CHAPTER XIII.--OFF ON A DESPERATE MISSION.

What business calling for the use of a typewriter was being transacted under the main divide of the Rocky Mountains?

Ned stood perfectly still in the darkness and listened. He could hear the click of the keys and nothing else. At length he moved stealthily forward over an even surface, feeling his way in order that he might not trip over some unseen obstruction and raise a racket in a tumble.

Presently he came to a rug hanging at the end of the chamber in which he was. From the other side of the rug came a faint light. The noise of the keys was more distinct here, and the boy knew that he had at least located the operator.

While he stood listening and undecided as to what course to pursue, the noise of the machine ceased and the operator--a young, well-dressed American--came toward him carrying a lighted candle in his hand. Ned crouched down in an angle of the wall and waited for him to pass.

The boy was not quite so anxious now to leave the strange rendezvous in which he found himself. Some mischief greater than smuggling opium and Chinamen over the border might be carried on there. His work seemed to be growing on his hands!

He had been sent to that district to investigate the cause of the frequent forest fires, and given an aeroplane in order that he might fly over the forests in making his observations. It seemed to him now, as he lay on his side against a wall of rock, waiting for the typist to pass with his light, that he was spending more time under the ground than in the air!

The main range of the Rocky Mountains in the northern part of Montana is noted for its rugged and irregular formation. It is declared by some that the home of the original cave dwellers was here. Many of the great canyons are known to be honeycombed with openings almost large enough to hide a small city in.

The typist moved straight ahead and his light disappeared from view. Then Ned advanced beyond the rug, which appeared to be of fine material, and flashed on his light. There was a table in the room, a couple of chairs, a row of pigeon-holes attached to the wall.

On the table was a typewriter, in the pigeon-holes were folded papers, neatly ticketed and enclosed in rubber bands. Aside from the underground smell the place was tolerably comfortable. The air was damp and chilly, but Ned was well clothed and did not mind that.

As has been said, the boy was now in no haste to leave the place. He believed that the mystery he had been sent out to solve would be solved there. For an hour or more he searched over the place, opening the folded papers and making a close examination of the typewriter and the stock of unused paper in the drawer of the table.

At length, his examination completed, he passed back into the chamber behind the rug and listened at the opening through which he had entered. A sound of the steady beat of blows reached his ears at first, then a low whistle. That was Jimmie, he knew. The lad had a habit of whistling softly to himself, usually without time or tune.

Waiting for a lull in the blows, he rapped softly on the box which backed up against the opening. Instantly the whistling ceased, and Jimmie's voice was heard.

"Come on out," the boy said. "I've been kicking my heels against this box for an hour, waitin' for you to signal back."

"Be sure there is no one watching," Ned cautioned.

He heard Jimmie walking away, then heard him coming back. In a moment the box was drawn away from the opening.

"You've been in there long enough to dig through to China," Jimmie said, as Ned stood by his side. "What did you find in there?"

"A double keyboard typewriter," grinned Ned.

"Quit your kiddin'," answered Jimmie. "You'll be claimin' next that you found a brass band in there."

Ned did not stop to explain to the boy all that he had discovered in the inner chamber. His work there seemed to be finished now, and he was anxious to get back to camp. There was no knowing what had been going on there during his absence.

"Where is Liu?" he asked.

"Watchin' outside," was the reply. "He's my guard. Goin' to shoot me if I try to get away."

"And the others?" asked Ned.

"Don't know," replied Jimmie. "They herded a lot of Chinks an' went off down the valley."

Liu now appeared in the entrance, bowed gravely to the boys, and stepped out on the ledge, with a Boy Scout challenge in the wave of his hand.

"He's all right!" Jimmie said. "You ought to see the breakfast he got up for me. That feller can cook--an' then some!"

"Call him," Ned suggested, "and we'll see if it is safe for me to go out."

"For you to go out!" repeated Jimmie. "For us to go out."

