"Say, boys," hailed Chief Biff, as the boys rolled up abreast of him and his men, "hain't seen hair nor hide of that car your dad was arter 'phonin' me about."

"Well, you soon will, chief," said Jack.

"Haow do yew know that?" asked the chief, his little eyes blinking curiously.

"Because it's right behind us now," declared Jack. "It's that red one."

"Ther dickens you say. How'd you come ter git erhead of 'em?"

"They must have stopped to fix a tire or something," said Jack.

But Biff was paying no attention to him. The majesty of the law was strong upon him. Calling his minions to his side he stepped into the middle of the road in front of the red car.

"Get out of the way!" shouted the man who was driving.

"Not much I won't," declared Biff valorously. "Halt that gasoline gadabout o' yourn instanter."

"What for, you old Rube?"

"Old Rube am I?" sputtered Biff, feeling that the law had been insulted in his person, "jes' fer thet yer under 'rest."

"What for?" demanded the driver of the red car angrily.

"Fer running daown and grievously wounding a man and then speedin' off without stoppin' ter see if you'd killed him dead or what all. That's what fer."

The driver of the red machine lost his blustering tone.

"Why, there's some mistake," he stammered, his face very pale, "I—er—we—er—that is, we didn't run anybody down."

"Oh, yes, you did," said Jack. "We saw you, and what's more we've got the man you struck right here in our car. You're a fine pack of cowards to run off like that. If we hadn't happened along he might have lain there for hours before help came."

"You saw us!" gasped the driver of the car, losing his bravado completely. "Well, I might as well admit we did run a man down. But we didn't think he was badly hurt and so we put on all speed to rush into town here and get a doctor for him. We'd have been here sooner only one of our tires punctured."

"Thet's a dern good story," said the chief, "but you'll hev ter 'splain that ter ther squire. Come on with me ter ther court-house. Too bad fer you thet them Chadwick boys had some sort of a do-funny dingus on their sky buggy that talks through the air, otherwise you'd hev got clar' away."

The man had, by this time, got out of the car which they halted at the side of the street. A crowd of curious villagers gathered and were staring at the scene and the actors in it.

At Chief Biff's words the driver of the red car flashed an angry look at the boys. His companions looked equally vindictive.

"So, it's to you we owe our arrest, is it?" he said in a low voice, coming quite close to Jack. "All right. You'll hear from me later. I'm not going to forget you or that other kid, either. Do you understand?"

Jack made no reply, and as he was anxious to get the injured man to the hospital as quickly as possible he drove off. At the institution the man was carried to a cot by two orderlies, and the doctor in charge told the boys that, so far as he could see, his injuries were not mortal, although he added that a fracture of the skull was possible.

"In which case," he said, "his recovery is problematical. How did you happen to pick him up?" asked the doctor, who knew the boys quite well.

Jack told him as briefly as he could, and received the physician's warm congratulations.

"It was fortunate that you happened along," he said. "Otherwise a long exposure to the sun, unattended, might have resulted in the man's death. Have you any idea who he is?"

"Not the least," replied Jack. "All that we know is that, just after he had plodded round the corner as if he was tired after walking a long way, that auto came whizzing round and struck him. Somehow he doesn't look like a tramp."

"No, he doesn't," agreed the doctor. "However, he should be conscious to-morrow if there are no complications, and we can find out. One thing is certain, he ought to be grateful to you."

"Oh, that's all right," laughed Jack, much relieved to hear that the man wasn't going to die. "It was all we could do."

They drove back through the village. Outside the court-house was quite a crowd. Events were few and far between in sleepy Nestorville, and the arrest of the autoists had caused quite a sensation. From a friend in the crowd the boys learned that the three men were being arraigned before Squire Stevens.

"Let's go in," suggested Tom.

"All right," nodded Jack, and they climbed out of the Wondership and ascended the long steps leading into the court-house. As they entered Squire Stevens' court-room, Chief Bivins spied them.

"Here they be now, Squire," he said. "Glad you came, boys. It saved me the trouble of serving subpoenas on you. These are the boys who saw the whole thing, judge."

"Was it an accident?" asked Squire Stevens, a dignified-looking old man with an imposing white beard.

"Yes, entirely so," said Jack, who did not bear any malice.

"But after they had struck the man, these young men ran away?"

"Yes," Jack was forced to admit. The men shot him a glance of hatred.

"I understand you have been to the hospital," went on Squire Stevens. "Did you learn how badly the man they hit is hurt?"

"The doctor told us that his injuries don't appear to be serious," said Jack, "but that it was possible there might be complications."

"In that case I shall have to hold you young men under bond," said the squire. "Will you be able to furnish it?"

"In any amount," said the man who had driven the car, in a loud, boastful voice. "My father, Evans Masterson, owns the Boston Moon, the evening paper. If I can telephone to him he will soon get us out of this scrape."

"Very well, then," said the Squire, frowning slightly at young Masterson's tone. "I shall fix your bond at $500, as you were driving the car and directly responsible for the accident, and that of your companions at $100 each."

Young Masterson gave an ironical bow. Chief Biff Bivins escorted him to the telephone. The elder Masterson, who had had a good deal of experience with his son's escapades, at first administered a lecture over the 'phone which ended by his saying that he would come post-haste to Nestorville and extricate his son and his chums from their unpleasant fix.

But the boys did not wait for this. As soon as the case was over they hastened back to the Wondership. The run home was made without incident and it was not till the Wondership was safely in its shed that Jack suddenly thought of the odd cylinder of lead that he had picked up by the man's side as he lay on the road.

"I ought to have left it at the hospital," he thought, "but I entirely forgot it."

He drew it out and looked at it. He now saw that the lead cylinder enclosed a glass vial carefully corked and sealed. The bottle was wrapped in flannel. Jack could not withstand the temptation of pulling it out and looking at it. He hardly knew what he had expected to see, but he was distinctly disappointed, as was Tom, to find that the carefully protected vial contained nothing more than some dark, almost black, stuff that looked like sand. In it were particles that glittered like mica.

"Pshaw!" he exclaimed in a disappointed tone, "nothing but a bottle full of sand. Wonder why in the world that fellow carried trash like that so carefully wrapped up for?"

The solution of the question, which was near at hand, was to have an important bearing on the lives of the Boy Inventors, and that in the immediate future.



CHAPTER XIII.

THE LEADEN TUBE.

The following day, while they were experimenting and practicing with the radio telephone, the boys received word that the man in the hospital was conscious and wished to see them, if possible.

"Perhaps now we shall get some explanation of that queer tubeful of sand," said Jack, as he hung up the telephone receiver, having informed the physician that they would be at the hospital shortly.

"It's certainly a queer sort of thing for a man to carry about—a glass vial full of black grit so carefully protected, unless he is crazy or something," commented Tom.

"I think that there is some explanation back of all this," said Jack, "and for my part the sooner we get to the hospital, the better I shall be pleased. The man told the doctor he was a miner and his name is Zeb Cummings. Perhaps that sand is gold-bearing or something like that."

"That might be the case," agreed Tom.

The boys decided to take out the electric car. It was in perfect running order and the indicator showed that there was plenty of electricity in storage for the start. They told Mr. Chadwick where they were going and then rolled out of the High Towers gates onto the broad, smooth road bordered with pleasant green elms.

They bowled along smoothly and silently with the car working as perfectly as delicate clockwork. They had gone about a mile from the house and were on a steep grade which the car took as easily as if it had been going down hill, when their attention was attracted by a sudden shout from the vicinity.

Jack brought the car to a halt. The voice came again.

"Hi! Help me! Ouch! Help!"

"What in the world is the matter now?" wondered Tom.

"Somebody in trouble in that field yonder. We'd better get out and see what's up," proposed Jack.

The shouts seemed to issue from beyond a high bank at one side of the road. On its summit was a hedge which prevented the boys seeing what was going on in the field that lay beyond.

As they got out of the car, however, Jack spied a bicycle at one side of the road. A satchel that he remembered very well was slung from its frame.

"It's the professor in trouble again!" declared Jack.

"I do believe you are right," replied Tom as they scrambled up the bank. "That's sure enough his wheel."

They found a gate in the hedge and on the other side an odd sight met their eyes. Kneeling on the ground was the professor. His right arm was thrust almost up to the shoulder into a hole in the ground. He was shouting lustily for help and appeared to be imprisoned in his queer posture.

"Some animal has got hold of his hand," cried Jack. "Come on, Tom."

"Oh, boys, thank goodness you've come," gasped the scientist.

"What's the matter?" demanded Jack.

"I can't get my arm out of this hole," declared the professor.

"How did you get it in?" asked Tom.

"A fine specimen that I dropped accidentally rolled into it," was the reply. "I reached in to get it and now I can't get my hand out."

"But you got it in easily enough," said Jack in a puzzled tone.

"Ah, yes," replied the professor, "but then I didn't have my hand clenched. Now my fist is closed and I have the specimen in it. Oh, boys, it's a beauty. One of the finest I have ever seen. It shows distinct monolithic traces."

"But if you don't drop it you can't get your hand out," argued Tom.

"I know that. That's why I shouted for help," said the professor simply.

"You'll have to let go of it," decided Jack, almost choking with laughter at the plight of the eccentric little man.

"Let go of it? My dear sir," murmured the professor in a shocked tone, "this specimen is worth at least twenty dollars, not to speak of its scientific value."

