Bert Bobbsey was thinking rapidly. Something that he had nearly forgotten came suddenly to his mind, and he hoped it would clear him of the accusation.

And what he had seen, that brought back to his mind something that he had nearly forgotten, was the sight of an elderly gentleman driving past the school in a sled. It was aged Mr. Carford, whose runaway team Bert had helped stop that day on the hill.

"Will you let me call in Mr. Carford?" asked Bert of the principal.

"Call in Mr. Carford?" repeated Mr. Tetlow in some surprise. "What for?"

"Because, sir," said Bert eagerly, "he saw me lend my knife to Jimmie Belton last night, and he can tell you that I went on home, leaving my knife with Jimmie."

"Ha! Do you mean to say that Jimmie dropped it in the ice on the school steps?"

"No, Mr. Tetlow, I don't mean to say that. But I can prove by Mr. Carford that I went home last night without my knife. Please call him in."

Bert thought of the strange old man, who had made such an odd remark concerning the Bobbsey family. And Bert was determined to find out what it meant, but, as yet, he had had no chance, as his father was still away on a business trip.

"Very well, we shall see what Mr. Carford has to say," spoke the principal. "And I will have Jimmie Belton in also."

Mr. Tetlow pressed a bell button that called the janitor, and the latter, who was still chopping away at the frozen steps, came to see what was wanted.

"Just call to that old gentleman going past in the bob sled to come in here," said Mr. Tetlow. "He is Mr. Carford."

"Tell him Bert Bobbsey wants to see him," added the boy, amazed at his own boldness.

"Yes, you may do that," said Mr. Tetlow, as the janitor looked toward him. Somehow the principal was beginning to doubt Bert's guilt now.

From the office window Bert watched the janitor hail the aged man, who paused for a minute, and then, tying his team, came on toward the school. Bert's heart was lighter now. He was sure the old gentleman would bear out what he had said, and Bert felt he would be glad to do him a good turn in part payment for what Bert and his chums had done in catching the runaways.

"Mr. Carford," began Mr. Tetlow, who knew the aged man slightly, "there has been trouble here, and Bert Bobbsey thinks perhaps you can help clear it up. So I have asked you to step in for a moment." Then he told about the big snowball, and mentioned how he had come to suspect Bert.

"But Bert tells me," went on Mr. Tetlow, "that you saw him lending his knife to Jimmie Belton last night. May I ask you, is that so?"

"Why, yes, it is," said the aged man slowly. "I'll tell you how it was." He nodded at Bert in a friendly way, and there was a twinkle in his deep-set eyes.

"It was just toward dusk last evening," went on Mr. Carford, "and I was on my way home to Newton. I'd been in town buying some supplies, and near the cross roads I met Bert and another boy."

"That was Jimmie," said Bert eagerly.

"Well, I heard you call him Jimmie—that's all I know," said Mr. Carford. "Bert was cutting a branch from a tree, and when I came up to them I offered them a ride as far as I was going. They got in, and Bert here was whittling away with his knife as he sat beside me. Yes, that's the knife," said Mr. Carford, as the principal showed it to him.

"I was making a ramrod for a toy spring gun I have," explained Bert. "It shoots long sticks, like arrows, and I had lost one of my best ones, so on the way home I cut another. Then just before Mr. Carford gave us the ride, Jimmie came along and asked me to lend him my knife. I said I would as soon as I had finished making my arrow. I did finish it in the sled and I gave him my knife just before we got out."

Mr. Tetlow looked inquiringly at Mr. Carford, who nodded in answer.

"Yes," said the aged man, "that was the way of it. Bert did lend that other boy—Jimmie he called him—his knife. I saw the two boys separate and Jimmie carried off Bert's knife. But that's all I do know. The snowball business I have nothing to do with."

"No, I suppose not," said the principal slowly. "I am sorry now that I said what I did, Bert. But there still remains the question of how your knife got on the steps. Do you think Jimmie had a hand in putting the snowball there?"

"I don't know, Mr. Tetlow. I wouldn't like to say."

"No, of course not. I'll have Jimmie here." The principal called a messenger and sent him for Jimmie, who came to the office wondering what it was all about.

Without telling him what was wanted Mr. Tetlow asked Jimmie this question quickly: "What did you do with Bert's knife he lent it to you last night?"

