Kitabı oku: «The Motor Rangers' Cloud Cruiser», sayfa 8

CHAPTER XXII.
A SERIOUS ACCIDENT

Shortly after the battle with the condors, the professor announced that, inasmuch as they were passing above a favorable landing place, he intended to make a landing. The spot selected was an open space beside a fairly large river, the glint of which could be plainly seen like a glittering ribbon beneath them.

Preparations for a landing were at once begun, and the Discoverer commenced nestling down toward the earth. The professor announced that the first task of the evening would be to replenish the supply of gas in the bag from the hydrogen tanks.

The anchorage was made without a hitch, and the Discoverer moored as securely as before; but in view of their experience of the night before, the travelers decided to have everything ready to “slip and run” in case the unpleasant experience was repeated.

As soon as the dirigible was secured, the task of adding to her depleted gas supply was begun. Two of the cylinders were dragged from their resting place and deposited on the ground, while the filling tube was made ready.

The Discoverer was anchored almost on the banks of the stream, a rapid one, with a rocky bottom and steep banks. While the others were working about the Discoverer, Ding-dong Bell set himself to examining the gas cylinders.

They were about ten feet long and very slender in proportion to their length. They were heavy, too, as the tremendous pressure within them made it necessary to construct them of the thickest and strongest steel, – the very finest grade obtainable, in fact.

Ding-dong, with his natural curiosity, started lifting one, and found that to raise one end was all he could manage, and that only by dint of puffing and blowing.

Joe Hartley, looking around from his work on the filling tube at which he was assisting Nat and the professor, noticed what his chum was up to.

“Say, put that down! You’re not strong enough to lift it,” he jeered. “Those things aren’t for kids to monkey with.”

“They’re not, eh?” puffed Ding-dong valiantly, “I’ll soon show you.”

With a supreme effort he managed to raise the cylinder and move it a short distance.

“Here, stop that!” shouted the professor as he espied what the boy was doing. “Don’t you know those things are dangerous unless handled carefully? They’ll go off like a bomb under a sudden shock.”

“That one must have got a sudden shock when it saw Ding-dong,” scoffed Joe. “Most people do.”

It was too much for Ding-dong. He set down the cylinder and made a jump toward his tormentor. In doing so, his foot struck the cylinder which, as it happened, was only just balanced on the steepish slope leading down to the precipitous river bank.

The gas container began rolling downward. The professor gave a shout.

“Stop it! Stop it! Don’t let it fall over the river bank or – ”

Before he could complete the sentence, Ding-dong was valiantly off after the rolling cylinder. He grasped it, but its weight and the velocity it had attained, caused it to evade him, and while he fell sprawling in an effort to regain his balance, the cylinder bounded on toward the brink of the steep river bank.

“Down on your faces! Down on your faces! Everybody!” fairly roared the professor.

They all obeyed blindly, not sensing the utility of the order, but realizing its urgency in the tones of the professor’s voice.

The cylinder gave a leap as it struck a stone, and then bounded over the edge of the river bank.

Bo-oo-oo-oo-m!

An explosion that shook the ground followed almost instantly. From the bed of the river a geyser of mud and water and rocks spouted up, showering everything for a radius of several yards. The explosion the professor had dreaded had taken place; but, by a miracle, no one was hurt. No doubt the fact that the detonation took place below the river bank accounted for this fact.

But the lecture that Ding-dong received! And he admitted that he deserved it.

“If you ever catch me mo-mo-monkeying with that h-h-high-diddle-diddle g-g-g-gas again you can ber-ber-ber-blow me up with it,” he declared.

“That ‘high-diddle-diddle gas,’ as you call it, is much too precious for that,” said the professor with a laugh he could not restrain, “but I shall adopt other measures.”

The boys had a good opportunity then to see the destructive force stored in one of those innocent-looking cylinders. Peering over the river bank they could see that a great hole had been blown in its bed, and rocks riven and split in every direction.

“It’s as explosive as dynamite,” exclaimed Nat.

“It is, indeed,” said the professor. “The condition of that river bed gives mute evidence of that.”

“Just think what would happen if a spark should ever enter that gas bag of ours,” said Nat, with a slight shudder.

“We wouldn’t be able to think,” said Joe succinctly.

“Come, let us get back to work,” suggested the professor, “roll that gas cylinder closer to the filler tube and we will make the connections.”

Gingerly enough, as you may imagine, the lads rolled the cylinder toward the end of the filler tube, which now lay extended on the ground. The end of the tube was fitted with a union, which, in turn, was screwed on to the nozzle of the gas cylinder. Then the professor turned on the vapor, of whose power they had just had such a striking example.