"I think you'd better remain here," Ned replied.

Jimmie looked at his chum in amazement. The light back there was not good, but Ned saw several questions in the boy's eyes.

"Liu can protect you, can't he?" Ned asked.

"That's what I don't know," was the reply. "He will do his best, of course, but his best might not be good enough."

Ned was thinking fast. If he permitted the boy to leave, the fact of his escape would be likely to scatter the outlaws--and he very much wished to keep them together for a short time.

"I think," he said, "that we have found the men we want--with the goods. If you leave now they will make a quick getaway. You see that, don't you?"

"Of course," was the reply. "An' I see, too, that if I remain I'm the one that's likely to make a quick getaway--to a country no one comes back from."

"There may be some other way," Ned said, thoughtfully. "Give me a chance to think it over."

"Oh, I'll stay, all right," Jimmie went on, "if it will do any good. I guess they won't eat me alive."

As he spoke the boy put his hand to his eyes and gave them a long rub.

"There's smoke in here," he said. "Don't you smell it?"

"I was thinking of that," Ned replied, anxiously. "There may be a fire in the canyon."

Regardless of consequences, Jimmie rushed to the ledge and looked out. The sun was no longer in sight, for a mist of smoke hung over the canyon and over the slope to the east.

"There's goin' to be the biggest blaze ever!" Jimmie cried.

Liu came to the side of the boys and pointed to the south.

"The fire came through a gully over there," he said. "I was watching it from here. It was not put out yesterday, and worked its way over the divide. When it gets to going strong here no one can live in this cavern. I'm going to get out."

"That's the idea!" Jimmie cried.

The canyon was a veritable fire trap. For years the boughs and the turp of the trees had been dropping down. Ned knew that the blaze would mount to the cavern and be drawn into it. The atmosphere of the place indicated openings at the rear which would serve as chimneys.

"Oh, the devils!" Jimmie cried. "To set a fire like that!"

"They didn't set it, I tell you," insisted Liu, speaking as if in the defense of his employers.

"Who did, then?" demanded Jimmie, half angrily.

"It came through from the other side, just as I told you," replied Liu, with the utmost good nature. "There'll be a pass through the range some day where the fire found its way through."

"But they set the fire on the other side," Jimmie urged. "They set it for the purpose of burning our aeroplane an' driving us out of the district. When we go out of the district they'll go with us, wearin' steel bracelets!" he added.

"I rather think," Liu said, "that they set the fires over there to draw the foresters, away from this section, and so protect their business. That is what they have been doing right along."

"Yes," Ned said, "there has been a forest fire for every cargo of opium, for every gang of Chinamen, that has been brought in over the border."

"So that is the real trouble?" asked Jimmie. "How do you know so much about it?"

Ned smiled and pointed to the slope to the east, where columns of fire were cutting their way through the timber.

"It strikes me," he said, "that now is a pretty good time for us to get out of this. The outlaws won't come back so long as this danger exists, and we shall not be missed for a long time--or rather, Liu and Jimmie will not be missed."

"They'll think we ran out to escape the heat and lost our lives in the fire," Liu said.

Ned stood hesitatingly at the mouth of the cavern while Liu gathered a few articles he wanted to take with him.

"If I thought the fire would reach the cave when the big trees in the canyon get to going," he mused, "I'd go back and get the papers--or more of them."

"It surely will get into the cave," Liu said. "You see, the summit scoops down here quite a lot, and the timber line is almost to the top. The gulch below is quite high up on this elevation, still it is not so very high as compared with some of the summits to the north and south. So, you see, the timber line here is capable of getting up a good deal of a blaze, especially where the canyons are full of trees. The fire will come up here, all right."

Ned darted away, was gone a minute or so, and returned with hands full of folded papers.

"What you got?" demanded Jimmie.

Ned laughed but made no satisfactory reply. After stowing the papers away in the numerous pockets of his borrowed suit, he led the way down the ledge, away from the cave he had first seen in his fall down the canyon, and which had proved so profitable to his search.

