changed the organ so that it played a different tune and let some hot water run out of a little faucet.

"Do you know how to run the engine?" asked Bert.

"Sure I do!"

"What's your name?" asked Charlie.

"Bob."

"Bob what?" Dannie wanted to know.

"Bob Guess."

"Bob Guess! That's a queer name," remarked Bert.

"Well, it isn't exactly my real name," the ragged lad went on. "I'm an orphan. I haven't had any real folks in a long time. I was taken out of the asylum by this man, so he says. He adopted me, I reckon, and he said he gave me that name 'cause he had to guess what my real name was. So I'm called Bob Guess."

"A queer name," murmured Bert. "But I'd like to know how to work a steam engine."

"So'd I!" agreed the other boys.

"Pooh! It's easy," said Bob Guess, who seemed to like to show off. For he turned another little faucet, thereby sending out a cloud of steam, and causing Charlie Mason to jump back.

"Don't be skeered! It won't hurt you!" laughed Bob.

"Isn't it hot?"

"Not after it comes from the boiler. Look, I can hold my hand right in it," which Bob Guess did, letting a cloud of steam envelop both his rather dirty hands.

"Whew!" whistled Dannie, in amazement.

"I'm going to try it!" said Bert, rightly guessing that at a short distance from the faucet the steam cooled off; which was true, as you know if you have ever "felt" of the steam coming from a house radiator on a cold day.

But as Bert stretched out his hand to test the steam as Bob had done, Mr. Blipper called from where he stood talking to the driver of the last truck.

"Stop monkeying with that engine, Bob!" yelled the red-faced man. "You want to get it all out of kilter again!"

"I was only testin' the steam gauge," the boy answered.

"Well, you let it alone, do you hear, and water the horses."

"I have watered 'em!"

"Well, water 'em some more! I'm not going to stop again till I get to the Bolton County Fair if I can help it."

"He's sort of cross, isn't he?" asked Charlie, as Bob moved off.

"More than that—he's mean!" declared the ragged lad.

Bert and his chums stood looking at the steam engine and listening to the organ, while Nan and the smaller children danced. Then up came Mr. Blipper.

"I guess this is a dollar's worth of music," he announced.

"I believe so," agreed Mr. Bobbsey, with a smile. "The children have enjoyed it. Thank you!"

"Um!" grunted Mr. Blipper. "Here you, Bob!" he roared. "Come and shut off this steam. We're going to travel!"

He climbed up on the seat, and Bob, after hanging the water pail on a hook beneath the truck, shut off the engine. The organ ceased playing, and the trucks containing the merry-go-round lumbered off.

"Good-by!" called the Bobbsey twins.

"Good-by!" echoed Bob Guess.

"I wonder if we'll ever see him again," murmured Bert.

And he was to see the strange lad again, under queer circumstances.

"Come, children, your ice cream will get cold!" called Mrs. Bobbsey, who had come from the pavilion to summon the little guests.

"Ice cream get cold! Ha! Ha!" laughed Grace Lavine.

"I like mine cold," chuckled Dannie Rugg.

Back across the fields ran the merry, laughing children. The Sunday school picnic, in spite of the danger at the bridge, had turned out most wonderfully.

Soon the caravan of the merry-go-round was but a series of faint specks down the dusty road. It was taking a route that would not take it across the broken bridge.

The Bobbsey twins and their friends sat about eating ice cream and cake, and some of them talked about the strange boy and the organ that was played by steam.

"I'm going to have an organ like that when I grow up," said Freddie.

"An' I'm goin' to help you play it, an' ride on a lion," added Flossie, and the others laughed.

Picnics, however delightful, cannot go on forever, and this one came to an end as the afternoon shadows were falling. Mr. Bobbsey had been very busy helping his wife and the other ladies, and now, as the time came for him to go home in the small auto in which he and his wife had ridden to the grove, he rolled down his sleeves, and looked about him.

"What are you after?" his wife asked.

"My coat. I hung it on a tree limb right here, I thought."

"Yes, I saw you," said Nan.

"But it isn't here now!" her father went on.

"Here's some sort of coat," announced Bert, picking up one from the ground under a tree near the ice cream pavilion.

"That's where I hung my coat," said Mr. Bobbsey. "And this coat isn't mine. Mine was a good, new one. This is an old, ragged one. Dear me! I hope my coat hasn't been stolen! It had some money in one pocket, and also some papers I need at the lumber office! Where is my coat?"

CHAPTER V

SAM IS WORRIED

While fathers, mothers, and other relatives were gathering up their own children, or children of whom they had charge, to see that they were safely loaded into the two big trucks to go home from the picnic, the Bobbsey twins—at least Bert and Nan—were searching for their father's coat. Flossie and Freddie were too small to pay much attention to anything of this sort. The smaller twins were talking about the merry-go-round and starting over again the dispute as to who should ride on the wooden lion.

"Are you sure you left your coat hanging on the tree limb?" asked Mrs. Bobbsey.

"I'm certain of it," her husband answered. "And this old coat never was mine—I wouldn't own it!"

He dropped to the ground the ragged garment that had been found lying beneath the tree.

"I thought maybe you had hung your coat over by the ice cream shed," went on Mrs. Bobbsey. "You may have done that and have forgotten about it."

"No, I didn't do that," said the father of the Bobbsey twins. "I remember hanging my coat on the tree, for I recall noticing what a regular hook, like one on our rack at home, a broken piece of the branch made. My coat was here. But it's gone now, and this old one is left in place of it."

There was no question about that. Search as Mr. and Mrs. Bobbsey and the children did, over the picnic grounds, the lumberman's coat, with money in one pocket and papers in another, was gone.

"Who do you s'pose could have taken it?" asked Nan, as her father looked about him with a puzzled air.

"I don't know," he answered, "unless——"

"Maybe it was tramps!" interrupted Bert.

"There weren't any tramps here on our picnic grounds," said Mrs. Bobbsey. "Some of the drivers of the merry-go-round trucks looked like tramps, but they didn't get off their seats, did they?"

"Not that I noticed," her husband answered. "Well, there's no use looking farther. My coat is gone—stolen I'm afraid. This old one is left in its place. I haven't any use for this," and he kicked it to one side. "Never mind. It isn't cold. I can ride home without a coat."

"There's a lap robe in the auto," Mrs. Bobbsey said. "You can wrap that about you if you get chilly on the way home."

"Yes," agreed Mr. Bobbsey, "I can do that. Trot along, Bobbsey twins. Get into your picnic truck, and we'll see who gets home first."

"Like Little Red Riding Hood and the Wolf," laughed Flossie.

While Mr. and Mrs. Bobbsey walked over to where Mr. Bobbsey had left the runabout auto in which he and his wife had come to the picnic grounds, Bert, Nan, and the other children took their places in the big truck.

"Merrily we roll along—roll along—roll along!"

Some one started that song as the trucks rumbled out of the picnic grove. On account of the broken bridge a different road home had to be taken; a longer one. Having a