Then with a whizz and a clink of ice, as the runners of the boat sc.r.a.ped 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 shouted as he whizzed by. His last words seemed whipped away by the wind and the children did not know what he meant.

"Maybe he meant next time he'd be sure to run into us," said Tommy Todd.

"Oh, he wouldn't do _that!_" declared Bert "That was Mr. Watson. He buys lumber from my father. I guess he meant that next time he'd give us a ride."

"Oh, my!" exclaimed Nan. "Would you ride in one of those dangerous things, Bert Bobbsey?"

"Would I? Well, just give me the chance! How about you, Tommy?"

"I should say so! They're great!"

"Oh, I can't bear them!" went on Nan. "Please let's stop and rest. My heart is beating so fast I can't skate for a while."

"All right--we'll call the race off," agreed Bert. Flossie and Freddie were a little startled by the closeness of the ice-boat, and they skated back to join their brother and sister.

And while they are taking a little rest on the ice I shall have a chance to let my new readers know something of the past history of the children about whom I am writing.

There were two pairs of Bobbsey twins. They were the children of Mr.

Richard Bobbsey and his wife Mary, and the family lived in an Eastern city called Lakeport, which was at the head of Lake Metoka. Mr. Bobbsey was in the lumber business, having a yard and docks on the sh.o.r.e of the lake about a quarter of a mile from his house.

The older Bobbsey twins were Nan and Bert. They had dark hair and eyes, and were rather tall and slim. Flossie and Freddie, the younger twins, were short and fat, with light hair and blue eyes. So it would have been easy to tell the twins apart, even if one pair had not been older than the other. Besides the children and their parents there were in the "family" two other persons--Dinah Johnson, the fat, good-natured colored cook, and Sam, her husband, who looked after the furnace in the Winter and cut the gra.s.s in Summer.

Then there was Snoop, and Snap. The first was a fine black cat and the second a big dog, both great pets of the children. Those of you who have read the first book of this series, ent.i.tled "The Bobbsey Twins," do not need to read this explanation here, but others may care to. In the second volume I told you of the fun the twins had in the country. After that they went to the seash.o.r.e, and this subject has a book all to itself, telling of the adventures there.

Later on the Bobbseys went back to school, where they had plenty of fun, and when they were at Snow Lodge there were some strange happenings, as there were also on the houseboat _Bluebird_. There was a stowaway boy--but there! I had better let you read the book for yourself.

The Bobbsey twins spent some time at Meadow Brook, but there was always a question whether they had better times there or "At Home," which is the name of the book just before this one.

You, who have read that book, will remember that Flossie and Freddie found, in a big snow storm, the lost father of Tommy Todd, a boy who lived with his grandmother in a poor section of Lakeport. And it was still that same Winter, after Tommy's father had come home, that we find the Bobbsey twins skating on the ice, having just missed being run into by the ice-boat.

"My! but that was a narrow escape!" exclaimed Nan, as she skated slowly about. "My heart is beating fast yet."

"So's mine," added Flossie. "Did he do it on purpose?"

"No, indeed!" exclaimed Bert. "I guess Mr. Watson wouldn't do a thing like _that!_ He was looking after the ropes of the sail, or doing something to the steering rudder, and that's why he didn't see you and Freddie."

"What makes an ice-boat go?" asked Freddie.

"The wind blows it, just as the wind blows a sailboat," explained Bert, looking down the lake after the ice-boat.

"But it hasn't any cabin to it like a real boat," went on Freddie. "And it doesn't go in the water. Where do the people sit?"

"An ice-boat is like this," said Bert, and with the sharp heel end of his skate he drew a picture on the ice. "You take two long pieces of wood, and fasten them together like a cross--almost the same as when you start to make a kite," he went on. "On each end of the short cross there are double runners, like skates, only bigger. And at the end of the long stick, at the back, is another runner, and this moves, and has a handle to it like the rudder on a boat. They steer the ice-boat with this handle.

"And where the two big sticks cross they put up the tall mast and make the sail fast to that. Then when the wind blows it sends the ice-boat over the ice as fast as anything."

"It sure does go fast," said Tommy Todd. "Look! He's almost at the end of the lake now."

"Yes, an ice-boat goes almost as fast as the wind," said Bert. "Maybe some day----"

"Oh, come on!" cried Flossie. "I want to go home! I'm cold standing here."

"Yes, we had better go on," said Nan. "I'm all right now."

As the five children skated off, no longer thinking of the race, Nan asked Bert:

"What are you going to do some day?"

"Oh, I don't know. I haven't got it all thought out yet. I'll tell you after a bit."

"Is it a secret?" asked Nan, eagerly.

"Sort of."

"Oh, please tell me!"

"Not now. Come on, skate faster!"

Bert and Nan skated on ahead, knowing that Flossie and Freddie would try to keep up with them, and so would get home more quickly. But they did not leave the smaller twins too far behind.

A little later the Bobbseys were safe at home. Tommy Todd went to his grandmother's house, and Flossie and Freddie took turns giving their mother an account of their escape from the ice-boat.

"Was there really any danger?" asked Mrs. Bobbsey of Bert.

"Well, maybe, just a little. But I guess Mr. Watson would have stopped in time. He's a good ice-boat sailor."

"But don't let Flossie and Freddie get so far away from you another time.

They might have been hurt."

Bert promised to look well after his little sister and brother, and then, having asked his mother if she wanted anything from the store, he said he was going down to his father's lumberyard.

"What for?" asked Nan, as she saw him leaving. "Is it about the secret?"

"Partly," answered Bert with a laugh.

Two or three days later the Bobbseys were again out skating on the ice, Nan and Bert keeping close to Freddie and Flossie. They had not been long gliding about when Freddie suddenly called:

"Oh, here comes that ice-boat again!"

"Surely enough, it is!" added Nan. "Oh, we must skate toward sh.o.r.e! Come on!"

"No need to do that," replied Bert. "It isn't coming fast, and Mr. Watson sees us."

"He's waving his hand at us!" cried Flossie. "I guess he wants to give us a ride. Come on, Freddie!"