The children tossed some chips into the lake, pretending they were boats, and then they walked around the yard to where long boards and planks were stacked into great piles, waiting to be taken away on boats or wagons.

Bert asked one of the workmen if they could play with some of the boards, and, receiving permission to do so, they had fun making something they called a house, and then on a see-saw.

"Oh, I always did love to see-saw!" said the little girl from Washington. "We don't get much of a chance to play that way where I come from."

"We have see-saw rides lots of times down here," answered Nan.

"Well, that's Because your father owns a lumberyard, and you can get plenty of boards to use for a see-saw," said Henry.

For an hour or more Bert and Nan entertained the Washington children in the lumberyard, and then, as it was getting close to dinner time, Nan told Bert they had better go back to their father's office.

They found Mr. Martin about to leave. And then Mr. Bobbsey thought of something.

"Look here, Henry!" he exclaimed to his friend, "there's no need of your going back to that hotel. Come out to the house--you and the children-- and have dinner with me. I want you and your boy and girl to meet Flossie and Freddie, and I want you to meet Mrs. Bobbsey."

"Well, I'd like to," said Mr. Martin slowly, while the eyes of Nell and Billy glowed in delight. "But, perhaps it might bother your wife."

"Oh, no!" laughed Mr. Bobbsey. "She likes company. I'll telephone out that we're coming, and Dinah, that's our cook, will be delighted to get up something extra. They'll be glad to see you. Come out to the house, all of you, and make me a nice visit. Can't you stay a day or so?"

Eagerly Nan and Bert waited for the answer, for they liked the Washington children very much.

"Oh, no, we can't stay later than this evening," said Mr. Martin. "I've got other business to look after. But I'll come out to dinner with you."

"Oh, we'll have lots of fun!" whispered Nan to Nell. "You'll just love Flossie--she's so cute!"

"I'll show you my dog Snap," said Bert to Billy. "You ought to have seen him scare a strange dog just before we came down here."

"I like dogs," said Billy. "We could have one in Washington if we had a barn to keep him in."

"We've got a barn," went on Bert. "You ought to have seen what happened there this morning to Flossie and Freddie," and then he told about the little twins having been hidden under the hay.

Mr. Bobbsey's automobile was in the lumberyard, and in this the trip was quickly made to the home of the four twins, after Mrs. Bobbsey had been told, by telephone, that company was coming

Nell and Billy were glad to see Flossie and Freddie, and the six children had fun playing around the house and barn with Snoop and Snap.

Mr. and Mrs. Bobbsey wanted Mr. Martin to stay two or three days with his children, but the Washington lumberman said it could not be done this time.

"I'm on a business trip," he said, "and I can't spend as much time in visiting and pleasure as I'd like, though I am trying to give Billy and Nell a good time. This is the first time I have ever taken them on a trip with me."

"And we've had such a lovely time!" exclaimed Nell.

"Packs of fun!" added her brother.

"I'm sorry we can't stay longer," went on Mr. Martin. "You folk must come to Washington some day."

"Yes, I expect to," said Mr. Bobbsey. "I've been counting on going there some day on some business matters."

"Well, when you come be sure to bring the children," said the father of Nell and Billy. "I think they would enjoy seeing the White House, the big Capitol building, the Congressional Library, Washington's home at Mt. Vernon and places like that."

"Could we see the Washington Monument?" asked Nan. She remembered looking at a picture of that in her geography.

"Oh, yes, I'd show you that, too," said Mr. Martin.

"And could we see the Potomac River?" Bert wanted to know.

"Surely!" laughed Billy's father. "I'll show you all the sights of Washington if you'll come and pay me a visit--all you Bobbsey twins!" he added.

"I wish we could go!" sighed Nan.

"Perhaps you can," said her father.

"Have you got any hay in Wash'ton?" asked Freddie, suddenly, and every one else laughed except himself and Flossie.

"Oh, I guess I could find enough hay for you and your little sister to hide under," answered Mr. Martin with a laugh, for he had heard the story of what had happened in the barn.

A little later Mr. Martin and his boy and girl had to leave. They said "good-bye," and while the father of the Washington children again asked Mr. and Mrs. Bobbsey to come to visit him at his home, Nell and Billy whispered to Nan and Bert:

"Be sure and come, and bring Flossie and Freddie with you!"

"We will!" promised Nan, but neither she nor Bert guessed what a queer little adventure they were soon to have in Washington.

A few days later school opened, and the Bobbsey twins had to go back to their class-rooms. At first they did not like it, after the long, joyous vacation on the deep, blue sea, but their teachers were kind, and finally the twins began to feel that, after all, school was not such a bad place.

Thanksgiving Day came, bringing a little vacation period, and after church in the morning, the Bobbsey twins went home to eat roast turkey and cranberry sauce. Then they went out to play with some of their boy and girl friends, having lots of fun in the barn and yard.

"But don't slide any more hay down on Flossie and Freddie!" begged Mrs. Bobbsey.

"We won't!" promised Bert and Nan, and they kept their word.

It was about a week after Thanksgiving, and Bert and Nan were on their way home from school one day, when, as they passed a red brick house on the street next to theirs, they saw, standing on the porch, a pleasant- faced, elderly lady who was looking up and down the avenue.

"That's Miss Pompret," said Nan to Bert. "I heard mother say she was very rich."

"Is she?" asked Bert. "She looks kind of funny."

"That's 'cause she isn't married," returned Nan. "Some folks call her an old maid, but I don't think she's very old, even if her hair is white. Her face looks nice."

"Yes, but she looks kind of worried now," said Bert. "That's the way mother looks when she's worried."

They were in front of the house now, and could see Miss Pompret quite plainly. Certainly the elderly lady did look as though something troubled her.

"Good afternoon, Miss Pompret!" called Nan, as she was about to pass by. Bert took off his cap and bowed.

"Oh, you're half of the Bobbsey twins, aren't you?" asked Miss Pompret, with a smile. "I often see you go past. I only wish you were a little bigger."

"Bigger? Why?" asked Bert, in some surprise.

"Why, then," explained Miss Pompret, "you might take this letter to the post-office for me. It's very important, and I want it to go out on this mail, but I can't go to the post-office myself. If you Bobbsey twins were bigger I should ask you to take it. Tell me, is the other set of twins larger than you two?"

"No'm; they're smaller," explained Nan. "Flossie and Freddie are lots littler than we are."

"But we're big enough to take the letter to the post-office for you, Miss Pompret," said Bert. He had often heard his father and mother speak of this neighbor, and the kindnesses she had done.

"Are you sure you are big enough to go to the post-office for me?" asked Miss Pompret.

"We often go for daddy and mother," said Nan.

"Well, then, if you think your mother wouldn't mind, I would like, very much, to have you go," said Miss Pompret. "The letter is very important, but I can not take it myself, as I have company, and I have no one, just now, who can leave. I thought I might see some large boy on the street, but--"

"I'm big enough!" exclaimed Bert.

"Yes, I believe you are!" agreed the elderly lady, looking at him through her glasses. "Well, I shall be very thankful to you and your sister if you will mail the letter for me. And, on your way back, stop and let me know that you dropped it in the post-office all right."

"We will!" promised Bert, and Nan nodded her head in agreement with him. Miss Pompret handed over the letter, which was in a large envelope. Nan