"Yes; not to notice how we were drifting," rejoined Frank quietly, "it's no use to blame Mr. Desplaines for this pickle. We have only ourselves to be angry with. I don't suppose he ever thought that two boys would not notice how they were drifting in a ten mile current."
"The point is how are we ever going to get out of it?"
How indeed?
As the boys looked about they saw little to encourage them. The chasm in which they were beleaguered was not more than fifteen feet across, but on either side shot up walls of rock so steep and smooth that not even a fern could find root on their polished surfaces.
Where the whirlpool sank into the bowels of the earth the walls came together at an angle forming a sort of triangular prison. At the top of this trap the boys could see a strip of blue sky and the outlines of the graceful tops of some bulbous stemmed palms but nothing else. Once a vulture sailed across the strip and sighting the two boys came lower to investigate. The sight of the carrion bird made both of the boys shudder.
"Ugh, he scents a meal, he thinks we're dead already," cried Harry disgustedly.
The sound of his voice echoed gloomily among the rocks.
"We're dead already," came back in sepulchral tones.
"I shan't try to wake that echo up again," said Harry in a low tone and shivering at the uncanny voice of the rock.
Neither of the boys spoke for a long time. They sat there silently, occasionally standing up to get the stiffness out of their limbs till the strip of sky above began to darken to gray.
"Well, here goes!" exclaimed Harry suddenly.
Frank glanced sharply up. He did not like the wild tone in which the words were spoken.
"What is it?" he asked sharply.
"I'm tired of this, I'm going to swim for it," replied Harry with a foolish, hysterical laugh.
Frank saw what had happened. The boy had become half-delirious under the mental strain he had undergone.
"Sit down, old fellow," he said kindly, "help will come soon I am sure."
"Yes, a steamboat will come sailing down the river and take us home in the captain's cabin I suppose," said Harry foolishly.
But nevertheless Frank's stern command to "shut up" and not make a foot of himself brought him to his senses and he said no more till the stillness was broken by a sudden cry from above.
"Bosses—oh, bosses."
"Ahoy there; castaways!"
Frank looked up.
The cry of joy he gave set the echoes flying in the gloomy canyon.
It was the black face of Sikaso that was gazing down on them and beside it was Ben Stubbs' weather-beaten countenance. Behind them were Billy, Lathrop and the rest.
"Hold on there and we'll get you out of that in two shakes of a duck's tail," cheerily hailed the old adventurer. "We guessed you'd be here and we brought a rope as long as a man of war's cable with us. Lucky thing we did."
The next minute a long rope of vegetable fiber came snaking down the side of the cliff and to one end of it clung Ben Stubbs. As he reached the bottom—the rope being cautiously paid out from above by his companions—the old seaman swung himself outward from the face of the rock and "in a brace of shakes," as he would have said, stood alongside the two boys. In a second his sharp eye took in Harry's wild looks and hysterical greetings and realized what had happened.
"Now, Frank," he ordered, giving the young aviator the end of the rope—"catch hold tight and when you are ready give the word."
"But Harry—" gasped Frank, "I can't leave him. Let him go first."
"I'll bring him up. He can't look after himself in the shape he's in and you are too weak to attempt to help him. Now no talking back. I'm boss now. Up aloft with you. Haul away there!"
The next minute Frank, clinging to the rope, was being hauled cautiously up the side of the sheer cliff by careful hands and shortly he was in the arms of his friends.
Ben Stubbs—to whom the rope with a weight at the end of it had been swung pendulum wise—next appeared at the summit with Harry in his strong grip. But it was a white faced inanimate burden he carried. The boy had swooned.
"He'll be all right in a few minutes," said Ben Stubbs as M. Desplaines and the others all tried to explain at once to Frank how Sikaso had guessed what had happened when the boys did not return. The Krooman had led the party by secret native trails to the cliff top. Frank clasped the huge black's hand with real gratitude and tears of thankfulness brimmed in his eyes.
"How can I ever thank you," he said.
"Um—white boys keep away Pool of Death, Sikaso much pleased," replied the Krooman turning slowly away with a sad expression on his face.
"His own son was drowned in it several years ago," said M. Desplaines briefly.
The morning after the events recorded in the last chapter was one of these sparkling ones that are occasionally to be met with on the West African coast and was the forerunner of a day of great bustle and activity for the boys. With the vitality of healthy youth Harry had completely recovered and was indeed surprised to find himself feeling so good after what he had been through. Privately he inspected his hair in the mirror to see if it had turned white and was secretly much astonished to find it the same color as before.
"I wish mine would turn white or potato color or something," said Lathrop, to whom Harry confided his expectation, "this red thatch of mine is a nuisance. At school I was always Brick-top or Red-Head and out here the natives all look at my carrot-colored top-knot as if they'd like to scalp me and keep it for a fetish."
Both boys laughed heartily over Lathrop's half-assumed vexation. As a matter of fact he had been the butt of many jokes in school on account of his blazing red hair and in Africa the natives with their love for any gaudy color had already christened him Rwome Mogo or Red-Top. Of this, however, he was fortunately ignorant, as he might have been tempted to go out and dispatch half a dozen of them if he knew of their term for him.
Down at the river bank, cross the evil-smelling lagoon at the back of the town, Frank and Harry had their hands full directing shouting, laughing Kroomen how to load up the canoes. From the canopied steam launch that lay alongside the rickety wharf the black engineer—an American Negro—watched with great contempt their labors, which they enlivened with songs from time to time.
"Them's de mos' good fur nuffingest niggahs I ever did see," remarked Mr. Rastus Johnson—that was his name—with undisguised contempt.
Nevertheless by noon the canoes had all been leaded and the farewells to the kind M. Desplaines and his family said. After a swift final inspection Frank pronounced everything ship-shape and even Doctor Wiseman who had been fussing about as Billy said "like a hen with one chicken—and that a lame duck," over his tin cases and poisonous looking bottles, announced that he was ready to start. The twelve chattering Kroomen who were to go as far as the Bambara country with the expedition were seated two in each canoe. They were along simply as camp attendants and packers and would by no means go any further than the borders of the Bambara country which they said was the dwelling-place of "bery bad man sah."
Just as the little launch, flying the stars and stripes out of compliment to the boys, was drawing out into the stream with a long blast of her whistle, a tall, black form came racing along the bank and with one bound cleared the five feet or so between the launch and the shore. It was Sikaso.
"So you came after all," said Frank, turning to him, after a bend in the river had hidden the waving Mr. Desplaines from sight and they were settling down in the launch.
"Sikaso see in the smoke I come—I come. If I see in smoke I no come—I no come," remarked the Krooman.
"He's traveling light anyhow," remarked Billy.
