While Tarzan and Erich von Harben were locating the mine and transporting the metal to the seacoast, Jason Gridley was in Friedrichshafen in consultation with the engineers of the company he had chosen to construct the specially designed airship in which the attempt was to be made to reach the inner world.
Exhaustive tests were made of the samples of Harben-ite brought to Friedrichshafen by Jason Gridley. Plans were drawn, and by the time the shipment of the ore arrived everything was in readiness to commence immediate construction, which was carried on secretly. And six months later, when the O-220, as it was officially known, was ready to take the air, it was generally considered to be nothing more than a new design of the ordinary type of rigid airship, destined to be used as a common carrier upon one of the already numerous commercial airways of Europe.
The great cigar-shaped hull of the O-220 was 997 feet in length and 150 feet in diameter. The interior of the hull was divided into six large, air-tight compartments, three of which, running the full length of the ship, were above the medial line and three below. Inside the hull and running along each side of the ship, between the upper and lower vacuum tanks, were long corridors in which were located the engines, motors and pumps, in addition to supplies of gasoline and oil.
The internal location of the engine room was made possible by the elimination of fire risk, which is an ever-present source of danger in airships which depend for their lifting power upon hydrogen gas, as well as to the absolutely fireproof construction of the O-220; every part of which, with the exception of a few cabin fittings and furniture, was of Harbenite, this metal being used throughout except for certain bushings and bearings in motors, generators and propellers.
Connecting the port and starboard engine and fuel corridors were two transverse corridors, one forward and one aft, while bisecting these transverse corridors were two climbing shafts extending from the bottom of the ship to the top.
The upper end of the forward climbing shaft terminated in a small gun and observation cabin at the top of the ship, along which was a narrow walking-way extending from the forward cabin to a small turret near the tail of the ship, where provision had been made for fixing a machine gun.
The main cabin, running along the keel of the ship, was an integral part of the hull, and because of this entirely rigid construction, which eliminated the necessity for cabins suspended below the hull, the O-220 was equipped with landing gear in the form of six, large, heavily tired wheels projecting below the bottom of the main cabin. In the extreme stern of the keel cabin a small scout monoplane was carried in such a way that it could be lowered through the bottom of the ship and launched while the O-220 was in flight.
Eight air-cooled motors drove as many propellers, which were arranged in pairs upon either side of the ship and staggered in such a manner that the air from the forward propellers would not interfere with those behind.
The engines, developing 5600 horsepower, were capable of driving the ship at a speed of 105 miles per hour.
In the O-220 the ordinary axial wire, which passes the whole length of the ship through the center, consisted of a tubular shaft of Harbenite from which smaller tubular braces radiated, like the spokes of a wheel, to the tubular girders, to which the Harbenite plates of the outer envelope were welded.
Owing to the extreme lightness of Harbenite, the total weight of the ship was 75 tons, while the total lift of its vacuum tanks was 225 tons.
For purposes of maneuvering the ship and to facilitate landing, each of the vacuum tanks was equipped with a bank of eight air valves operated from the control cabin at the forward end of the keel; while six pumps, three in the starboard and three in the port engine corridors, were designed to expel the air from the tanks when it became necessary to renew the vacuum. Special rudders and elevators were also operated from the forward control cabin as well as from an auxiliary position aft in the port engine corridor, in the event that the control cabin steering gear should break down.
In the main keel cabin were located the quarters for the officers and crew, gun and ammunition room, provision room, galley, additional gasoline and oil storage tanks, and water tanks, the latter so constructed that the contents of any of them might be emptied instantaneously in case of an emergency, while a proportion of the gasoline and oil tanks were slip tanks that might be slipped through the bottom of the ship in cases of extreme emergency when it was necessary instantaneously to reduce the weight of the load.
This, then, briefly, was the great, rigid airship in which Jason Gridley and Tarzan of the Apes hoped to discover the north polar entrance to the inner world and rescue David Innes, Emperor of Pellucidar, from the dungeons of the Korsars.
II PELLUCIDAR
JUST BEFORE daybreak of a clear June morning, the O-220 moved slowly from its hangar under its own power. Fully loaded and equipped, it was to make its test flight under load conditions identical with those which would obtain when it set forth upon its long journey. The three lower tanks were still filled with air and she carried an excess of water ballast sufficient to overcome her equilibrium, so that while she moved lightly over the ground she moved with entire safety and could be maneuvered almost as handily as an automobile.
As she came into the open her pumps commenced to expel the air from the three lower tanks, and at the same time a portion of her excess water ballast was slowly discharged, and almost immediately the huge ship rose slowly and gracefully from the ground.
The entire personnel of the ship's company during the test flight was the same that had been selected for the expedition. Zuppner, who had been chosen as captain, had been in charge of the construction of the ship and had a considerable part in its designing. There were two mates, Von Horst and Dorf, who had been officers in the Imperial air forces, as also had the navigator, Lieutenant Mines. In addition to these there were twelve engineers and eight mechanics, a negro cook and two Filipino cabin-boys.
