CHAPTER I DRIVEN FROM TOWN

"Come now, you boys git out of here! No tramps allowed in Freeport while Ezra Jenkins is constable! Move along, now, or I'll arrest ye! Here's my badge of authority!" And a crabbed old man, wearing a faded blue suit, with a big shining star of metal on his coat, tapped the emblem with his club.
 
Two boys, who had just joined each other, after having called at houses on the main street of the little New York village, where Constable Jenkins held sway as the entire police force, started at the sound of the harsh voice.
 
"Come; are ye goin' to move?" snapped the constable.
 
"I suppose we'll have to," answered the larger and stouter of the two lads, "but we haven't done anything."
 
"Ye're tramps, ain't ye?" inquired the constable. "Course ye are! Been beggin', ain't ye? Course ye have! I kin see the victuals stickin' out of yer pockets now! Move on an' git out of Freeport! We don't want any tramps here!"
 
"Come on, Mark," said the heavier of the two boys; "if our room is better than our company, they can have the room. I hope you'll get richer boarders than we are," the youth went on, turning to the constable. "We are going to shake the dust of Freeport from our feet. I think they ought to call this town Closedport instead of Freeport!"
 
"None of yer sass, now!" warned the constable, tapping his badge again.
"Jest you move on out of town!"
"I think we had better go," murmured the other boy, who was thin and small. "Don't make any trouble, Jack."
 
"All right," assented the other. "Ta-ta, Mr. Chief of Police! See you later!"
 
"Here, you young rascals!" cried the constable. "Come back here an' I'll lock ye up!"
 
But the boys started to run, and, as Mr. Jenkins was no longer young, and as his legs were rather stiff, he went only a little way before he had to stop. He shook his fist after the two lads.
 
"Do you suppose he would have locked us up?" asked the small boy, whom his companion addressed as Mark. His full name was Mark Sampson, but he was very unlike his strong ancestor who pulled over the pillars of the temple.
 
"He acted mean enough to do anything," replied Jack Darrow, who was quite a contrast in point of size and fleshiness to his companion.
 
"What shall we do now?" asked Mark.
 
"Keep on moving, I guess," was the reply, "At least until we get outside of Freeport."
 
"Well, I'm glad I've got company now. It was lonesome before I met you."
 
"Same here. We'll travel a way together, eh?"
 
The two boys had met under rather strange circumstances. Early that morning Jack Darrow, the stout one, had awakened from his sleep in a pile of hay in a farmer's field. Close to him was another youth, whose name he had inquired as soon as the owner of it awoke.
 
Then the two boys discovered that their conditions in life were very similar. Both were orphans, about the same age, Jack being sixteen and Mark fifteen years, and neither had a place he could call home.
 
"My folks have been dead for some years," said Jack, in telling his story to his companion. "I was hired out to a farmer in the upper part of New York, but he worked me so hard and treated me so mean that I ran away. I've been tramping ever since; don't my clothes show it? You see I was forced to go without taking my many trunks along," and he laughed, for he was of a jolly disposition.
 
"My people are dead also," said Mark. "I had a job with a man going around the country with a traction engine, threshing wheat and oats at different farms. But he used to beat me, so, one night, I ran away."
 
"And didn't bring any extra clothes with you, either," put in Jack.
 
"I never owned any to bring. I only had the one suit I wore."
 
And after that the boys had told something of their experiences and become very friendly.
 
The two boys walked on for a while in silence, kicking up the dust of the country road. Then Jack came to a halt, clapped his hand on his pocket, and said:
 
"I nearly forgot I had something to eat! Just think of it! And I haven't dined since yesterday! I wonder what the lady gave me. She looked good natured."
 
He sat down on a grassy bank along the highway, pulled the package of food out, and began to eat with every indication of satisfaction.
 
"Bread, meat, piece of pie and a piece of cake!" he announced, looking over his lunch. "What did you get, Mark?"
 
"I got the same as you, except I didn't get any pie or cake."
 
"I guess your lady hadn't baked this week. Never mind, you can have half my pie and half my cake."
 
"I'm sure I'm much obliged," said the thin youth.
 
"You needn't be," broke in Jack. "That's the law of the road. When two—well, I suppose I might as well say tramps, for that's what we are—when two tramps go off together, they whack up. And that's what we're going to do!"
 
It did not take long for the boys to finish their simple meal. Jack, true to his promise, shared his dessert with his companion.
 
"Well, I feel like going on now, and looking for a job," remarked the heavier weighted lad. "What do you say, Mark?"
 
"I guess we might as well get out of this town. They don't seem to care for us. But I wish I had a drink of water."
 
"Nothing easier," replied Jack. "There you are," and he pointed a short distance ahead, where a brook ran along the road. The boys got down on their faces near a little pool, the bottom of which was covered with white pebbles, and drank heartily. Then, refreshed by the water, their hunger appeased, and rested, they started on the tramp again.
 
"Any particular place you want to go to?" asked Mark.
 
"No, I'm not particular. East or west, the north pole or the south pole. I haven't any one to worry about me, no matter which way I go. I'd a little rather go north, though, as it is mighty warm to-day," and Jack laughed carelessly.
 
Little did he guess how soon his wish was to be gratified.
 
"Then we may as well keep on until we get to the next town," said Mark.
 
They walked on for some distance, their thoughts busy with their recent experiences, when they suddenly heard a noise at a distance.
 
"Sounds like a freight train," said Mark.
 
"So it is! Come on! Let's get aboard! Riding is easier than walking any day! Hurry up!"
 
And then the two boys broke into a run toward a slow moving freight on a track that crossed the country road a short distance away from them.
 
"Look out that you don't get under the wheels!" cautioned Jack to his companion.
 
"Oh, I'm used to jumping the cars," replied Mark, as he ran quickly up beside the rails.
 
The two boys reached the track along which the freight train was bumping and clicking. It was a long outfit, with many box, flat and gondola cars.
 
"Try for a gondola!" suggested Jack, indicating the cars with sides about five feet high, and open at the top.
 
The next instant he had swung up on a car, thrusting his foot in the iron step, and grasping the handle in a firm grip. Jack grabbed the next car, and landed safely aboard. Then, running forward, and clambering over to where his companion was, Jack pulled Mark down on the bottom of the gondola.
 
"No use letting a brakeman see you if you can help it," he explained.
CHAPTER II THE RUNAWAY TRAIN

On went the train, carrying the boys to a destination unknown to them. All they cared for was that they were going away from Freeport and its vindictive constable.
 
"How long have your folks been dead?" asked Jack, after he had settled himself comfortably in a corner.
 
"About five years," was the answer. "Father and mother went about the same time. They were poor, and I had no brothers or sisters. When I was all alone," the boy's voice trembled a bit, "I didn't know what to do. They wanted to send me to the poor-house, but I ran away. Then, after knocking about a bit, I got the job with the traction engine man, until he used me so I couldn't stand it."
 
"That's about my case," said Jack. "I had a brother, and he ran away before my folks died. I guess they felt bad about him. Anyhow, mother used to cry an awful lot. When I was left all alone I was taken care of by some poor folks, who kept me as long as they could. Then I had to shift for myself. I had a good many jobs, and then I thought I'd like to be a farmer. I was sent to a place but the man wasn't very kind. He whipped me because I made a mistake and pulled up an onion instead of a weed. Then he beat me because I gave the horse too many oats. He never told me how much to give. So I ran away, and I'm glad of it. I've been cold and hungry lots of times since, but I haven't been whipped."
 
"I guess that old constable would have licked us if he had the chance," put in Mark.
 
"No use worrying over that. He's a good many miles away now."
 
"Here! What are you boys doing there?" cried a voice.
 
Jack and Mark looked up, to see a brakeman gazing down at them from the top of a box car.
 
"We're taking a ride," answered Jack coolly.
 
"So I see," replied the brakeman. "Well, I guess it will come to an end right now. Hop off!"
 
"Are you the conductor?" asked Jack.
 
"No, of course not," said the wheel-twister.
 
"Then don't try to put us off," went on the boy, with an assumed haughty air. "Just send the conductor here to punch our tickets. We're traveling first class, and don't want to be disturbed any more than is necessary."
 
"Well, I like your nerve!" exclaimed the brakeman, climbing down. "Who are you, anyhow?"
 
The railroad man laughed. Then Jack smiled, for he knew he and his companion were safe. In a few words he told their stories, and the brakeman promised they might go as far as the train went.
 
"You boys are all right," said the brakeman. "I have two youngsters of my own at home, and I hope, if ever they get in a tight place, some one will help them. Can I do anything to fix you up?"
 
"Not unless you can lend us about one thousand dollars each," laughed
Jack, and the brakeman joined in with him.
"Or tell us where we can get work," put in Mark, who seemed quite worried.
 
"I can't say for sure where you can get jobs," the brakeman said, "but if I was in your place I'd get off at the next town. The name of it is Millville, and there are lots of factories there. Maybe you can strike something. I'll speak to the conductor and have him ask the engineer to slow up so you can jump off."
 
"We'd be obliged if you would," Jack said. "We may be tramps for a while, but we're both anxious to get work, and maybe Millville will be just the place for us."
 
"We're coming into it now," the brakeman went on. "It's about a mile from here. I'll go back, and when you hear five whistles from the engine you'll know it's slowing up and you are to jump off. I know the conductor will do that if I ask him."
 
The brakeman climbed up the ladder on the end of the box car next to the gondola where the boys were, until he reached the run-boards on top. Then he hurried along to the caboose, where the conductor was.
 
"We must listen for the five whistles," said Jack. "Get ready to jump,
Mark. Don't forget your baggage."
"No danger of that," chimed in the other, falling into the joyful mood of his companion, who never seemed to be cast down for long, no matter what happened.
 
The train was going down grade now, and the speed was much increased. Telegraph poles whizzed past at a rapid rate and the wheels sung a livelier tune as they clipped over the rail joints.
 
"It's a good thing the engineer is going to slow down for us," said
Jack. "We'd never be able to jump off at the rate we're going."
"Hark!" exclaimed Mark. "There goes the whistle!"
 
The boys listened. A long, shrill blast cut the summer air, and vibrated back to them over the tops of the cars.
 
"That isn't five whistles; it's one!" cried Jack. "It's the call for brakes! I wonder if anything has happened to the train!"
 
There was a pause. Then came another single shriek from the engine's whistle. It sounded appealingly, as if the steam monster was in distress.
 
"Look! Look!" shouted Mark. "We are going much faster than we were!"
 
At the same instant there was a crash and a jolting sound. The train seemed to break in two parts at about the centre. The forward section, drawn by the engine, went one way, and the other part, with the gondola containing the boys, in the lead, took another track. An insecurely fastened switch was responsible for the accident. The locomotive and nearly half the cars of the train took the main track, while the remainder of the outfit swung on to a siding.
 
The section of the train with the boys aboard had become a runaway freight!
 
"What has happened?" cried Mark.
 
"The train's broken in two!" shouted Jack. "Come on! Help twist the brakes!"
 
Both boys sprang to the wheel of the gondola. It was all they could do to give it a few turns, but they managed to make the brake-shoes grip the wheels to some degree, as was evidenced by the shrill shrieking.
 
"Can you climb up to the top of the box car?" asked Jack.
 
"Sure!" shouted Mark. "Go ahead!"
 
Though Mark was thin, he had a nervous strength almost equal to that of his stouter companion.
 
"We must set all the brakes we can!" Jack cried. "That's the only way to stop the runaway train!"
 
With their small arms they twisted the wheel on the box car. They got it as tight as they could, then ran along the top of the vehicle to the next one. About ten cars down they saw their friendly brakeman.
 
"That's the stuff, boys!" he shouted. "There'll be a smash-up if we don't stop the cars!"
 
He was twisting wheels with all his might. As fast as they could the two boys went from car to car, setting the brakes.
 
But in spite of their efforts, and the efforts of another brakeman besides the one they had spoken to, the speed of the runaway freight train increased. The grade was a steep one, and down the hill the uncontrolled cars rushed.
 
"I don't believe we're going to stop," said Jack.
 
"Shall we jump?" asked Mark.
 
"Not if you want to get a job in the mill or factory," replied Jack. "I reckon if you or I jumped that would be the last of us."
 
With a rush and a roar the train continued to speed along. The trees and telegraph poles whizzed past so quickly as to be almost invisible.
 
"I guess this is Millville," said Mark, as the runaway train passed a station, on several sides of which there were large buildings to be seen.
 
So fast was the runaway train going now that the boys had to lie down on their faces and cling to the run-boards on top of the box car to avoid being jolted off. The wind fairly whistled in their ears. Through the town they rushed, observing, as by a flash, the white, frightened face of the station agent as he watched them go past.
 
"Do you think there'll be a smash-up?" asked Mark.
 
"I don't see how it can be avoided," replied Jack. "This track has to come to an end somewhere. When it does, look out, that's all!"
 
On and on rushed the train! It's speed was now fearful, for the down grade had increased. It was of no avail to twist the brakes, for no strength would avail to slacken the awful speed. The boys, in common with the brakemen, could only cling and wait in terror for what was to come.
 
The cars swayed as they went around a curve. Jack lifted his head and peered forward.
 
"Hold fast!" he shouted. "We're going to strike something in a minute!"
 
He had looked up in time to see that the track siding came to an abrupt end about a quarter of a mile further on, the rails stopping in a sand bank.
 
Hardly had the boys time to take a tighter grip with their fingers on the boards to which they were clinging, when the whole string of freight cars seemed to crumple up like a collection of paper vehicles.
 
There was a grinding, sickening crash, a succession of heavy jolts, a piling up of one car on top of another, a splintering of wood, a rending of iron and steel, and then with one terrible smash, with one final roar, the runaway freight piled itself up in a mass of shattered cars against the sand hill, at the base of which the rails came to an end. It was a fearful wreck.
 
"Hold fast!" were the last words Jack cried to his companion. His voice sounded faint above the din.
 
"Where are you, Jack?" he heard Mark shout in reply.
 
Then all became dark, and the boys lost their senses as they were hurled into the splintered mass of wreckage.
CHAPTER III A STRANGE RESCUER

"For de land sakes, Perfessor, hurry up! Heah's de stupenduousness conglomeration dat eber transcribed dis terresterial hemisphere!" exclaimed a stout, jolly looking colored man a few seconds after the crash of the wreck had ceased echoing.
 
"What is it, Washington?" asked a mild mannered elderly gentleman, with long flowing hair and beard, who, with the negro, had been walking in a field close to the railroad.
 