Indeed the giant negro's only bit of baggage was a huge axe, the handle of which was dented and scarred as if by many combats. Billy was about to run his thumb along its edge when with a gesture the mighty negro waved him aside. Instead he took Billy's handkerchief from the young reporter's pocket and drew it gently along the axe blade.
It fell in two pieces on each side of his blade, severed by its razor-like edge.
"Sikaso is a good fellow to be friends with when he can make little ones out of big ones like that," remarked Billy, picking up the two fragments of his handkerchief, "that's a fine way to cut up a gentleman's wardrobe."
Bit by bit as the launch drove steadily up the muddy river—from whose jungle-grown banks arose a warm, moist vapor—Frank drew from the grim-faced old Krooman some of his history. He had been a mighty warrior in the old days, he said, and the weapon he carried was his war axe with which he had killed uncounted enemies. A rival tribe, however, had killed his father and mother and driven him to the coast with the few survivors of his village. Here he had shipped on an American trading brig for New York where he had picked up the knowledge of English he possessed. He also worshiped America as "free man's country." But Africa had called to him and some three years before he had returned on another ship and meant to die there, he said.
"Why did you wish to go with us?" asked Frank as the native concluded his story.
"It was written so in the smoke, white boss," replied the veteran simply. "The ju-ju in the smoke strong ju-ju. He knows many things."
"Is that the only reason you have for coming?"
"No, boss, I tell you truth," replied the old warrior, "some day I find the chief who kill my father and my mother and kill my friends." He glanced significantly at his axe.
"In the Moon Mountains maybe I find him—maybe not. But some day I shall and then—"
He said no more, but as Frank remarked to Harry when the former recounted his conversation to his brother later:
"I shouldn't much like to be that man when Sikaso meets him."
The launch and the small flotilla she towed forged steadily up the stream all that day and at nightfall drew alongside the bank at a spot where a clearing planted with bananas clearly indicated the presence thereabouts of a native village. As soon as the launch was moored to the bank the adventurers scrambled out—not sorry of a chance to stretch their legs—and looked about them wonderingly. They were really in equatorial Africa at last, and even as they looked there was a sound borne to their ears that brought home to them strongly how very far away they were from old New York. It was a pulsing, rhythmic beating something like a drum and yet unlike it. They looked questioningly at Sikaso.
"Tom-tom," said he briefly.
"Is it a friendly village, Sikaso?" inquired Doctor Wiseman.
"Friendly to some—not to all," replied the Krooman, who for some unaccountable reason had taken a strange dislike to the professor. "Come," he said, intoning to Frank and Harry, "we go see get chicken, maybe pork."
"Say, can't we come along, Frank?" asked Billy and Lathrop their faces falling.
Frank consulted Sikaso who merely said:
"Little fat white boy, with round, glass four-eyes talk too much."
"Well," laughed Frank, "I think I can promise for him that he won't do any talking that will cause any harm this evening."
"Talk too much, indeed," grumbled Billy highly offended, "why at home my folks were thinking of having a doctor treat me for bashfulness I'm so retiring in my disposition."
As soon as the laugh that this remark of the disgruntled reporter had caused had subsided—even old Sikaso giving a grim smile as he took in the purport of it—the little party set out down a native trail toward the village.
As the tom-tom beating increased in loudness as the village drew near, the boys' hearts began to beat a little faster. At last they were about to see a real African village—such as they had read about in Stanley's and Livingstone's books—and other less authentic volumes. They almost stumbled on the place as they suddenly emerged into a clearing. It was a strange sight that met their eyes.
Arranged in a circle were fifty huts that resembled nothing so much as a collection of old-fashioned straw covered beehives, enlarged to shelter human bees. All about them women and children were bustling; setting about getting the evening meal. Before one hut sat a woman, pounding something in a stone pestle—"like the drugstore men use at home,"—whispered Lathrop to Billy.
The arrival of the little band created a stir. The hideous old man, with a sort of straw-bonnet, who had been beating on the antelope skin drum called by Sikaso a "tom-tom" saw them and instantly picked up his instrument and waddled off with as much dignity as his age and a much distended stomach would allow him. The younger men, however, advanced boldly toward the party. Some of them carried, spears, others held Birmingham matchlocks of the kind the British and French Governments have in vain tried to keep out of the hands of the West African natives. These guns are smuggled in by hundreds, by Arab traders who exchange the "gas-pipe" weapons worth perhaps two dollars a-piece for priceless ivory, and even human flesh for the slave dhows.
"Seesanah (peace)," said Sikaso gravely, advancing in his turn.
"Seesanah," echoed the tribesmen, who evidently recognized Sikaso from their greetings. The boys stood grouped in the background—Billy Barnes and Lathrop even viewing with some alarm the advance of the savage-looking natives.
"Well, he seems to have fallen in with several members of his club," remarked the irrepressible Billy as old Sikaso and the natives talked away at a great rate.
"I'm going to get a picture of some of these niggers when they get through," he continued aside to Lathrop.
"What; you brought a camera?" asked the other boy.
"Sure thing," replied Billy, "and if their ugly mugs don't break the lens, I mean to get some good snaps."
He drew a small flat folding camera from his pocket as he spoke and got it ready for action.
"Do you think Frank would stand for it? It might make trouble you know," said Lathrop.
"Pshaw," retorted the cocksure Billy, "what trouble can it make? I wish I knew bow to say 'Look pleasant, please,' in Hottentot, or whatever language these fellows talk."
By this time old Sikaso's 'pow-wow' was over and he motioned Frank and Harry forward. After they had been introduced to the chiefs and headmen of the village, the "big chief," a villainous-looking old party with only one eye and his legs thrust into a red shirt—into the armholes that is, with the rest of the garment rolled round his waist—announced he was ready to give fresh provisions for calico, red and blue, and several sections of the brass rod that passes for currency on the West Coast. While Frank, Harry and Sikaso were bargaining behind a hut, over the price to be charged for a razor-backed porker of suspicious appearance the village suddenly became filled with an uproar of angry shouts and tumult.
"What can be the matter?" exclaimed Frank, as the boys, followed by the old chief and Sikaso, rushed from behind the hut to ascertain the cause of the disturbance.
Standing in the center of a crowd of excited villagers was Billy Barnes, his helmet knocked off and an arrow sticking through it. He looked scared to death as well he might, for by his side was a stalwart young African, brandishing a heavy-bladed spear above his head. At the young reporter's feet lay the ill-fated camera that had caused all the trouble.
What had happened was this. As soon as Frank and Harry and their companions had left him and Lathrop alone, Billy had started to carry out his determination to take some pictures. The first subject he selected was a serious-faced little baby, innocent of any clothing, that sat playing with a ragged dog at, the entrance of one of the beehive huts. He had just clicked the button and exclaimed:
"This will be a jim-dandy," when he felt something whistle through the air and the next minute his hat lay at his feet with an arrow in it. In an instant the child's father—convinced that Billy was putting Ju-ju medicine on the child—was upon him, armed with his big hunting spear and followed by half the village. Even Billy—scared as he was—did not realize how very near to death he actually came to being. Sikaso's shouted words in a native dialect caused the tribesmen to fall back but they still muttered angrily.