"But you can't stay here," said Jack decisively.

"And I won't let go of the specimen," declared the professor with equal firmness.

"What on earth are we to do?" said Jack, looking helplessly at Tom.

Not far off Tom had noticed a man digging potatoes. It gave him an idea.

"We can borrow that man's shovel and dig his arm out," he suggested.

"It's about the only thing to do, I guess," said Jack. "You go and see if you can get it. I'll keep the professor company."

Tom soon came back. The potato-digger accompanied him. The man was much interested in the eccentric man's plight.

"If that ain't the beatingest I ever heard on," he remarked, gazing at the professor, and then he tapped his head significantly and looked at the boys in a knowing way.

"Nobody home, eh?" he said with a grin. Fortunately the professor did not hear him; but the boys could hardly keep from laughing outright as they set to work with the spade. A few minutes of brisk digging set the professor at liberty and he was able to stand upright and triumphantly exhibit a small black rock which looked in no way remarkable, but which, it was evident, he esteemed highly.

"Ah, my little gem," he said, gazing at it fondly. "You thought you'd escape me; but you didn't. A wonderfully fine specimen, boys."

"Tell yer what," said the yokel, from whom they had borrowed the spade, "I'll pay you fifty cents a day to clean up my back pasture yonder. It's chock full of them black rocks."

"It is?" exclaimed the professor eagerly. "I must visit it some day. It would be worth writing a paper about. Most remarkable. A whole field of these stones. Well, well, this is a great day for science. But how did you boys happen to come along so opportunely?"

Jack explained, and then, suddenly, he thought of the tube of queer-looking black sand. Possibly the professor would know what it was. He drew it out and briefly narrated how he came in possession of it. The professor took the little glass vial out of its protecting lead and flannel. He adjusted his glasses and held it up to the light. Then he uncorked it and sprinkled a few grains on the palm of his hand.

He regarded it carefully for a few minutes and then drew out a huge magnifying glass. The next instant he dropped his scientific calm and uttered a sharp exclamation of astonishment.

"Where is the man who owns this?" he exclaimed. "We must see him at once."



CHAPTER XIV.

IN THE HOSPITAL

"We are on our way to see him now," said Jack. "He is in the Nestorville hospital."

"May I go with you?" asked the professor, with astonishing eagerness for him.

"Why, of course. But that black sand," said Jack. "What is it—gold-bearing material of some kind?"

"Gold!" exclaimed the professor with fine scorn, "gold would be dross beside it. Of course I haven't analyzed it yet, but if it is what I think it is, it is the most valuable stuff in the world."

The boys exchanged bewildered glances. Clearly their discovery of the injured man, Zeb Cummings, had an aspect they had not hitherto suspected. But the professor refused to tell them what the sand was, or what he thought it was, till he had seen Zeb Cummings himself.

Leaving the potato-digger under the firm impression that they were all crazy, they hurried back to the road, the professor's bicycle was placed in the tonneau, and Jack drove just within the speed law to the hospital.

They found the injured man sitting up in bed, his great yellow beard gleaming like gold. His head was bandaged but even the pallor induced by the accident had not materially altered the ruddy glow of his thick coat of tan.

"So these are the boys who saved me," he said, extending a big, gnarled hand. "Shake, pardners. The doc here tells me if I'd laid much longer out there in the sun, there might hev been a first-class funeral fer Zeb Cummings."

"Oh, that's all right," said Jack easily. "I'm only glad that we came along when we did."

"Well, you sure acted different from them other varmints," said Zeb with deep conviction. "The doc tole me all about it."

His face suddenly grew grave as he changed the subject.

"Did you find anything on the ground thereabouts after I got knocked out?" he asked.

"What sort of a thing?" asked Jack.

"Oh, nothing that looked very valuable. Jes' a little lead roll with a bottle full of what looked like black sand in it."

"Got it right here," said Jack, producing the bottle which the professor had given back to him.

"Glory be!" exclaimed Zeb Cummings, as he took the lead-wrapped vial as though it was something precious. "I was afeard that if anyone found it they might hev thrown it away, bein' as it don't look as if it amounted ter anything much."

"Is it valuable?" asked Jack, who could not restrain his curiosity.

"That's jes' what I don't rightly know," rejoined Zeb. "I reckon I'd better tell yer how I come ter git it an' then you kin judge fer yourselves."

"We'd like to hear," said Jack, who had felt all along that there was some mystery about the yellow-bearded giant.

"All right! Sit down and I'll tell yer ther yarn. But say, who is yer friend? No offense meant, ye understand."

"This is Professor Jerushah Jenks," said Jack.

"What, the guy that knows all about rocks and such like?" burst out the miner.

"I believe I have achieved some small fame in that line," said the professor.

"Wa'al if this don't beat pay dirt I'm a Piute," exclaimed the miner. "Give us your hand, Professor. I was on my way ter see you when that thar buzz wagon busted me higher nor a turkey buzzard."

"On your way to see me?" echoed the professor in amazed tones.

"Yes, siree bob, that very identical thing," was the bronzed miner's reply.

"But I don't quite understand. You see I——"

"That's all right, Professor. We'll git down ter pay dirt direc'ly," said the miner. "You know of the Scientific Society in Bosting, of course?"

"I am a member of that body, sir," was the dignified reply of the little man.

"Well, they giv' me your name. Said you was the biggest bug on rocks, minerals and sich in the country and so I sets out to pay a call on you."

"But you were many miles from where I live," said the professor. "The railroad, or the trolley——"

"Don't carry folks for nothing," interrupted Zeb, "and nothing's my capital right now."

"You mean that you were walking from Boston?" asked the professor.

"That's right," was the reply. "Landed there on ship from round the Horn last week. Got paid off but some sneak thief in the boarding house I was stopping at got my roll. So I had to hoof it."

"But what did you want with me?" asked the professor.

"I wanted you ter tell me ef that thar stuff in the glass tube is worth anything or nothing," was the reply.

"Why, do you know where there is more of it?" asked the professor, and the boys could see that he was oddly excited, although preserving an appearance of outward calm.

"Yes, siree," was the emphatic reply. "I know whar thar's enough of it to load a freight train."

"Shades of Huxley!" gasped the professor, actually turning pale. "Do you mean that?"

"I sure do, Professor. It's all down on a map what Blue Nose Sanchez give me afore he passed in his checks."



CHAPTER XV.

A TALE OF THE COLORADO.

"Do you fully realize what you are telling me?" asked the professor. The doctor and the nurse had left the room, and the miner, the scientist and the boys were alone.

"Course I do," was the rejoinder of the yellow-bearded giant with the bandaged head. "There ought ter be a fortune in it 'cording to what Blue Nose Sanchez said. Was he lyin', Professor?"

"I don't think so. But tell us your story," urged the man of science.

"Well, it begins some months ago. I was prospecting down along the Colorado River. It was in a mighty bad place. Don't rightly know just how I ever got thar, but thar I was. Wonder was I wasn't killed ten times over 'fore I got to whar I was. But I guess I'm pretty tough.

"That Colorado River is a pretty tough place down where I was. Nothing but desert all around, and just a swift dashing current at the bottom of a canyon that looks like it went into the middle of the earth with steep, dark walls that seem to go straight plum up to the sky.

"But I was lured on by the thought of making a big strike. At last I got down to a place where the banks was so high and steep that it was like twilight even at noon. Grub was gittin' to be a question with me, and I'd about made up my mind to turn back, but I thought I'd make one more last try.

"I set to work on a rocky bank with my pick but nary a color—that's what we call a trace of gold—could I uncover.

"Wa'al, says I to myself, it's up stakes fer you, Zeb, unless you want to starve afore you git back to civilization. But as it was evenin' then I decided to stay whar I was that night and strike back early the next day.

"Here's whar Blue Nose Sanchez comes inter ther story. They called him 'blue nose,' I guess, because of a premature blast that had blown powder into his nose and turned it that color. Anyway, he was a mighty homely specimen.

"It was just gittin' light in the canyon, although it must have been broad day up above, when I hears an almighty hollering up the gulch. The next thing I knows, round a bend comes a small boat. There's two men in it. They must have been crazy to try to make the passage, for the river is just a mass of rapids and whirlpools, and I never heard of anyone trying to shoot 'em.

"But thar was these two fellows in this boat, and they was scared, too, I kin tell you. Wa'al, I stood thar like a stuffed pig on the bank watching 'em as they came toward me at the speed of an express train. Suddenly one of 'em, the chap that was trying to steer, twisted the oar he was guiding the boat with and it cracked under his weight. He went overboard in a flash.

"The next moment, with a yell of fright that I kin hear yit, the boat was hurried past me on that water that boiled like yeast in a kittle, and in a flash it had disappeared round another bend. What became of it I never knew, but it must have been upset and the man in it drowned. No boat could have lasted long in that water, even with an oar to steer it, and that was gone.

"I waded out inter ther water as far as I dared and by some freak of the current the man who had toppled out of the boat came within my reach. I grabbed him and dragged him ashore, more dead than alive. I done what I could for him and he came to after a while. That was how I met Blue Nose Sanchez.

