the surface of the lake like a thing of life.

"Oh, but this is lovely!" cried Nan gleefully. "How fast the boat spins
along!"

"I wish there were more ice boats around," answered Bert. "We might then
have a race."

"Oh, it is pleasure enough just to sail around," said Nan.

Many other boys and girls wished a ride on the ice boat, and in the end
Bert carried a dozen or more across the lake and back. It was rather
hard work tacking against the wind, but the old sailor had taught him
how it might be done, and he got along fairly well. When the ice boat
got stuck all the boys and girls got off and helped push the craft
along.

"It is 'most supper time," said Nan, as the whistle at the saw-mill blew
for six o'clock. "We'll have to go home soon, Bert."

"Oh, let us take one more trip," pleaded her twin brother.

The other boys and girls had gone and they were left alone. To please
Bert, Nan consented, and their course was changed so that the _Ice Bird_
might move down the lake instead of across.

It had grown dark and the stars which might have shone in the sky were
hidden by heavy clouds.

"Not too far now, remember," said Nan.

The wind had veered around and was blowing directly down the lake, so,
almost before they knew it, the _Ice Bird_ was flying along at a
tremendous rate of speed. Nan had to hold on tight for fear of falling
off, and had to hold her hat, too, for fear that would be blown away.

"Oh, Bert, this is too fast!" she gasped, catching her breath.

"It's just glorious, Nan!" he cried. "Just hold on, it won't hurt you."

"But--but how are we to get back?"

Bert had not thought of that, and at the question his face fell a
little.

"Oh, we'll get back somehow," he said evasively.

"You had better turn around now."

"Let us go just a little bit further, Nan," he pleaded.

When at last he started to turn back he found himself unable to do so.
The wind was blowing fiercely and the _Ice