Stepping swiftly up to the camera Sikaso with a single blow of his axe smashed it to pieces.
"Here, that's no way to treat my camera!" Billy was indignantly beginning, when Frank gripped his shoulder in an iron-clutch and whispered:
"Shut up; if you don't want to make more trouble."
Billy was starting on an angry remonstrance when he caught Frank's eye. The young leader was really angry and Billy prudently refrained from saying any more.
As for Sikaso—after demolishing Billy's machine, he turned to the tribesmen and addressing them in stately tones said—as he afterward translated it to Frank:
"Village fools. You see there is no magic in the little black box. It is nothing but a child's plaything for the fat, spectacled idiot." (This part of the oration Frank did not communicate to Billy.) "You see I have smashed it. Do I fear? Do I look now like a man in terror of the white man's medicine. It is nothing. It is broken and gone like the cloud before the wind, like the shadow on the mountain side."
The effect of all this was soothing and the boys left the camp, to order some of their packmen to bring home the provisions, with light hearts. As for Billy his ears burned by the time Frank got through reading him a lecture.
"I'm sorry," he said bravely, "and I won't do it again. Gee! talk about 'press the button and we'll do the rest.'"
"They nearly did it—didn't they," laughed Frank, his good humor quite restored.
It was a week later, and the launch having towed the expedition as far up the river as Frank decided was necessary—before they struck out into the unknown land of the cannibals, winged men, and the ivory hoard—had returned to civilization several days before, carrying with it letters from all the adventurers which they felt might be the last they would write for some time. The spot selected for the permanent camp was a sort of park-like space covered at its edges with masses of manioc and banana bushes. Beyond towered huge tropical trees and beyond these again the blue outlines of the distant Moon Mountains in which, according to old Barr's map, lay the ivory cache.
It had been a busy week. The Golden Eagle II had been re-erected and her own wireless and the field wireless apparatus put in order. As our readers who have followed this series are familiar with the manner of setting up the great Chester aeroplane and her fittings, it would be tedious to repeat the description of the process. Suffice it to say that thanks to the clever simplicity of the "knock-down" arrangement, by which the ship could be taken apart and set up again, the operation of equipping her for active work was a comparatively light one. The extra gasoline and supplies for the camp in general were stored in a separate tent removed from the circle in which the boys' tents and those of Ben Stubbs and Professor Wiseman were pitched.
There was, too, a newcomer in the camp—a Portuguese named Diego de Barros. He was not a particularly well-favored individual, but he bore the reputation of having great power over the natives and of being very friendly to the white traders who penetrated into the interior. Once or twice there had been ugly talk about his being in league with the Arab slave and ivory traders, but he had managed to clear his name and along the Ivory Coast enjoyed the reputation of being an honest, reliable man. He had joined the boys' camp a few days before and his manner of coming was this.
While everybody was busy getting things in shape there had come a loud hail from the quarters of the native helpers, just outside the white man's encampment, announcing that a canoe was coming up the river. All hands had hastened to the river bank to find de Barros just putting his foot ashore from the canoe in which two natives had paddled him from the coast. He had with him some bales of cotton goods and a few gewgaws of various kinds and was bound, so he said, on a trading expedition into the back country. Further down the river he had heard, he explained, that the boys were camped where he found them, and he had determined to pay them a visit. The brief stay that the boys had interpreted this as meaning, however, had extended itself into three days and still Diego showed no inclination to leave.
"If he doesn't move on soon I shall be compelled to ask him to go," said Frank in an annoyed tone to Harry. "I don't want to be inhospitable, but we can't afford to have strangers hanging round the camp, there is too much at stake."
Harry agreed with him and the two boys decided to tell the Portuguese that evening as tactfully as possible that they were on a private enterprise and could not accommodate strangers. This decision arrived at, Frank turned to the steel strong box that was never out of his sight and drew from it the precious map of the Moon Mountains. Seated at the little camp-table—(the conversation just related had taken place in the Boy Aviators' tent)—the two pored over the document for hours. With dividers, compass and parallel rulers Frank, who was a skilled navigator, laid out an aerial course that would bring them, he calculated, unerringly to the spot marked by a red cross where—so old Luther Barr declared—lay the ivory that was to save Mr. Beasley from financial ruin and disgrace.
Frank laid his finger on the spot and exclaimed enthusiastically:
"There it is, Harry, and we are not so far from it now. In a few days we shall know whether we are on a wild-goose chase or not."
"Why, no doubt has ever entered your head that the ivory is there?" questioned Harry.
"Well, old fellow, you know there are others interested in this ivory beside ourselves—Muley-Hassan for instance."
"You think he had got ahead of us?"
"I did not say I thought so, I only say that it is possible that he may have done so."
"How could he have got wind of our coming?"
"In Africa there is a sort of underground wire for news," replied Frank. "I have no doubt that hundreds of natives far in the interior are by this time apprised of our coming."
Harry looked alarmed.
"That's bad," he said.
"Well, it couldn't be helped: but we may have other enemies nearer at hand."
"What do you mean?"
"That I don't like the looks of that Portuguese fellow. If he got wind of what we are doing he would be likely to ruin the whole object of our expedition."
"That's so. We'll have to get rid of him."
"Well, we are going to, and if he won't go for gentle means we'll try rough ones."
"Hullo, what's that?" exclaimed Harry suddenly.
The flap at the end of the tent toward which both of their backs had been turned had been suddenly drawn aside and in one quick, backward glance Harry made out the smiling figure of de Barros standing in the doorway. It might have been fancy, but he thought for a minute that the Portuguese had a peculiarly villainous expression on his dark, handsome features.
"Ah, senors," he said, as Frank, with a quick movement swept the map off the table—but not before de Barros's quick eyes had spied it. Fearing to replace the precious chart in the strong box, while the Portuguese lingered, Frank tucked it into his pocket.
"Ah, senors, good afternoon," grinned the unwelcome visitor. "I have come to say 'adios.' I am going up the river to-night and may not see you again for a long time."
"I am sorry to have you leave," said Frank with a heartfelt wish that de Barros would hasten his departure.
"I knew you would be," smiled the Portuguese, "but it is the lot of man to meet and part. Adios, senors, I go to make ready."
He vanished as suddenly as he had come upon the scene.
"What do you make of that?" inquired Harry.
"I don't know what to think. I have an idea that he was listening to every word of our conversation just now and that he saw the map before I had time to sweep it off the table."
Harry looked vexed.