"Well, sir, Blue Nose was a mighty sick man, even then. He had fever and was a ravin' lunatic at times, but at intervals he made out to tell me suthin' of his story. Him and his partner, a fellow he called Foxy Joe, was on their way to find a little island down ther river where no white man but only one had been. This man was a friend of Foxy Joe's and the two met up in Yuma. Foxy's friend had a lot to tell him about a wonderful island some Injuns had told him about whar there was some sort of mysterious mineral. By what Joe could make out this mineral was nuthin' more nor less than radium."

"Radium!" exclaimed the boys.

"That's right," went on the miner. "Foxy's friend allowed that there was cartloads of it lyin' loose thar 'cording to the description the Injuns give him, and he showed Foxy a sample of the stuff. That sample is in this little lead-wrapped bottle. It's wrapped in lead 'cos otherwise it 'ud make sores on you when you carry it about. It's workin', workin' all the time, frum what I kin make out.

"Well, 'cordin' ter ther way Blue Nose Sanchez tells it, Foxy and the man who knew about the island and had a rough plan of it the Injuns drew fer him, had a fight, and Foxy kills him, or thinks he has. Blue Nose sees it and sees Foxy take the map and the little lead-wrapped bottle off the body. He suspects somethin' and tells Foxy that he'll give him up to the law if he don't let him in on it. So Foxy tells him all about it and him and Sanchez, who was then a mule rustler, agrees ter go partners and go git ther radium, or whatever it is.

"They builds this boat, the one that disappeared, and in order that Foxy shouldn't play no tricks, that bein' his disposition, Sanchez 'lows he'll take both the sample and the map. Foxy sees no way out of it but to give in and that's the way it's fixed.

"The boat is taken out of Yuma in sections and then put together in a place whar nobody ain't likely to come nosin' around. Then they starts out on what I guess was the most darn-fool enterprise any two locoed fortune-hunters ever undertook. How it ended you know. They both got fever, but Sanchez was the worst. He died that same evening, his tumble in the water havin' made him worse. I buried him there as best I could and then, as he had wished, I takes the sample and the map.

"'Some day,' he told me, just afore he closed his eyes for good, 'you'll be glad you saved me, even though it was too late.'

"Well, I beat it back and get out of the canyon more dead than alive and finally make a small strike. I go to San Francisco with it and try to git ther stuff analyzed, but everyone I tole about it laughed at me and said I was crazy. So, thinks I, I'll come East. My money was about all gone, so I shipped afore ther mast on a Cape Horn ship, and got here.

"Now, you have me tale, old top," grinned the good-natured miner, and added: "Well, has my toe-and-heeling been worth its salt?"

The professor nodded solemnly.

"What is it?" cried Jack, his heart beating with a strange, wild hope.

Tom and Zeb echoed Jack's eager question.

"My friends," declared the little man of science pompously, "we have reason to believe that a wonderful discovery has been made, namely, Z.2.X."



CHAPTER XVI.

ZEB CUMMINGS.

"Z.2.X., the most radio-active stuff in the world!" exclaimed Jack.

"I suppose that approximately describes it," said the professor, "but what do you know about it?"

Jack explained how ardently his father had wished for the missing element to make his system of radio telephony the most efficient in use.

"Well, if what Sanchez said was true, and the map is right, there is plenty of it right on that island," said the miner.

"Yes, that may all be," objected the professor, "but how are you going to get at it?"

"Wa'al that's a poser. You can't reach it in a boat and you can't reach it over the desert," said Zeb. "The country all round there is dry as an oven and, anyhow, if you got to ther banks of ther Colorado right by ther island ther's no way of gitting down to ther island. Sanchez says that the Injuns told Foxy's friend that a long time ago, when first they found the stuff on the island, there was a way of getting down to it. But an earthquake sunk the river bed and nobody had been thar since the Injuns that found it. He said that they first come to take notice of it by reason of the way it shined at night. But only a few of the tribe would go near on account of their thinking the place was haunted."

"Have you got that map?" asked the professor.

"Yes, if you'll reach my coat I'll show it you," said the miner.

Jack gave him the ragged garment off a hook at the back of the door. Zeb fumbled in the pockets for a minute and then brought out a knife.

"A rip more or less won't make no difference," he said, and cut a slash down the lining. There, carefully stowed inside, where it could not be suspected, was a folded, time-yellowed paper.

The miner opened it slowly and spread it out on the counterpane. The boys, not without a sense of shock, noted a dark, rusty-looking stain upon it. It struck them that the marks might be the life blood of the treacherous Foxy's friend who had met a tragic end in Yuma.

Zeb, with a broad and blackened forefinger, traced the course of the Colorado. At length his finger paused at an island marked in red. There was some fantastic Indian lettering, or sign-drawing, about it, and underneath, in a white man's handwriting, were the words: "Rattlesnake Island."

"I reckon Foxy Joe's friend must hev written that in," commented Zeb.

"It looks that way," said the professor, who had poured the sample of mineral-bearing sand back into the vial and restored it to Zeb Cummings.

"Rattlesnake Island," repeated Jack. "Are there any rattlers down that way?"

"Yes, and gila monsters and tarantulas and centipedes," replied Zeb cheerfully. "But you soon get used to 'em."

Some other islands were marked on the map, but Rattlesnake Island was the only one designated by name.

"That must be the place whar all that stuff is, then," decided Zeb. "I wish thar was some way of gittin' thar."

"If there is even only a small fraction of the mineral-bearing sand there," said the professor, "there's a fortune in it."

"Wa'al if you can't git it out what good is it?" said Zeb philosophically. "Anyhow, I'm glad that Sanchez spoke the truth with his dying words. Maybe thar is some way, except by water, in spite of what he said."

"Maybe there is," said Jack. "It seems a shame to think of all that rich stuff lying there neglected and unobtainable."

"It does indeed," agreed the professor. "In that sample I find traces of metals from which filaments for electric lights could be made and substances invaluable in medicine for X-ray purposes as well as the Z.2.X. which your father is convinced would make the radio telephone as practical as the wireless telegraph."

They would like to have stayed there all the morning poring over the map and asking further questions of the rugged miner, but at that moment the nurse came in and declared that the injured man must have quiet.

And so there, for the present, the matter rested. The professor departed for his home greatly excited over the events of the morning, but his excitement was a little allayed by the fear that he would be late for his mid-day meal with dire results from Miss Melissa.

As for the boys, they could talk of nothing else. The idea of that lonely island, lying at the bottom of an unscalable canyon in the midst of a burning, desolate desert, appealed powerfully to their imaginations. Their minds were in a whirl over the strange coincidence that had brought them in contact with a man who knew where possibly inexhaustible supplies of the mysterious Z.2.X. lay ready for the taking, provided it could be reached.

"I'd give a whole lot to be able to fix up an expedition to go out there and get that stuff," said Jack with a sigh.

"So would I," agreed Tom. "But I guess, as Zeb Cummings said, it will be a long time before anyone sets foot on Rattlesnake Island."



CHAPTER XVII.

IN THE LABORATORY.

That afternoon Jack broached to his father the events of the morning. Mr. Chadwick's enthusiasm may be imagined as his son told him of the professor's hasty analysis of the contents of Zeb Cumming's glass vial.

But there remained the insuperable obstacle of the remoteness of the island where the deposits lay, and the difficulties—in fact, almost the impossibilities—that barred the way. For the time being, however, the matter was set aside while further experiments with the radio telephone were conducted. As a means of increased transmitting power, Mr. Chadwick had in mind a series of sending devices attached to one mouthpiece. In this way he believed he could at least partially overcome the resistance of the atmosphere, and get a higher percentage of current.

He had been working on the idea all the morning and was anxious for a test. The Wondership was, therefore, wheeled out, and before long the boys were in the air once more. As before, they sailed in the direction of Rayburn. As they passed above the farm where they had met with their adventure the day before, they turned to each other with a laugh.

Below them they could see men working on the damaged roof of the barn and Tom burst into an uncontrollable fit of laughter as he recalled the queer sight the farmer presented dangling from the grapnel high above his broad acres.

"That reminds me," said Jack. "We must send him some money for that roof."

"How about his personal feelings?" grinned Tom.

"I guess he wiped that score out when he blazed away at the balloon bag."

"Just the same, I think we'd better go pretty high up," advised Tom. "He might fancy trying another shot at us."

"That's so," agreed Jack, studying the men moving about far below.

He pulled a lever and the Wondership began to rise. It was as well he did so perhaps, for as they shot upward they could see that their presence had been noted. They watched the men scurrying about and pointing upward. But whether the Wondership was too high, or his animosity had cooled after his involuntary ascension, the farmer made no hostile demonstration, and they were soon out of Perkins' sight.

Apparently the new device worked fine, for all through the afternoon, at various heights and distances, they kept in perfect touch with Mr. Chadwick. Every intonation of his voice was borne plainly to their ears, Tom at times taking the wheel and the receivers while Jack relieved him at the engines.

The storm which had threatened the night before, still was hovering about, as was evidenced by the white thunderheads piled on the horizon. But the electricity in the air did not, as is sometimes the case, interfere with the powerful impulses sent out from workshop and airship. Although the air felt heavy, the instruments worked perfectly.

The boys flew over hill and dale for more than seventy miles prior to any perceptible weakening in the current. But once it began to fail it reduced rapidly until the messages were scarcely audible. But the experiments were kept up till almost dusk, when Mr. Chadwick told the boys to come back.