"I doan perzackly know, Perfessor, but it seems like there was a discontinuation ob de transportation facilities, when some sudden construction on de elongated tempestuousness attached to de railroad made de cars go bump! bump! Bang! Smack! Crash!"
 
"Washington! Washington! When will you stop using words that don't mean anything!" cried the old man, hurrying forward. "I presume you mean there has been a railroad wreck?"
 
"That's it, Perfessor. De extenuatin' circumstances ob transmigration—"
 
"That will do, Washington!" said the aged man, somewhat sternly. "You must stop talking, and act. This is no time for foolishness. There may be people hurt. Come along and let us see what we can do."
 
"Yes, sah!" replied the negro, calming down.
 
Then the two hurried down along the track, piled high with the debris of the runaway freight train.
 
"My! My! This is a terrible wreck!" cried the old man, as the two climbed over the mass of wreckage.
 
"Hi, Perfessor!" called the colored man, suddenly. "I've found something!"
 
"What is it, Washington?"
 
"It's a boy, an' he dead!"
 
"Oh, that's too bad!"
 
"An' heah's another, an' he's dead! Dis catafterme is de most—"
 
"Now, Washington, remember what I told you. No big words wanted at the present time. Where are the boys?"
 
"Here, Perfessor," and the negro showed the old man where Mark and Jack were lying, close together on a pile of sand. The professor bent over them. He felt of their hearts and listened to their breathing.
 
"Here!" he cried, suddenly. "They're not dead! They're only stunned!
Maybe we can save them! Hurry, Washington, and carry them to my cabin.
You take one and I will bring the other!"
"You don't need to carry any ob 'em," answered the colored man. "Dis chile is strong 'nuff, I reckon, to tote dem two boys," and, suiting the action to the words, he stooped down, put an arm around each of the prostrate forms and lifted one on each shoulder. "'Bout face! Forward march!" he cried.
 
With the old man following, the negro made his way along a path that led over the fields, until he came to a long and rather narrow shed built on the edge of the woods.
 
"Be sure no one is in sight before you go in!" cautioned the old man, as he opened the door, which was fastened with several padlocks. "It would never do to have my secret discovered now."
 
"Nobody in sight, master!" exclaimed the colored man, as he turned, with the two unconscious boys on his shoulders, and gazed about "De coast am clear."
 
"Then hurry inside and we will see what we can do for the poor lads. I fear they are seriously hurt."
 
The negro slipped in as the old man held the door open, hurriedly closing it afterward, and bolting it on the inside.
 
"Put them on my bed," went on the gray-haired man. "Then hurry back to the wreck! There may be more people hurt, whom you can aid. Don't stop to talk, but hurry back. I will see to the boys."
 
Not very willingly the negro left the shed. When he was gone, and the door was securely fastened after him, the old man went over to where Mark and Jack lay, both still unconscious.
 
"Poor lads!" sighed the old man. "I hope I can save them."
 
He went rapidly to work. Loosening the clothing of the boys he soon found that no bones were broken. Then from a medicine chest he took several bottles. In a tall glass, such as druggists use for mixing prescriptions, he put several liquids, and stirred the whole together. Then he moistened a little cotton in the preparation, and placed the white stuff under the noses of the lads, holding it in place with cloths. He had about completed this when a knock was heard at the door.
 
"Who is there?" he cried, starting up in alarm.
 
"Mr. Washington Jackson Alexander White," was the answer.
 
"Give the countersign!" demanded the old man, sternly, making no move to undo the bolts that held the door tight.
 
"De North Pole, an' long may it stand!" was the rather odd reply.
 
"Right! Enter!" said the professor, opening the door to give admittance to the colored man.
 
"Did you find any more victims of the wreck?" asked the old man.
 
"No, sah; Mr. Perfessor Amos Henderson, I did not," answered Washington.
 
"Just plain Professor will do," said Amos Henderson, quietly. "You needn't give my full name every time."
 
"All right, Perfessor," went on the colored man. "I didn't find no mo' pussons entangled in the distribution of debris. Dere was a lot ob railroad men dere, but dey wasn't hurted. Dey was lookin' fer two boys what was ridin' on de train when it went kersmash."
 
"I hope you didn't say anything about these lads, Washington."
 
"Not one single disjointed word, Perfessor. Dis chile knows when to persecute de essence ob quietude an' silence."
 
"There you go again! How many times have I told you not to try and use big words, Washington? Use simple language. I take it you mean there were no others injured in the wreck?"
 
"Perzackly."
 
"It is a miracle how these boys escaped instant death," the old man went on.
 
"I reckon as how it were owin' to de fack dat dey struck in a bank ob soft sand dat concussioned de fall," explained Washington.
 
"You mean the soft sand saved them?"
 
"Dat's de correctness ob it."
 
"I think you are right," the old man continued, as he fastened the door securely. "The shock of the sudden stopping of the runaway train, as it reached the end of the siding and crashed into the bank, probably threw the lads up in the air, and they came down in the sliding sand where we found them. Otherwise they would surely have been killed. As it is they have had severe shocks."
 
"Are dey goin' to die, Perfessor?"
 
"I hope not, Washington, but I must see to them."
 
Amos Henderson went over to the bed on which the two boys were stretched out, each with the piece of cotton soaked in the preparation over his mouth and nose.
 
"I am using a very powerful remedy," the old man muttered. "If they are not too badly hurt they will recover. Ah, yes, there is a little color in their pale cheeks."
 
He bent over the boys. As he had said, Jack's face was tinged with a light pink, and Mark's eye-lids were moving slightly.
 
"They are coming around all right," exclaimed the aged professor. "Hurry, Washington, and get some hot beef broth ready. Put the kettle on to boil and make some strong tea. They will want something to eat shortly after they recover their senses."
 
The colored man, humming softly to himself, began moving about the shed. It was a rough looking place from the outside, but, within, was fitted with many comforts. There was a gasoline stove, a table, several chairs, a bed, and a large case full of books. But the queerest sights of all were on the walls.
 
They were literally covered with cog wheels, levers, handles, springs, pieces of machinery, patterns, models, and strange devices. The room had two doors. One was that by which the old man and the negro had entered. The other was behind the bed, and was clamped and fastened with so many bolts and bars, with locks similar to those on big safes, that it would seem a rare treasure was concealed behind the portal.
 
The old man gave no heed to the wonders that surrounded him. Instead he gave all his attention to the boys. He sat down beside the bed and watched them as their breathing became stronger. From time to time he felt of their pulses, and nodded his head as if satisfied.
 
"Is the beef tea ready?" asked the old man, after a half hour had passed.
 
"It am, Perfessor."
 
"Then turn down the flame a bit so it will keep the stuff warm, and come back into the work shop with me. I want to get that last bolt in the engine."
 
"Are dem young gen'men all hunky-dory?"
 
"They are coming on nicely," was the old man's reply. "They will recover consciousness in half an hour and we can feed them, and give them some medicine. Come along, Washington."
 
The two passed out through the much-locked door behind the bed, the undoing of the fastenings taking some time. As the portal swung open it disclosed a long shed which seemed to be occupied with a big, strange object.
 
The old professor and the negro had not been gone more than five minutes before Jack opened his eyes. He turned over on one side. As he did so Mark slowly lifted his head.
 
"Hello!" cried Jack, faintly.
 
"What's the matter?" asked Mark.
 
"Matter? What? Where?" inquired Mark, sitting up.
 
"Here! Everywhere!" replied Jack, raising himself slowly on his elbow.
"All I remember is a terrible crash. Now look at all those wheels.
Wheels! Wheels! Wheels! I wonder if they can be in my head?" and he
tried to smile.
"No, they are real wheels, and they are on the walls," announced Mark.
 
"Then where in the world are we?" went on Jack. "In a machine shop or a railroad wreck?"
 
"Looks like—" began Mark, when he was interrupted by a voice calling:
 
"Hurry up, Perfessor! De boys has awakened from de unconsciousability!"
 
And, to the astonishment of Jack and Mark, the old man and his negro helper hurried from the inner room and stood in front of the bed.
CHAPTER IV THE AIRSHIP

"Do you feel better?" asked the professor, anxiously, as he came forward and felt of the boys' pulses.
 
"A great deal," answered Jack. "But what has happened? Where are we?
What are all these wheels for?"
"Slowly, slowly," said the old man with a pleasant laugh. "One question at a time. For the first: what happened was a railroad wreck."
 
"I remember now," said Jack, slowly. "We tried to stop the cars."
 
"And you didn't succeed very well," went on the old man. "However, the sand bank did it for you, and stopped you two at the same time. As for your second question, you are here in my shop. As to the third, those wheels are parts of my great invention. But I will tell you about that after a while. I must give you some medicine now, and something to eat. Here, Washington!"
 
"Comin', Perfessor!"
 
Jack and Mark were more surprised than before when they saw a big colored man, seemingly as strong as an ox, coming toward them with two steaming bowls of beef broth. Washington was grinning with delight.
 
"Dis am de best beef stew dat eber transpositioned itself into yo' vicinity!" he exclaimed, setting the bowls down on a table near the bed.
 
"Now, Washington," cautioned the old man. "No big words, remember."
 
"All right, Perfessor," was the answer.
 
"Do you boys feel like eating?" asked the aged inventor.
 
"I do," replied Jack. "There was a time, though, when I thought I'd never get a chance to eat again. That was just before the crash."
 
"You were both knocked unconscious," the professor went on. "Washington and I happened to be near by and brought you here. Fortunately I am something of a doctor as well as an inventor, and I used a strong medicine I have."
 
"I'm sure we're much obliged to you," answered Mark.
 
"Let me see how much improved you are by eating," suggested the old man. "I can trust Washington to cook good meals, even if he does use big words."
 
Then, while the colored man grinned cheerfully at them, Jack and Mark, sitting up on the bed, for they were still weak and sore, ate the broth. After that both boys said they felt better.
 
"See if you can walk," suggested the inventor.
 
Mark and Jack stepped on the floor. They both uttered cries of pain.
They were stiff and lame from the shaking they had received.
"A day in bed will do you no harm," said their strange rescuer. "I have some liniment that will soon take the soreness out of every one of your muscles."
 
Though the boys protested at being made to remain in bed, the old man insisted. He made them take off most of their clothes, and then brought out some liniment. Under his direction Jack and Mark rubbed themselves well, and experienced almost immediate relief. It was now getting dusk, and Washington lighted a big lamp that hung in the centre of the room, first taking care that the shutters were tightly fastened.
 
The colored man prepared a simple supper for Mr. Henderson, and afterward got himself a meal. When the dishes were cleared away the old man, who had noted with smiles the anxious glances Jack and Mark were casting about the strange room, said:
 
"I suppose you boys would like to ask lots of questions."
 
"I'd like to know what all this machinery is for," spoke Jack.
 
"And what is behind that door," Mark went on, indicating the much-locked portal.
 
"I knew it!" exclaimed the old man. "I knew it! Now if I tell you will you promise to keep it a secret until I give you leave to speak?"
 
Of course the boys promised eagerly.
 
"Do you think you have rested enough now to take a look inside?" the inventor asked, nodding toward the locked door.
 
"Sure!" exclaimed Jack.
 
"Then put on your coats and trousers and I'll introduce you to my pet."
 
Wonderingly, the boys followed him. It took nearly a minute to unfasten the various bolts and bars, but at last the portal swung open. The place was dimly lighted by a single big lamp, but in the glare of it the boys caught sight of a strange, weird object. It looked like an immense cigar, and swayed slowly back and forward. It seemed to be covered with a net-work of cords. On the ground beneath it was what seemed to be a good-sized boat, with a large cabin amidships.
 
"What in the world is it?" cried Jack.
 
"It's my airship!" exclaimed Professor Henderson. "The only successful airship ever invented. It is the electric Monarch!"
 
"What is it for?" asked Mark.
 
"To navigate the realm of the stars and moon!" cried the old man. "With that I will rival the eagles in their flight!"
 
The boys were a little alarmed. The professor was strangely excited. His eyes sparkled in the reflected light of the lamp. Jack and Mark thought they might have been brought to the abode of a madman. They shrank back a little. But they were reassured a moment later when, with a pleasant laugh, the old man said:
 
"Don't be frightened, boys. I know what I am talking about. Here, Washington, more light! We will show them what we have done, hidden away from the sight of the curious, unbelieving world. Let them see my Monarch!"
 
"We'll illuminationness dis abode like it was de orb ob day shinin' heah!" exclaimed the negro, as he started several more lamps aglow.
 
"Are the shutters closed?" asked Mr. Henderson, anxiously.
 
"Tight as a drum-head," was the reply.
 
"Now look!" exclaimed the inventor, turning to the boys.
 
They were more than astonished at what they saw. They had no idea that the rough shed held such a perfect piece of machinery.
 
Up near the roof of the place, which was quite high, there swayed an immense bag of oiled silk. It was shaped like a cigar, big in the middle and tapering at both ends. The bag was enclosed in a net of ropes which extended down to the lower part of the airship.
 
This lower part, as the boys could see, was just like a steam launch in shape, only much lighter in weight. It had a sharp bow, and a blunt stern. From the stern there extended a large propeller, the blades being made from sheets of aluminum.
 
The main part of the ship proper, or the part suspended from the gas bag, was covered by a closed and roofed cabin about forty feet long, ten feet wide, and extending five feet above the gunwale of the ship. The cabin had four windows on each side, a companionway fore and aft, and a sort of look-out or conning tower forward, which, the professor explained, was the place for the steersman.
 
"Because this ship can be steered wherever you want to go," he said, pointing to the big rudder that was hung aft, an opening in it allowing the screw or propeller to revolve.
 
The boys were lost in admiration of the wonderful airship. They were consumed with curiosity as to how the machinery worked, and they thought no more of their knocks and bruises than as if a mosquito had bitten them. The professor watched their faces with delight. He loved boys and mechanical apparatus.
 
"Now we will enter the Monarch," he said. "Turn on the lights,
Washington."
There was a click, and the cabin of the airship was flooded with a soft glow of incandescent lamps.
 
"Come on!" called Mr. Henderson, leading the way. The boys followed, marveling at the wonders on every side.
 
They found the cabin of the strange craft divided into three parts. First came a sort of parlor, with a table and seats arranged on the sides. In the front part of this was a passage leading to the conning tower, or the place for the steersman. Behind the parlor came the sleeping quarters and dining room combined. The bunks were arranged to fold against the wall, and a table in the centre could be shut up when not in use and hoisted to the ceiling, giving plenty of space.
 
Next came the engine room, and as they entered it the boys could hardly restrain from giving cheers of delight. It was almost filled with machinery, and occupied a little more than half of the whole boat, being twenty-two by ten feet in size.
 