Tarzan was commander of the expedition, with Jason Gridley as his lieutenant, while the fighting men of the ship consisted of Muviro and nine of his Waziri warriors.
As the ship rose gracefully above the city, Zuppner, who was at the controls, could scarce restrain his enthusiasm.
"The sweetest thing I ever saw!" he exclaimed. "She responds to the lightest touch."
"I am not surprised at that," said Hines; "I knew she'd do it. Why we've got twice the crew we need to handle her."
"There you go again, Lieutenant," said Tarzan, laughing; "but do not think that my insistence upon a large crew was based upon any lack of confidence in the ship. We are going into a strange world. We may be gone a long time. If we reach our destination we shall have fighting, as each of you men who volunteered has been informed many times, so that while we may have twice as many men as we need for the trip in, we may yet find ourselves short handed on the return journey, for not all of us will return."
"I suppose you are right," said Hines; "but with the feel of this ship permeating me and the quiet peacefulness of the scene below, danger and death seem remote."
"I hope they are," returned Tarzan, "and I hope that we shall return with every man that goes out with us, but I believe in being prepared and to that end Gridley and I have been studying navigation and we want you to give us a chance at some practical experience before we reach our destination."
Zuppner laughed. "They have you marked already, Hines," he said.
The Lieutenant grinned. "I'll teach them all I know," he said; "but I'll bet the best dinner that can be served in Berlin that if this ship returns I'll still be her navigator."
"That is a case of heads-I-win, tails-you-lose," said Gridley.
"And to return to the subject of preparedness," said Tarzan, "I am going to ask you to let my Waziri help the mechanics and engineers. They are highly intelligent men, quick to learn, and if some calamity should overtake us we cannot have too many men familiar with the engines, and other machinery of the ship."
"You are right," said Zuppner, "and I shall
see that it is done."
The great, shining ship sailed majestically north; Ravensburg fell astern and half an hour later the somber gray ribbon of the Danube lay below them.
The longer they were in the air the more enthusiastic Zuppner became. "I had every confidence in the successful outcome of the trial flight," he said; "but I can assure you that I did not look for such perfection as I find in this ship. It marks a new era in aeronautics, and I am convinced that long before we cover the four hundred miles to Hamburg that we shall have established the entire air worthiness of the O-220 to the entire satisfaction of each of us."
"To Hamburg and return to Friedrichshafen was to have been the route of the trial trip," said Tarzan, "but why turn back at Hamburg ?"
The others turned questioning eyes upon him as the purport of his query sank home.
"Yes, why?" demanded Gridley.
Zuppner shrugged his shoulders. "We are fully equipped and provisioned," he said.
"Then why waste eight hundred miles in returning to Friedrichshafen ?" demanded Hines.
"If you are all agreeable we shall continue toward the north," said Tarzan. And so it was that the trial trip of the O-220 became an actual start upon its long journey toward the interior of the earth, and the secrecy that was desired for the expedition was insured.
The plan had been to follow the Tenth Meridian east of Greenwich north to the pole. But to avoid attracting unnecessary notice a slight deviation from this course was found desirable, and the ship passed to the west of Hamburg and out across the waters of the North Sea , and thus due north, passing to the west of Spitzbergen and out across the frozen polar wastes.
Maintaining an average cruising speed of about 75 miles per hour, the O-220 reached the vicinity of the north pole about midnight of the second day, and excitement ran high when Hines announced that in accordance with his calculation they should be directly over the pole. At Tarzan's suggestion the ship circled slowly at an altitude of a few hundred feet above the rough, snow-covered ice.
"We ought to be able to recognize it by the Italian flags," said Zuppner, with a smile. But if any reminders of the passage of the Norge remained below them, they were effectually hidden by the mantle of many snows.
The ship made a single circle above the desolate ice pack before she took up her southerly course along the 170th East Meridian .
From the moment that the ship struck south from the pole Jason Gridley remained constantly with Hines and Zuppner eagerly and anxiously watching the instruments, or gazing down upon the bleak landscape ahead. It was Gridley's belief that the north polar opening lay in the vicinity of 85 north latitude and 170 east longitude. Before him were compass, aneroids, bubble statoscope, air speed indicator, inclinometers, rise and fall indicator, bearing plate, clock and thermometers; but the instrument that commanded his closest attention was the compass, for Jason Gridley held a theory and upon the correctness of it depended their success in finding the north polar opening.
For five hours the ship flew steadily toward the south, when she developed an apparent tendency to fall off toward the west.
"Hold her steady, Captain," cautioned Gridley, "for if I am correct we are now going over the lip of the polar opening, and the deviation is in the compass only and not in our course. The further we go along this course the more erratic the compass will become and if we were presently to move upward, or in other words, straight out across the polar opening toward its center, the needle would spin erratically in a circle. But we could not reach the center of the polar opening because of the tremendous altitude which this would require. I believe that we are now on the eastern verge of the opening and if whatever deviation from the present course you make is to the starboard we shall slowly spiral downward into Pellucidar, but your compass will be useless for the next four to six hundred miles."