With a hiss and a roar the gas poured through the filler tube into the bag, and several small wrinkles, which had developed in its upper surface, began to fill out. Two cylinders were emptied before the professor and Mr. Tubbs announced that the bag was full enough.

The evening passed off quietly. As before, the evening meal was eaten on the ground, and the adventurers utilized the cabin of the Discoverer for sleeping quarters. Old Matco, the Indian, shared the meal, but refused to sleep within the cabin. Instead, he rolled himself up outside, on the substructure, like an animal of some sort. He had the true aborigine’s dislike of sleeping under a roof. It savored to him of a trap possibly.

The old fellow, now that he had become used to aerial navigation, did not seem to object to it in the slightest. He rather appeared to like it, in fact, and took a childish delight in watching the various operations that went on on board. It appeared that he had no intention of detaching himself from the party as yet, and indeed, seemed to have the liveliest gratitude to them for rescuing him from his unpleasant position at the end of the swinging rope.

The professor was of the opinion that Mateo might prove useful to them, so no move was made to urge him to return to his tribe. Indeed, they were now in the country of another tribe of Indians altogether, – so Matco informed them, – a tribe as warlike and resentful of the intrusion of white men as his own. This was not encouraging news, but the adventurers resolved to make the best of it, and guard against surprises by keeping a good watch.

Nothing occurred during the first part of the night, and when Ding-dong and Joe came on duty at midnight the professor and Nat had nothing to report.

“Don’t forget that time you shot at the mule,” warned Nat, addressing himself to Ding-dong.

“Oh, no danger of my doing that again,” Ding-dong assured him; “b-b-b-b-besides, they d-d-don’t have mules in this p-p-part of the country.”

“That’s good logic, at all events,” laughed the professor, who had heard the story of how Ding-dong shot at a mule in mistake for an Indian the night the Motor Rangers camped in the petrified forest in the Sierras.

Ding-dong and Joe marched up and down for some time, without anything occurring to mar the quiet of the night. But on what was, perhaps, the stuttering lad’s twentieth parade around the dirigible, he heard a queer, inexplicable sort of noise coming from the river.

“Indians,” was his first thought. But then:

“That sounds like somebody snoring, and Indians who were coming to attack us wouldn’t announce their presence like that,” thought Ding-dong.

The snoring noise continued. Joe was on the other side of the dirigible, while Ding-dong was on the river end of it.

“It’s a good chance to distinguish myself,” thought the lad, “after the mess I made of that gas cylinder this afternoon. I’ll just creep down there and see what on earth that racket is.”

He began tiptoeing softly toward the river bank, while the grunting, snoring sound still continued.

“I do believe it’s some one asleep down there,” exclaimed the lad to himself. “Maybe I’ll make a prisoner and get even on Joe for laughing at me.”

His mind full of these visions of glory, Ding-dong at last reached the river bank. Behind him he could hear Joe softly calling, but he made no answer.

“I’m going to investigate this thing alone,” he said to himself.

Lying flat on his stomach Ding-dong peered cautiously over the bank. He could see the gleam of the water about ten feet below him and – what was that? Two dark figures, that appeared to have bulk of considerable size, moving about in the water? One was larger than the other, and it didn’t take the boy long to make out that whatever the mysterious objects were, they were not human beings.

“Wonder if they’re panthers?” thought the boy with a sudden chill. But then he recollected that panthers are not in the habit of prowling about in the river bottom.

“And I never heard of a panther grunting,” considered Ding-dong, “I guess I’ll just – ”

But what Ding-dong had “just” made up his mind to do was never revealed. The bank at the point where he had been leaning over, was cut out beneath by the action of the river, and in scrutinizing the dark objects he had leaned rather far over.

Suddenly the bank caved in, and amidst a shower of gravel, rocks and small bushes, Ding-dong went rolling down into the river.

Splash!

He landed in a deep pool, which, luckily for him, was of sufficient depth for him to avoid injuring himself. Still clutching his rifle he rose to the surface, puffing and blowing, and scrambled out.

“Well, here’s a fix,” thought Ding-dong, “just like my luck. I’m always getting in bad.”

All this time he had quite forgotten about the two dark, moving objects, to whom he owed his present predicament. But their existence was rudely recalled to him as, out of the darkness, something rushed at him, snorting loudly and angrily, and advancing like an express locomotive.