"That's tough luck," he said. "If he overheard even a part of our talk he must realize the object of our presence in Africa. And," he went on, "I don't know a man on the Dark Continent whom I would trust less than Diego de Barros, even the little we've seen of him."
"It can't be helped now," said Frank briefly; "come on, let's go and put the finishing touches on the good old Eagle."
They worked the rest of the afternoon putting the big aeroplane in shape for her flight to the Moon Mountains which it had been determined to make the next day. It was almost dusk when Harry, who was working over the engines, asked Frank for the reserve park-plug box.
"It's in one of the canoes. I'll go and get it," said Frank, and at once set off toward the river bank for that purpose. His path led through a thick grove of bamboos which hid him from the view of the camp after he had traversed a short distance. As he merged on the river bank, whistling softly to himself, the young leader suddenly felt himself pinioned by arms that seemed of enormous strength—though, as the attack had come from behind, he could not see the faces of his assailants. The next minute he was lying flat on his back, bound and helpless with a bit of greasy cloth shoved in his mouth for a gag.
"Keep still, senor, and you shall not be hurt;" said a quiet voice near at hand, and Frank saw bending above him the sallow features of the smiling Portuguese.
"I just have to trouble you for that map I saw you put in your pocket, that is all," went on his captor, while the two huge negroes who had made Frank prisoner stood to one side immovable as carved figures.
"It is lucky for me that you came down to the river bank," grinned the Portuguese as he ran his hand over Frank's clothes, to ascertain the hiding-place of the precious map of the ivory cache, "otherwise I should have had to delay my departure till to-night, and possibly have cut your throat while you slept."
Frank felt as if his heart would burst with rage and mortification as the greasy, smiling Portuguese deliberately drew out the priceless document and gazed at it in triumph. He laid it on the ground beside him while lie resumed his search for other clues.
"That ivory belongs to my master—Muley-Hassan—now," he sneered; "did you think for a minute that we would ever let you white fools get it back again."
It was well for the Portuguese that Frank's hands were not free then. Had they been the dark-skinned traitor would have had a fight on his hands in a few seconds. But suddenly events took a strange turn.
The two blacks uttered a sharp cry of warning as the bushes parted and a huge form dashed out, whirling about its head a glistening axe.
It was Sikaso!
The next minute would have been Diego's last but that his two followers lifted him to his feet and, picking him up like a child, ran for his canoe with him. With a few rapid strokes they were in midstream and paddling up the river with powerful strokes while Sikaso raged impotently on the shore.
"Oh for one of the white men's fire-tubes!" he sighed, and even as he spoke a sharp reminder of the efficiency of these same "fire-tubes" whizzed past his ear in the shape of a bullet from Diego's revolver.
In a few steps the old black was beside his young leader and with a couple of strokes of his keen blade had set him free.
"Quick, Sikaso; the canoes—we must pursue him. Call the boys and Ben while I cast off the canoes. Quick, we have not a minute to lose."
Although Diego in his hurry had not carried off the map but left it lying on the ground, still Frank realized that the Portuguese had not actually needed the document to aid Muley-Hassan to find the cache. The Arab was no doubt familiar with the location anyway, but to head off all danger of the boys getting there first, it was vital to stop Diego at all costs. In a few bounds Frank reached the little indentation in the bank where the canoes were kept.
As he gained it he fell back with a groan and, brave boy as he was, he leaned weakly against a tree for support as the true extent of the crushing disaster that had occurred was borne in on him.
The canoes were gone!
The cunning rascal, Diego, had devised his plan well.
The painters of all the craft had been cut, and by this time they were doubtless miles down the stream.
The consternation with which the news of the loss of the canoes was received by the young adventurers may be imagined. It meant that they were cut off from communication with the coast entirely unless some unforeseen circumstances arose. But in spite of the oppression that naturally affected them at the first news of their serious loss, Frank's confident manner had its effect in restoring some sort of hope. Like the born leader that he was, Frank, the minute he recovered from the first effects of his bitter dismay, set about cheering up the others.
"We've always got the Golden Eagle," he comforted, "and anyway it's likely if no one stops them, that some at least of the canoes will drift down the river to the coast. M. Desplaines will no doubt be able to surmise something serious has happened when he hears of their arrival and will send aid. In the meantime we have to consider what we are to do about the ivory cache."
As a matter of fact, as the boys learned later, none of the canoes ever reached the coast, being intercepted by river-tribes.
"I vote for going ahead," cried Harry, catching the optimistic note that his brother's words conveyed.
"That's the stuff," cried the young leader, "that is exactly what I was going to propose."
"How about you, red-top?" asked Billy turning to Lathrop.
"Of course I'm on," was the reply.
"I hate to dash your enthusiasm," said Frank, "but you fellows must see that it is impossible for all of us to go. My plan is to take Ben Stubbs along and leave you fellows and Sikaso here to guard the camp. Then, too, there is the possibility of a relief expedition arriving as soon as they discover that we have lost our canoes."
Old Sikaso leant apart on his mighty war-axe. He seemed to regret heartily that he had not had an opportunity of testing its metal on the head of the knavish Portuguese.
"What do you say to that plan, Sikaso?" asked Frank, who already placed a high value on the old warrior's judgment.
"That it is good, my white brother. Sikaso will stay with the four-eyed one and the ruddy-haired one and we will see that no harm comes to the camp of the young white warriors."
"It is well," replied Frank, who was falling into a trick of addressing the stately Krooman in the same grandiloquent fashion as the latter was in the habit of using, "I place my trust in you."
"Hum," snorted Billy, "four-eyes and red-top that's a nice combination for you! I'd like to do something to show that old chap that we can do just as much as anyone else when it comes to a show-down."
This remark, however, was made sotto voce to Lathrop, as Billy really stood in great awe of the six foot-two of ebony flesh and muscle that was Sikaso.
But Stubbs was delighted at his selection to accompany the boys in their aerial dash for the ivory cache. He spent half the night by lantern light pottering about the great craft and stocking her up with provisions and equipment for the journey. By the time he had finished it was almost midnight and he turned in to join the boys in the land of dreams where Frank and Harry, and doubtless the others, too, were already busy shooting down Diegos and hippopotami and flitting through the air above the great African forest and performing all sorts of wonderful feats.
At dawn everybody was up and about and after farewells had been said the Chester boys and their sturdy old companion clambered into the chassis of their craft. Frank had already laid out his course, which lay about two points west of north. The boy calculated that this direction would bring them within a few miles at any rate of the cache. To find it they would have to trust to persistence and a modicum of luck.
Old Sikaso, who had, of course, never seen anything even remotely resembling an aeroplane, stood apart from the excited group clustered about the big craft and gazed at it with astonishment, not unmixed with awe. The other Kroomen—the packers and camp-workers, however, gathered close about the machine and the boys had a lot of trouble keeping their busy fingers from unscrewing nuts and loosening turnbuckles.
