This trip he circled out further from the camp, growing a little more confident because nothing had happened to disturb him.

In the meantime the camp slept in peace—­ that is, the lads did until nearly time for the change of guard.  Then the whole party was aroused with the sudden, startling conviction that something serious had happened.

All at once the crack of a rifle sounded on the still night air.  It was followed by another shot, and another, until four distinct reports had rolled across the plains.

In wild disorder the Pony Rider Boys tumbled from their cots, and, grasping their weapons, leaped from the tents.

“What’s the row?” inquired the Professor.

“Wow!  Wow!  Wow!  Yeow!” shrieked a shrill voice to the northward.

“It’s Chunky.  He’s giving the alarm!  We’re attacked!” cried the lads.

Bang !  Bang!

They saw the flash of the fat boy’s weapon before the report reached their ears.

A moment later the other boys caught sight of Stacy dashing into camp, hatless, waving his rifle and yelling as if bereft of his senses.

“What is it?  What is it?” cried the boys with one voice.

“Indians!  Indians!  The prairie’s full of them!”

CHAPTER X

 Meeting the attack

Instantly the camp was thrown into confusion.  The lads ran here and there, not knowing what to do.

“Get behind the ponies!  That’s the only cover we can find here.  Run for it!”

And run they did, the Professor outdistancing all the rest in his attempt to secrete himself where the enemy’s weapons would not be likely to reach him.

In a moment more, the camp of the Pony Rider Boys was deserted, and behind each sleeping pony lay a boy, with rifle barrel poked over the animal’s back, ready to shoot at the first sign of the redskins.  Stacy, in his excitement, had forgotten that not a cartridge was left in his magazine, and the others were too fully occupied to remember to tell him.

For all of half an hour did the party lie protected.  The boys began to grow restive.  Tad’s suspicions were being slowly aroused.

“I’m going to do a little scouting,” he told them, slipping from behind the pony and skulking along back of the tents.  The moon was shining brightly now.  He could see a long distance.  Not a human being was in sight.

“I thought so,” he muttered, retracing his steps.  “See here, Stacy Brown, what did you see—­ what did you shoot at?” he demanded sternly.

“I—­ I shot the chute—­ I—­ I mean I chuted the shot—­ I mean—­”

“Say, what do you mean?”

“I—­ I mean—­ say, leggo my neck, will you?” roared Chunky.

“Fellows, he doesn’t know what he means.”

“Guess he’s been feeding on crazy grass out on the prairie,” was Ned’s conclusion.