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 the avalanche, of which the luckless Ding-dong was the centre, had not rushed to the river bank. Ding-dong, far too much astonished to raise his rifle, was standing stupidly gazing at the animal that was rushing toward him when Joe fired.

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

The shot aroused every one on the Discoverer, and they came crowding down to the river, to find Joe and Ding-dong examining, by their electric pocket lights, the carcass of a large animal with a peculiarly shaped snout. Explanations ensued, and the professor announced that it was 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 some steaks from Joe’s prize.

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

“I guess you’d have been his,” laughed Joe, “that is, if you didn’t move any quicker than you were when I saw you.”

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

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

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

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

At eight o’clock the Discoverer was ready to resume her flight. She took the air without any accident, and under her replenished supply of gas rose with tremendous buoyancy. In fact, the descending plane had to be adjusted to keep her from shooting up too rapidly. No one on board had any desire to repeat that flight to the chilly regions of the upper air. As Ding-dong put it, “N-n-n-no more on my per-per-plate, thank you.”

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

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

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

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

Excitement ran at fever heat. The boys could hardly leave the deck to eat a hasty meal. The field glasses were in constant demand. The professor announced that he would donate a handsome rifle to the first lad 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 ordered down 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 the professor, “I don’t think that a foot or two more of elevation would give you a very much extended view.”

It was about one-thirty when Mr. Tubbs, who was at the wheel, called the professor’s attention to something odd on the horizon. “It’s glittering,” 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 a mirror in the sunlight, – and then vanished.”

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

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

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

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

“I cannot say,” rejoined the professor. “It may have been that, or it may 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 existence of the city we are in search of?” asked Nat.

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

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

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

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

It was an hour later that Nat, who had the glasses, set them down with an 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 only caught a glimpse of it, but it looked as if there was the glint of water in among those queer, sharp-pointed peaks off there.”

“Speed up the engine if you can, Master Bell,” said the professor, with an 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. “The old documents say that the lost city is on an island in a lake set in the midst of mountains, over which there is no way of climbing but by the lost and secret roads of the Incas.”

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

“I w-w-w-wish I’d s-s-seen it f-f-first,” sputtered Ding-dong, who was leaning 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 by the fact that, as he made it, he half turned, and losing his balance plunged over the rail.

The Discoverer was then nineteen hundred and fifty feet above the surface of the earth!

CHAPTER XXIV.
THE CITY OF A VANISHED RACE

But even in that instant of deadly peril, Ding-dong did not lose his presence of mind, or, perhaps, instinct of self-preservation would be a better phrase.

As he felt himself lose his balance, he clung to the network of the rail, and hung there head downward between the sky and the earth for one instant. But that brief molecule of time was enough for Joe and Nat to secure his feet, as they flashed over the rail, and drag him back on board.

“Go to the cabin, sir,” ordered the professor, who was white and shaky, as, indeed, were the others.

There was no gainsaying his words, but Ding-dong, as usual, had to say something. He was the most unperturbed person on board, in fact.

“I d-d-d-d-didn’t do it on p-p-purpose, you know,” he remarked, as he walked off.

“Good heavens!” exclaimed the professor, leaning against the rail, “what trouble is that boy going to get into next?”

The stuttering lad’s narrow escape had so unnerved them all that there was no answer.

“Well?” said the professor at length, as if seeking a reply to his question.

“Don’t ask me, sir,” gasped out Nat. “I haven’t got my breath back yet.”

It was, perhaps, half an hour later when the entire craft was electrified by a cry from Joe.

“Nat was right! It is a lake!”

No need to ask to what he referred. The professor ordered the Discoverer sent higher, so as to give them a larger horizon, or, rather, a bird’s-eye view.

As the craft rose upward in obedience to her planes, they saw beneath them, but still at some little distance, what Nat has since declared was the most wonderful sight he has ever seen or hopes to see.

Rimmed by bare, gaunt mountains, inhospitable and bleak, lay a small lake, set like a turquoise in dull gold. In the midst of this lake was an island, and on this island, even at that height, they could perceive, were buildings rising in terraced formation. At the extreme summit of the island, which rose to a peak, was something that flashed and glowed in the sunlight almost blindingly.

“It’s the golden dome of the lost city!” gasped Nat.

“Say, Nat,” said Joe in rather a shaky voice, laying one hand on Nat’s arm.

“What is it, Joe?” asked Nat, without taking his eyes off the wonderful sight before him.

“Nothing; only – only I feel a bit scared,” was Joe’s quavering confession.