As they returned the radio 'phones were kept working and as the distance decreased the impulses grew stronger.

"If only I had some of that Z.2.X.," said Mr. Chadwick, "I believe it would be possible to send a message across the ocean or the continent."

Not long after this Jack heard again from his father. It was a commonplace message enough. Sent merely to keep the air-line in operation.

"Here is Jupe with the afternoon mail," he said.

"Anything for us?" asked Jack, enjoying the novel sensation of talking through the air concerning such everyday matters.

"Yes, there's one from Ned Nevins," was the rejoinder, "and here is one for me from my New York brokers. Let me see—ah-h-h-h!"

The last was a sharp exclamation, as if Mr. Chadwick had received a sudden shock. It was followed by silence. Again and again Jack flashed the red signaling lamp but there was no reply.

He was seriously worried. The sudden sharp intake of breath, almost like an outcry, that he had heard, oppressed him with a sense of apprehension. What could have happened? Turning to Tom he called for full speed ahead for the trip back.

Tom was not slow in responding. He speeded the motors up to their top capacity. In the air there were no speed laws to look out for, or other motorists or pedestrians to avoid. It was a clear road. The steel stays and stanchions of the stanch Wonder ship fairly hummed as she shot forward, while an indefinable fear clutched at Jack's heart.

He knew that his father was subject to fainting spells and he had been overworking recently. Fast as the Wondership was cutting through the air it felt like an eternity to Jack before the gray walls and the well-laid-out grounds of High Towers came into view.

The boys lost no time in landing, and not waiting to place the Wondership in her shed, set out to look for Mr. Chadwick. Jupe came shuffling by on his way from the cornpatch.

"Where's dad, Jupe?" asked Jack.

"In his labveroratory, ah reckons," answered the old colored man. "Leastways ah ain't obfustucated any obserwations ob him round der contagiois atmosferics."

"Come on, Tom," said Jack. "Let's get to dad's workshop as quick as we can."

"Why, Jack, you—you don't think that anything has happened to him, do you?" asked Tom.

"I don't know. He was talking quite cheerfully to me and then, without any warning, he gave a sort of gasp and then everything was silent."

The next minute the boys entered the workshop of the inventor.

Jack's worst fears were realized as they gazed at the scene before them. On the floor, stretched out inanimate before the radio telephone apparatus, lay Mr. Chadwick. His right hand grasped a letter.

His head lay in a pool of blood, oozing from a cut at the back of his head.

"Dad! dad! What has happened?" cried Jack, in an agony of alarm, as he fell to his knees at his father's side.

But Mr. Chadwick did not answer. The next moment Tom's shout for help brought everybody about the place running toward the workshop where the alarming discovery had been made.



CHAPTER XVIII.

INTO THE STORM.

"Carry him into the house and get him to bed," cried Mrs. Bagley, the housekeeper, wringing her hands distractedly. "Oh dear! poor gentleman, he's bin a-workin' too hard, that's what's the matter."

Jupe and Hank Hawkins, the handy man, picked the unconscious man up and carried him to bed, where he was made comfortable.

Jack and Tom made an investigation of the workshop. At first the cut on Mr. Chadwick's head had given Jack the impression that he might have been the victim of foul play.

But a brief survey of the place soon dispelled these conclusions. When he fell, the inventor struck his head against the sharp corner of a table right behind him, Jack concluded, and in this way inflicted the wound.

The letter that his father had been reading when he was stricken still lay on the floor. Jack picked it up. It was from the brokers in New York, the same missive Mr. Chadwick had referred to over the radio 'phone just before the silence that so alarmed Jack.

Glancing over it Jack's eyes widened. He perceived at once that the cause of his father's sudden attack no doubt lay in the shock he had received when he opened the envelope. The letter was curt and to the point.

"Your securities wiped out in panic," it said. "Wire us and advise what to do."

That was all, but it was enough. Jack knew that most of his father's money was invested with the firm that had written the letter, and now they had been wiped out in a money panic. Jack had no idea how much of his father's fortune was affected, but it was evident from Mr. Chadwick's collapse that he had been dealt a heavy blow.

He was in the midst of talking to Tom about the letter when the housekeeper came running from the house.

"Oh, here you boys are!" she exclaimed. "You must get Dr. Mays at once. Those red drops he gave your father are finished and I can't find any more."

"I'll telephone," said Jack promptly, stuffing the letter into his pocket.

"I've already tried that," said Mrs. Bagley, "but the line is out of order."

"Can't we get some other doctor?" asked Tom.

Mrs. Bagley shook her head.

"Dr. Mays is the only one who understands your father's case," she said. "You must get him as soon as possible."

"Is dad conscious yet?" asked Jack anxiously.

"Yes, he has been trying to tell me something but I won't let him talk."

"We'll get Dr. Mays right away," said Jack, but then he suddenly recollected that the electric car was slightly out of order. There would be no time to stop and repair it then.

Luckily the Wondership still stood outside the shed. Five minutes later the boys were soaring aloft, bound for the doctor's house, which was some distance away. It was not till they had fairly started that they noticed the change in the weather.

The thunderheads they had seen earlier in the day now spread and covered the whole sky with a dark pall. The air was very still, as if nature was holding her breath. Far off, though in plain view, the sea was lying like a smooth sheet of steel-gray velvet. A sailing ship, with sails flapping, was becalmed some distance from shore.

"Going to rain," said Tom.

"Worse than that, I think," said Jack. "We're in for the storm that's been making up for two days now."

"Well, we can get there and back before it breaks."

"Easily. Let those motors out, Tom, we want to make good time."

It was oppressively hot, and had it not been for Jack's anxiety he would have enjoyed the swift cooling passage through the thundery air. But he was strangely troubled. Did that letter mean that his father was on the verge of ruin?

Suddenly he bethought himself of Ned Nevins' letter. He opened it, having pushed it into his pocket when they entered the workshop, where Mr. Chadwick had placed it before opening the ominous epistle from his brokers. It was a friendly, chatty note from the boy, and enclosed the checks covering the joint dividends of Jack and Tom in the Hydroaeroplane Company.

"Well, at any rate, that's something," declared Jack to Tom, as he handed him the letter and his check.

"Yes, but if Uncle Chester is ruined, it's only a drop in the bucket," said Tom.

"Well, it's no use crossing your bridges till you come to them," said Jack, "and anyhow, that letter may be only a false alarm. I've heard they get these financial panics in Wall Street just like kids get the measles, and they get over them as quickly."

"I trust it will be so in this case," said Tom.

"So do I," said Jack hopefully, but a cold fear that his father was ruined possessed him, and made his heart feel heavy as lead.

Suddenly, from the purple firmament, came the sound of distant thunder. Following it a puff of wind, hot as the exhalation of an opened oven, blew in their faces. In the distance they saw a ragged streak of lightning tear the cloud curtains.



CHAPTER XIX.

THE "LIGHTNING CAGE."

"Look at that, will you!" exclaimed Tom.

"What, you are not scared, are you?" asked Jack.

"N-no, but I must say I'm not fond of thunderstorms Particularly when we are carrying all that gas over our heads."

"That new invention of mine will take care of that all right," said Jack confidently.

He referred to a new device of his with which the Wondership was equipped for protecting balloon bags from lightning. In a thunderstorm a balloon, or gas-filled dirigible, is subject to sudden variations of electric charge which, under certain conditions, might produce sparks leading to its annihilation.

More especially was this the case with such a craft as this Wondership, carrying as she did so much metal and steel wiring. The netting of the bag, with the idea of making it as conductive as possible, was of metal, connecting with the other metal parts of the craft so that when a steel drag rope was lowered to the ground a discharge of lightning striking the balloon would be passed off harmlessly into the earth, as is the case with a lightning conductor.

It might be supposed that making the outside of a balloon a good conductor would invite danger from lightning. But the Boy Inventors knew that this was not the case. While the ordinary balloon envelope is a fairly good insulator against low voltage, it is unable to resist the high tension of atmospheric electricity.

Jack ascertained these facts by touching an electroscope with a bit of balloon cloth of the kind used on the Wondership, and charged with 2,000 volts of electricity. The electroscope instantly responded.

This showed that the balloon bag increased the electrical tension immediately above and below it as much as it would do if it was a perfect conductor, but the destructive action of a lightning bolt would be greater in proportion to the resistance opposed to it. So that, in reality, Jack's device was one of the safest that could be imagined for protecting balloonists in a heavy storm.

In effect, the occupants of the Wondership were enclosed in a cage. Lightning might zip through the wires and stays, but it could not touch them. As to the danger of letting out gas through the valve in a strong electric field, which is almost certain to produce sparks, the boys did not have to worry about that for to deflate the bag they simply pumped some of its contents back into the reservoir with the powerful gas pumps.

But after all, Jack's device had never been tested. It looked as if it was due to be. The wind came in sharp puffs, now hot and now cold.

Ragged, white clouds, like wind-driven fragments of filmy lace, began to whip across the dark heavens. The sea turned a peculiar light green and was flecked with whitecaps.

"We're in for it," said Jack. "Better get up the storm curtains, Tom."

While Jack steered, Tom drew up the waterproof curtains and top which, in rainy weather, made the Wondership quite dry and weather-tight. Mica portholes gave light inside this extemporized cabin, and enabled the steersman to see.