The two boys did not know the use of one quarter of the machinery and apparatus they gazed on. There were electric motors, storage batteries, two gasoline engines similar to those used in automobiles, pumps, large and small tanks, instruments for measuring the electric current, for telling the temperature, the amount of moisture in the air, the speed of the wind, the speed of the ship, the height to which it went, besides compasses, barometers, telescopes, and other instruments.
 
There were levers and wheels on every side, switches, valves, electric plugs and handles. Lockers arranged close to the wall and along the floor held supplies and materials. Everything was new and shining, and the professor smiled with pride as he touched piece after piece of machinery, and looked at the different instruments.
 
"Now we'll go out on the stern," he said.
 
The boys followed as he ascended the companion steps and emerged on a small platform at the rear end of the cabin.
 
"Do you know what this is?" asked the professor, touching a long, thin, round object.
 
"Looks like a gun," replied Mark.
 
"That's just what it is. It's a machine gun that will fire one hundred shots a minute, and it can be turned in any direction, as it works on a swivel. I don't know that we'll have any use for it, but I thought I'd take it along."
 
Then the professor pointed out where the propeller shaft ran from the engine room out through the stern, and showed how the rudder was worked by wire ropes extending from it to the conning tower.
 
"In short we have everything necessary to successfully navigate the air," he went on. "Not a thing has been overlooked. All I have to do is to fill the big bag of oiled silk with a new gas I have discovered and up we go. This is really the most important part of the invention. Without this powerful gas the airship would not rise above the earth.
 
"But I have found this gas, which can be made in unlimited quantities from simple materials that we can carry with us. The gas has enormous lifting power, and if it was not for that I would not dare make such a large and comfortable airship. As it is, we can sail through the air as easily as if we were on an ocean liner on the sea and much more quickly.
 
"I generate the gas in the engine room as I need it," the professor went on. "It goes to the oiled silk bag through two tubes. When we have arisen to a sufficient height I start the electric engine, the propeller whirls around, and the ship moves forward, just as a steamboat does when the screw is set in motion. Then all I have to do is to steer."
 
"It's great!" cried Jack with sparkling eyes.
 
"It certainly is," agreed Mark.
 
From the stern the professor took the boys to the conning tower, where there were several wheels and levers, that placed most of the important machines and engines in the boat under the direct control of the steersman. A lever turned one way would send the ship ahead. Turned in the opposite direction it would reverse the course. A wheel like that on an automobile served to direct the rudder and so guided the Monarch's course. Other levers controlled the speed of the engines, and the supply of gas that filled the silk bag.
 
"Here is where we shall carry our supplies of condensed food," the professor went on, leading the way back into the middle room. "We will take along capsules that will supply us in a small space with meat, vegetables, soups, tea and coffee, besides milk.
 
"The water we will get as we speed along, dropping down to earth whenever it is necessary. As for clothing, I have an abundant supply."
 
He opened a locker and disclosed a pile of fur garments. There were big coats, caps and boots, everything made with a furry surface within as well as without.
 
"Any one would think you were going into some cold country, professor," said Jack, looking at the warm garments.
 
"So we are! We are going to find the north pole!" exclaimed the old inventor.
 
"The north pole?" cried Mark.
 
"That's what I said. Do you boys want to go along in the Monarch to a place where never mortal man has been?"
 
At that instant there came a loud knock at the door.
CHAPTER V A PLAN TO SEEK THE NORTH POLE

"Hark! What was that?" exclaimed Professor Henderson in a hoarse whisper.
 
"Sounded like some one at the door," replied Mark.
 
"Quick, Washington! Put out the lights! You boys creep back and hide under the bed. My secret must not be discovered now when everything is ready for the trial!"
 
The boys started back toward the living room, Washington began putting out the lights and then, with the professor, joined the boys. The shed containing the airship was in total darkness, and the negro, turning down the lamp in the cabin, shrouded that in gloom also.
 
Once more the knock was repeated. It was a peculiar one; first two raps, then a silence, then three blows, followed at intervals by six single raps.
 
"Who is there?" asked the professor, going close to the door.
 
"A friend," was the reply.
 
"Give the countersign."
 
"The North Pole, and long may it stand!" was the queer answer. It was the same the colored man had given when he sought admission after his second trip to the wreck that afternoon.
 
Slowly the inventor unfastened the door. As he cautiously opened it a roughly dressed man slipped in.
 
"What's the need of all this foolishness?" he demanded. "Why have you made it so dark? It's like a pocket. Is any one here?"
 
The two boys had crawled under the bed before the door was opened, in accordance with the instructions from the old man. The inventor and Washington were the only ones visible in the cabin.
 
"Why don't you turn up the light?" went on the visitor in fretful tones.
"Are you sure no one is here to learn our secret?"
"Do you see any one?" asked the professor, not wishing to disclose the boys' presence. "Do you think I am so foolish as to waste the labor and toil of years?"
 
"I didn't think so," said the man, "but as I came along I thought I saw lights in the balloon shed."
 
"Very likely," admitted Mr. Henderson coolly. "Washington and I were out there doing some work."
 
"All right," was the rather ungracious answer. "I have those chemicals you wanted."
 
"Give them to me!" implored the old man in an anxious tone. "I thought you would never bring them."
 
"Oh, I don't forget so easily. Here you are," and the newcomer passed over a package. "Now when are you going to sail?"
 
"In about a week," answered the inventor.
 
"Then I guess I'll stay until you go," spoke the stranger. "I don't want to be left behind."
 
At this the old professor seemed strangely excited. His hands trembled as he placed the chemicals on a shelf.
 
"You don't like it, I see," observed the stranger with a sort of snarl. "But I know you too well, Professor Henderson. You would be only too glad to go and leave me behind after all I have done for you."
 
"My only desire, and you know it, James Taggert," broke in the old man, "is to preserve my secret from the world until I see whether I can succeed or not. I do not want to be laughed at if I fail. I admit you have been of service to me, but, rather than risk failure, rather than run the chance of having my plans made known before I am ready to have them, I would do anything. I know you too well to imagine that you have aided me from pure love."
 
"Well, go on," snarled the man, as the professor paused.
 
"You have some object back of it all," continued the professor. "I do not know what your motive is, but I say, rather than have my plans spoiled, I will make you a prisoner and keep you here until after I have sailed. I am all ready to start,—tonight, if need be!"
 
"So that's your game, is it?" cried Taggert. He turned toward the old man with an ugly look.
 
"Washington!" cried the professor. "Bind him! Put him in the little room and see that he does not escape!"
 
The next instant the big negro had folded his arms around Taggert. The white man struggled, but he was like a baby in the grasp of a giant, for Washington was very powerful. He procured a strong cord, and, before Taggert could resist had him firmly bound. Then, picking the man up in his arms, Washington carried him back into the balloon shed.
 
"Help! Help!" cried Taggert, and then his cries were smothered.
 
"Don't hurt him!" cautioned the professor, calling into the darkness to
Washington.
"I only guv him a soft piece ob wood to bite on," replied the negro. "He mustn't expostulate sounds too freely 'cause it might keep us awake."
 
In a few minutes Washington returned.
 
"I made him as comfortableness as de existin' circumstanceableness would permit ob," he announced.
 
"That's right. I did not want to do this, but I was forced to," the inventor said. "I will release him as soon as we are ready to sail. But I am forgetting the boys. Come out," he called, and Jack and Mark, much mystified and somewhat frightened by what had taken place, crawled from under the bed.
 
"I am sorry you witnessed what you did," the professor said to them. "But I could not have this man spoil my plans. Some time ago he discovered my secret, and to keep him from publishing it broadcast I was forced to take him into my confidence. He has given me some aid in getting rare chemicals, but he wants a heavy price. He demands a half interest in the Monarch, and to be taken to the north pole."
 
"Then you are really going to search for the pole?" asked Jack.
 
"I am, my boy, and, what is more, I am going to find it. Why, it is simple with the wonderful gas I have discovered. That is the whole secret of what will be my success. It is easy enough to make an airship that will move, but the trouble is no one has yet been able to make a gas strong enough to lift the heavy weight of the ship high into the air. That is where I have the advantage."
 
"I wish I could see your ship sail," said Jack.
 
"You may if you like," exclaimed the old man. "Do you remember what I asked you when the knock interrupted us? I asked you if you wanted to go to the north pole. Now I have taken a great liking to both you boys. I haven't even asked your names yet, but I like you. I need some help in running the ship, also in making my explorations in the frozen north. Would you like to go along?"
 
For a few seconds the boys did not know what to say. It was a strange and sudden proposition. They had been through so many adventures in the last few hours that their brains were fairly bewildered. But to both of them there came a great desire to make this wonderful trip through the air. Before they could make a reply Professor Henderson spoke again:
 
"Perhaps you had better think it over a bit," he said. "I realize that it comes rather suddenly. Supposing you go to bed, and we'll talk more in the morning. Come, Washington, make up a couple of bunks for the boys in this room. You can sleep in the balloon shed as usual."
 
In a few minutes the colored man had made rude but comfortable beds on two bunks, like shelves that folded against the wall. Then, with an armful of bed clothes, he retired to the big shed.
 
"Better use a little more liniment," advised the old man. "I don't want you sore and stiff if you go with me."
 
Accordingly Jack and Mark rubbed their arms and legs well. Something in the stuff must have been very soothing for they soon fell asleep.
 
It was broad day when the boys awoke. At first they could not realize where they were. They saw a colored man moving about and cooking something on the gasolene stove.
 
"Did yo' gen'men obtain a sufficient percentage of restful slumberation?" he asked with a broad grin.
 
"We slept fine," said Mark.
 
"Washington, is breakfast ready?" asked Mr. Henderson, coming in from the balloon shed.
 
"It am prepared," was the reply.
 
"Hello, boys! How did you sleep?" asked the inventor, observing that
Mark and Jack were awake.
"Fine!" they said in a chorus and with a smile.
 
"Well, wash up and we'll have something to eat. You'll find soap, water and towels out in the shed," and he pointed to where he had just come from.
 
The boys found two big tubs full of cool water. In an instant they had stripped and were splashing around like ducks. It was a treat to get a good bath. They came back into the cabin glowing. Not even a reminder of the soreness and stiffness of the railroad accident remained. They did full justice to the meal of coffee and ham and eggs Washington had prepared.
 
"Now, Washington, you had better take the prisoner something, and get your own breakfast," the professor said. "I want to have a talk with the boys."
 
Whistling a merry tune, the colored man took out a tray of food to
Taggert, who was still bound so he could not escape.
"Now I'd like to hear your names, and all about you," the old man said.
 
The lads told their simple stories from the time each of them had started to shift for himself until they had accidentally met, and been hurled from the train.
 
"And have you thought over what I asked you last night?" asked the professor, when they had finished.
 
"I have," said Jack, "and I'd like to go along."
 
"Good! You shall go!" exclaimed the inventor. "How about you, Mark?"
 
"I'll go, too."
 
"All right. Now we have plenty to do," the old professor went on. "The actions of this man Taggert will hasten my plans. There are a few finishing touches to put on the ship. Come out into the shed."
 
Delighted at the chance of helping about the mysterious Monarch, the boys followed the professor. They found the shed lighted by windows in the roof, from which the curtains had been rolled back. The windows on the side were not opened.
 
By daylight the airship looked larger than before. It was a wonderful machine. The professor and his colored helper busied themselves in the engine room. Now and then the two boys were allowed to aid.
 
As he hurried about from one part of the ship to the other the professor told them how he had come to build the Monarch. He said he was an old bachelor and alone in the world, and had long desired to sail to the north pole. The failure of many land expeditions had convinced him that an airship was the only feasible method. Accordingly he had come to this rather deserted part of the country, built his cabin and shed, and then had begun the putting together of his airship.
 
The engine parts, the various pieces of apparatus, and the machinery, he bought from many different sources, so as not to excite suspicion. At last after much labor the great undertaking was done.
 
"The Monarch has never been tested," said the professor, "but I know it will sail. I have made many small models and they worked perfectly."
 
Several busy hours were spent. Much more machinery was put in the ship, the food lockers were stored with supplies, the gasolene tanks filled, and the supply of fur clothing increased.
 
"There!" exclaimed the professor at length. "We are about ready to sail. I could start in an hour if necessary. All I have to do is to fill the silk bag with my wonderful gas, which is all ready to generate."
 
"Den you'd better start to generationess it right off quicker than sooner!" shouted Washington, running from the rear of the shed. "Hurry up, Perfessor!"
 
"What's the matter?" asked Mr. Henderson anxiously.
 
"Dat prisoner man has escaped!" cried Washington. "He's clean gone!
Flown away! Jumped his bail!"
"That's bad!" exclaimed the professor. "He'll work some mischief now! I guess we'll have to start on our trip at once!"
CHAPTER VI AWAY IN THE AIRSHIP

"Quick, Washington!" cried the professor. "Jump in the engine room and start the gas generator. Mark, you bring in from the cabin all those wheels and things on the walls! Jack, load those packages there into the locker in the after part of the Monarch! But handle them carefully! They contain explosives and ammunition for the machine gun!"
 
If there had been hurry and bustle before, there was ten times as much now. The professor gave one look at the place where Taggert had been concealed. The man had worked off his bonds and escaped while his captors were in the airship's cabin.
 
Soon there was a queer hissing noise from the engine room of the Monarch. The gas bag began to distend.
 
"She's fillin', Perfessor!" cried Washington.
 
"We must tie her down," muttered the old man. "Otherwise she will rise and take the shed with her. I say, Washington!"
 
"Yes, Perfessor."
 
"We must get some one to help us open the shed roof to let the ship rise out. We can't do it alone."
 
"Guess it's a extraunordinary contract," agreed the negro.
 
"Then you go out and see if any one is in sight. Try to hire them for the work, but don't tell them about the ship. They can work up on the roof. I will see to the gas machine while you are away. Hurry now!"
 
The colored man went out. In the meanwhile the professor and the two boys continued to load up the Monarch. They had nearly everything that the inventor intended to take along piled in its proper place, when footsteps were heard outside. Then the noise of some persons on the roof was audible. In a few minutes Washington came in.
 
"I found three men," explained the negro. "One is dat old hunter as helped us before, Andy Sudds. He was goin' huntin' but he said he'd help take the roof off fer a dollar. De oder two is does farm hands, Tom Smith an' Bill Jones. Dey was goin' down to do post-office, but dey said dey'd help fer fifty cents apiece. All three is up on de roof now."
 
"Good!" exclaimed the professor. "It's lucky I had the roof made in sections when I built this shed. Now it can be taken off in a hurry. Come on, boys! There are some more things that must go in the ship!"
 