“You may well feel awe-stricken,” said the professor, whose eyes were gleaming, “ours are the first eyes to behold that island since the mysterious catastrophe that wiped out the race that inhabited it, occurred.”

There came a sudden voice at their elbows.

“L-l-l-looks like C-C-C-C-Coney I-I-Island.”

It was the incorrigible Ding-dong, who had taken advantage of the excitement to slip out of his place of involuntary confinement.

But, in the general interest in all that was occurring, no attention was paid to him. In the midst of the eager talk, and still more eager scrutiny of the island, old Matco, who had come out upon the deck and had stood silently gazing at the lost city, uttered a sharp cry.

Then, raising his hands above his head and fixing his eyes upon the sun, he began muttering what seemed to be a prayer.

This done, he turned to the professor and poured out a rapid flood of eager, emphatic words in his corrupt Spanish. So fast did he speak that the professor had difficulty in following him. But by paying close attention he managed to make out the old man’s meaning.

“What does he say?” asked Mr. Tubbs, as the old Indian ceased his torrent of words, and leaned back, looking quite exhausted.

“Why, it’s like fiction,” said the professor. “The old man says that we are fulfilling a tradition of his race which says that one day winged men from the sky would discover the city.”

“Well, that’s a good omen,” said Nat.

“W-w-w-whatever that may be,” sputtered Ding-dong. “Guess you mean n-n-no men.”

But the professor paid no attention to the irrepressible youth. Instead, he assumed rather a grave look.

“Why, I’m not quite so sure that it is a good augury,” he said slowly. “The old man says that the prophecy or tradition goes on to say that the wrath of the long-dead Incas shall be visited on the violators of their hidden city, and that a terrible end will overtake the sky men who invade it.”

As the professor talked the old Indian fixed his eyes on him as if he realized what he was saying. As the man of science concluded, he nodded solemnly, as if indorsing all that had been told.

“Oh, well,” said Nat, “we are not going to turn back for the sake of an old Indian ghost story.”

“Of course not,” said the professor; “but I thought if any of you are superstitiously inclined, I would warn you.”

“I guess it would take more than talk like that to turn us back now,” said Joe. “I’d face a legion of spooks to investigate that place.”

The others agreed with him. Indeed, as the Discoverer grew nearer, the marvels of the lost city grew more and more awe-inspiring.

What had appeared in the distance to be a mere huddle of terraced buildings, were now seen to be stately palaces, some of them with trees still growing amidst them. The buildings rose in this form till they reached their climax at the great gold-plated dome that capped the summit of the wonderful isle.

The walls, so far as could be seen, were white, but profusely ornamented with barbaric magnificence.

Not a little of the mystic effect of the island was gained from the precipitous and rugged cliffs of the mountains that walled the lake.

“However do you suppose a lake came to be in such a situation?” wondered Nat, addressing the professor.

“In my opinion,” said the scientist, “that lake is what was once the crater of a volcano, more enormous than any yet known.”

“And what we thought were separate mountains were once only part of the summit of that volcano?” asked Nat wonderingly.

“I think we would be correct in assuming so. In many parts of the world the craters of extinct volcanoes are found to be filled with water, just as this one is.”

“The water must be of immense depth,” said Joe.

“In some cases it has been impossible to touch bottom, even with the longest lines and the most perfect sounding apparatus,” was the astonishing reply.

“But how does an island come to be in the middle of such a deep lake?” was what Mr. Tubbs wanted to know.

“What we call an island is probably the summit of another peak of the crater,” said the professor, “or it may have been formed, like those volcanic islands of which we have such a keen recollection, by the action of earth’s internal fires.”

The dirigible dropped lower. It was now almost directly above the lost city. It could be seen that surrounding the golden dome was a vast, semi-circular platform or courtyard of stone, with other stones set up perpendicularly around it.

“It is precisely like the arrangement of the Temple of the Sun in Peru,” said the professor.

“It will make a good place to land,” spoke the practical Joe.

“Doesn’t it seem almost like a sacrilege to bring a modern dirigible to earth in the very courtyard where the rites of ancient religion were practiced?” spoke Nat, who was an imaginative lad.

“Not at all,” said the professor, “and as for that ancient religion, if we had lived in the days when it flourished, I fancy we wouldn’t have liked it much. Like most ancient religions, it was a creed of bloodshed and violence. Human sacrifices may have been indulged in on those very stones we see beneath us.”