This had hardly been done when a wild gust of wind struck the Wondership and sent it staggering off its course. But in a jiffy Jack regained control of the craft and headed her straight for the white house occupied by Dr. Mays, which could now be seen, its lofty cupola poking up above the trees surrounding it.

"Glad we're nearly there," said Tom. "I don't much like this."

"We're O.K.," Jack assured him. "We went through a lot worse than this in that circular storm in Yucatan."

"Can't we drop and run along the road?"

"It's much longer by the road than by the air line, and remember we are in a big hurry."

"That's so. But we've got the return trip ahead of us."

"Well, if it gets too bad, we'll have to come back by road," said Jack, "but I haven't got a doubt that she'll stand anything that will come out of this storm."

Crash!

The sky was rent from end to end by jagged lightning. With a deafening roar the thunder broke, rumbling and crashing in the sultry air.

S-w-i-s-h!

The rain came in torrents, tearing at the storm curtains. It beat frantically at them with a noise like that of surf on a beach. But inside the boys were snug and dry, and the Wondership forged steadily forward. It was a weird experience for the boys. About them the artillery of heaven thundered and flashed. They could see each other's faces and the black outlines of their craft in the livid flare of flash after flash of lightning.

Jack, with his hands firmly gripping the steering wheel, anticipating every move of the storm-tossed Wondership like a skillful pilot, felt his pulses throb. There was something fine in battling with the elements like this in a stanch craft they had perfected. He felt that no other airship then in existence would have been able to keep up the fight.

All at once there came a crash that drove his eardrums in. The Wondership staggered and then seemed to leap into lambent flame. Blinded, Jack threw his hands before his eyes, utterly forgetting for the minute the steering wheel.

Tom gave a shout of alarm, as he felt the craft stagger as if dealt a mortal blow, and then begin to drop earthward.

"We've been struck!" he yelled in panic.



CHAPTER XX.

THROUGH THE AIR.

For the fraction of a second the faculties of both boys were paralyzed. A tingling sensation was in their limbs. Jack was the first to recover his wits. He snatched his hands from his eyes and seized the wheel. In a jiffy the Wondership's earthward plunge was checked. Once more she regained an even keel.

"Wh-what happened?" stuttered Tom anxiously.

"We were hit by lightning," replied Jack.

"Goodness! I thought we were goners, for a minute."

"I confess that I did, too. But I guess the 'electric cage' worked. Everything seems to be shipshape."

Jack was right. Thanks to his ingenious invention, the lightning, which had struck the aircraft, had been diffused through the safety "cage" and safely convoyed to the earth by the ground chain made of light manganese bronze, which had been lowered when the storm broke.

"Just the same I don't want to get hit again," said Tom. "I thought for a minute the world had come to an end."

"My fingers are tingling yet," said Jack, "and I can see stars, but I think if it hadn't been for the cage we would have likely been blown to smithereens."

By this time they were almost over the doctor's house and extensive grounds. Jack manipulated the Wondership against the storm, flying in a circle, and snapped on the powerful searchlight. With the help of its rays he picked out a good landing place, and having set the pumps at work abstracting gas from the bag, they soon made a good landing.

Doctor Mays stood on his porch as they left the ship and ran through the downpour for the house.

"Gracious, boys!" he exclaimed, "but you certainly gave me a fright. I thought when that bolt hit you that you were going to be annihilated."

"How did it look from below?" asked Jack.

"As if you were enveloped in blue flame. Then suddenly a ball of red fire slid from the ship to the ground——"

"Down the conducting rope," put in Jack.

"And exploded with a loud bang when it struck the ground," continued the doctor. "But all's well that ends well, and now tell me what brings you here, for I know it must be urgent business or you'd never have ventured through such a storm."

Jack hastily told the doctor of his father's stroke. The medical man looked grave.

"I'll go with you just as soon as I can pack my bag," he said. "Your father had been overworking. I warned him of what would happen if he did not rest up, some time ago, but he has, seemingly, disregarded my advice."

In a few minutes the doctor, muffled up in a raincoat, was ready to start. But he stipulated that the run to High Towers should be made by the road.

"I like excitement as well as anybody," he said, "and I've been up in your Wondership before——"

"When it was the Roadracer," interpolated Jack.

"Exactly; but I must confess that when I saw you a short time ago looking like a floating ball of fire, I lost my taste for aerial travel."

"We'll go back by road, then," said Jack, as through the rain, which was falling in torrents, they ran to the Wondership.

"My, but you have it snug in here," said the doctor, as he entered the tight, waterproof cabin.

"Hang up your coat, doctor," said Tom, and he took the physician's dripping mackintosh and slung it on a hook attached to one of the stanchions. Then the start was made, with the bag partially deflated and lying in limp, wet folds on its framework.

Through the night, under skies fretted with lightning, the Wondership shot forward. Out on the open road Jack ordered full speed, the great searchlights illuming the roadway as if it were day. He felt little apprehension of meeting other vehicles. The night was too bad to permit of any save emergency traveling.

The roads were deep in mud, and water spurted up from the wheels of the flying car as it raced through the storm. But seated snug and dry in the cabin none of them bothered about this. Little was said. Jack had to concentrate his mind on handling the Wondership, for driving under the conditions, and at such speed, required all the wheel-handler's attention.

On and on they flew, down hills and over bridges, under which, ordinarily, quiet streams flowed, but now swollen by the rains, they boiled and raced like angry torrents. They flashed through villages and past farmhouses without encountering a soul, while overhead the tempest roared and raged and flared.

They were shooting down a hill at top speed when Jack suddenly gave a gasp. Right in front of them, vividly outlined in the searchlight's glare, was an obstacle. A big wagonload of hay, covered with a tarpaulin, and deserted by its driver who, despairing of mounting the hill in the storm, had unhitched his horses and driven off till the weather cleared.

The wagon was in such a position that it blocked the road, which was sunken between high banks at that point. Jack ground down his brakes in chagrin.

"Blocked!" he exclaimed disgustedly.



CHAPTER XXI.

VAULTING TO THE RESCUE.

"What awful luck," muttered Tom.

"Isn't there any way we can get by?" inquired the doctor anxiously. "It's important that I should reach Mr. Chadwick as soon as possible."

Jack made no reply, but bent over the gas-valve. In an instant the gas was hissing into the balloon bag. Its wet folds swelled out, and presently Jack started the propellers. Like a racehorse leaping a barrier, the Wondership rose skyward.

"Hold fast!" cried the boy in a triumphant voice.

"Wow!" yelled Tom, "there are more ways of killing a cat than by choking it with cream."

The next moment the Wondership was in the road on the other side of the hay wagon, having hurdled it like a high jumper, and was once more on her way.

"Jove, you boys are marvels!" exclaimed the doctor. "Is there anything you can't do with this craft, or auto, or whatever it is, of yours?"

"Lots of things, I guess," said Tom, "but we haven't found many of them yet."

At uninterrupted speed the journey was resumed. At times so swift was the pace that the Wondership seemed to be half flying. Thanks to her shock absorbers, but little motion was felt, although in places the roadway had been washed out by the torrential downpour and was very rough.

"Whereabouts are we?" shouted Tom, as they rushed along.

"Near the Coon Creek Bridge," flung back Jack over his shoulder. "We ought to sight it at any moment now."

He peered through the blackness ahead. The searchlights failed to show any bridge. But the young driver saw an abandoned cottage by the roadside which had formerly been used as a toolhouse. Just beyond it he knew the bridge should loom up with its white railings.

But there was not a sign of it.

Not till it was too late to stop did Jack realize what had happened. The bridge had been washed away by the rising waters of the creek and he was tearing at top speed for the steep banks.

It was a moment for lightning thinking. Right ahead loomed a black pit which he knew marked the water course.

Suddenly it flashed into Jack's mind that in former times, before the bridge had been built, there had been a ford at the point.

The banks, steep elsewhere, almost wall-like in fact, were still graded at the place where the old crossing spot had been.

He jerked over the steering wheel with a suddenness that threatened to overturn the Wondership. The auto-craft plunged wildly to one side and then rushed downward.

Before he realized it, Jack had steered her into the rushing waters of the swollen creek.

"All the power you've got," he cried to Tom, as the Wondership careened and tipped madly and then recovered an even keel. Jack headed her up stream while Tom, who hardly knew what had happened, blindly obeyed orders.

Jack's chief fear was that the rush of the torrential water would carry him too far down to make a landing on the opposite side of the old ford. In that case they would be in a bad fix, for the creek ran for some distance between steep walls of limestone rock.

It was a hard struggle. The twin propellers beat the air furiously, clawing the Wondership up stream, while the water hissed and roared all about her, and the engine labored with a noise like that of a giant locust.

And then, almost before he knew it, and before either Tom or the doctor realized in the least what had happened, they found themselves safe on the other side. They had gained the opposite slope of the ford with hardly an inch to spare, but that was enough.

The Wondership sped up the bank as if glad to be free of the battle with the swollen creek, and not half an hour afterward they rolled up to High Towers.

Dr. Mays was met almost tearfully by Mrs. Bagley.

"How is he?" was his first question.

"He seems to be better, doctor, but something is worrying him," said the worthy woman.

"I'll go up to him at once. You boys had better stay here," said the doctor.

The physician was upstairs a long time. When he came down he looked grave.

"Is dad any better?" asked Jack anxiously.