Thus urged, Mark and Jack worked with a will. Washington helped, and then went up on the roof to aid the three emergency toilers. By this time several sections of the covering to the shed had been taken off and the place was quite light.
 
All the while the gas machine in the ship continued to generate the vapor. It flowed into the cigar-shaped bag through two rubber tubes. As the bag distended more and more, the Monarch tugged and pulled at the anchoring ropes on the floor of the shed, as if anxious to be away.
 
The boys worked with a will. The last articles were placed in the various rooms of the airship's cabin, until the balloon shed was stripped quite bare. The professor was busy in the engine room. The noise of the gas generating machine increased.
 
Then came a series of sharp explosions as one of the gasolene engines was started. This was followed by the hum of an electric dynamo, and the whizz and purring of a big motor.
 
The inventor was testing the many machines to see that all worked right. Suddenly he switched on the incandescent lights in the ship's cabin. Next he turned on the powerful searchlight in the bow, and the shed was illuminated by a glare that rivaled the sun. The professor then revolved the big propeller slowly and tested the rudder.
 
"Everything is in good shape!" he cried. "We will start in five minutes if they get the roof off so we can rise. Those anchor ropes will not hold much longer!"
 
Up on the roof, however, the men were working with a will. Board after board was torn away and the different sections moved to one side. At last the whole top of the shed was off. All that remained was to let the Monarch out.
 
Suddenly from where the three emergency helpers were working there came a cry of astonishment, mingled with fear. For the first time Andy Sudds, Tom Smith and Bill Jones, characters well known to Amos Henderson, had looked down into the shed, and caught sight of the tugging, swaying airship. The interior had been quite dark up to this point, which accounted for them not having noticed the ship before. But when they saw the strange affair so close beneath them they were startled.
 
"Jumpin' rattlesnakes!" cried Andy Sudds. "What have I struck?"
 
"It's a yellow elephant!" exclaimed Tom Jones.
 
"A sea serpent!" ejaculated Bill Smith.
 
They leaned over from the edge of the roof eaves to which they were clinging and peered down into the big balloon shed. Certainly the airship presented a queer sight to the three men.
 
"Is everything ready?" asked the professor of Washington.
 
"Eberyt'ing am circumulated to completeness," replied the negro.
 
"Jump in, boys! Untie the ropes, Washington. We'll start!"
 
"Hurry! Hurry! Perfessor!" cried Washington, as he looked out of a side window. "Here comes dat man we tied up in de shed! He's got anoder man wid him, an' dey got guns!"
 
"It's Taggert! He is after me!" exclaimed the inventor. "He must not be allowed to get on the ship! Come on, Mark and Jack! Never mine unknotting the ropes! Cut 'em! We have no time to lose! Jump in, Washington!"
 
The boys clambered over the sides of the airship. Washington followed their example. The anchor ropes were cut.
 
"Hi, there! Stop!" cried a voice from outside. "Don't you dare start that ship!"
 
"Here we go!" shouted Professor Henderson in a joyful tone. "Now to see if the Monarch fulfills her promise!"
 
He hurried into the engine room. The noise of the gas generating machine increased. The gasolene engine went faster, and the motors and dynamos added to the noise. There was a loud hissing sound. The professor had opened a valve admitting the full force of gas into the oiled silk bag. Then came a snapping sound as several anchoring ropes that had not been cut, broke.
 
Up rose the Monarch like some immense bird, through the opened shed roof. Out into the air went the big yellow bag. And then a strange thing happened.
 
Andy Sudds, the hunter, and Bill Jones and Tom Smith, the two farm hands, who had been peering over the edge of the shed down at the airship, leaned over too far in their anxiety to observe everything. As the gas bag brushed past them they were startled. They lost their balances and the next instant all three toppled right into the bow of the Monarch as she arose, and were lifted up into the air with her.
 
"Hold on, there! Stop!" cried Taggert, who by this time had come close to the shed.
 
"It's too late!" shouted back the professor, poking his head from a window in the engine room.
 
"Hey, there! You're carrying me off in your ship!" yelled Andy Sudds as he scrambled to his feet after his tumble into the bow of the Monarch.
 
"And me!" ejaculated Bill Jones.
 
"And me!" exclaimed Tom Smith. "I didn't figure on coming with you."
 
"It's too late!" the old inventor cried. He turned some wheels and levers and the airship arose faster. Then he switched on the electric machinery. The big propeller began to revolve. Swifter and swifter it went. The Monarch, which had risen several hundred feet, started forward at a swift pace. "We are off for the north pole!" shouted the inventor. "Hurrah! The ship works! I knew it would!"
 
"Here!" roared Andy Sudds. "I don't want to go to the north pole. I want to hunt muskrats down by the creek."
 
"You can hunt seals and whales up north," the professor called to him.
 
"But I've lost my gun!" the hunter exclaimed, soberly, yet a little appeased at the prospect of big game.
 
"I'll give you a better one," promised Mr. Henderson. "You shall have all the hunting you want."
 
"I can't go to the north pole," fairly yelled Bill Jones, starting back toward the engine room. "I had a job plowing on a farm. If I don't go back I'll lose my place."
 
"You can hire out to me," suggested the professor. "I need a crew, and I didn't have time to ship one."
 
"What about me?" asked Tom Smith. "I was working on a farm like Bill."
 
"I'll hire you also," spoke the inventor of the Monarch.
 
"Hi, Perfessor! Shall I shut off de gas?" Washington suddenly cried.
 
"For a while," was the inventor's reply. "We are high enough now. Then oil up the engines and dynamos, they need it. You boys can help," he said to Mark and Jack. "I must see to my instruments and find whether everything is working right."
 
The two boys were delighted to have a chance in the engine room. Under Washington's direction, the colored man showing quite a knowledge of the apparatus, they oiled the various bearings until everything was running smoothly.
 
Until now they had no time to realize what an experience they were going through. Things had happened so quickly that it was hard to realize they were sailing through the air in a wonderful ship, probably the most successful navigator of the upper regions ever invented.
 
It was not until Jack looked over the edge of the airship from the engine room window that he felt what a trip up among the clouds meant. Below the earth was spread out like a good-sized map, with little threads of silver for rivers, patches of green for big fields, and narrow gray ribbons where there were roads.
 
"It's wonderful!" he cried to Mark.
 
"And to think we were chased out of town yesterday by a constable," spoke his companion. "This is a great change. I'd like to see him catch us now."
 
"Dis prolonguated elevation into de airy space ob de zeneth am extremely discommodatiousness to a pusson what ain't used to it," remarked Washington with a broad grin as he oiled a whirring motor.
 
"Yes—er—I guess it is," admitted Mark.
 
"Are your teeth all fast after that effort?" asked Jack with a laugh.
 
"Neber yo' mind my teeth," said Washington. "Golly! What's de matter now?"
 
The Monarch was darting from side to side like a kite that has lost its tail in a high wind.
 
"It's only the professor trying the steering apparatus," said Jack, looking forward toward the conning tower. This proved to be true, for, in a moment, the airship resumed a straight path, and the professor, coming back to the engine room, cried:
 
"She answers her helm perfectly. It certainly is a success in every way! But now, since the machinery is working well, and I have the Monarch headed due north, in which direction she will sail alone for a while, I want you boys to come into the dining room, while we talk over matters with our unexpected visitors. We must lay plans and divide up the work of running the ship."
 
Jack and Mark went with the old man into the middle room of the craft. There they found the old hunter and the two farm hands. None of the three had quite gotten over his fright at being suddenly carried off through the air.
 
"Everything has turned out for the best," the inventor began. "I feared my forced start would spoil my plans, but you see I got a crew almost at the last moment. Now we will—"
 
He was interrupted by a sudden cry from the engine room.
 
"Help! Help!" rang out the voice of the colored man. "Hurry up an' help, Perfessor. I'm caught in some cantankerous conglomeration an' I'm bein' killed! Help! Help!"
 
Followed by the boys and the three men the old inventor hastened aft, alarm showing on his face.
 
CHAPTER VII HELD BY ELECTRICITY

As they reached the engine room they saw a queer sight. Washington was close to the buzzing dynamo which he had started to oil. His hands grasped two large copper switches used to turn the current on and off.
 
"Let go and come away from there!" cried Mr. Henderson.
 
"I can't! I'se stuck fast!" yelled the negro, writhing in pain.
 
Andy Sudds started on the jump to assist the unfortunate man.
 
"Don't touch him!" exclaimed Mr. Henderson. "He's held fast by electricity! If you attempt to pull him away with your bare hands you'll be caught just as he is! Wait a minute!"
 
The inventor rapidly opened a locker. From it he took out a pair of rubber gloves. Putting these on he hurried to where the negro was still squirming in pain and terror.
 
"Help! Help!" Washington yelled. "I'm burning up!"
 
"Wait a moment! I'll save you!" shouted the captain of the Monarch. The next instant he reached up, and turned off the electric current. Washington fell in a limp heap on the floor of the engine room. He was freed from the grip of the electricity that had held him as in a vise. The professor ran to a medicine closet and got a remedy which he administered to the unfortunate one.
 
In a little while the colored man was better. He sat up, opened his eyes, which had been closed, and remarked:
 
"Dat was a mighty close call fer dis chicken!"
 
"What made you go near the switch?" asked Mr. Henderson. "I have warned you several times never to put both hands on a copper switch at the same time. One hand does not matter, but two make the connection."
 
"I knows it now, Perfessor," said Washington humbly.
 
"Then I hope you'll remember it. That applies to all of you," he went on. "If ever you have occasion to touch any electrical machinery, don't do it with both hands at the same time, if there is danger of forming a connection. Always use rubber gloves, and you'll be in no danger. Rubber is a non-conductor. Remember, Washington."
 
"I'll recollection it on de next obstreperous occasion," promised the negro.
 
"You must feel better when you can use your big words," said Mr. Henderson with a laugh. "Now," he continued, "I was about to give a few general instructions about the airship, when Washington interrupted us.
 
"You men who are here against your will I am sorry about. I could not stop and let you off a while ago, because there was a man at the shed whom I did not want to meet. But if you want to go back to your homes I will let the airship down to the earth and you can go. I would like to have you stay with me. I can promise you all good wages, since I am well off as regards money.
 
"To you, Mr. Sudds, I can promise such game hunting as you never had before. And to you two farm hands I can promise such sights as you never saw before. Do you want to continue with me, now that you have had a chance to think the thing over?"
 
All three said they did.
 
"Then I'll divide our forces," went on the captain and owner of the Monarch. "I will be in general charge of the ship, just as if I was a commander of an ocean steamer. I expect to be obeyed in every particular. Washington will be the engineer, with the two boys to help him. Tom Smith and Bill Jones will be in charge of the kitchen, and I will show them how to prepare the condensed foods. Andy Sudds will be a sort of look-out and the hunter of the expedition. I will steer the ship and keep watch of the different instruments.
 
"In order that you may know a little bit about the Monarch I will tell you how she is run. In the first place, she is lifted above the earth by the power of a very strong gas I discovered. It is much lighter than hydrogen, or the gas ordinary airships are filled with, and has a greater lifting power than the hot air used in the old balloons.
 
"By putting more gas into the silk bag above us I can rise higher. The less gas I use the lower we go. The gas is let into or out of the bag by means of valves which are operated from the engine room or the steering tower. The forward motion of the ship is brought about by means of the propeller at the stern. This propeller works by electricity. The electricity comes from storage batteries which are kept charged from the dynamo run by one of the gasolene engines. I also have an electric motor that is run by either a gasolene engine or the storage battery. If one breaks down I can use the other. The motor alone will run the propeller if the storage batteries fail, and I have to run the electric machine directly from the gasolene engine.
 
"That apparatus there," and he pointed to a complicated machine, "is where the lifting gas is generated. A gasolene engine runs it. Those tubes carry the gas from the machine to the bag above."
 
Then the professor pointed out the levers that started and stopped The Monarch, those that sent it higher into the air or toward the earth, the wheel for steering, and told the boys and men how to read the instrument that gave the heights, the force of the wind, the temperature, and much other information. He showed them how the entire control of the ship could be accomplished from the conning or steering tower by the turning of one wheel or another.
 
"Rattlesnakes an' mud turtles, but she sure is a bang-up affair," observed Andy Sudds. "But about that gun—"
 
"That's so. I promised you a gun in exchange for the one you lost," said
Mr. Henderson. "Wait a moment."
He was gone a little while. Presently he returned with a fine rifle, at the sight of which the old hunter's eyes sparkled.
 
"That's a beauty!" he exclaimed. "It beats mine."
 
"It is a magazine gun," explained the professor. "It fires sixteen shots with one loading," he explained.
 
"And I can kill sixteen white bears, sixteen seals or sixteen whales!" exclaimed Andy with delight. "Well, I certainly am glad I come along, Professor."
 
"I have a gun for each of us," Mr. Henderson went on, "in case we should meet with enemies. But we may not need them. There is also the machine gun at the stern."
 
Then the professor initiated his crew into the mysteries of the kitchen and dining room. Nearly all the foods carried on the Monarch were of the condensed type. A small capsule made a plate of soup. There were other pills or capsules that held meat extracts, condensed cereals, tea, milk, coffee, sugar, salt, pepper and everything needed in the general eating line. All the cooking was done by electricity.
 
As has been said, there was plenty of clothing to withstand the rigors of the arctic regions. There was an abundance of gasolene for the engines and for heating the ship. In short, Professor Henderson seemed to have forgotten nothing that would make his trip to the north pole a success.
 
After he had explained all he thought necessary, he told the two farm hands to see what they could do in the way of preparing a meal, as it was nearly noon, and everyone was hungry. Rather awkwardly at first, Bill and Tom started in. They soon got the knack of things, however, and once they had found out how to run the electric stove they were right at home making soups and other dishes from the condensed foods. The first meal on the Monarch was voted a success.
 
Meanwhile the airship was sailing on. It was not moving very rapidly, for the professor wanted to give the machinery a chance to warm up. After the meal the inventor took the two boys into the steering tower with him, telling Washington to speed up the engines.
 
In a few minutes the boys were aware that they were moving forward at a faster pace. The air, as it came in the opened window of the conning tower, rushed past with great force.
 
"I think we'll go a little higher," said Mr. Henderson.
 
He turned a small lever. All at once the boys experienced a sensation as if they were in a rapidly ascending elevator. Up and up they went, for the professor had admitted more gas to the big silk bag above them.
 