The boys agreed that this put quite another light on the matter, and the descent was made without further comment. The dirigible came to rest in the lost city of the Bolivian Andes at three o’clock in the afternoon. Mr. Tubbs was left to guard the Discoverer with old Matco, who refused to move one step through the silent, long-deserted streets. But the boys and the professor set out on a tour of exploration.

The streets, they found, were like those of mountainous cities in Europe, and consisted mostly of steps. It was one of the most uncanny feelings that any of them had ever experienced, this walking through a city of the dead. For, although the ancient places were mostly in ruins, from earthquakes the professor judged, the city yet seemed lifelike enough for some of the vanished race to turn a corner at any instant.

For some reason, the boys kept very close to each other and to the professor, showing no disposition to wander. They found that, as they approached the lake, the buildings grew poorer in character and were not carved or decorated like those closer to the temple. The remains of a splendid wharf remained, however, which set the boys to wondering what had become of the boats that must have once plied between the city and the shore.

This, in turn, suggested ruminations upon the means employed by the vanished race of reaching the lake, for to climb over the mountains was obviously impossible. The professor opined that, at some time, a tunnel must have existed. This set the boys crazy to try to find it, but the man of science declared that, in all probability, the tunnel, if it had ever existed, had been ruined by earthquakes long since.

They stood by the lake side for a time looking into its dark blue depths, and then began a return up the street, climbing the steps cut in the rock.

“Where’s all the treasure we were going to find?” asked Joe, as they climbed the steep causeway worn by the feet of a race long since passed out of existence.

“I don’t imagine we are likely to find much that is valuable,” said the professor. “My belief now is, that when the Spaniards came the inhabitants of this city concealed everything valuable in it in some place known only to themselves.”

“Maybe the lake bottom,” suggested Joe.

“That is not improbable. At any rate, I think we shall have to content ourselves with the glory of having discovered this wonderful place. It is far more perfect than the ruins of Peru are described as being.”

“What about taking that gold plating off the sacred dome?” said the practical-minded Joe.

“Not with my consent,” said the professor. “I would wish this city to be the Mecca of antiquarians from all over the world.”

“I agree with you,” said Nat. “It would be vandalism of the worst sort to strip that rock.”

“Oh, I was only joking,” said Joe, with a rather red face.

“Here’s a peculiar-looking building,” went on Joe, a few moments later, as they passed a tower-like structure, higher than the other buildings, and without windows.

“Let us survey it,” said the professor. “See, here is a door. It has fallen in, it is true, but I imagine we can squeeze through.”

By dint of getting on their hands and knees they managed to crawl under the richly carved and broken portal, Nat pausing to notice that the carvings seemed to be of various astronomical bodies.

Within the tower they found themselves standing at the bottom of a tall, narrow, perpendicular shaft. It was, in fact, like looking up a circular chimney. At the top was something which at first sight seemed to be a big glass lens; but the professor pronounced it to be pure crystal.

“This is the most amazing find yet!” he exclaimed with enthusiasm. “I believe that this tower formed a sort of rude telescope, through which different observations were carried on.”

He clasped his hands in scientific fervor. Indeed, they had seen enough that afternoon to turn the brain of the least imaginative man of science!

Nat informed the professor of the carvings he had noticed.

“That settles the matter,” said the professor enthusiastically. “Good heavens, what a find! It has long been a controversy between various scientific men as to whether or no the ancient races understood astronomy in the true sense. The finding of this rude telescope will go far toward – Gracious! what was that?”

“What?” cried Nat, considerably startled.

“Why, a hand reached out and grasped my hat and – ”

Before the professor could conclude his sentence the boys saw a small brown paw project from a ledge above him and whisk his unlucky hat from his head.

“It’s a monkey!” cried Nat.

“A lot of them!” exclaimed Joe.

“T-t-t-there they go,” cried Ding-dong, as a dozen or more apes of the prehensile tailed type rushed off amidst the ruins, chattering and squealing and tearing and clawing at the professor’s unlucky headgear.

“Just to think,” sighed the man of science with resignation, “that I came all this way, and we have made all these discoveries, and yet my ill-fortune with hats pursues me still.”

“I’d give several dozen hats to have seen what we’ve seen,” Nat reminded him.

“That is so! that is so!” Professor Grigg agreed; “but – ”

“Look out!” cried Joe, behind him, suddenly.

The professor leaped back just as an ugly flat head, with a pair of malicious leaden eyes, protruded itself at his elbow from between the crevices. It was the head of an immense snake.

Without more ado the explorers made haste to get out of the astronomical tower.

“Exploring is certainly strenuous work,” commented Joe as they gained the open air.