"Anything more like a pack of monkeys on a picnic I never saw," exclaimed Billy as for the twentieth time he chased a long, skinny native away from the propellers, where he would have assuredly been decapitated if he had remained till the engine was started.
A few turns with the clutch thrown out showed the engine was running as true as on the day the Golden Eagle made her trial trip. The muffler was cut out and the effect of the wide-open exhaust on the Kroomen was magical. Within a second from the time that Harry threw in the switch and the gatling gun uproar of the exhaust made itself manifest, not a solitary one was to be seen. From the greenery of the jungle that rimmed the clearing, however, their frightened faces could be seen peering, like some strange sort of fruit among the tropical growth. Only old Sikaso stood his ground.
But even that stolid old warrior grasped his great war-axe a little tighter and stood erect as if about to face an unknown enemy as jets of blue flame and smoke shot from the detonating exhaust.
"All ready, Harry?" cried Frank to the younger boy who was at his old station by the engines.
"Ay, ay!" came the response in a hearty tone. "Then let her go."
With a quick movement Frank threw in the clutch.
The mighty propellers began to beat the air with the whirring sound of a swarm of gigantic locusts in full flight, and after a short run the great aeroplane took the air in a long graceful rising arc. Half an hour later, to the watchers in the camp, she was little more than a speck against the sky.
Frank, his eye constantly on the compass, kept the ship on a true course for the Moon Mountains which, now that they were flying far above the dense forest region, lay a rugged mass of blue and brown, piled like some giant's playthings—on the northwestern horizon.
Even from the distance at which the boys viewed them they conveyed an almost sinister impression in their rugged shapes. Their harsh outlines cut the sky in a serrated line like the teeth of a huge saw.
"Look, look, Frank!" shouted Harry suddenly as they were passing high over a small clearing.
Both Frank and Ben peered over the side in answer to the boy's excited hail.
Far below them was a strange sight.
In the center of the clearing were four huge African elephants solemnly conducting a sort of Brobdingnaggian game of tag. One of the great beasts would tap the other with its trunk and then would scamper away till it in turn was "tapped" by a blow that would have swept a small regiment off its feet.
Frank pushed over a lever and swung the ship in a circle so that they might watch the great animals to better advantage. Suddenly the boys saw one of the elephants, evidently seized by sudden rage, start goring one of its companions with its huge tusks. The attacked animal had no chance, and but for the boys would speedily have been killed.
"I'm going to give that big bully a shot," exclaimed Harry, and he got out one of the heavy rifles from the rack under the starboard transom.
"Wait, I'll drop a bit," said Frank.
In response to his manipulation the aeroplane dropped till she hovered not more than two hundred feet above the great animals. Then a strange thing happened. The shadow of the craft fell upon the center of the clearing in front of the dueling beasts and the on-looking pachyderms, and as it did so the bully stopped goring its mate and gave a snort of astonishment.
Its note of surprise quickly changed to a loud trumpet of terror as the great pachyderm saw swooping above it what must have appeared to it an aerial inhabitant even larger than itself. Its note of fright was echoed in a chorus that sounded like an assemblage of cracked trumpets as the others also sensed the impending danger.
"Now let him have it," shouted Frank.
Harry's rifle cracked and the big bully staggered. Twice more the boy fired and the huge creature staggered on to its knees and then with a mighty groan rolled over on its side. The others, even the wounded one, had made off as soon as they had caught sight of the hovering Golden Eagle.
Even from the height at which they were the boys could see that the dead animal had an enormous pair of tusks, no doubt extremely valuable.
"We ought to have them there figure-heads," commented Ben Stubbs. "What do you say if we drop down and get them?"
Frank looked at his watch. It was half-past nine.
"We cannot be more than a hundred miles now from the foot of the range," he said, "and I suppose we have plenty of time. We might as well drop and get them as let some native tribe have the find and then get skinned out of them by an Arab trader."
As he spoke the boy set the planes for descending and the Golden Eagle settled down—after a few minutes rapid falling—fairly in the center of the clearing. It was almost a fairylike spot. On every side it was hedged in by the densest jungle vegetation, the solid walls being broken here and there by elephant paths leading off into the green tangle.
The little glade in which the Golden Eagle had settled was covered with short, yellow grass and had been trampled almost bare of vegetation, apparently by the gambols of countless generations of elephants.
"This must be one of the elephant playgrounds I have read about," exclaimed Harry, looking about him.
"No doubt it is," replied Frank. "But look at those tusks, why there's ivory enough there alone to give us all a nice wad of pocket money."
Ben Stubbs, with one of the small axes, at once set about hacking out the dead elephant's huge tusks and a long job it was. Finally, however, he managed to cut them free and clear and the boys loaded them into the aeroplane.
"Now we are all ready for a fresh start," said Frank as they clambered in after him and settled down in their places; but a startling interruption occurred.
With a wild yell, that struck a sudden chill to the heart of every one of the little group, a band of beings that at first sight looked like nothing so much as huge gorillas, burst from the forest on every side.
Their heads were misshapen and flat and their protruding lips were daubed with white and red clay which gave them a ghastly unearthly look. From their ears hung huge ivory pendants. They carried elephant skin shields and were armed with spears and bow and arrows. As if they did not consider themselves sufficiently hideous, several of the tribe had cut their faces in long stripes and the hardly healed scars of these wounds rendered their already sinister faces terrifying indeed.
Desperately Harry threw over the wheel and the engines started faithfully to respond but not before half a dozen of the savages had thrown themselves on to the aeroplane.
Their weight held her down although she scudded over the ground; and in the meantime the other natives started pouring a shower of arrows and spears into her. Fortunately none of these struck the boys although Frank felt an arrow whiz through the loose sleeve of his shirt.
"Get those fellows off or I can't get the ship up," he yelled.
Harry and Ben Stubbs fired their automatics into the clinging mass of savages.
Two dropped and the aeroplane began to rise but the others desperately clung on.
"Get 'em off," shouted Frank, as he desperately strove to raise the air-craft.
As he spoke he fell back with a cry of pain.
An arrow had struck him on the shoulder inflicting a painful wound.
Like a flash Harry took in the situation and leaped to the steering wheel. As he did so the savage with whom he had been contending clambered clear into the chassis. At the same instant Ben Stubbs' revolver dispatched the last of the men clinging to the planes and the Golden Eagle began to rise.
As she shot upward the savage who had climbed into the chassis gave a wild shriek of real terror. But his outburst didn't come before he had made a savage lunge at Ben Stubbs with a short heavy knife. The solo adventurer dived under the black's arm and struck it upward as he lunged and the weapon went whirling groundward out of the air-ship.