Suddenly the earth which the boys had dimly perceived below them as if it was a small map in a big geography, faded out of sight. At the same instant there was a sudden moisture and chilliness to the air. Then a dense white mist enveloped the Monarch.
 
"Oh!" cried Mark. "What has happened?"
 
"We are going through a cloud!" called the professor. So dense was the vapor that the boys, though within five feet of the captain, could not see him. His voice sounded far off.
 
Then came a sudden rush of light. The mist cleared away. The boys could see clearly, but as they glanced down they noticed rolling masses of white below them.
 
"We are above the clouds!" said the professor. "Be careful not to exert yourselves, as it is hard to breathe in this rarefied or thin atmosphere."
 
The boys experienced some difficulty, but by avoiding any exertion were not much bothered.
 
"Now we'll go down a bit," said the inventor, after the ship had whizzed along for several miles above the masses of vapor. "I want to get an idea where I am."
 
He turned some more wheels and levers. In a few minutes the ship was again surrounded with a white cloud. Then it passed away, and the earth came into view.
 
Suddenly the professor looked forward. He seemed to be gazing intently at something.
 
"I wonder what that is?" he muttered. He took down a telescope and adjusted it, peering forward with strained eyes.
 
"Can it be possible!" he exclaimed. Then he dropped the glass and frantically signaled to the engine room.
 
"We must look out for ourselves!" he cried, "Come here, Andy Sudds!"
CHAPTER VIII SURROUNDED BY EAGLES

There was a sudden tremor all over the airship as Washington, in the engine room, in obedience to the signals, turned off the power. Then sounded a hiss as the captain let some gas from the bag. The ship began to sink toward the earth.
 
The black cloud that the professor had been gazing at came nearer. It grew larger and seemed to be made up of a number of small moving objects.
 
"Quick, Andy!" cried the old inventor. "We shall need your services now!"
 
"What's the matter?" exclaimed the old hunter, as he hurried forward with his gun in readiness.
 
"Eagles!" cried Amos Henderson.
 
"Eagles?"
 
"Yes! A whole flock of them. Just ahead! See that dark cloud! They are coming this way! They think the ship is a rival bird and they will attack it. Strong as the Monarch is, the silk in the gas bag is frail. If the birds tear that we will fall to the earth and be killed! Use your gun! See if you can drive them off!"
 
Andy kneeled down on the forward part of the ship. He aimed at the black mass, in which scores and scores of birds could now be seen. Then his gun sent out fire and lead.
 
Bang! Bang! it spoke, and two birds dropped toward the earth. Again the gun belched forth, and more of the eagles were killed. As fast as Andy could pull the trigger he fired.
 
"We must all get guns!" cried the professor. "It is the only way to save the ship! Come on, boys! You'll find weapons in the dining-room lockers!"
 
Mark and Jack hurried after the rifles. The professor was greatly excited. Bill and Tom came running forward. The inventor rapidly handed out the guns.
 
In the meanwhile the ship was slowly settling toward the ground. The captain hoped to get low enough to escape the onward rush of the big birds, but he had counted without the anger of the eagles. They thought the airship was a rival in the realms of space and were determined to destroy it.
 
On and on they came in spite of the number among them that were killed. Every one on the ship, except Washington, who had to attend to the engines, was firing. The birds never stopped or swerved from their course.
 
Then with a rush and roar, a flapping of wings that sounded like thunder, and shrill cries and screams that almost drowned the noise of the guns, the eagles surrounded the Monarch. They struck at it with their talons. They opened wide their sharp beaks and snapped at the wood and iron.
 
Some of the fierce birds even attacked the men, and boys, and were beaten off with the butts of the rifles. Others of the eagles rose higher in the air and struck at the oiled silk bag. At first the yielding surface offered no resistance and was not damaged. Then one fierce bird, with wide-opened beak, struck at the thin cloth and tore a hole in it as large as a man's hand.
 
The sudden settling of the airship told that something was wrong. Then the professor, glancing aloft, saw what had happened, and hastened to his helper.
 
"Quick, Washington!" he shouted. "Start the gas generator at full speed! We must pump lots of the gas in to keep us afloat! We are in great danger!"
 
"Why not try the machine gun on the eagles?" shouted Jack.
 
"Good idea!" exclaimed the inventor. "You two boys work it!"
 
At last the eagles, alarmed by the number killed, and frightened by the noise of the guns and the shots, halted in their rushes at the airship. Some of the wounded ones wheeled away. Then others followed until, finally, the whole colony of birds sailed off.
 
"There they go!" cried Jack.
 
"Yes, but I fear too late to do us any good," spoke the professor. "The airship is slowly settling."
 
"Can't it be fixed?" asked Mark.
 
"I suppose I could let it down to earth and patch up the hole, but I fear to do so," answered the inventor. "The Monarch is not under control, and if I attempt to make a landing I may smash her all to pieces. She may settle down until within a few hundred feet of the earth and then plunge like a meteor. We would all be killed then."
 
"Is there no other way?" asked Jack.
 
"None, unless we could patch up the hole in the gas bag while we are up aloft. I can hold the ship there for a while yet. Another reason why I do not want to land is that we are over a thickly settled portion of the state now, and if I go down to earth we will be surrounded by a curious crowd that will delay us."
 
"Is that netting strong?" asked Mark, suddenly, pointing to the cords that confined the gas bag.
 
"Two strands would support a man's weight," said Mr. Henderson.
 
"And have you anything to mend the silk bag with?" went on the boy.
 
"Yes, but why do you ask?"
 
"Because," answered Mark, "if you'll let me I'll climb up and mend the hole the eagle made."
 
"Dare you do it?" cried the old professor, hope shining in his face.
 
"Try me and see."
 
The professor quickly prepared a piece of silk, kept on hand to repair breaks in the bag. It was coated with a very strong and fresh cement. The silk was to be inserted in the tear made by the eagles, when it would at once harden and prevent the further escape of gas.
 
Mark made ready for the perilous ascent. He took off his coat, and removed his shoes so his feet could better cling to the frail-looking though strong cords.
 
"Slow down the ship!" commanded the captain. "Now, Mark, try! I hope you succeed! Move cautiously. You don't want to lose your life!"
 
Mark said nothing. He grasped the piece of oiled silk, coated with the cement, in his teeth, clinching it by a strip that was free from the sticky substance. Then he stood on the rail of the Monarch and began his climb aloft. Surely few ascents were made under such fearful conditions. The airship was now more than a mile above the earth. One false step and the boy would plunge into eternity. Nothing could save him.
 
Up and up he went, testing every cord and mesh before he trusted his weight to it. On and on he advanced. The frail gas bag swayed in the wind that was springing up. It seemed like a thing alive.
 
"Careful! Careful!" cautioned the professor in strained tones. Everyone on the ship held his breath. Up and up Mark went. At last he reached the place where the eagle's beak had torn the bag.
 
He braced himself in the meshes of the net. Then, leaning forward, he fixed the patch under the rent, and pressed it into place. The cement did not take hold at first. Mark pressed harder. Would the leak be stopped?
 
"Will he make it?" asked one.
 
"I don't think so."
 
"He must make it!"
 
"If not we are lost!"
 
"You are right!"
 
For a moment there was a doubt. Then the sticky stuff adhered to the silk bag, and the patch was made fast. A shout from Washington in the engine room told that the gas had ceased to rush out. Mark had succeeded.
 
Washington hastened to turn the gas generator to half speed. Before he could do so, however, there had been a great increase in the volume of vapor in the bag, caused by the sudden stopping off of the vent. Up shot the airship, the accumulation of gas lifting it higher from the earth. So suddenly did it shoot up, from having been almost at rest, that there was a tremor through the whole craft.
 
"Look out, Mark!" cried Jack. He looked up to where his comrade clung to the netting.
 
"Hold fast! We'll stop the ship in a second," exclaimed the captain.
 
But it was too late. The sudden rising of the craft had shaken Mark's hold, which was not of the best at any time, since the gas bag was a yielding surface to lean against.
 
The next instant the boy, vainly clutching the air for some sort of grip for his hands, toppled over backward. His feet slid from the meshes of the net, and he plunged downward toward the earth, more than a mile below!
 
CHAPTER IX THE FROZEN NORTH REACHED

"He'll be killed!" shouted Jack.
 
"He's a goner!" yelled Washington, looking up from the engine room window.
 
The old professor groaned and shut his eyes. He did not want to see the boy fall.
 
Bill and Tom, with old Andy Sudds, had been watching Mark at his perilous task, standing directly beneath him. Andy was the closer. He leaned quickly backward when he saw what had happened.
 
Mark's body, turning over in its descent, was at the ship's side. Out shot the hands of the old hunter. His fingers were curved like the talons of an eagle. The long arms seemed to reach a great distance, and then, just as it seemed that Mark would plunge downward to his death, Andy grasped and held him.
 
"There!" exclaimed the hunter. "That was a close call, my boy!"
 
Mark did not answer. The fearful danger he had been saved from had so frightened him that he became partially unconscious.
 
"Is he dead?" faltered Jack.
 
"He has only fainted," answered Amos Henderson. "I'll soon bring him around."
 
The inventor hurried into the cabin and came out with some liquid in a glass. This he placed to Mark's lips and soon the color came back into the pale cheeks.
 
"What happened? Where am I?" asked the boy, sitting up and looking around.
 
"You're all right," answered Andy. "It was a close call though. I reckon you won't want to mend any more airships right away."
 
"I remember now," went on Mark, who had been dazed by the suddenness of it all. "I fell, didn't I?"
 
"Yes, and Andy caught you," put in Jack. "He was just in time."
 
Mark said nothing, but the fervor with which he shook the old hunter by the hand showed how deep his feeling was.
 
In a little while the fright and excitement caused by the accident had passed over. The ship now rode evenly and neither rose nor fell, in consequence of the gas supply in the bag remaining the same, there being no leak. The patch Mark had put on fitted so closely that there was not the least escape of gas now.
 
"Well, we might as well start ahead," said Amos Henderson, at length. "We have had excitement enough in this neighborhood, and maybe we'll be better off if we go forward."
 
Accordingly he went to the conning tower, set the propeller in motion, and soon the Monarch was moving northward at great speed. With his eyes on the compass in front of him the captain held the ship on her course.
 
They were about half a mile above the ground now, the captain having allowed the Monarch to settle. They could see that they were passing over a populated part of the country.
 
"Come up here!" yelled Captain Henderson to the boys from the steering tower. "I'll explain a few things to you."
 
Willingly enough the boys joined him. He was busy making a calculation of figures on a piece of paper. The steering wheel was lashed and the compass pointed to indicate that the ship was rushing due north.
 
"We're making satisfying progress," said the professor. "At this rate we will not be long on the journey."
 
"How fast are we moving?" asked Jack.
 
"About fifty miles an hour," replied the inventor. "That is 1,200 miles a day, counting that we run day and night at this speed. But we will hardly do that, not that we could not, for there will be no dangers of collisions up here. I think we have the air all to ourselves.
 
"But there will be contrary winds, and we may be blown off our course. That is the only disadvantage an airship is under. It can't sail against the wind like a ship on the water. Still, we have many advantages. Now I figure that we can count on an average of at least twenty-five miles an hour all day long and part of the night.
 
"We started from about the middle of New York state, and to the north pole would be about 3,000 miles. We ought to make the distance in about five days, or say a week, to be on the safe side. We will move as fast as we can, from now on, though, especially during the daylight."
 
The professor turned some wheels and levers and the speed of the airship increased a little. It was kept at about the same height.
 
The sun was beginning to descend in the west, for it was getting late in the afternoon. Down below, on the earth, the landscape had changed from that of cities and towns to a stretch of dense woods.
 
"Must be near supper time," observed Mark.
 
"Your fright didn't deprive you of your appetite, then?" asked Amos
Henderson.
"Not a bit," replied the boy.
 
In a few minutes Tom and Bill were preparing a meal of the condensed foods, cooked on the electric stove. Everyone voted the victuals excellent. Then, as night settled down, the bunks were made up and the boys, together with the two farm hands, were glad to seek some rest, for the day had been an exciting one. Washington and the professor agreed to divide the night into two watches, as they were not familiar enough with the workings of the ship to dare to leave it unguarded. The machinery might need attention any moment.
 
The boys and their companions were soon asleep, and no thoughts of their strange position, that of slumbering on an airship high in the atmosphere, disturbed their dreams.
 
The last thing Jack wondered was whether the passing of the Monarch would not be taken by people on the earth for the flight of some giant comet, as it sailed aloft, all lighted up. But he was too tired to pursue this speculation long.
 
Morning dawned without anything unusual having occurred. The ship had been kept going at a slow speed all night, and no accidents happened. Breakfast was served, and then each of the crew took up his duties.
 
The professor, having made a careful examination of the ship to see that everything was in order, showed Jack and Mark how to steer the craft, and how to start, stop, raise and lower it from the conning tower or the engine room.
 
Then he let them practice a bit, and two more delighted boys there never was, as they sent the craft ahead up or down, starting and stopping her with a few turns of a wheel or lever.
 
"You may want to know how to run her some day in an emergency," said
Amos Henderson. "No telling what will happen."
"We hope nothing will," spoke Jack.
 
"There's no telling," prophesied the inventor.
 
For several days the ship moved ahead at moderate speed. The machinery, excepting for some minor accidents, worked smoothly. The gas bag did not leak, which was the accident most dreaded, and it was not necessary to run the gas generator, which proved a saving of the valuable chemical from which the lifting-vapor was produced.
 
Now and then, when in need of water, the craft was lowered to the earth in a secluded spot near a stream or lake, and the tanks were filled for drinking and washing purposes. But so far, from the time of the hasty flight, no one on the earth had spoken to the voyagers. Nor, so far as was known, had their presence been noted, though the black speck in the sky might have furnished plenty of talk all over the country for those who observed it. The weather was pleasant, but it was noticed that it was constantly growing colder.
 
One morning Jack, who was the first up, stuck his head out of the cabin door before he had finished dressing. He quickly popped back again.
 
"Whew!" he exclaimed. "Colder than Greenland!"
 
"What's that about Greenland?" asked the professor, who had just awakened.
 
"It's awful cold outside," said Jack, shivering from the remembrance.
 
Without a word the professor, wrapping a dressing-gown about him, hurried to the engine room, where several thermometers were kept. One was outside, and could be read through a glass side.
 
"No wonder you felt cold," he said to Jack, when he returned. "It's ten degrees below zero!"
 
The boys hurried to complete their dressing. The professor did likewise, as he was anxious to take some observations.
 
"Get out the fur garments," he said. "We must take no more chances now. It will become colder rapidly, and ordinary clothes will be of no protection."
 