"He is suffering from a nervous breakdown due to overwork," said the doctor. "The cut on his head is a mere flesh wound. But he appears to have something on his mind. Do you know what it is?"

Then, and not till then, for in the rush of events he had completely forgotten it, Jack remembered the letter from the brokers.

"Dr. Mays," he said, "you are an old friend?"

"I hope so, my boy. You may confide in me freely if you know any reason for your father's disquiet."

"If you will read this, doctor, you will understand," and Jack handed him the letter.

Dr. Mays read it with knitted brows.

"So this explains it," he said as he returned it to Jack. "Your father kept muttering about foolish speculations and ruin, but would not tell me what he meant. Now it is all clear. Poor Chadwick, I'm afraid from what he said that his fortune, all but a small amount, is wiped out."

"But will he get better, doctor?" asked Jack anxiously, disregarding the monetary aspect of the affair.

"That all depends," said the doctor seriously, "on his freedom from anxiety."

"You mean that he must not worry over money matters?"

"Precisely; but, as that letter states he is ruined, it will be hard to set his mind at rest. If there were only some way of meeting the situation!"

In the crucible of that moment an idea was borne to Jack that was destined to lead him into strange paths.

"I think I know of a way," he said quietly, "that is, if the brokers' message is not exaggerated."

But it was not. The next day confirmatory reports arrived of the wreck of Mr. Chadwick's fortunes. In his room, attended constantly by Dr. Mays, his friend as well as physician, the inventor raved of his losses.

"We have got to think of some way of easing his mind," said Dr. Mays, who had placed his regular practice in the hands of another doctor so that he might be with Mr. Chadwick. "If only his fortune could be won back."

"I think I know of a way," said Jack quietly.

The doctor stared at him as if he thought the boy had taken leave of his senses.

"You know of a way?" he questioned incredulously.

"Yes, sir. At least if the information Tom and I have on the subject is correct."

"I don't follow you," said the puzzled doctor. "Your father has lost thousands."

Jack nodded.

"I know all that," he said.

"And yet you are prepared to get it back?"

"I said I thought there was a possibility," was Jack's quiet reply.

"And what may that be?"

"Did you ever hear of Z.2.X., doctor?" was the entirely unexpected question.



CHAPTER XXII.

"Z.2.X."

"Z.2.X.? Well, such things are rather out of my line, but I have heard of it—yes," replied the doctor, looking more puzzled than ever. "But what do you know about it?"

"Till two days ago—nothing," replied Jack, "but now I believe that I know where there is a trainload of it."

"Good heavens, boy, you don't know what you're talking about. Why, the stuff is as valuable—as valuable as radium. Possibly it is worth more."

"Then even a small quantity would restore my father's fortune and his health?" asked Jack, persisting in his line of inquiry.

"Undoubtedly it would restore his fortune, and in my belief his health, which he is unlikely to gain otherwise."

"Then I'll do it," said Jack, speaking for himself and Tom, for the two lads had discussed the idea the night before. "Those dividends from our share of the hydroaeroplane plant will fit out an expedition, and if we fail—well, we can still sell out our interest and help dad get on his feet again."

The telephone bell jangled. Jack answered it. The voice that came over the wire was that of Professor Jenks. His tones trembled with excitement as he spoke to the boy.

"I have analyzed that sample from the Colorado River," he said.

"Well, what is your verdict?" asked Jack, with a painfully beating heart.

"That when all the expenses of reduction and refining and transportation and digging are deducted that it will be worth at least $100 an ounce," was the reply. "It would bring an even higher price, for the placing of a large amount on the market will probably have the effect of lowering it."

"Great Scott!" breathed Jack, "and there's a whole island of it there for the taking."

"Yes; but how are yow going to get it? The cliffs are unscalable, the river unnavigable. It might as well be in Mars for all the good it does anyone," objected the professor.

Jack's next words were direct, to say the least.

"I've figured out all that," he said. "We can get it, if it's there to be got. I've a reason now for going out there if it's possible to come to some arrangement with Zeb Cummings. Can you meet me at the hospital this afternoon to talk over the matter?"

"Are you serious?" gasped the professor.

"Perfectly," Jack assured him. "If we can't get at it by earth or water we can reach it from the air, can't we?"

"Heaven bless my soul, I never thought of that," choked out the professor. "I—Melissa's calling me. I'll meet you at the hospital this afternoon."

"Tom and I will be there," said Jack, but the professor, at the imperious bidding of Melissa, had hung up the receiver.

The result of the conference held that afternoon at the bedside of Zeb Cummings was the formation of the Z.2.X. Exploration Company, the members being Jack, Tom, Zeb Cummings and the professor. The capital was to be furnished in equal amounts by the professor and the boys, and Zeb Cummings was to be an equal partner in the enterprise, he having furnished the information on which Jack hoped to rehabilitate his father's fortunes.

As for the professor, he did not so much regard the pecuniary side of the expedition as the opportunity he would have to write an epoch-making book and confound his scientific rivals. In their enthusiasm, the adventurers did not take into consideration the fact that the map might be wrong, or that the strange metals be just visionary deposits. The boys' enthusiasm drowned all doubts in their minds; Zeb and the professor never were as optimistic.

Dr. Mays, when he had been placed in full possession of the facts and considered them, decided that under the circumstances the boys could go and undertook to quiet any apprehensions Mr. Chadwick might have concerning the trip. It was found that enough had been saved from the wreck of the inventor's fortunes to enable him to live comfortably while the boys were away, besides which he had royalties from several inventions coming in. Still, the bulk of his fortunes had vanished and the radio telephone was not yet a practicable instrument to put upon the market.

But with Z.2.X. the boys hoped to make it a perfect transmitter of speech over great distances.

Of course, Jack's plan was to utilize the Wondership on the enterprise of finding Rattlesnake Island and its treasures. After long consultations with Zeb, who was now convalescent, it was decided to ship the craft, in sections, to Yuma on the Colorado River and make the start secretly from some point below there.

It was in the midst of these plans, and while the boys' workshed was littered with lists of provisions and equipment that Dick Donovan injected himself into the situation. The red-headed young reporter descended upon them one day when they were busily packing the Wondership away in big crates, which were labeled in various ways so as to give no inkling of the contents.

Of course Dick, being in a way a member of the firm, had to be told what was going on, and the result was that after a lot of hard pleading the boys consented to allow him to come along.

"He's got red hair," said Zeb, "and that ought to make him good on the trail, same as a buckskin cayuse."

The boys didn't quite see the logic of this, but they knew from former experiences that the young reporter was a good campmate, and they were, on the whole, glad that they had included him. But when young Donovan came to High Towers, he was not aware that he was followed by Bill Masterson, who, as we know, was the son of the proprietor of the Boston Moon, on which paper young Masterson also worked as a reporter.

Ever since Dick Donovan had written for his paper, the Boston Evening Eagle, the wonderful story of the boys' adventures on the trail of the giant sloth of Brazil, other Boston reporters had regarded him as worth watching. In some way, young Masterson learned of Dick's frequent visits to High Towers while the preparations for the Colorado trip were going forward.

"It's my idea," he told his father, "that those Boy Inventors are planning another big stunt and that Dick Donovan is to go along and write the story. Do we want to get beaten again?"

"We do not," said his father, a heavily-set, dictatorial man, perpetually at war with the Evening Eagle. "That last beat of Donovan's on the Brazil story jumped the Eagle's circulation sky high."

"Well, why not let me trail along after them and find out what I can?" said young Masterson. "No use letting the Moon get soaked again, and besides, I want to get even on those young fellows, anyhow, for the mean trick they played in having me arrested, even if it didn't come to anything, and the case was dropped.

"Jove!" he cried suddenly, as a new train of thought was suggested to him. "I'll bet I've got it. This trip, or whatever it is, they are planning has something to do with that miner, Zeb Cummings, the chap I ran down."

"Well, it's worth keeping a weather eye on, anyway," decided his father. "I guess you'll get the assignment."

"And I'll run it down, too," declared young Masterson boastfully. "I owe that red-headed, chesty Donovan a grudge anyhow."

That evening young Masterson met by appointment the two youths who had been with him in the automobile the day that Zeb was run down. They were both sons of wealthy men, and had more money than was good for them. Masterson found that both Sam Higgins and Eph Compton were willing to do all they could to harm the boys who had been responsible for their arrests, and so it came about that Jupe, on his way to the village to post some letters, was enticed into talk one night, and while he was chatting and accepting the good cigars three amiable young men pressed upon him, the mail was abstracted from his pocket.

There were two letters, one from Dick to his city editor telling him of the progress made and informing him of the day for the start, and the other from Jack to his father, who was a guest of Dr. Mays. Jack gave full details of their plans and other information concerning the trip, so that the three plotters, a few days before the expedition set out, knew as much about it as the boys themselves.

Armed with this information, Masterson, Higgins and Compton had no difficulty in getting money from their parents, all of whom would have described themselves as "keen business men." As for Jupe, he was too badly scared to say anything about the loss of the letters, and as Masterson, after steaming them open and abstracting what he wanted of their contents, posted them to their proper destinations, the boys started out on their long journey west without the slightest idea that anyone but themselves and one or two others knew of their plans.