The air was now filled with smoke. The canyon below was not yet in full flame, but a column of destruction was creeping upon it from the south. It seemed to Ned that there were numerous small fires, though how this could be true he could not understand.

The boys made their way along the ledge without coming upon any of the men who had occupied the cavern. It was evident that the few left after the departure of the men with the Chinamen had fled before the clouds of smoke. The ledge wound up on the plateau from which Ned had dropped the night before, and here they paused to decide on some course of action.

The light breeze was from the west, so the fires below were in a measure protected from it by the bulk of the summit, but Ned knew that the heat would in time bring the air into the burning spaces with a rush, merging the little blazes into one gigantic one which might repeat the disasters of August, 1910.

Now and then, from far to the east, there came a signal in the shape of a gunshot. The faithful foresters were at work there, trying to head off the advancing flames before they passed beyond control. The place to combat a forest fire, of course, is ahead of it, and not where the red line is running through the sputtering timber.

"If I could get the aeroplane," Ned said, as he looked over the country from the plateau, "I might get to the fighting line and do some good."

"Where is it?" asked Liu.

"At the camp."

"The others won't dare bring it out, of course?" asked Liu.

"Doubtful," Ned replied. "Frank has always taken a great interest in the machine, and was studying its mechanism when I left, but I don't think he will attempt to operate it. He ought not to, anyway."

"If the men who left here to pinch the boys," Jimmie said, "showed up at the camp, an' Frank got a chance to mount the aeroplane, you bet your life he's shootin' through the air with it this minute, or hidin' in some valley."

"But there were three of them," Ned urged, "and all couldn't ride."

"They'd try!" gritted Jimmie, "unless Pat got cold feet an' run away."

Ned glanced up at the sky, now very thick with smoke, as the boy spoke. He looked with indifference at first, then with interest, then with anxiety. There was a shape moving up there, coming slowly toward the plateau.

"There they are!" shouted Jimmie, whose attention had been attracted to the sky by Ned's fixed gaze. "Frank's runnin' the machine. I'll bet dollars to apples that he'll dump her into the canyon when he tries to land here."

The aeroplane, indeed, looked as if there were an uncertain hand at the helm. She wavered, tipped in the air currents, dipped wickedly, circled staggeringly, but finally swooped down on the plateau and, more by good luck than good handling, settled down within a dozen feet of the lip of the canyon. Frank and Jack were aboard. Pat, they said, had taken to his heels at the first suggestion of his joining the others in the ride.

Ned examined the machine carefully and found it in excellent shape, although the gasoline was getting low.

"Better go an' get some," Jimmie suggested.

Ned looked toward the line of smoke off to the east.

"We can reach the firing line with what we have," he said, in a moment, "and that may be sufficient for the present."

"What you goin' to do?" demanded the boy.

"Going to see if I can't help fight this fire," was the reply.

"From here?" laughed Jack.

Ned indicated a distant line of hills where the forest still stood green on the slopes.

"We'll fight the fire from there," he said. "We can see the location well enough now, but the smoke will soon shut it out from here."

"What can we do when we get there?" asked Jack. "We are safe enough here. The smoke and heat may scorch us a little, but we'll live through it, and that is more than we can say about the safety of the place you point out."

"Pat will be making his way here," Ned said, "and you may as well remain here and meet him. I'll take Frank and go over to the place where the foresters are fighting the blaze."

Jimmie was on his feet in an instant.

"Me for the ride with you!" he shouted.

"Some one may have to run the machine back," Ned said. "You can't do that, my little man, and Frank can, so Frank goes."

"I don't see what you can do over there that the foresters can't do," Liu said.

"There is no knowing how useful the aeroplane may be," Ned said.

Then the machine was rolled back as far up the plateau as possible, the boys took their seats, and then they were lost in the dense clouds of smoke in the sky.