The boys and the professor donned heavy fur coats, with immense gloves and caps that covered all of their faces but the eyes. Then they went outside. Jack was the first to look over the side of the ship. As he did so he uttered a cry of astonishment.
 
Down below, about three-quarters of a mile, was a great white, snowy waste. Giant mountains of ice were heaped on every side. It was a cold, frosty silent world that the Monarch was flying over. They had reached the frozen north! They were at the beginning of the entrance to the land of the Pole!
CHAPTER X LOST IN AN ICE CAVE

"I'm not surprised that the thermometer is down below zero," remarked
Jack. "There's enough ice under us to supply the whole United States."
"It is getting colder!" exclaimed the inventor as he glanced at an instrument near him. "It is fifteen below zero now!"
 
In truth the Monarch was far to the north. She had gone faster than the inventor calculated. A glance downward showed that all traces of civilization had been left behind.
 
There was nothing to be seen but snow and ice, ice and snow, piled in fantastic heaps,—mountains, ridges, hills and valleys.
 
The professor hastily made a few calculations.
 
"I believe we are somewhere over Greenland or Baffin Bay, but whether we are over the land or sea I cannot tell. At any rate we are still going north," and he glanced at the compass.
 
They were about to retrace their steps to the dining cabin, when there was a sudden settling of the Monarch. It seemed to be plunging downward.
 
"What's the matter?" cried Jack.
 
The inventor hurried to the engine room. A glance at the registering needle of the instrument for telling the height attained, showed that the ship was sinking fifty feet a minute.
 
"Some conglomerous contraption has disproportionated herself," cried
Washington. "What shall I do, Perfessor?"
"Start the gas generator at full speed!" cried the inventor. "Heat the vapor before it goes to the bag! The cold has contracted the gas in the holder above so that it will no longer support us! Work quick, Washington!"
 
Washington sprang to set the gas machine in operation. He seemed to be having trouble with it.
 
"She won't work!" he called. "She's busted!"
 
Faster and faster the airship continued to sink. The inventor hurried to Washington's help, but it seemed that nothing could be done. On board the Monarch there was deadly fear in every heart.
 
"I can't keep her afloat!" the professor groaned.
 
Down and down went the craft. The inventor and Washington were working furiously. The boys, old Andy and Tom and Bill hurried to the engine room.
 
Then came a sudden jolt. The airship had struck the ice!
 
"Shut off the engines!" cried the professor. "Stop everything or we'll go to smash! We must set to work to repair the gas machine and raise the ship."
 
The Monarch had settled down on a vast ice plane. So gently had the ship sunk through the air that she had suffered no injury. She rested on an even keel and there was still enough lifting power in the gas contained in the bag to keep that afloat, so that the vapor holder tugged gently at the confining meshes of the net.
 
"Ma goodness sakes alive!" cried Washington as soon as he had poked his head out of the warm engine room. "De atmospheric conditions am such dat dey is conducive to de utmost congestion of mah circulatory systemation!"
 
"I suppose you mean it is too cold for your blood," spoke the inventor, with a smile.
 
"Yo' has conducted mah meanin' to de utmost circumspection, Perfessor," was the answer.
 
"You'd better get out a suit of furs," suggested the captain, for Washington had not yet donned these garments. The colored man ran back into the cabin, got out the heaviest set he could find, and put it on.
 
The professor and the boys, together with the two helpers, were clothed to withstand the rigors of the arctic regions. In a little while Washington was warmly dressed. Then the professor led the way over the rail and down on the ice.
 
"Are we on land or sea?" asked Jack.
 
"It's hard to say, but I think we are on land," replied Amos Henderson. "However, it doesn't make much difference. We are pretty far north. The thing to do is to get the airship in shape as quickly as possible."
 
"Can we help?" asked Mark.
 
"I hardly think so," answered the old inventor. "Washington and I understand every piece of machinery. If we need any help we will call on you. In the meanwhile you may take a look around if you wish."
 
"I'd like to stretch my legs a bit," spoke up old Andy. "I ain't used to stayin' cramped up in a ship like I have been. I'd like to see some of that big game you talked about, Professor."
 
"Take your gun along, and you may spot a polar bear or a walrus," suggested Mr. Henderson. "Some fresh bear steak would not go badly at all."
 
Delighted at the prospect at getting a shot Andy hastened after his gun. Then after a hasty breakfast, with the two boys and the two helpers as companions, all warmly wrapped in furs, the hunter set forth across the fields of ice and snow.
 
It was a strange experience for all of them. There was not a sign of life to be seen. On every side there was nothing but the cold whiteness—a coldness and a whiteness that was like death itself. They walked on for more than a mile, and saw nothing but the desolate waste.
 
"There's something!" called Jack in a hoarse whisper, coming to a halt and pointing to a small hill of ice in the distance.
 
"It's a polar bear!" yelled Mark. "He's right behind the ice!"
 
"There are two of 'em!" cried Bill. "This is no place for me! Come on,
Tom!"
"Hold still! Let me get a shot!" pleaded the old hunter.
 
He could see the two animals plainly, now that his eyes had become used to the difference between their shaggy coats and the surrounding snow and ice. Andy kneeled down and took careful aim. A shot rang out, and one of the bears toppled over.
 
"Good shot!" cried Jack.
 
Once more the hunter pulled the trigger. A dull click was the only response. Andy quickly cocked the gun again, thinking it had missed fire. Again the hammer fell with only a click. The hunter quickly threw open the magazine.
 
"The chamber is empty!" he cried. "I have fired my last shot!"
 
"And there comes the bear!" yelled Mark. "He's in a fit of rage!"
 
The fierce beast, in anger at the sight of his enemies, was coming toward the men and boys at top speed. On the first alarm Bill and Tom had turned to flee. Andy, swinging his gun by the muzzle, and loosening a long hunting knife in his belt, awaited the bear's onslaught. Mark and Jack were too surprised to run, and stood their ground, not knowing what to do.
 
"Run away!" shouted Andy. "I'll tackle the beast! I'm not afraid!"
 
"We're not going to leave you!" yelled Jack. "I have a revolver!"
 
Quickly he drew out the small weapon, a present from the inventor. Taking hasty aim he fired several shots, but his aim was poor. One bullet struck the bear on the nose, and, instead of stopping the beast, only made him the more angry.
 
The brute was now but fifty feet away and coming on at a rapid pace over the uneven lumps of ice and snow.
 
"Run, I tell you!" called Andy. "Do you boys want to be killed?"
 
He aimed a furious stroke at the bear, but as he did so his foot slipped and he came down heavily on the ice. Mark and Jack uttered cries of terror and fright.
 
With blood dripping from his wounds, foam falling from his red jaws, and with every appearance of rage, the maddened beast rushed on the old hunter.
 
"He'll be killed!" yelled Mark.
 
"If I only had a gun!" groaned Jack.
 
Andy rolled to one side. As he did so he uttered a loud cry, and then, to the astonishment of the boys, he disappeared from sight as if the frozen earth had opened and swallowed him up. At the same time the bear, that was just about to cast himself down on the fallen hunter, seemed to drop down through some hole into the earth.
 
For an instant Jack and Mark looked at each other with fear in their eyes.
 
"What has happened?" inquired Mark, in an awestruck voice.
 
"I don't know," answered Jack. "But look! there are spots of blood over there. That is where the bear was!"
 
The boys ran forward. As they did so their feet seemed to slip from under them. Down and down they felt themselves going. Faster and faster they slipped. They gazed with frightened eyes about them and saw they were on some giant slide of ice, that led into unknown regions.
 
"Where are we going?" gasped Mark.
 
"I don't know!" yelled back Jack. "At any rate we're getting a good coast!" He could joke even in the face of danger.
 
With a jolt the two boys came to the end of their sudden journey. For a moment they were so startled and shaken up that they could hardly see. Then, as their senses came back, they gazed around.
 
There were white glistening walls of ice on every side. Above glittered a tiny patch of light, showing where the blue sky was.
 
"Where are we?" asked Mark.
 
"You're with me an' the bear!" exclaimed a voice.
 
The boys started. They saw, lying near them, old Andy. At his feet was the polar bear, dead, with the hunter's knife sticking in his heart.
 
"And what place is this?" asked Jack.
 
"It appears to me like a big ice cave," answered the hunter.
 
"Yes, and we're lost in it," spoke up Jack, and gave something of a shudder.
 
"That's right, my boy," answered Andy Sudds.
 
CHAPTER XI ATTACKED BY SEA LIONS

Frightened and alarmed at the unusual sight of an enraged polar bear rushing in their direction, Bill and Tom had turned and fled at the first appearance of danger. They were not cowards, and would probably have faced a mad bull, but that was something they were used to, while a bear was something new.
 
So they raced back over the ice toward the place where the disabled airship rested.
 
"Quick!" yelled Bill.
 
"They'll all be killed!" cried Tom.
 
"Who?" asked the professor, dropping his tools.
 
Rapidly the two helpers told what had occurred, and how they had left Andy and the boys as the bear was rushing at them, the hunter having no more cartridges in his gun.
 
"Take two rifles from the chest!" exclaimed the inventor. "Washington and I will follow as soon as we get our furs on! Hurry now!"
 
Tom and Bill needed no second bidding. Seeing that the magazines of the rifles they took were filled, they hastened again over the ice and snow in the direction of Sudds and the boys. As they hustled along, the sun, which had been hidden by clouds, emerged and shone with dazzling splendor on the ice fields. It almost blinded the men.
 
As they ran on they heard a shout behind them. Turning, they saw Washington and the professor, each with a gun, following. They waited for the pair to come up.
 
"How far away is the place?" asked Mr. Henderson.
 
"We must be close to it now," said Bill. "Yes, there is the bear Andy killed," pointing to where the dead animal was stretched on the ice. "But where are the boys?"
 
"And where is Andy?" asked Amos Henderson.
 
Not knowing what had become of the hunter and the boys, the rescue party was puzzled. They looked on every side but saw no traces. The ground was so uneven that the professor suggested the hunter and boys might be lying wounded in a hollow, and screened from sight.
 
"We must scatter and look for them," he said.
 
Meanwhile the three in the ice cave had been looking about them. They saw what had brought them into the place. It was a big cavern hollowed out by nature in the frozen crystals, and leading to it was a smooth inclined plane of ice.
 
"How are we going to get out?" asked Jack, after all three had taken a survey of the cavern.
 
"Can't we walk up the place where we slid down?" asked Mark.
 
Jack was already busy trying to climb up the slippery place. It was much harder than it seemed. The incline was a glare of ice, and Jack's first attempt sent him sliding back with considerable force to the cavern floor.
 
"There's only one way to do it," said Andy. "You must take my hunting knife and cut steps in the slide. Then you will have some support for your feet."
 
The boys saw this was good advice and followed it. But the ice was frozen almost as hard as stone, and after chipping and cutting away for half an hour they only had three niches.
 
"At this rate we will have to stay here several days," said the old hunter, and there came an anxious note in his voice. "I wish we could send word to some of the others."
 
"Hark! What was that?" asked Jack suddenly.
 
All listened. There came a faint report, like that of a gun.
 
"It's the professor, Washington, and the two farmers searching for us!" exclaimed Mark. "They are firing their rifles."
 
"That's it! They can't find us because we are down in this hole," said
Andy. "If I only had a cartridge now I could give an answer."
There came another report. This time there was no doubt that signal guns were being fired, for the shot sounded quite close.
 
Jack put his hand in his pocket. His fingers touched something.
 
"Hurrah!" he cried. "I have my revolver and there are four shots left!"
 
He passed it over to Andy, who shot twice at intervals of about a quarter of a minute.
 
"Where are you?" they heard a faint voice calling from somewhere above their heads.
 
In reply Andy fired the last shot. It was responded to, and then, a few seconds later, a dark object loomed up at the opening at the top of the inclined plane. The prisoners, looking up, recognized the professor.
 
"Hello, down there!" he shouted.
 
"Hello, up there!" answered Andy.
 
"We'll get you out!" called down the inventor. "How did you get there?
What do you need in order to come up here?"
"We slid down," said the hunter in reply, "and we didn't do it for fun either. If you're going to get us out you'll need a long rope."
 
The professor, sizing up the situation, sent Bill Jones back to the ship on the run to bring a long stout cable. While this was coming there were questions and answers sent up and down the inclined shaft that told each of the two parties what had happened. In a short time the rope was brought, and one end fastened to an iron bar thrust into the ice, while the other was thrown down to the prisoners. With this as an aid and guide they were able to walk up the incline and soon were on the surface again.
 
"There, I forgot something!" exclaimed the old hunter as he emerged from the mouth of the shaft.
 
"What?" asked the professor.
 
"The polar bear," was the answer. "I think I'll go back after him. The skin may be valuable."
 
"There are plenty more," said the inventor. "We have no time to go back after this one. I must hurry to the ship."
 
Pulling up the rope, and strapping their rifles on their backs, the party of rescued ones and rescuers began their march to the airship. They decided to leave the bear Andy had first shot on the ice, and come back later for some steaks.
 
It was a bright day, and though it was very cold, being about twenty degrees below zero, there was no wind, which was a great relief. The party marched on, with Andy in the lead. He had reloaded his rifle with some ammunition the helpers had brought from the ship, and he was almost wishing he would meet another bear or two, now that he was ready for them.
 
Just as the adventurers turned around the side of a large ice hill, which hid the airship from their sight, they heard a queer noise.
 
"What's that?" asked the professor.
 
"Sounded like some beast roaring," answered Jack.
 
"Look out!" shouted Andy, springing back, and bringing his gun to bear.
"We're in for it now!"
"Sea lions, by their looks!" exclaimed the inventor. "A whole crowd of them and they are right between us and the ship!"
 
The next instant the party came into full view of the beasts. There were about two hundred of them, great big brutes, with sharp tusks. At the sight of the men and boys the animals set up a chorus of roars that sounded as if several score of real African jungle lions had broken loose. At the same time the beasts, with curious hitchings of their unwieldly bodies, advanced on the adventurers!
 
"Get your guns ready," cried Andy. "These fellows mean business! Make every shot tell!"
 
He had already begun firing and two of the sea lions toppled over in quick succession, testifying to his good aim. Then the boys, the two helpers, the professor and Washington began a fusillade that made the icy regions echo and re-echo as though a battle was in progress.
 
But the number killed among them, and the sound of the guns, did not halt the progress of the beasts. On and on they came, their roars increasing in fierceness.
 
The continuous firing could not be kept up long. Already the old hunter's gun was empty, and there was no spare ammunition now. One after another the rifles of the others were emptied of their cartridges. Still the beasts came on.
 
