“Dat’s what,” spoke the negro as cheerfully as though that was the regular program.

The other passengers were returning to their berths to finish dressing, and soon the excitement that followed the accident had almost disappeared.  Breakfast was served, and there was nothing to do but to wait for the arrival of the wrecking crew.

“What’s the matter with taking a stroll across the prairie?” suggested Jerry, when the boys and the professor had finished their morning meal.  “There’s no fun sitting here in the car all day.”

“Good idea!” exclaimed Ned.  “I’m with you.  Maybe Chunky will be afraid to come, for fear train robbers will carry off the dining car while he’s gone.”

“Oh, you let up!” retorted Bob.  “You like to eat as much as I do.”

“Not quite as much, Chunky, but I admit I like my three square meals a day.”

“Where are you going, boys?” asked the professor, looking up from his book, as he saw the three chums leaving the car.

“Out for a walk across the prairie,” replied Ned.

“Wait, and I’ll go with you.  I might get some new specimens.  I must never waste an opportunity,” and, placing in his pockets several small boxes to hold any possible captives he might get in his butterfly net, the scientist was ready.

It was pleasant on the vast plain that stretched away in every direction from the derailed train.  The sun was shining brightly, but not too warm, and there was a gentle breeze.

“This is fine!” exclaimed Jerry.

The boys and the professor strolled on for several miles, the three chums enjoying the walk very much, while Mr. Snodgrass was continually finding some new insect, or a flower, until his specimen boxes were full.

“Well, we’ve come quite a distance,” said Ned, as they got on top of a small hill and looked about.  “We can’t see the train anywhere.  I guess we’d better be thinking of starting back.”

“Maybe we had,” agreed Jerry.  “But what’s that dark line out there?” and he pointed to the horizon.

“A cloud isn’t it?” asked Bob.

“It’s too low, and it doesn’t move like a cloud,” objected Jerry.

They watched it for some time, as it got larger and larger.

“Why it’s all around us!” suddenly exclaimed Bob.

And so it was.  The travelers were hemmed in by a peculiar, moving ring, that seemed to get smaller and smaller.

“What do you think it is, Professor?” asked Ned.

“That?  Why—­ er that is—­ um—­ curious, I can’t just say what it is,” replied Mr. Snodgrass.

“I have a small telescope,” said Ned, producing it from his pocket, “We’ll take a look through it,” and he adjusted it, focusing it on the dark ring, that was, every moment, growing closer and closer to the little group on the hill.

CHAPTER IX

 A lucky escape