With a cry of despair the savage rushed to the edge of the car and was about to throw himself into empty air when Ben leaped forward to try to restrain him.
But it was too late.
As the boys' sturdy companion gallantly attempted to save the savage's life a flight of arrows whizzed up from below.
With a groan the man on the edge of the car pitched forward into open space, pierced to the heart with an arrow sped by one of his own tribesmen. Down he shot like a stone to the earth below, while the Golden Eagle—as if rejoicing in her escape, shot upward and onward.
Frank's wound fortunately turned out to be nothing very serious—though painful enough—and after it had been treated with antiseptics from the medicine chest he declared that, aside from the stiffness and soreness, he felt no ill effect.
"Those fellows certainly gave us a sample of what we may expect," remarked Harry, examining the hole in his shirt where the arrow had ripped through.
"It was quite as narrow an escape as I care to experience," agreed Frank. "How about you, Ben?"
"Wall," said the old adventurer, "I don't know as how I think that kind of excitement is as beneficial fer the health as the rest cure."
Meanwhile the Golden Eagle, plowing through the clear African air at fifty miles an hour, rapidly drew nearer and nearer to the mysterious Moon Mountains.
As they neared the range the extraordinary character of it was revealed more and more clearly. Seamed with deep gloomy abysses and almost bare of vegetation, except a few scanty groves of palms and the hardier tropical trees, they seemed indeed fitted to be the theater of dark mysteries and the haunt of savage tribes.
"Well," exclaimed Harry, as he scrutinized the strange mountain mass through the glasses, "I should say that if those Winged Men are to be found anywhere, here is where they'd reside."
"I should think they'd use their wings to get out—a nastier looking lot of mountains I never saw," was Ben's reply.
Frank made no comment, but the sinister character of the mountains they were so rapidly approaching impressed itself on his mind nevertheless. Eagerly he scanned the range for the first sign of "The Upturned Face." Harry and Ben, too, gave quite as eager scrutiny toward the discovery of this striking mark of the ivory's hiding-place.
All at once it shot into view with a suddenness that made the boys' beads swim.
It was as clear as daylight. The line of the mountain for which Frank had the Golden Eagle II now directly headed was unmistakably the outline also of a hawk-nosed facet.
If the mountains themselves had an evil, menacing look, the stone face possessed this same quality in an infinitely greater degree.
"Well, if we've got to go looking for ivory right under that face the sooner we find it the better," exclaimed Ben. "I'd hate to be shipmates with the fellow who sat for that portrait."
"No human being ever sat for it, Ben," laughed Frank; "it's a mere freak of nature which has so disposed the mountain mass at this point as to give the semblance of what the map-maker terms The Upturned Face."
"Well, if I had a mug like that I'd turn it down instead of up before some one did it for me," was Ben's comment.
The Golden Eagle landed on a plateau about halfway up the mountain, beneath the upturned face. It made an almost ideal camping-place, considering the rugged nature of their surroundings. In one part of it a small grove of bananas and palms had taken root, and their smiling greenery offered a refreshing contrast to the dark oppressive gloom of the giant rock masses piled all about. From the center of this oasis in the rocky range bubbled a tiny spring of water as clear and cold as if it had been filtered and iced. Frank's first act was to send out a wireless to the River Camp, telling of their arrival.
"Well, thank goodness, we've got something green and pleasant to look at," remarked Ben, as they set about transforming the chassis of the Golden Eagle into a comfortable tent by means of running up the canvas curtains on the aluminum frames provided for that purpose. Thus equipped, the chassis served the uses of an improved tent, as the floor was well above the ground and out of all danger of the unwholesome, vapors rising from the ground and also the scorpions and other reptiles.
But if the oasis itself was a pretty spot, it was made doubly so by the contrast it afforded to the scenery surrounding it. On all sides shot up frowning walls of rugged black rock which seemed to have been torn and ripped in some remote period by a terrific convulsion of nature. In places, too, the rock masses seemed to have been seared by subterranean fires. Frank gazed upward at the terrific character of the scenery about them.
"We shall need the rope-ladder," he announced suddenly after a long silence.
"The rope-ladder?" inquired Harry, "what for?"
Frank laughed.
"I mean the rope-ladder we use in the Golden Eagle. As you know, the only way to locate the cache is to strike a direct line down from the nose of the upturned face. That will bring us to the small cairn or pile of rocks that marks the Arab's hiding-place."
"He could hardly have chosen a better," remarked Harry. "Who would ever guess, unless they had the key to the mystery, that these mountains held such a fortune in tusks."
The rest of that day was spent in overhauling the outfit which they would need to use on their expedition of the morrow. Luckily the boots they wore had been fitted with "hob-nails" so that they were ideal for the tough climb that they had ahead of them. Each member of the three was to carry a pick and of course they all were to be armed, carrying several rounds of ammunition each in their cartridge-belts.
That night after a supper of fried ham, canned corn and pancakes—all cooked by the skilful Ben over a fire of wood collected from the little grove—Frank sent out a wireless to the members of the camp on the river bank and felt much reassured when Lathrop's "All well—good luck," came back through the air. It was delightfully cool on the mountain-side after the oppressive fetid air of the river and its neighborhood, and as Ben had remarked before they turned in:
"Fine weather for sleeping."
But sleep would not come to Frank. He tossed and turned on his transom bed and several times gazed out into the night through the canvas curtains. An unaccountable feeling of unrest possessed him. Could they get the ivory out of the cache before Muley-Hassan and his band arrived by land?
Fast as they had traveled through the air Frank realized that the Arab, who doubtless by this time had been informed by the treacherous Diego of the boys' bold dash, would push on at furious speed in order to head them off. That he would come accompanied by a well-armed band Frank could not doubt. He and Harry and Ben could only put up a feeble resistance against such an attack. There was only one chance to secure the ivory and that was to get at it before the Arab arrived. It all depended then on how quickly they could find the cache. Frank lit the lantern and shielding it so that it would not strike in the eyes of his sleeping brother, drew out the map and scanned it attentively.
Yes, here were the directions written in the queer hand of Muley-Hassan's follower.
"A line from the nose straight down to the cairn of stones."
It seemed simple enough and certainly the nose of the Upturned Face was as clearly to be made out as a ship at sea. But Frank had been too long trained in the hard school of adventure to underestimate the difficulties of any piece of work. They faced a hard job and none realized the fact better than the young leader.
At last he blew the lantern out and once more composed himself to sleep. He was just dozing off when a sufficiently startling interruption occurred. One which drove all further thoughts of rest from his head.
It was an extraordinary sound that brought the boy out of his bed with a bound and caused him to clutch his revolver with a heart that beat loud and thick in spite of himself.
Clutching his weapon the boy rushed to the door of the chassis tent and gazed out.