"We must retreat!" shouted Andy. "Back to the ice cave! They can not get us there!"
 
"But what about the airship! We must regain that at any cost!" called the professor.
 
"Wait until these beasts go away!" yelled Andy. "If they get us down it's only a matter of seconds before they'll kill us with those tusks! Run back!"
 
All turned to execute this command. There was only a narrow opening in the slowly encircling ring of sea lions, and this the adventurers made for, running toward the ice cave. They had passed beyond the mass of the beasts, when a loud cry from Jack startled them. At the same time he pointed ahead.
 
There, coming on at full speed was a pack of polar bears! The adventurers were between the two forces of enraged animals!
CHAPTER XII A MYSTERIOUS MESSAGE

"It's all up with us now!" shouted Andy. "I wish I had never come to the north pole!"
 
"How shall we escape?" yelled the professor.
 
Not knowing what to do, the whole party stood still. Behind them were the sea lions, roaring and snorting. In front of them, a hundred feet away were the bears, growling and howling.
 
"Turn to the right!" cried Jack. "There is a big hill of ice we can climb!"
 
The adventurers turned. As they did so Mark glanced back at the sea lions, and uttered a cry of surprise.
 
"The lions are running away!" he shouted.
 
Sure enough, the seals, though their progress could not be called "running" were retreating with their hitching, lumbering gait, away from the adventurers.
 
"But the bears are coming!" called Andy.
 
"They aren't after us! It's the sea lions they want!" exclaimed Jack. "I don't believe they will pay any attention to us!"
 
"The boy is right!" came from Andy. "The bears want fresh meat and are going to tackle the lions. We're safe, but we'd better not stay around here long!"
 
Jack's surmise was correct. The white bears did not follow the adventurers when the latter had run to the right. Instead, increasing their pace, the polar bears sprang into the midst of the sea lions and soon there was a fierce battle between the two animal forces.
 
It was a fearful sight and the adventurers gazed at it in wonder, mingled with terror. The bears would seek to enfold the lions in their strong fore-paws, while the lions would try to sink their long tusks into the vitals of the enemy.
 
Nearly a dozen had been killed on either side, but still the battle raged fiercely. The men and boys were so fascinated by the sight that they did not move, but stood staring from a small hummock of ice they had mounted.
 
"I think we had better go!" called Professor Henderson. "No telling when they will get tired of fighting each other and turn on us. Besides I am anxious about the ship." And off they started.
 
The ship rested in the same position it had settled in when the gas contracted. No harm had come to it as the fall had been so gradual.
 
"I'll have the gas machine in operation in about an hour," Professor Henderson said. "Meanwhile, Bill, you and Tom had better get some dinner for us. I'm hungry and I dare say the others are. Have some hot coffee, for it is growing colder."
 
"I was thinking I didn't feel quite so warm," observed Andy. "While there was a lot of excitement I didn't notice it, but now I am chilled through."
 
"No wonder," remarked the inventor. "It's forty degrees below zero!"
 
All were glad to go inside the ship which was warmed with gasolene stoves. Bill and Tom took off their heavy furs and began preparing a meal, which was soon smoking on the table. Everyone had a good appetite, and, just as the boys, with Andy and the two farmers were about to sit down, the professor came into the dining room.
 
"It's all right!" he exclaimed. "Washington and I have the machine fixed. The gas is generating and we will be able to rise and continue our journey in about an hour."
 
This was good news, and, during the dinner the adventures of the morning were talked over in detail.
 
"We certainly had excitement enough for one day," observed Jack.
 
Rising from the table and donning their furs Jack and Mark went out on the deck. They glanced up at the gas bag, and found it was filling out from the pressure of the vapor being pumped into it from the machine.
 
"I wonder if we'd have time to walk out on the ice a little?" asked Mark. "I haven't had a chance to look around, we've been so busy since we landed."
 
"We'll ask the captain," spoke Jack. "I'd like a little stroll myself."
 
The inventor had no objections.
 
"Don't go far away," he cautioned. "We'll start very soon now, and don't go near those animals."
 
The boys promised, and then, climbing over the rail, and down the ice hummocks they walked along a broad level expanse that stretched out for about a mile.
 
They had not gone far before Jack, who was in the lead, came to a halt.
 
"Look here!" he called to Mark, who came hurrying up.
 
"What is it?"
 
"There's a pile of bones frozen into the ice! Looks as if there had been a fight here between bears and sea lions, and this is all that was left. They ate each other up, all but the bones, which became covered with ice."
 
"Those aren't animal bones, Jack!"
 
"Why not?"
 
"See, there is the skull of a man! And another! There are a dozen skulls!" and Mark pointed to where they showed from underneath the crystal ice.
 
"You're right!" Jack shouted. "And see! Here is something that looks like a copper cylinder! Maybe it has something inside! We must tell Professor Henderson!"
 
Full of the importance of their discovery, the boys hastened back to the airship. The old inventor was much interested. Directing Washington to keep a careful eye on the gas machine, and taking an axe with him, the captain returned with the boys to where the bones were.
 
"They are certainly the remains of human beings," was the professor's opinion. "I don't know that it would be any service to dig them out, but that copper cylinder may be of value."
 
A few blows with the axe served to chop out the object. It was about two feet long and nearly three inches in diameter, and seemed to be securely sealed.
 
"We'll take it back to the ship and open it," said the inventor. "It is too cold to do it here."
 
Back to the Monarch they hurried. Then, with a file, the professor removed one end of the copper case. From within he drew out a roll of paper, a watch, a knife and a few trinkets such as a man would carry about him.
 
"Some white man did this!" exclaimed the old inventor, his hands trembling with eagerness as he unrolled the paper. "Let us see if he has left any word behind to tell of his death."
 
All crowded around while Amos Henderson glanced at the mysterious message that had so curiously come to them. Some of the writing was very faint, but by the aid of a magnifying glass it was deciphered. Then, amid a deep silence the professor read the paper.
 
"Whoever may find this, take warning and do not seek to find the north pole. Danger lurks there. My name is Andre Christiansen, and I am a Dane, educated in America, who set out to find the pole. I discovered it but was taken into captivity by the fierce people who dwell around it. They determined to get rid of me. With a party I was sent away. I was to be killed and buried in the ice. Before they could kill me we were all attacked by polar bears. All the other men were killed and I was wounded. As I write this I am dying. I write it with my blood and a piece of bone. Send word to Denmark of my death, kind friend whoever you may be that finds this. If you reach this far in your search for the pole, be warned and go no farther. This is all I can write. I am nearly dead. I put the message in this copper cylinder which I brought along. I hope it will be found. Good-bye."
 
For a few moments after the professor ceased reading the strange message no one spoke. They were all thinking of the terrible fate that had befallen Andre Christiansen; to die all alone in that icy land, yet who, in the agony of death had thought to warn some explorer who might come after him.
 
"Poor fellow," murmured Amos Henderson. "He must have died soon after putting the message in the cylinder."
 
"And then the bears finished up their work by eating him and the men who wanted to kill him," said Andy. "They left only the bones."
 
"How long ago do you suppose that was written?" asked Jack.
 
"There is no telling," replied the professor. "But it must have been several years. I have read of all recent polar expeditions, and within the last twenty years there has been no one of this name to venture toward the pole. Besides the copper cap on the cylinder has become rusted on, and that would indicate the passage of considerable time."
 
"I wonder if there are people at the pole?" came from Mark.
 
"We'll go and see!" exclaimed the professor.
 
"You don't mean to say you are going further north after what that message says?" asked Andy Sudds.
 
"Certainly; why not?"
 
"We may all be killed."
 
"We'll try not to have that happen," said the professor. "I am glad you boys found this. It is a valuable relic," and Amos Henderson put the message, the trinkets and the cylinder carefully away.
 
"I—I guess I won't go—" began Andy.
 
At that instant the airship gave a sudden tremble. Then the whole craft shivered. Next it began to rise in the air.
 
"Here we go!" cried the professor.
 
CHAPTER XIII FORWARD ONCE MORE

The airship rose rapidly. Washington had continued to operate the gas machine until there was a sufficient quantity of vapor to overcome the contracting influence of the cold atmosphere.
 
"Forward once more!" cried the professor, hurrying to the engine room.
"This time we may reach the north pole!"
He and Washington soon started the motors, the dynamos and engines. The propeller revolved rapidly. The adventurers were under way again.
 
"Jack and Mark, go into the conning tower and steer!" called Mr. Henderson from the engine room. "Take her up about half a mile, and send her straight north by the compass. I have to adjust some of the machinery."
 
Delighted at the prospect of running the airship, the two boys hurried forward. Mark went to the steering wheel, which was similar to the kind used on automobiles. The Monarch was heading to the west, having no one to guide her, but Mark soon brought her around until her bow was poked directly for the north.
 
Under the guidance of the two boys, the airship rushed forward. They had become somewhat used to the queer feeling of being high up in the air, and now it did not seem wonderful to be sailing among the clouds, though two weeks before they would have laughed at the idea of such a thing. Andy and the two farmers had, likewise, become a little indifferent to the strange sensations, and, aside from being careful not to go too near the rail of the ship when it was sailing aloft, they took no more precautions than as if they were on the deck of a steamboat.
 
For several hours the ship was kept on her course. The boys remained in the conning tower, gazing ahead. Not a single thing could be observed but a monotonous expanse of whiteness. Now and then they would run into a bank of clouds which obscured their vision as if there was a heavy fog.
 
"Look at the clock!" exclaimed Mark suddenly, pointing to the time-piece.
 
"What's the matter with it?" asked Jack.
 
"Can it be right?" went on Mark. "Surely it isn't nine o'clock, and the sun shining as brightly as if it was noon."
 
"It's nine o'clock at night!" exclaimed the professor, entering the steering tower in time to hear Mark's words.
 
"But it can't be," argued the boy. "Look how the sun is shining."
 
"You must realize where you are," was the reply. "We are so far north, my boy, that we are in the land of the midnight sun. From now on we will have daylight all the while. We are nearing the pole, where it is light six months of the year, and dark the other six. We are having summer here, now."
 
"I guess it don't feel much like summer outside," said Mark. "The thermometer indicates fifty below zero!"
 
"So it does," said Amos Henderson, glancing at the instrument which, though it was outside, could be read through the glass in the tower. "Well, we may have struck a cold wave. Ordinarily we will not have much more than twenty below zero when the sun shines."
 
"That's cold enough for me," said Mark.
 
The professor announced that the airship's machinery was now in good shape. He said he expected to come to the end of the journey in about three days more, provided no accidents occurred, and there were no storms to delay the Monarch.
 
"I think we will divide the night into four watches," he said. "Washington, Jack, Mark and I will take them in turn. During the day we will all be on duty, but from six in the morning to six at night we will stand watch and watch."
 
It was arranged that Jack should take the first period, the professor the second, Mark the third and Washington the fourth. As the first watch had passed Jack was excused and the inventor said he would take charge of the ship. Then, as every one was tired from the happenings of the day, they all went to bed, excepting Amos Henderson, who entered the tower to steer the ship.
 
The engines, dynamos and motors ran without much attention save such as the pilot might give them occasionally, for he could leave the ship with the steering wheel fastened, a few minutes at a time, as there was no danger of collisions. So the Monarch continued to race toward the north.
 
It was almost time for Mark's tour of duty to begin. The two boys, who were sleeping together, were in a deep slumber, when Washington ran in and shouted at the top of his voice:
 
"Wake up everybody! De perfessor is killed dead!"
 
Andy, Mark, Jack and the two helpers sat up in their bunks, rubbing their sleepy eyes and wondering what had happened.
 
"What's the matter?" asked Jack.
 
"Mr. Henderson is dead! He's in the engine room!"
 
"What killed him?" inquired Andy.
 
"He must hab got a shock from de dynamo!"
 
Andy jumped from his bunk and hurried to the engine room. There, as the negro had described, Professor Henderson was lying white and senseless on the floor.
 
The old hunter stooped over the inventor and felt of his heart.
 
"He is alive!" he exclaimed. "His heart beats! We must carry him to a bunk!"
 
Aided by Washington, Andy carried the professor to the sleeping room, where he was made comfortable in one of the beds. The captain was so near death that he could not be seen to breathe, and only the faint flutter of his heart told that life existed.
 
"We're lost!" cried Washington. "If he dies we'll never get back home again. He is de only one dat knows how to mix de chemicals for de gas!"
 
This was alarming news. Without the mysterious vapor the ship would not keep afloat long, nor could it be worked back from the desolate land of ice and snow. How much of the gas was left no one knew.
 
"Did he ever get a shock like this before?" asked the hunter of
Washington.
"Once, but not so strong."
 
"What did you do for him? What medicine did he take?"
 
"Glory! Glory!" shouted the negro, jumping up and down in his excitement. "I remembers it now. Wait a second!"
 
He hurried to the engine room, and came back in a little while with a small bottle.
 
"Perfessor done say," he began, "dat if eber I seed him senselike, when he done gone and got a shock from de 'lectrisititeness, I was to gib him two spoons full ob dis."
 
Andy took the bottle, which contained a red liquid. Bill got a spoon from the locker where the dishes were kept. With hands that trembled the old hunter poured out some of the fluid. Then, with Jack's help he forced open the inventor's mouth and put the medicine in.
 
"I hope it works!" murmured Andy.
 
He poured out a second spoonful. This was administered to the unconscious man. In a few seconds his face that had been pale showed a little color. His chest expanded as he drew a long breath. Then the old inventor opened his eyes and asked faintly:
 
"What happened? Where am I?"
 
"You are all right now," spoke Andy in a gentle voice. "You are out of danger I hope, and safe on the Monarch."
 
"Is the airship all right?" asked the captain eagerly.
 
"Yes, and sailing along like a bird," was the answer. In fact every one had forgotten that the craft was forging ahead, and that all the machinery was working.
 
A look of relief crossed Professor Henderson's face, and he sat up.
 
"I remember now," he said. "I was adjusting the dynamo, and I touched a live wire. The current was very strong. It is a wonder I was not killed. But how did you bring me around again?"
 
"Washington happened to remember some medicine you had told him to use in emergencies."
 
"Oh, yes: I'm glad I had some on board. It is a remedy for those shocked with electricity. But I must see to the machinery."
 
"No, you must not," said Andy firmly. "You are too weak to get up yet, and you have a bad burn on your hand."
 
"All right," agreed Amos Henderson, for he felt weak and sick from the shock. "Some one had better see to the steering now," he added, and then he leaned back in the bunk and closed his eyes.
 
