CHAPTER XV.
A SIGNAL THAT MEANT “DANGER.”
Spinning along at a height the barograph showed to be 1,500 feet, wasan exhilarating experience. The slight feeling of apprehension whichthe Motor Rangers had felt when they set out on their novel cruise,soon wore off, and was replaced by a buoyant sensation.
“Well, Master Nat, what do you think of it?” inquired the professor,emerging from the cabin and coming “aft” to where Nat was standing bythe smoothly running motor.
“It’s glorious,” replied Nat enthusiastically. “I had no idea, though,that it was possible to get used to it so soon.”
“Well, a craft of this kind is vastly different from an aeroplane,”commented the man of science. “It is my belief that the aerialtrans-Atlantic liner of the future will be a dirigible.”
“I wouldn’t mind undertaking the trip in the _Discoverer_,” declaredNat, with glowing eyes and cheeks.
“What speed are we making?” inquired Joe Hartley.
“About forty miles an hour,” said the professor; “but you can tell theexact speed by stepping into the pilot-house and examining theinstruments.”
The lads followed his advice, and found that the speed recorderregistered a shade more than the professor had assumed. Mr. Tubbs hadthe wheel, and was gazing straight ahead, like a steamboat pilot.
The pilot-house of the _Discoverer_, in fact, was not unlike that of asteamer, although much smaller, of course. The registers andindicators, too, that were fastened to the walls, or rather theframework of the _Discoverer’s_ “hull,” were totally unlike any thatthe lads had seen before.
Joe Hartley, who had been appointed chief cook and bottle washer, soonleft, to begin his preparations for lunch. But Nat lingered on,fascinated. Joe’s meal proved an excellent one, and the fact that theywere so high above the earth did not affect the boys’ appetites in theleast. In fact, Ding-dong Bell observed that he had never felt sohungry in all his life before.
After the meal was concluded, the motors of the craft were slowed downa bit, so as to economize on gasolene as much as possible. The factthat the westerly wind had increased made it possible to slow theengine down and still make good progress.
“I wonder what they think of us down below there?” said Joe, as hestood by Nat’s side, leaning over the forward deck-rail and watchingthe dwarfed figures of the inhabitants of a village above which theywere passing, scurrying to and fro like ants.
“I guess they must think we are some sort of demoniacal bird,” grinnedNat. “Hark!”
Faintly, very faintly, borne to their ears, came the sound of churchbells ringing furiously.
“They must be going to hold services in our honor,” hazarded Joe.
“More likely they are going to pray that we don’t harm them,” respondedNat. “According to the professor, the people of this country are a veryignorant lot.”
By afternoon the _Discoverer_ was flying above rugged country. Thefoothills of the great Andean range had been reached, and they were inBolivia. It gave the boys a thrill to think that they were actually atlast in the hoped-for vicinity of the lost city of the mysterious oldIncas.
* * * * *
As the sun grew lower, the great altitude to which they had attainedstruck them with a sharp sense of chilliness.
“This part of the world ought to be called Chile,” observed Joe, as heand the professor and Nat stood on the forward deck just below thepilot-house.
“If you will come into the cabin and see what I have in that big chest,we can possibly get over that difficulty,” said the professor, with asmile.
The lads accompanied him within and found that the chest referred tocontained a variety of warm clothing.
“I knew that the late afternoons and nights on the Andean heights werebitterly cold,” said the professor, as the boys selected some garments,not forgetting a coat-sweater for Ding-dong. “I therefore took theprecaution to be prepared to meet them.”
It was not long after this that the professor addressed a few words toMr. Tubbs, and the _Discoverer_ began to drop. Then came a suddensignal to Ding-dong to slow up his engines. This being done, thelateral planes of the dirigible, which have not yet been mentioned,were inclined at an angle that brought her to earth with an easy,gliding motion.
“Are you going to land for the night?” asked Nat, who had watched themaneuvers with interest.
“Such is my intention,” said the professor. “It is too late in the dayto get any observations now, and I don’t fancy traveling at night inthis region. We might blunder miles off our course.”
The boys agreed that this was so, and then gave their full attention towhat was going forward. Immediately beneath them was a charming,park-like savannah, set in the midst of dense forests of gigantictrees, from whose branches hung great twisted creepers, looking notunlike big snakes.
It formed an ideal landing spot for the big dirigible, which, in a fewmoments after the descending planes had been set, grazed the ground andthen settled. Instantly the professor shouted an order for theanchoring process to begin.
The boys had been drilled in this before the voyage was started, andfell to work with a will on their task. By running the propellerslowly, with the descending planes set at a sharp angle, the_Discoverer’s_ body was naturally held against the ground.
Nat and Joe leaped off on opposite sides, both armed with sledges. Withthese heavy hammers they drove sharp, barbed steel stakes into theground till they were almost as firm as rocks. Each stake had a ring atits top through which ropes were rapidly looped. The ends were then ledback on board and secured. This was done so that in case of a suddenattack the great aircraft could be released by those on board. Ofcourse, in such an event, the stakes would have to be left behind, butas an extra supply was carried, this would not be such a serious matter.
Ten minutes after she nestled to the ground, the _Discoverer_ wassecured as snugly as a vessel at her wharf. The engine was shut off andthe various necessary adjustments of the controls and apparatus of thepilot-house made. This done, the entire party stepped “ashore” for thefirst time in many hours.
“We will sleep on board, but cook our supper here,” decided theprofessor.
This plan just suited the boys, and they scattered in all directions toobtain firewood for the encampment. While they were doing this, Mr.Tubbs set about the task of getting the needed utensils from on boardthe cloud cruiser. He had been busily engaged on it for some time whenthe professor looked up from some calculations he was making on theback of an old envelope.
“It appears to me those boys are a long time gone,” he said. “I hopethey are all right.”
“Oh, they are all right,” spoke the moving-picture artist easily. “Theytook the rifles with them, and agreed that in case of any danger ordifficulty befalling them, they would fire three times.”
“In that case——” began the professor.
But he halted with an abrupt exclamation of consternation. Mr. Tubbs’sface likewise took on a perturbed look at the interruption.
From the forest, to their right, three shots, fired in rapidsuccession, had resounded.