"Smoke, smoke?" queried the Professor. "Where?"

"There, to the southwest."

"That's so, it is smoke. It surely is."

"Must be somebody's camp-fire," decided Tad, studying the wisps of vapor that were curling lazily up on the clear, warm morning air.

"Indeed, it must be," declared the Professor. "We must get in touch with them at once, for they no doubt will soon be on their way. We have not a minute to lose."

The Professor began bustling about excitedly.

"It will be an hour or more before we can hope to get there with our old local freight train," objected Ned. "They probably will be gone long before that."

"Yes. I have it," cried the Professor. "I will hurry over there on my pony. You boys come along at your leisure. Even if they do not wish to wait for the rest of our party, I shall be able to get directions at least, and perhaps to hire some one to pilot us on to the Red Star."

This seemed to be good judgment, so the boys hastened to saddle the Professor's mount, and in a few moments he was jogging away as rapidly as the uneven ground would permit, his eyes fixed on the distant spiral of smoke curling lazily upward.

"Guess we had better follow as fast as we can," suggested Tad.

"Chunky, get busy. What are you standing around with your hands in your pockets for while Rome is burning?" shouted Ned Rector. "Hurry up! Take down those tents, pack all the stuff over to the mules and--"

"And what are you going to do while I'm doing that?" drawled Stacy.

"Me? I'm going to boss the job. What did you suppose I was going to do?"

"Oh, that's about what I thought you would be doing. I'll pack my own stuff. You can leave yours here for all I care," laughed the fat boy, sauntering to his tent without the least attempt to hurry.

"Don't tease him so," advised Tad in a low voice.

"What, tease Chunky Brown? You couldn't tease Chunky with a club. I just say those things to get him started. He says such funny things."

Nevertheless, the camp was struck in record time that morning, and the pack mules loaded so rapidly that they turned back their soulful eyes in mild protest.

"Got a new job for you to-day, Chunky," announced Ned Rector while cinching the pack girths.

"What is it?"

"We've decided to let you follow along behind with a sharp stick and prod the mules so they will make better time."

"Think I'll wait till after twelve o'clock to-night," answered the fat boy.

They were off soon after that, but the mules had never seemed to move as slowly as they did that morning. Instead of an hour, more than two hours had pa.s.sed before they finally came within hailing distance of the camp-fire. For some time, they had been finding difficulty in keeping it in sight, as the fire appeared to be dying down.

Tad shouted to attract the attention of the campers or the Professor to let them know the Pony Riders were coming. There was no reply, which caused the lads to wonder.

So they pushed the mules all they could, a vague apprehension that all was not as it should be, growing in their minds. They soon came upon the object of their search. What they found was a smouldering camp-fire.

"The camp is deserted," groaned Tad.

Not a person save themselves was within sight or sound. Professor Zepplin, too, had disappeared.

CHAPTER XI

CHUNKY OBJECTS TO EGG WATER

"Well, doesn't that beat all!" marveled Tad.

"Certainly does," agreed Ned.

"Yes, but I don't understand--what does this mean?" exclaimed Walter.

"I'm a poor guesser," answered Ned.

"It means that we are all alone," replied Tad. "Beyond that I could not guess."

Chunky had been viewing the scene with solemn complacency.

"We've got the mules, anyway," he nodded.

"Precious lot of good they'll do us," returned Walter.

"And we've got the food and--and I don't have to build a fire, either," added the fat boy.

"Yes, we have some things to be thankful for, that's a fact," laughed Tad. "My idea is that the Professor, finding the men had just left here, has hurried on to overtake them. I don't think we have any reason to worry."

"Then we had better stay right here," answered Ned.

"Yes. That is all we can do for the present."

"Think we had better unpack?"

Tad considered the matter briefly.

"I think we had better wait a little while," he decided.

"I think you are right. I hope we don't have to. We have enough food in our pockets to keep us going until night and--"

"Don't we get anything to eat until night?" wailed Chunky.

"Not unless you can browse," retorted Ned. "There's plenty of green stuff hereabouts."

"You can eat with the mules if you wish to. I don't."

"Might as well keep the fire up," decided Tad, gathering up a fresh supply of green stuff which he dumped on the graying ashes. "The smoke will help the Professor to find us quickly when he comes back."