Jack ran to the conning tower. He found that the ship, under the influence of a strong wind, was going due west, instead of to the north. He shifted the steering wheel and brought the Monarch on her course again, pointing to the north pole. Then he called for Mark, and the two boys arranged that between them they would run the ship until Professor Henderson recovered.
 
Andy and Washington, who were watching beside the professor's bunk, where he reclined, seemingly in a deep slumber, were startled as he suddenly sat upright.
 
"Hark!" the old man exclaimed. "Listen! Do you hear it?"
 
"Hear what?" asked the hunter, in a soothing tone, wishing to humor the sick man.
 
"Do you not hear a terrible rushing, roaring wind? The ship! The ship is in danger!"
 
The thrilling words sent a chill to the hearts of the watchers. There was no sign of a storm. In fact it was strangely quiet outside, the only noise heard being that of the engines of the ship.
 
"His mind wanders," said Andy.
 
He had no sooner spoken than a cry from Jack, who with Mark was in the steering tower, startled them. His voice ran out through the cabins as he cried:
 
"A whirlwind! A whirlwind! We are running straight into a whirlwind!"
CHAPTER XIV TOSSED BY A TORNADO

"Shut down de engines!" cried Washington.
 
"Lower the ship!" exclaimed Mark, who had run back from the tower.
"Close to the earth we may escape the wind!"
"Is it headed toward us?" asked Andy.
 
"Straight," answered Mark. Jack tried to steer to one side, but the currents of air sucked the ship right back into the path again!
 
"The captain knew more than we gave him credit for," muttered the hunter. "He heard the storm coming."
 
The air, that had been so strangely quiet, now vibrated with a curious humming. It seemed to make the whole ship tremble. Then, just as the craft began to settle down, the upward pulling force of the gas being lessened under Washington's manipulations, there came a terrible roaring. The wind howled like a thousand demons seeking to tear the Monarch to pieces.
 
"It's a regular tornado!" cried Andy.
 
Then the storm picked the downward-falling ship up as if it had been a feather and tossed the craft into the air. The adventurers were in a sad plight.
 
There was nothing to be done. The forces of nature were ten times stronger than those of man. To start the engines and try to run the ship out of the grasp of the wind would only mean to strain the craft to a dangerous point. There was but one thing to do, to run before the tornado, as ships on the sea scud before the gale. In this way the airship might be saved, if it was not dashed down to earth.
 
As soon as this plan manifested itself to be the best one, Washington stopped drawing gas from the bag. He wanted to keep the ship as high as he could. Jack still held his place in the conning tower, but he could do nothing to guide the craft, and it would have been folly to attempt it, so fearful was the force of the wind.
 
"Which way are we headed?" asked Mark, making his way back to the tower where Jack was.
 
"Almost due west," was the reply. "About two points to the south, too."
 
"Then we are being driven away from the north pole," said Mark.
 
"We're as helpless as kittens tied up in a sack," said Andy. "If only I could do something I'd feel better. But I've got to sit here and take what comes."
 
The sick man stirred uneasily. Then he muttered in his delirium something about the tornado that was tossing him from side to side of the bunk.
 
Strangely enough there was nothing to the storm but wind. There was no rain or snow, and the air was remarkably clear, excepting for the darkness of the clouds. Aside from the way in which the ship was blown along there was nothing to indicate that the breeze was rushing along at tempest speed. There were no trees bent to the earth, and no clouds of dust. The sky clouds kept pace with the airship.
 
"I wonder where we are?" asked Jack, who with Mark had come back from the tower.
 
"We'll have to guess at it," replied Andy. "It would be as much as a man's life is worth to go outside and take an observation."
 
"Don't hab to do dat," broke in Washington. "See here!"
 
He stooped over and pulled on an iron ring that was fastened in the floor of the dining-room cabin. A section of a board came up.
 
"Look!" exclaimed the negro pointing down. All leaned forward and saw that a heavy plate glass had been set over a hole cut through the floor of the ship. By means of this strange window one could look directly down toward the earth. Jack kneeled and peered through the glass. He rose to his feet with a cry of fear.
 
"What's the matter?" asked Andy.
 
"We are right over the ocean!" exclaimed the boy. "I can see immense waves not three hundred feet below! The airship must be falling and we'll be dashed into the sea!"
 
At these words Washington ran to the engine room. He looked at the height indicator.
 
"We's four hundred feet in de air, an' a—we's agoin' down!" he muttered.
 
Jack, who had followed him, saw by the instrument what the dreadful truth was. Blown from her course, the Monarch was now over an open polar sea, into which she might be dashed at any moment. The tornado still howled and roared outside, making it impossible to inflate the gas bag, so strong was the pressure of wind on it. And without a fresh supply of gas, the ship must fall.
 
There was no abatement to the tornado. The ship was tossed more violently than ever. Jack peered through the floor-window again.
 
"We are nearer the water!" he exclaimed as he arose. "The sea is covered with icebergs. They are crashing together in the big waves. If we fall the ship will be ground to pieces in the floes!"
 
"Try the gas machine again!" urged Andy. "Maybe the wind has lessened."
 
Washington started the machine. He kept one eye on the needle of the indicator that told the gas pressure in the bag, and the other on the height register. The black pointer of the latter went lower and lower. It was now at one hundred, and kept on going down slowly, until it stood at seventy-five. Soon only sixty-five feet stood between the airship and her passengers, and the angry, swirling water beneath, where the icebergs crashed and ground together.
 
Then Washington, who was ready to faint with fear and despair, gave a cry of joy. He had noticed that the height indicator stopped. At the same time the gas register showed that the vapor from the machine was entering the bag.
 
"Glory! Glory!" cried the negro. "We's saved now. De ship is goin' up, and the gas is workin' in. De wind must be goin' down!"
 
Then, while all save Professor Henderson, who was still unconscious, crowded into the engine room, they saw that what Washington said was true. The pressure of the wind had lessened, permitting the bag to fill with the gas. This served to lift the ship, and the pointer on the height indicator began to move upward. Higher and higher went the craft, until in a few minutes the register showed six hundred feet. They had been saved from death in the sea.
 
"Hurrah!" cried Jack. "I believe the tornado has left us!"
 
Indeed the roaring of the wind was less now. The ship was no longer violently tossed. In a few minutes the wind died away almost completely, and, aside from the rising motion, and a slight swaying, the Monarch rode on an even keel. The danger was over.
 
"Is the ship safe?" called Professor Henderson from his bunk.
 
"All safe!" exclaimed the hunter cheerfully. "We had a little blow, but it is all over, and the Monarch behaved like the King she is—or, perhaps I ought to say Queen, seeing that all ships are ladies. But how do you feel, professor?"
 
"I am much better," was the answer, showing that the medicine had done its work. "I feel hungry," he went on. "What time is it?"
 
"Six o'clock," answered Jack, looking at the dial.
 
"Night or morning?"
 
"Morning, I guess."
 
"Then we'll have breakfast," said the professor with a smile.
 
He stepped from the bunk. As he did so there was a sudden lurch to the ship. Then it began to sink suddenly.
 
"We are going down!" cried the captain. "What has happened?"
 
"The gas bag is leaking again!" shouted Washington from the engine room.
CHAPTER XV PRISONERS OF THE ESQUIMAUX

The hearts of all were filled with new terror. They had just come safely through one danger only to fall into another.
 
The professor limped to the engine room. A glance confirmed his fears.
The gas was escaping from the bag in large quantities.
"I am afraid the patch we put on has come loose," he said. "The tornado must have unfastened it. Are we over land or sea?" he asked anxiously.
 
Jack hurried to where the sheet of thick glass was set into the floor of the cabin. He peered down toward the ground.
 
"We are over land, or, at least, a big ice field," he said, looking up." We must have crossed some arm of the sea, or, perhaps, a bay." Then, as he looked down through the window again, he gave a frightened start. "There are people below us!" he cried. "I can see hundreds of them! They are waiting for us to land!"
 
The ship was fast settling, and, because of that fact, and for the reason that the propeller was sending it ahead, the Monarch was approaching the ice at a sharp angle.
 
"Stop the engines!" commanded the professor. "Our only hope is in coming down easily. If we strike the ice hard we are lost!"
 
Lower and lower sank the Monarch, like a bird with a broken wing. In a few minutes there came a sudden jar that told the ship had struck the ice. Then, with a swish and rustle the silk bag, emptied of gas fell on the roof of the cabins. The Monarch had come down between two big hummocks of ice, and rested almost in a level position.
 
The adventurers peered from the windows. At first they could see nothing but a vast expanse of frozen whiteness. Then the ship, in an instant, seemed to be surrounded by men, women and children, all dressed in furs, only their faces showing.
 
"Here they come!" cried Andy.
 
The Esquimaux showed no fear of the airship nor the strange beings that inhabited it. They advanced boldly, many of them bearing rude weapons, spears, stone axes, and bows and arrows of bone. They were a fierce looking crowd.
 
"I can't have them come inside the ship," spoke the professor, "they will tear the machinery apart."
 
"Shall I fire on them?" asked Andy, getting his rifle ready.
 
"Not for the world!" cried the captain. "They are ten to our one, and probably this is but a small part of the tribe. Our only safety lies in peaceful means. Come, we must put on our fur garments and go outside. That may induce them to let the ship alone."
 
"They may take us prisoners," objected Jack.
 
"Better be prisoners with the airship safe than with it all broken so we can never use it," said the old inventor. "If we lose the ship then we are lost indeed. If we go out to them, they may be afraid to venture in alone. Come, we must hurry!"
 
Obeying the captain's advice, they all donned their fur garments, and each took a revolver and several rounds of ammunition. These small weapons could be concealed about them without much trouble.
 
Then the whole party emerged from the cabins out on the forward deck of the Monarch. It was high time, for several of the Esquimaux, with their big stone axes, were advancing to batter in the doors. At the sight of the adventurers, who had only been dimly observed through the windows, there arose a great shout among the savages.
 
Rapidly the air-travelers climbed over the ship's rail, down on to the ice, and walked boldly among the Esquimaux.
 
"Show a brave front!" exclaimed the captain, in a low voice. "Perhaps they mean no harm after all."
 
But this idea was soon dismissed. With a shout the foremost of the natives rushed on the party of whites, surrounded them, and, before any one had a chance to draw his revolver, had he desired to do so, each member of the Monarch's crew was seized and bound with strong thongs of walrus hide.
 
"Well, they've got us," groaned old Andy. "I wish I'd taken a few shots at them first!"
 
The old inventor watched narrowly every move the Esquimaux made. At first several of the natives showed a desire to penetrate the interior of the Monarch. But the commands of one big man, evidently the chief, who was clad entirely in white furs, deterred them. Scores crawled up the ice hummock and looked the strange craft over with wondering eyes, but none molested it.
 
Suddenly the man in the white furs uttered a loud cry. It was answered from a dozen throats, and then great activity was manifested. Big sledges, made of bone for a framework, with laced thongs for a body, were brought up, and dogs were harnessed to the vehicles. While some natives were attending to this, others scattered in different directions, returning presently with large supplies of dead fish, seals, and a large polar bear.
 
"This is evidently a hunting party," said Mr. Henderson. "They have been away from their main town or camp for several days, and were on their way back when they saw our airship. I wonder what they will do with us."
 
He was not long left in doubt. The chief of the Esquimaux approached the adventurers, who, bound with thongs, were sitting on the ice. He addressed Washington in a strange language, but Washington, with a motion of his head nodded toward Captain Henderson, to indicate that he was the commander of the party. To the old inventor, therefore, did the native in the white furs speak next.
 
He made a motion of a person reclining on a sledge and indicated that the captives were to be taken away in that fashion. Then the chief motioned to his mouth and pretended to chew.
 
"He seems to want us to take a sleigh ride and get something to eat," said Mr. Henderson. "I suppose we might as well go along."
 
He nodded an assent to the Esquimaux chief, thinking the sign for that would be understood. It was, evidently, for the chief nodded back and smiled.
 
The rude sleds were brought close to the party from the Monarch. Then the captives were bundled on the vehicles like so many logs of wood, and bound to the runners with hide thongs. Next a fur robe was thrown over each one, a hole being left for them to breathe, and a dog driver took his position at the front of each sled.
 
With cracks of the whips and wild shouts the natives started off at a rapid speed. Then it was the prisoners appreciated the extra fur coverings, for when the vehicles were in motion the keen wind cut like a knife on the little portion of the face left exposed.
 
A sharp pang of regret struck the professor's heart as he realized that he was being carried away from his beloved airship, which was left in the hands of the enemy. They might wreck it he realized, to get the valuable wood and metal in the different parts. If they did, it would mean that the adventurers would be doomed to remain in the land of perpetual ice and snow forever.
 
For several hours the journey was continued. The dogs drawing the sleds never seemed to slacken their speed, but, urged by voice and whip, sped on over ice and snow.
 
Suddenly a loud cry sounded. The sleds, as if in obedience to a command, came to a halt. The captives raised their heads and saw that the whole party had come to a stop. Several of the Esquimaux began opening bundles and took out pieces of frozen fat meat. With this they went from team to team among the dogs, and fed the brutes that seemed ravenous from hunger.
 
The animals provided with a meal, the Esquimaux fed themselves. It was a primitive feast. The men simply bit off chunks of fat and blubber and swallowed them almost whole.
 
"I'm pretty hungry, but I don't believe I could eat that," observed
Jack.
"Wait until you get a chance," advised Mark. "Maybe they are not going to offer us any. As for me, I am starved enough to tackle most anything."
 
Presently the Esquimaux chief approached the captives, who had been drawn close together on their sleds. The leader of the natives had in his hands some queer looking stuff. At a sign from him several of the other Esquimaux loosened the bonds that bound the prisoners.
 
"Um!" grunted the chief. "Um! Um!" At least his words sounded like that.
 
"I guess he wants us to eat," said the professor.
 
He took some of the food the Esquimaux chief held out. The stuff did not look very inviting, about as much like cold fat as anything. The professor bit into it.
 
"It's good!" he exclaimed. "It's chopped up meat and suet, and it's cooked! Eat it!"
 
They all did, for they were very hungry and cold. Then the captives were bound again, the dogs were harnessed, and the journey was resumed. The sun still shone, though it was getting late, but the prisoners were all sleepy, for, by the run of hours, it was now night.
 
On and on went the sleds. Jack had dozed off, when he was aroused by a shout. He raised his head to look about him, and was filled with terror at what he saw.
 
The sled he was on, as well as all the others, was coasting down a great hill of ice at fearful speed! The dogs were gone, and the fleet of sleighs, under their own weight, were dashing down the Mountainous side of a great glacier!