The professor's going was not unaccompanied by difficulties. Miss Melissa had insisted that if he was to accompany the expedition, she was going along, too. This being manifestly impossible, the man of science was driven to the subterfuge of placing a bag of fossils in his bed to represent him. On the night of the start, Miss Melissa looked into his room every few minutes to make sure he had not escaped.

It was not till morning that she discovered that the man of science had effected his escape through his bedroom window, climbing down a latticework to the ground. At first she was half inclined to pursue him, but thought the better of it when she read the note the professor had left behind.

"Well," said Miss Melissa to her little maid, "there's one good thing—he won't be cluttering up the house with old stones and rocks for some time to come."

"What shall I do with them fossils what he put in his bed to make believe it was him, miss?" asked the maid.

"You may throw them into the creek at the back of the house, Mary," said Miss Melissa, and went placidly about her dusting and sweeping and "setting to rights."

But of all this, the professor, on the train speeding westward, was blissfully unconscious. Perhaps even if he had known it, he would not have cared much, for even his scientific mind was warmed and thrilled by the prospect of the aerial search for the mineral treasures of Rattlesnake Island.



CHAPTER XXIII.

ON THE BORDER LINE.

The long train of gray-coated coaches, filmed with the arid dust of the desert, rolled into Yuma, the little town at the junction of the Gila and Colorado River, popularly supposed to be the hottest place in America. The boys, glad that their long journey had come to an end, felt that it was living up to its reputation as they alighted and stood in the blistering heat while their personal baggage was thrown off.

The professor, however, was quite oblivious to the scorching rays of the afternoon sun. He darted about seeking specimens, and he had soon gathered up quite a collection of small rocks. In the meantime Zeb Cummings, who was quite in his element, had helped the boys get their things together and see them loaded on a mule wagon which rattled them off to a small hotel, for they did not want to make themselves any more conspicuous than was necessary.

The boys wore gray flannel shirts, khaki trousers, stout high boots and broad-brimmed hats, and had fastened red handkerchiefs round their throats to keep off the sun from the back of their necks. Zeb had a similar outfit.

The professor, however, still wore his baggy black garments, his only concession to the heat being a big green umbrella, which looked like a gigantic verdant mushroom. As they drove off in a rickety sort of bus, having with difficulty persuaded the professor to leave off specimen hunting for a while, the boys did not notice that from the opposite side of the train three young men had alighted who, from a point of vantage behind a water tower, watched their movements.

The trio were Bill Masterson and his two cronies, Sam Higgins and Eph Compton.

"Well, here we are, Eph," said Bill, as they watched the boys drive off.

"Yes, and here they are, too," grunted Eph.

"I'm glad we've got here at last, though. Keeping out of sight on that train was beginning to get on my nerves."

"Same here," said Sam Higgins, stretching himself. "But I guess we succeeded in keeping ourselves hidden all right."

"Sure," rejoined Masterson. "They haven't a notion we are here."

In the meantime the lads found accommodations till the next day at the small hotel on a back street where Zeb had insisted on their coming so as to escape observation. Yuma is full of prospectors and miners, and every stranger in town is suspected of having some sort of a scheme, he explained, and as a consequence is closely watched.

Zeb's first care, therefore, was to circulate a story that the professor, a noted savant and geologist, was going into the desert with his party to collect specimens. This appeared to satisfy the landlord, who was at first inclined to be curious.

The professor had hardly been shown his room before he was out again with his hammer and satchel and his attention was almost at once attracted by a big stone that held up one corner of the barn at the back of the hotel. The boys knew nothing of what he was doing till they heard a loud, angry voice crying:

"Hey, you in ther preacher's suit! Quit tryin' ter pull thet thar barn down, will yer?"

"But, my dear sir," came the professor's voice, in mild expostulation, "are you aware that you have built your barn on the top of a splendid specimen of primordial rock?"

"Don't know nuthin' about a prime order of rock," came back the other voice.

The boys looked out of the window. They saw the landlord of the hotel, a surly-looking fellow, with a big black mustache and tanned cheeks, striding across the yard to the professor, who had blissfully resumed his chipping.

The landlord reached out one brawny hand to grab his guest, when something happened that made him temporarily cease hostilities. A big chunk of rock suddenly flaked off under the professor's assault. It flew in the air and the next instant a yell of pain apprised them that the landlord had got it right in the eye.

The professor looked round as the man emitted a bellow of rage.

"Bless me, where did that bit of rock go? Ah, there it is! Right at your feet, sir," and he darted forward with a smile of satisfaction and, picking up the chunk of rock that had struck the indignant landlord, placed it in his satchel.

"Thank you very much for stopping it, sir," he said, with a bow, and then, before the thunderstruck landlord could say anything, the scientist strolled off under his umbrella in search of more specimens. The boys fairly choked with laughter.

But the landlord was too dumfounded even to speak for a minute. His face grew as purple as a plum. He appeared to be about to burst.

"He's locoed," he burst forth at last, "locoed as a horn toad, by the 'tarnal hills."

Then, holding a hand to his eye, he reentered the hotel and could be heard shouting for hot water to bathe his injury.

Zeb, who had been out looking for a trustworthy man to take their effects out to a spot along the river where they could put the Wondership together without exciting undue curiosity, returned shortly before supper with news that he had been successful in his search, an old, wrinkled prospector named Pete McGee, who had learned the secret of silence during the long years he had spent on the desert.

After the evening meal old McGee put in an appearance and a bargain was struck. But if he was, as Zeb put it, "close-mouthed" on some subjects, he was not on others.

"So yer are a'goin' out inter the desert, hey?" he asked the boys.

"That's our intention," said Dick.

The old man shook his head.

"The desert's a tough place," he said. "A mighty tough place. Reckon it's likely yer are er goin' prospectin', maybe?"

The boys returned an evasive answer. But old McGee rambled on with the crisscross wrinkles forming and fading round his washed-out blue eyes.

"Wa'al, I had my share on it, ain't I, Zeb?" said the old man to Zeb, who had just strolled up, smoking a short, black pipe. The professor, after adjusting his difficulties with the landlord, was sorting and labeling specimens in his room.

"Reckon you have, Pete," responded the yellow-bearded miner. "You didn't never find that thar lost Peg-leg Smith mine, did yer?"

"No; but I will some day," declared the old man, a fanatic gleam shining in his faded optics. "I'll find it some day, Zeb. I never got to it, but I come mighty close—yes, sir, ole Pete he come mighty close."

"Tell the boys about Peg-leg Smith's lost mine," suggested Zeb.

"Give me the fillin's, then, an' I will," said old Pete, holding out a blackened and empty corncob, "though I'm surprised they ain't never heard on it. Thought everybody had heard of Peg-leg's mine."

"Wa'al, you see they come frum ther East," explained Zeb apologetically.

"Ah, that accounts fer it," said old Pete indulgently. "You couldn't 'spec Easterners ter know nuthin' 'bout it. 'Wa'al, young sirs, somewheres out on the desert ter the east uv here thar is three buttes a stickin' up, and right thar is Peg-leg Smith's lost mine whar they say the very sands is uv gold.

"Who was Peg-leg? Wa'al, that's in a way not very well known. Anyhow, his name was Smith, and he was shy an off leg, and so he gets his name. Back in 1836 Peg-leg he blows inter Yuma with a party of trappers that hed worked down ther Colorado.

"They decides to quit trapping and go ter gold huntin', and makes their way up the Gila River and then cuts off inter ther desert. Frum Yuma they goes southeast and kep' on fer four days across the desert. At ther end of the fourth day they 'lows that ther water ain' a-goin' ter hold out a turrible lot longer, and they decides to look fer a water-hole in a canyon at ther end uv which stands three lone buttes sticking up, like sentinels against ther sky.

"Wa'al, they hunts ther canyon through but nary a drop of water. In time they reaches ther buttes. They climbs to ther top ter see what might lay beyond, but they see nuthin' but ther same God-forgotten country.

"But Peg-leg, who fer all he was minus a limb, could travel with any of 'em, he finds at the top of the southernmost butte a lot of chunks of black rock lying round promiscous, an' some of them has specks an' chunks of yaller as bright as Zeb's beard on 'em. Peg-leg he opines ther yaller is nuthin' but copper, or maybe fool's gold.

"That night they camps, feelin' considerable blue, fer ther's mighty little water left an' they've come too far ter go back. But in ther distance thar's a big mountain and they make up their minds they'll find water thar or bust and wither on the desert.

"Ther next evening, more dead than alive, they reaches the mountain and finds a little spring. It was ther finest thing they'd seen fer a long time, and in honor of Peg-leg, who suggested going to ther mountain, they calls it Smith Mountain, and that's its name to this day. In time they worked round to San Bernardino and then Smith he hunts up a mineral sharp who tells him that what he had found was gold.

"Wa'al, Smith was a curious feller, frum all accounts, and it was not till '49 when ther big gold rush came that he thought much more about those three buttes with the gold lying round loose as dirt on 'em. Then he got ther gold fever. He went to 'Frisco and gets up an expedition to find them three buttes.

"They got down inter ther desert country all right and locates Smith Mountain. But the dern Indians they had with 'em as guides cleaned out the camp one fine night, and they had a hard time getting back to civilization alive. Well, that's where Peg-leg Smith goes out of the story."

"Wasn't he ever heard of again?" asked Jack.