There was a bright moon which threw into inky blackness the depressions of the rugged mountains and threw up their projections into a blue glare. It was almost as light as day under that wonderful African moon. Had there been any one near the boy must have been able to see them.
But look as he would there was not a soul in sight. All about him stretched the barren frowning mountains sleeping under the moon.
But the sound that he had heard?
There was no mistaking it. It had been too like the low humming of a human voice for him to have been misled. Perhaps he had been dreaming?
But as if to give the lie to any such supposition the strange sound that had so alarmed him at that moment made itself manifest once more:
"A-hooo-A-AH-HOOO-00-a-ho-ho-ho-o-!"
It started softly and gradually ran up the scale till it reached a crescendo shout and then died out in a soft sound like a woman's wail. Heard anywhere the sound would have been alarming enough, but coming as it did in the midst of these unknown, mysterious Mountains of the Moon it struck a chill to the boy's heart and caused his scalp to tighten in a manner that even the bravest man or boy in the world would have had no reason to feel shame over.
A human enemy, a foe he could see, Frank would have faced with iron nerve; but this strange wailing noise coming from what quarter of the compass he could not judge—was so uncanny that he was really disturbed. He bounded into the chassis and roused Ben and Harry. He had hardly whispered to them the extraordinary intelligence when again the voice arose.
"A-ho-ho-h-o-o-o-A-h-hoo-ho-AH-HO-HO-O-O-O-AH-ho-h-o-o-o-o-o-o!"
"Well, who?" roared Ben angrily, "come out and show yourself, you human hyena, and I'll put so much lead in your system you'll be worth a nickel a pound. Come, you old Ah-Hoo, and I'll show you who I am quick enough—shiver my topsails!"
But the only reply to Ben's tirade was the dismal echo of his voice among the rocky chasms.
"Shiver my topsails!" roared the echo and then the hills bandied the cry about from ridge to ridge till it died out in a whisper:
"My topsails!"
"Hum," remarked Ben, "I don't think I'll talk so loud around here. There seem to be a lot of folks listening. Such a dreary hole as this I never—"
"Never," sighed the echoes, "—never."
"Here, I can't stand this," cried Harry. "I'm going to send a bullet up there the next time that fellow starts 'Ah-hooing."'
But as the strange mournful cry rang out once more the boys paused in bewilderment.
There was no locating the sound.
It seemed to fill the air. To come from every quarter of the compass at once.
The mysterious cries were not repeated that night although the boys laid awake till daylight listening for any repetition. No theory they could advance, although these ranged all the way from cannibals and gorillas to ghosts, had any effect on the solution of the mystery. They finally agreed to trust to solving it in some chance way, and like sensible boys did not continue to worry themselves over the unsolvable.
Frank's first action was to send out a wireless to the river camp and to his great relief he found that events there were still proceeding with the same regularity as before. Nothing had occurred to mar the even life of the young adventurers left behind. This was the tenor of the message, but there was something about it that worried Frank. Lathrop, he knew, was an expert wireless operator, but the sending that he performed that morning was so jerky and irregular that the rankest amateur might have done better.
"What is the matter?" asked Frank sharply after the sending had become even more unskilled and shaky.
There was no answer; which caused Frank a vague feeling of apprehension. He speedily drove this impression from his mind, however, with:
"Pshaw! the sleepless night I passed has made me nervous."
After breakfast there was so much to be done that there was no more time to waste on gloomy forebodings and the boys started, as soon as the camp had been put in order, on their expedition up the mountain-side to the Upturned Face—which was to be the starting point for the uncovering of the secret ivory hoard.
The climb was quite as stiff as Frank had anticipated and, laden as they were with the rope-ladder and the other equipment, it was rendered even tougher. All three carried water-canteens covered with wet felt, containing half-a-gallon each. Frank had insisted on this as it was doubtful if they could find water at the summit of the mountain.
As the sun rose higher in the sky and beat down on the bare rock ridges over which the adventurers were making their way, it became as uncomfortable as any expedition on which the boys had ever beer engaged.
"Talk about New Mexico or Death Valley," exclaimed Harry, "I feel like a piece of butter rolled up in a paper and I've melted."
"I feel like a Welsh rarebit myself," laughed Frank, "how about you, Ben?"
"I feel like a pot of boiling tar with a fire lighted under me," growled the veteran angrily; "consarn these rocks, I'd give a whole lot for a bit of that shade we left behind us."
Despite the discomfort and the heat, however, they struggled on up the mountain-side, frequently using the rope-ladder to get over rough places, and at about noon they stood beneath the steep rock cliff that formed the nose of the upturned face.
It was easy enough then to reach a spot below the tip and Frank, with a long cord he had brought for the purpose, laid out a straight line from the point down the southern slope of the mountain-side. While they were busy about this they were startled by a repetition of the same strange cry, half-warning, half-savage, that they had been so alarmed by the night before.
"A-ho-o-o-o-AH-H-O-O-O-a-h-o-o-hoo-o-o-o-o!"
"Great Scott," yelled Harry, "what on earth do you think of that?"
Frank—considerably startled himself—had, however, made a determined effort to ascertain the source of the sound as it rose and fell in its strange cadence.
"I've got it!" he shouted; now with a cry of triumph.
"Got what?" cried Harry, as if he feared his brother had suddenly become infected with some strange complaint—"rabies or the pip?"
"The noise—I mean I know where it comes from," cried the excited boy.
"Where?" chorused Ben and Harry.
"From somewhere about the Upturned Face," cried Frank triumphantly, "Hark!"
The strange wailing cry rang out once more. They all listened intently.
Sure enough it seemed to proceed from the sinister countenance carved in the living rock above them.
"Well, here's where we end this mystery for all time," shouted Frank, drawing his revolver, "who is game to follow me?"
Of course Harry and Ben rushed to his side, and while the echo of the mysterious cry was still sobbing and sighing among the crags they dashed back up the mountain-side utterly oblivious now to the heat or anything but their determination to discover who or what had uttered the extraordinary cry. The side of the nose—or the nostril so to speak—was formed of a wall of rock fully twelve feet in height.
"You fellows give me a boost up there and I'll travel right along the face till I find out where the racket comes from."
On Ben's strong shoulders Frank was soon hoisted up to a height where he could lay hold of a projecting bit of rock and shin himself up on to the top of the nose.
"Look out he doesn't think you are a fly and try to brush you off," laughed Harry from below.
"No danger of that," shouted back Frank, "unless I lit on him in the Golden Eagle."
The surface of the face was as remarkable as its profile.
Apparently some forgotten tribe had at some time or other been struck by the facial outline of the rocks and had cut into the flat surface, which was upturned to the sky, eyes and a mouth, the latter well provided with teeth, in each of which was drilled a tiny triangular hole.
While Frank was puzzling over the meaning of these apertures there came a repetition of the weird cry, but this time the lad was so startled that he almost lost his balance and fell backward.
