CHAPTER XIII.

ON THE TRAIL.

"Come, come, boys! Are you going to sleep all day?" exclaimed Professor Snodgrass, the next morning.

His cheery voice awoke the others, and they sat up on the hard cots.

"Where are we? Oh, yes, I remember now!" said Bob. "I thought I was back at the gold mine."

"I dreamed I was back in Cresville," added Jerry. "I wonder how all the folks are. We must write some letters home."

After breakfast, which the Mexican and his wife served in an appetizing style, the travelers decided to delay their start an hour or two, and spend the time writing. Professor Snodgrass said he had no one to correspond with, so he wandered off with his net and specimen box, but the boys got out paper, pens and ink, and were soon busy scratching away.

In about two hours the professor returned, having collected a number of specimens and escaped getting into any difficulties or dangers for once.

"We'd better start," he called. "I'm anxious to get to that underground city. If that turns out half as well as I expect, our fortunes are made."

"Will it be better than the gold mine?" asked Bob, with a grin.

"The gold mine!" exclaimed the naturalist. "Why, I had rather reach this buried city than have half a dozen gold mines!"

He was very enthusiastic and seemed anxious to get on with the journey. The automobile was made ready, and, bidding their hosts good-by, the travelers were again under way.

As they progressed the road became rougher and more difficult of passage. In places it was so narrow that the automobile could barely be taken past the thick growth of foliage on either side.

The forest fairly teemed with animal life, while the flitting of brilliantly colored birds through the trees made the woods look as if a rainbow had burst and fallen from the sky. Parrots and macaws, gay in their vari-tinted plumage, called shrilly as the puffing auto invaded their domains.

It was necessary to run the car slowly. The professor fretted at the lack of speed, but nothing could be done about it, and, as Jerry said, it was better to be slow and sure. So they went on for several miles.

About noon the travelers came to the edge of a broad river, which cut in two the road they had been following.

"Here's a problem," said Jerry, bringing the car to a stop. "How are we going to get over that? No bridge and no ferry in sight."

"Perhaps it isn't as deep as it looks," suggested the professor.

"Tell you what!" exclaimed Ned. "We'll all go in for a swim and then we can tell whether it's too deep to run the auto across."

His plan was voted a good one, and soon the boys and Professor Snodgrass were splashing about in the water. Their bath was a refreshing one. Incidentally, Ned found out that he could wade across, the stream in one place coming only to his knees, while the bottom was of firm sand.

While the travelers were splashing about in the cool water, they might not have felt so unconcerned had they been able to look through the thick screen of foliage on the bank of the stream, and see what was taking place there.

Several dark-complexioned men, in company with Vasco Bilette, had dismounted from their horses and were watching the bathers.

"Well, I'm glad they decided to stop," remarked Vasco. "Our horses are tired from following their trail. They will probably camp for the night on the other bank, for they would be foolish to go farther when they can find good water and fodder."

"You forget they do not have a horse to consider," spoke one of the Mexicans. "Their machine does not eat."

"No more it does," said Bilette. "But they cannot go much farther. If necessary, we can cross the river and get at them."

"Is that Noddy boy and his puff-puff carriage to join us?" asked one of the crowd of Mexicans.

"That is the plan," replied Vasco. "He thought we could follow the trail on horses better than he could in the automobile, because that makes a noise, and those we are pursuing might hear it. So Noddy has kept about five miles behind. As for us, you know that we have been only a mile in the rear, thanks to the slowness with which they had to run their machine.

"Ah, the _Americanos_ have finished their bath. Here they come back," went on Vasco, as the boys and the professor began wading toward the shore, near which they had left their auto.

Suddenly the professor set up a great splashing and made a grab under the water.

"I've got it! I've got it!" he yelled, holding something aloft.

"Got what?" asked Jerry.

"A rare specimen of the green-clawed crab," was the answer, and the naturalist held up to view a wiggling crawfish. "It bit my big toe, but I grabbed it before it got away. This was indeed a profitable bath for me. That specimen is worth one hundred dollars."

"If there are crabs in there I don't see why there aren't fish," spoke Ned. "I'm going to try, anyhow."

Quickly dressing, he got out a line and hook, cut a pole and, with a grasshopper for bait, threw in. In three minutes he had landed a fine big fish, and several others followed in succession.

"I guess we'll have one good meal, anyhow," observed Ned.

"Shall we stay on this side and eat, or cross the river?" asked the professor.

"Might as well stay here," was Jerry's opinion.

So the portable stove was made ready and soon the appetizing smell of frying fish filled the air. The travelers made a good meal, and Vasco Bilette and his gang, hiding among the trees, smoked their cigarettes and wished they had a portion.

"But never mind, when we have the _Americanos_ at our mercy we will be the ones who eat, and they will starve," was how Vasco consoled himself.

Dinner over, the travelers took their places in the auto, and, with Jerry at the wheel, the passage of the river was begun. Following the course Ned had tried, the machine was taken safely over the stream, and run up the opposite bank. No sooner had it got on solid ground, however, than, with a loud noise, one of the rear tires burst.

"Here's trouble!" exclaimed Ned, as Jerry brought the car to a sudden stop.

"Might have been worse," commented Bob. "It might have blown out while we were in the water, and that would have been no joke."

"Right you are, Chunky," said Jerry. "Well, I suppose we may as well camp here for a spell; at least until the repairs are made."

He set to work to put in a new tube, Ned and Bob assisting him, while the professor wandered off after any stray specimens that might exist. He found several insects that he said were rare ones.

The fixing of the tire proved a harder job than Jerry had anticipated. It was several hours before it was repaired to suit him, and by then the sun was getting low.

"What do you say that we camp here for the night?" proposed Ned. "We can't get on much farther anyhow, and this is a nice place. It's more open than in the forest."

This was voted a good plan, so a fire was made and a camp staked out. From their side of the river Vasco and his companions viewed these preparations with satisfaction.

"They cannot escape us now," said the leader of the Mexicans. "We can easily cross the river after dark and get close to them. I wish Noddy would hurry up."

At that instant there was the sound of wheels in the road, to the left of which Vasco and his men were concealed. In a little while Noddy, with Dalsett, Berry and Pender, rode up in the machine.

"Where are they?" asked Noddy, eagerly.

Vasco pointed through the screen of bushes to the other side of the bank, where the professor and boys were encamped.

"Good!" exclaimed Nixon. "We'll pay them a visit to-night."

All unconscious of the nearness of their foes, the Cresville boys, having had a good supper, sat talking about the camp-fire. The professor was engaged in sorting over the specimens he had gathered during the day.

At this same time Noddy and Dalsett, with Vasco and the six Mexicans the latter had provided, were preparing to cross the river, under cover of the darkness.

They did not undress, but waded in as they were, the gleaming camp-fire on the other side serving as a beacon to guide them.

"Softly!" cautioned Vasco, as the nine crawled up on the opposite bank, and began creeping toward the campers.