For a moment Jimmie was confused. A strange look came over his face. He clapped his hand to his pocket and exclaimed:

"I—I lent it to Danny Rugg."

"Danny Rugg!" cried Bert.

"No, I didn't exactly lend it to Danny," explained Jimmie, "for I knew, Bert, that you and he weren't very friendly. But after you let me take it last night, to start making that sailboat I was telling you about, I forgot all about promising you that I'd bring it back after supper. Then Danny came over, and he helped me with the boat. When he saw I had your knife, and when he heard me say I must take it back, he offered to leave it for you when he came past your house the next time."

"And did you give it to him?" asked the principal.

"Yes, I did," answered Jimmie. "I thought he would do as he said. He took the knife when he went home from my house."

"But he never gave it to me!" said Bert quickly.

"I am beginning to believe he did not," said the principal. "I think we will have Danny in here."

The bully came in rather defiant, and stared boldly around at those in the office. Mr. Tetlow resolved on a surprising plan.

"Danny," he said suddenly, "why did you put Bert's knife on the step, and let it freeze there to make it look as though Bert had helped place the snowball in front of the door? Why did you?"

"I—I—" stammered Danny, "I didn't—"

"Be careful now," warned the principal. "We have heard the whole story. Jimmie has told how you promised to leave the knife with Bert, but you did not."

Danny swallowed a lump in his throat. He was much confused, and finally he broke down and admitted that he had been present and had helped roll the snowball on the steps.

"But I wasn't the only one!" he exclaimed. "There was—"

"Tut Tut!" exclaimed the principal. "I want no tale-bearing. I think those who did the trick will confess now, after I tell them what has happened. Danny, it was very wrong of you to play such a joke, but it was much worse to try to throw the blame on Bert by leaving his knife there."

"I—I didn't do it on purpose," said Danny. "The knife must have slipped out of my pocket." But no one believed that, for Danny was known to have a grudge against Bert, and that was reason enough for trying to throw the blame on our little hero.

But Bert was soon cleared, for, a little later, when Mr. Tetlow called the school together, saying that he had been mistaken in regard to Bert, and relating what had come out about the knife, several of the boys who, with Danny had placed the big ball on the steps, admitted their part in it.

They were all punished, but Danny most of all, for his mean act in trying to make it look as though Bert had done it.

"Well," said Mr. Carford, as he took his leave, having helped to prove Bert's innocence "this time I have had a chance to do a Bobbsey a favor, in return for one you did me, Bert."

"Yes, sir," answered Bert, not knowing what else to say. He was puzzling over what strange connection there might be between his family and Mr. Carford.

"Come up and see me sometime," said the aged man. "And bring your brother and sisters, Bert. I'll be glad to see them at my place. I'm going to stay home all this winter. I'm getting too old to go to Snow Lodge anymore."

Bert wondered what Snow Lodge was, but he did not like to ask.

Thus was cleared up the mystery of the big snowball, and Bert's many friends were as glad as he was himself that he had been found innocent.

There came more snow storms, followed by freezing weather after a thaw, and the boys and girls had much fun on the ice, a number of skating races having been arranged among the school pupils.

The end of the mid-winter term was approaching, and the Christmas holidays would soon be at hand. Then would come a three week's vacation, and the Bobbsey twins were talking about how they could spend it.

"It's too cold to go to the seashore," said Nan with a shiver, as she looked out of the window over the snowy yard.

"And the country would be about the same," added Bert.

"Oh, it's lovely in the country during the winter, I think," said Nan.

"We could get up a circus in the barn, with Snoop and Snap," said
Flossie, who was busy over a picture book.

"Then I'm going to be the ring-master and crack a big whip and wear big boots!" cried Freddie.

"I do hope papa will be home for Christmas," sighed Nan, for Mr. Bobbsey's business trip, in relation to lumber matters, had kept him away from home longer than expected.

"I have good news for you, children," said Mrs. Bobbsey, coming into the room just then with a letter. "Your father is coming home to-morrow."

"Oh, how nice!" cried Nan.

"I hope he brings us something," said Freddie.

"I'll have a chance to ask him about Mr. Carford," thought Bert. "I wonder what that old man meant by his strange words?"