CHAPTER XXIII.

  OVERBOARD!—1950 FEET UP!

  The adventure might have had a serious termination for the lad if Joe,who had heard the collapse of the bank and the subsequent roar of theavalanche, of which the luckless Ding-dong was the centre, had notrushed to the river bank. Ding-dong, far too much astonished to raisehis rifle, was standing stupidly gazing at the animal that was rushingtoward him when Joe fired.

  The creature gave a leap into the air, a queer kind of squeal, “like astuck pig,” Ding-dong said afterward, and fell dead.

  The shot aroused every one on the _Discoverer_, and they came crowdingdown to the river, to find Joe and Ding-dong examining, by theirelectric pocket lights, the carcass of a large animal with a peculiarlyshaped snout. Explanations ensued, and the professor announced that itwas a tapir, a species of water animal common in South America.

  Matco assured them that the meat of the creature was very good eating,and much esteemed by his people, and he was permitted to cut somesteaks from Joe’s prize.

  “If I hadn’t ter-ter-tumbled into that pool, though, he’d have beenmer-mer-mine,” declared Ding-dong positively.

  “I guess you’d have been his,” laughed Joe, “that is, if you didn’tmove any quicker than you were when I saw you.”

  “You watch me. I’ll do something great yet,” declared Ding-dong, with apositiveness that deprived him of his stammer.

  “It must have been great the way you went over that bank,” laughed Joeunfeelingly.

  The professor made Ding-Dong put on dry clothes, and then theinterrupted rest of the travelers was resumed. The remainder of thenight passed without incident, and a breakfast that took place soonafter dawn was eaten amidst much rallying of Ding-dong on his adventureof the night before.

  “I’d like to have seen any of the re-re-rest of you ber-ber-braveenough to have gone near that snor-snor-snoring,” sputtered the lad,valiantly helping himself to some more tapir steak, which was found tobe as good as the old Indian had declared was the case.

  At eight o’clock the _Discoverer_ was ready to resume her flight. Shetook the air without any accident, and under her replenished supply ofgas rose with tremendous buoyancy. In fact, the descending plane had tobe adjusted to keep her from shooting up too rapidly. No one on boardhad any desire to repeat that flight to the chilly regions of the upperair. As Ding-dong put it, “N-n-n-no more on my per-per-plate, thankyou.”

  “Do you think we shall sight the city to-day?” inquired Nat, as he andthe professor stood on deck, just below, and in front of, the pilothouse.

  “Impossible to say, my lad,” was the rejoinder. “As I told you, thedirections to reach it are vague in the extreme. We may have to cruiseabout for several days before we satisfy ourselves of its existence ornon-existence.”

  Nat looked disappointed. The boys, at a consultation among themselves,had about decided that that day ought to find them at their long-soughtgoal. Their expectation had been keyed up to such a height that delaywas exasperating.

  At noon the professor took his observations, and declared that, if thecity existed in that part of the country, they ought to be withinstriking distance of it.

  Excitement ran at fever heat. The boys could hardly leave the deck toeat a hasty meal. The field glasses were in constant demand. Theprofessor announced that he would donate a handsome rifle to the firstlad to spy a sign of the mystery of which they were in search.

  If the boys had been eager before, this offer doubled their alertness.Ding-dong even climbed into the rigging till he was sternly ordereddown by the professor.

  “I thought if I got higher that I c-c-c-c-could see it s-s-s-sooner,”he explained.

  “As we are now at a height of two thousand feet,” observed theprofessor, “I don’t think that a foot or two more of elevation wouldgive you a very much extended view.”

  It was about one-thirty when Mr. Tubbs, who was at the wheel, calledthe professor’s attention to something odd on the horizon. “It’sglittering,” he said, “and may be a ledge of quartz or something.”

  “Can you still see it?” asked the professor.

  “No,” was the rejoinder. “It just flashed up for an instant,—like amirror in the sunlight,—and then vanished.”

  “Keep a sharp lookout for its reappearance,” said the professor, with ahint of suppressed excitement in his voice.

  “Shall I steer in the direction in which I last saw it?” asked thenavigator of the _Discoverer_.

  “Yes. If the old documents are correct we are so near to the locationof the lost city now that any clue is worth following.”

  “Then you think that the glitter may have come from the city?” askedNat.

  “I cannot say,” rejoined the professor. “It may have been that, or itmay have been the sunlight flashing, for an instant, on a hidden lake.”

  “But wouldn’t a lake up here come pretty near to proving the existenceof the city we are in search of?” asked Nat.

  “How do you draw such a conclusion?” inquired the professor, withscientific exactitude.

  “I thought you said the old documents said that the lost city was on anisland in a lake.”

  “Ah, yes; but there may be many lakes of the kind described in theseregions,” was the reply. “Any more unusual signs yet, Mr. Tubbs?” heasked presently.

  “No,” was the rejoinder; but the moving picture man’s keen eyes scannedthe distance like those of a hawk.

  It was an hour later that Nat, who had the glasses, set them down withan excited face.

  “I can see a lake!” he cried. “At least, I’m almost certain it is one.”

  “Where?”

  The professor’s voice had caught the infection of the boy’s excitement.

  “Off there—in the same direction that Mr. Tubbs saw a glitter. I onlycaught a glimpse of it, but it looked as if there was the glint ofwater in among those queer, sharp-pointed peaks off there.”

  “Speed up the engine if you can, Master Bell,” said the professor, withan expression in his voice that the boys had never heard there before.

  “We must investigate this at once and lose no time,” he went on. “Theold documents say that the lost city is on an island in a lake set inthe midst of mountains, over which there is no way of climbing but bythe lost and secret roads of the Incas.”

  “I guess you get the rifle, Nat,” said Joe, without a trace of envy inhis voice, though.

  “I w-w-w-wish I’d s-s-seen it f-f-first,” sputtered Ding-dong, who wasleaning far out over the rail.

  “You’d have shot a tapir with the rifle, I suppose,” scoffed Joe.

  “No; I’d have shot a-a——”

  “Good heavens!” cried the professor, as both Nat and Joe sprang forward.

  The abrupt conclusion of the stuttering boy’s speech had been caused bythe fact that, as he made it, he half turned, and losing his balanceplunged over the rail.

  The _Discoverer_ was then nineteen hundred and fifty feet above thesurface of the earth!