The call seemed to proceed from his very feet. Then, all at once, he realized what it was.
The strange sounds proceeded from the mouth of the stone face.
Frank ran to the edge of the steep declivity that formed the nose.
"Say, Harry, and you too, Ben, examine the surface below there very carefully for any holes. They will probably be small ones and in a row."
"None this side," announced the searchers after a lengthy quest.
"Try the other," ordered Frank.
They did so and after a few minutes of careful scrutiny Harry shouted that they had found a row of small holes pierced in the rock just below where Frank stood.
"Then we have solved the mystery of the voice," exclaimed Frank.
"What do you mean?" demanded Harry.
"That it is nothing more or less than an arrangement of holes through which, when the wind blows in a stiff puff, air is forced with violence enough to cause the cry that disturbed us so much last night," was the reply.
This indeed was the solution, and had the boys known it there are many such rocks in Africa, carved out by some forgotten race, and the weird cries that the vent-holes give out in the wind doubtless acted as a powerful "fetish" to keep away troublesome enemies.
"No wonder the niggers down below don't come near the Moon Mountains," said Harry, as they all buckled over the simple explanation of the phenomenon that had caused them so much alarm. "I wouldn't care to, myself, unless I knew just what made that cry."
"It certainly was as depressing as anything I ever heard," said Frank, "and now having solved the great mystery—let's get back to work."
The three adventurers went at the job with a will. The line was about a hundred feet long and the method of procedure was this: Frank tested the straightness of the line, as accurately as possible with his eye, while Ben and Harry carried it stretched between them. The end of each hundred feet was signalized by a stone, and Harry, who was at the end of the line, carried his end to this mark before they laid out a fresh hundred feet. In this way they must have measured off very nearly half-a-mile of the mountain-side when Frank gave a sudden sharp cry and pointed to a depression in the dark range immediately below them. As the others looked they echoed his cry and gave a dash forward.
Directly beneath them, about in the center of the little dip, was a cairn of rough stones perhaps four feet in height. In a few bounds they had reached the pile, which they knew meant the discovery of the ivory cache and the end of the most difficult part of their expedition. Little did they imagine the amazing things that were yet to happen to them and of which they were but on the threshold.
"Good Lord, look at that, boys!" exclaimed Frank, as they stood at the foot of the cairn.
There was a good reason for the boy's exclamation.
Distributed around the base of the pile were a dozen or, more human skulls.
"Are they those of white men?" asked Harry in an awed tone. Frank shook his head.
"No, they are those of negroes I believe," he replied after a careful examination, "and I imagine that Muley-Hassan killed them after they erected the cache so that they would not be able to spread the knowledge of its whereabouts to any of the marauding tribes who might even brave the ghostly voice when such a great treasure of ivory tempted."
A shout from Ben, who had been walking round the pile examining it from every view-point interrupted them. They looked up and saw the old adventurer pointing to the mountain summit where it cut the sky. Outlined against the deep azure was the object that had caused his exclamation. It was the figure of a man that had apparently been watching them intently.
But as they gazed the strange, crouched form suddenly vanished.
It was late afternoon of the day that Frank, Harry and Ben had left the River Camp. Lathrop, Billy, Barnes and old Sikaso had wandered into the jungle with their rifles, intent on bringing down some sort of game to replenish the camp larder. For hours they tramped about in the thick jungle and a fair measure of success had fallen to their rifles. Shortly before sundown the trio met in a glade not more than a mile from the camp and compared notes. To Billy's gun had fallen a plump young deer and Lathrop had brought down, not without a feeling of considerable pride, a species of wild hog which Sikaso proclaimed with a grunt was "heap good."
Flushed with triumph and carrying their own bag, the young hunters set out for the camp, arriving there at dusk. As has been told, it was not long after that that Frank's wireless from the Moon Mountains winged its way through the air and Lathrop was able to flash back in response an "all-well" message. The boys turned in early, Billy and Lathrop to their tent and old Sikaso to the rough shelter he had contrived for himself and which he declared was far more comfortable than any tent. Like a wild beast the savage old warrior disliked to have anything approaching a roof over him. It appeared to savor too much of a trap of some kind.
Billy might have been asleep five hours or so and it was approaching midnight when he heard a noise outside the tent door and a second later old Sikaso announced his presence by a whispered:
"Awake, Four-eyes, there is danger."
"What do you mean, Sikaso," demanded the half asleep reporter, "danger to our friends?"
"No; to us, and here and soon," was the disquieting response, "arouse your friend. We have no time to lose."
Billy was wide awake now and made a motion as if he would light the lantern.
Sikaso stopped him with a quick gesture.
"Do not light the lamp, my white brother," he whispered in the same tense tones, "to do so would be to reveal to those who are now approaching that we are awake and expect them. Rather let us pretend that we are unaware that they come and spring upon them like the leopard when she is least expected."
"Yes, but—" exclaimed Billy in a bewildered tone, "what do you mean, Sikaso, what enemies are coming? How do you know that they are approaching?"
"I have seen it in the smoke," was the somber reply; "the smoke never lies. After I lay down on my skins I could not sleep, I felt there was danger approaching us. From where I knew not. So I made the "fetish" fire. In it I saw a band of men coming toward us down the river and at the head of them was a dark man—a man you know well, my white brother with the four eyes."
"Diego!" exclaimed Billy divining the other's thought.
"Yes, Diego; cursed be the day that my war-axe did not cleave his ugly skull; but beside Diego there is another. Hearken to the words of Sikaso, the elephant in his rage is not more merciless, the serpent not more cunning, the crocodile not more savage in onslaught than this other. He is Muley-Hassan, the Arab, and the deeds he has done, my brother, when recounted turn strong men's blood to water."
Small wonder that Billy, as he hastily roused Lathrop, felt a shudder run through him. He had heard enough from Frank of the ways of Muley-Hassan to know that they could not well fall into the hands of a more pitiless foe and that now, with the Golden Eagle gone and the Boy Aviators already at the ivory cache, it was probable that the slave-dealer's rage would render him even more savage than was his wont.
In a few rapidly whispered words Billy apprised Lathrop of the situation. Like Billy, the other boy had no lack of pluck but his heart sank, as had his companion's, as he sensed the full meaning of Sikaso's warning.
"But perhaps the smoke was mistaken," he said eagerly, willing to grasp even at that straw of hope; but the old warrior's answer dashed his aspirations to the ground.
"The smoke is never mistaken," he said simply; but with such calm conviction that the boys, despite themselves, realized that the old Krooman had really the knowledge of grave peril approaching.
"Had we not better arm the other Kroomen?" asked Billy anxiously.
"It would be useless," was Sikaso's reply, "they are cowards. At the first sight of blood they would run to the forest like the sons of weaklings that they are."