"No, siree, not hide nor hair on him. Nobody never knows what became of him arter they got back to San Bernardino. Some says that he went back alone lookin' fer the three buttes and was lost in the desert and that his bones is out thar some'eres to-day, an' others says that he got so plum disgusted he went back home to St. Louis. But nobody rightly knows.

"The next heard of ther three buttes was many years later when an Indian, who worked on Governor Downey's ranch, not far from Smith Mountain, developed a habit of goin' away fer a few days and then comin' back with bits of black rock chock full of gold which he traded fer firewater and such. He didn't seem ter care if he got full value or not.

"'Plenty more where those came from,' he'd say.

"Wa'al, they set a watch on him and found that he always headed off inter ther desert by way of Smith Mountain, which would be the nat'ul way of gettin' ter ther three buttes that Peg-leg had described.

"Guv'ner Downey he come to hear about this in course of time, and he come down frum Sacramento to question ther Injun. But in ther meantime ther pesky coyote had gone and got himself killed in a quarrel over cards and so there they was up agains' a blank wall ag'in."

The old prospector paused to fill his pipe.



CHAPTER XXIV.

"THE THREE BUTTES."

"The Injun bein' dead, the guv'ner did the nex' best thing. He questioned his squaw. But she couldn't tell 'em much 'cept that the Injun told her he got his last water at t'other side of Smith Mountain and then traveled toward ther sun till erbout mid-afternoon when he found mucho, mucho oro.

"The guv'ner made two or three tries to locate them buttes, but he failed. Then come along a man named McGuire, who said he knew where the buttes was and showed black rocks with gold in 'em to prove it, jes' like the ones Peg-leg and ther Injun had found, they was. Well, McGuire he gets five other dern fools and off they starts and that's the end of them. They ain't never heard of ag'in.

"Then comes a prospector who gets lost, and in hunting for water finds these same three buttes and the black, gold-specked rocks that are scattered about. But he wasn't bothering about gold just then, so he keeps on and in time finds the water hole at the foot of Smith Mountain.

"He comes back to Los Angeles and tries to organize a company to go to ther three buttes. But he falls ill and when he learns he's goin' ter die he tells Dr. De Courcy, that's his physician, that he knows whar Peg-leg's lost mine is an' gives him a map an' directions. Arter ther man dies, Dr. De Courcy spends all his money trying ter find ther buttes, but he fails. Then comes a young chap named Tom Cover of Riverside. He's wealthy and fits out a dozen or more outfits to hunt fer ther three buttes. But after setting out on his twelfth trip he never comes back, so they know that Peg-leg Smith's mine has claimed another victim."

"Is there anything to prove that Peg-leg really ever found the Three Buttes?" asked Tom, whom this romance of the desert, like his companions, had strangely interested.

"You tell 'em, Zeb," said the old man. "Likely they wouldn't believe me."

"Proofs?" said Zeb, "plenty of 'em. The records of the old Bank of San Francisco show that McGuire deposited thousands of dollars' worth of gold nuggets there, and my old dad knew Peg-leg Smith and saw the black rocks with the gold fillings that he brought out uv ther desert. Them three golden buttes is out thar somewhar's, and some day somebody's goin' to locate 'em and then there'll be another millionaire in the country."

Old McGee chuckled over his pipe. It was clear that, ancient and feeble as he was, he still believed with all the fanaticism and optimism of a prospector that he would be the one to find the three buttes of gold.

"It stands ter reason thar's gold out thar," declared old man McGee, waving his pipe about argumentatively. "Ther good Lord never made nuthin' thet wasn't of some use, even ther fleas on a houn' dawg, for they keep him frum thinkin' uv his troubles. Very well, then, the desert is good fer nuthin' else but mineral wealth, and Providence made it so plagued hard ter git at so that everyone couldn't git rich at oncet."

The boys had to laugh at this bit of philosophy, but as they went to bed they could not help thinking of the toll of lives the great barren stretches of the Colorado desert has exacted from gold-seekers. In Jack's dreams he seemed to be traversing vast solitudes of sand and desolation dotted with bleaching bones, and he woke with a start to find that it was daybreak and that Tom was shaking him out of his sleep.

Below, old man McGee was ready with his team and had already got on his wagon some of the crates from the freight shed. They made a hasty breakfast and then started out. There was hardly anybody about and they congratulated Zeb on his strategy in conducting affairs with such secrecy.

But as they passed into the outskirts of the town, where the Mexicans and Indians lived, Dick Donovan uttered a sudden exclamation.

"Hopping horn-toads!" he gasped.

"What's up?" asked Jack, who sat beside him.

"Oh, nothing," said Dick, "the wagon gave an extra hard jolt, that was all, and I thought my head was coming off."

But the cause of Dick's exclamation had been this: From behind a squalid hut he caught sight of three shadowy figures, dimly seen in the half light, apparently watching the wagon and its occupants.

They quickly withdrew as they saw Dick looking at them, but not before the young reporter had received a startling impression that one of them at least was familiar to him. The wagon drove out over the desert and rumbled along till it came to a deep arroyo, or gulch, in which stood a deserted, bleaching hut.

"This is the place," said Zeb.

"Sure, you can stay thar fer a year an' a day an' nuthin' but tarant'las an' rattlers ull ever bother ye," said old McGee cheerfully.

The cases they had brought were quickly unloaded and lowered into the arroyo which led down to where they could see the turgid flood of the Colorado flowing between low banks. For at this spot the river is a very different stream from what it is above and below, where it makes its way to the Gulf of California between unscalable walls of cliffs and is a succession of cruel rapids and unpassable falls.

When old McGee drove back for the second and last load, for the Wondership was constructed so as to "take-down" very compactly, Dick elected to go with him. When they arrived at the freight depot the young reporter took the first opportunity to wire his paper in Boston.

"Find out if Bill Masterson is in town," was the substance of his message.

They were not to return to the camp till after the mid-day meal, so he had plenty of time to receive an answer. This is it:

"Masterson and two others left for the West five days ago."

* * * * *

"The same day that we did," mused Dick. "I wonder—but no, I'm sure. One of those three figures lurking behind that hut was Masterson, and he's planning some mischief, sure as a gun."



CHAPTER XXV.

INTO THE BEYOND.

"Well, this is something like camping," said Tom that evening, stretching himself out luxuriously under a mesquite bush.

"See here, young feller," said Zeb, who by unanimous consent had been put in charge of the adventurers. "Are you on a pleasure trip, jes' dropped in as a visitor like, or air you a part of this expedition?"

"I guess I'm a part of it all right," said Tom, with rather a sheepish grin. "At least I was under that impression."

"Same here," said Zeb dryly. "Thar's lots to be done yet afore we're all shipshape fer ther night. Ther's lamps ter be filled and tent ropes set right an' then I want a trench dug around ther tents."

"What's the trench for?" asked Jack, who had been busy with the three tents, for they had decided on Zeb's advice not to use the old roofless shack to sleep in.

"No tellin' what kind of varmints, from skunks to rattlers, ain't makin' a hotel out of it," he said, "not to mention tarant'las, which has a most unpleasant bite, and scorpions and centipedes that ain't much nicer bedfellows."

This was quite enough to make the boys willing, nay anxious, to set up the waterproof silk tents.

"What's the trench for?" asked Zeb. "Well, if it should come on ter rain in ther night it'll keep us dry to have a trench round each tent."

"Rain!" exclaimed Tom incredulously. "Why, it doesn't look as if it ever rained here."

"It doesn't, not more'n about two inches a year," rejoined Zeb, "but when it does you'd think ther flood gates uv heaven had been ripped wide open."

"Do you think it will rain to-night?" asked Jack.

"It looks uncommon like it," answered Zeb. "See them clouds off there yonder?"

He pointed to some heavy-looking masses of vapor hanging above a dim range of saw-backed mountains off to the east.

"In my opinion they're plum full of rain," he said.

"In that case we'd better get ready with the trenches," declared Jack. He picked up one shovel and gave another to Tom. The latter made a wry face but said nothing. Tom liked hard work no better than most boys, but he realized that the work had to be done, and so tackled it with the best grace he could.

Secretly he wished himself to be with Dick Donovan, who had been assigned to go fishing to see if he couldn't get "something" fresh for supper. The professor, as usual, was off somewhere collecting specimens.

But the task of digging the trenches was not as arduous as it had appeared. The sand was soft and yielding, and the shovels made rapid work with it. Soon a fairly deep trench was dug round each of the temporary shelters.

By the time the lanterns had been filled, and Zeb had cut a goodly stack of mesquite wood, everything was ready to begin preparations for supper.

"We'll have a blow-out to-night," said Zeb. "Canned salmon, beans, crackers, cheese and canned fruit, but don't expect to get that right along. I've lived on beans and bacon for six months in this very neck of the woods, and thought myself lucky to get that."

"Hullo!" came a cry from the direction of the river.

"There's Dick!" exclaimed both boys, and then as the young reporter came into sight, "What luck, Dick?"

"What do you know about this?" and Dick held up a fine string of glittering fish. There were catfish, perch and two eels.

"Good; we won't go hungry," said Zeb. "Nothing better than fried eels and catfish."

He greased the frying pan with a strip of bacon rind and then skinned the scaleless catfish and eels as if he had been doing nothing else all his life. Soon the savory odors of the frying with crisp slices of bacon, and the aroma of coffee, filled the camp.