Zuppner shook his head, dubiously. "If this weather holds, we may be able to do it," he said, "but if it commences to blow I doubt my ability to keep any sort of a course if I am not to follow the compass."
"Do the best you can," said Gridley, "and when in doubt put her to starboard."
So great was the nervous strain upon all of them that for hours at a time scarcely a word was exchanged.
"Look!" exclaimed Hines suddenly. "There is open water just ahead of us."
"That, of course, we might expect," said Zuppner, "even if there is no polar opening, and you know that I have been skeptical about that ever since Gridley first explained his theory to me."
"I think," said Gridley, with a smile, "that really I am the only one in the party who has had any faith at all in the theory, but please do not call it my theory for it is not, and even I should not have been surprised had the theory proven to be a false one. But if any of you has been watching the sun for the last few hours, I think that you will have to agree with me that even though there may be no polar opening into an inner world, there must be a great depression at this point in the earth's crust and that we had gone down into it for a considerable distance, for you will notice that the midnight sun is much lower than it should be and that the further we continue upon this course the lower it drops—eventually it will set completely, and if I am not much mistaken we shall soon see the light of the eternal noonday sun of Pellucidar."
Suddenly the telephone rang and Hines put the receiver to his ear. "Very good, sir," he said, after a moment, and hung up. "It was Von Horst, Captain, reporting from the observation cabin. He has sighted land dead ahead."
"Land!" exclaimed Zuppner. "The only land our chart shows in this direction is Siberia ."
" Siberia lies over a thousand miles south of 85, and we cannot be over three hundred miles south of 85," said Gridley.
"Then we have either discovered a new arctic land, or we are approaching the northern frontiers of Pellucidar," said Lieutenant Hines.
"And that is just what we are doing," said Gridley. "Look at your thermometer."
"The devil!" exclaimed Zuppner. "It is only twenty degrees above zero Fahrenheit."
"You can see the land plainly now," said Tarzan. "It looks desolate enough, but there are only little patches of snow here and there."
"This corresponds with the land Innes described north of Korsar," said Gridley.
Word was quickly passed around the ship to the other officers and the crew that there was reason to believe that the land below them was Pellucidar. Excitement ran high, and every man who could spare a moment from his duties was aloft on the walkingway, or peering through portholes for a glimpse of the inner world.
Steadily the O-220 forged southward and just as the rim of the midnight sun disappeared from view below the horizon astern, the glow of Pellucidar's central sun was plainly visible ahead.
The nature of the landscape below was changing rapidly. The barren land had fallen astern, the ship had crossed a range of wooded hills and now before it lay a great forest that stretched on and on seemingly curving upward to be lost eventually in the haze of the distance. This was indeed Pellucidar—the Pellucidar of which Jason Gridley had dreamed.
Beyond the forest lay a rolling plain dotted with clumps of trees, a well-watered plain through which wound numerous streams, which emptied into a large river at its opposite side.
Great herds of game were grazing in the open pasture land and nowhere was there sight of man.
"This looks like heaven to me," said Tarzan of the Apes, "Let us land, Captain."
Slowly the great ship came to earth as air was taken into the lower vacuum tanks.
Short ladders were run out, for the bottom of the cabin was only six feet above the ground, and presently the entire ship's company, with the exception of a watch of an officer and two men, were knee deep in the lush grasses of Pellucidar.
"I thought we might get some fresh meat," said Tarzan, "but the ship has frightened all the game away."
"From the quantity of it I saw, we shall not have to go far to bag some," said Dorf.
"What we need most right now,
however, is rest," said Tarzan. "For weeks every man has been working at high pitch in completing the preparation for the expedition and I doubt if one of us has had over two hours sleep in the last three days. I suggest that we remain here until we are all thoroughly rested and then take up a systematic search for the city of Korsar ."
The plan met with general approval and preparations were made for a stay of several days.
"I believe," said Gridley to Captain Zuppner, "that it would be well to issue strict orders that no one is to leave the ship, or rather its close vicinity, without permission from you and that no one be allowed to venture far afield except in parties commanded by an officer, for we have every assurance that we shall meet with savage men and far more savage beasts everywhere within Pellucidar."
"I hope that you will except me from that order," said Tarzan, smiling.
"I believe that you can take care of yourself in any country," said Zuppner.
"And I can certainly hunt to better effect alone than I can with a party," said the ape-man.
"In any event," continued Zuppner, "the order comes from you as commander, and no one will complain if you exempt yourself from its provisions since I am sure that none of the rest of us is particularly anxious to wander about Pellucidar alone."
Officers and men, with the exception of the watch, which changed every four hours, slept the clock around.
Tarzan of the Apes was the first to complete his sleep and leave the ship. He had discarded the clothing that had encumbered and annoyed him since he had left his own African jungle to join in the preparation of the O-220, and it was no faultlessly attired Englishman that came from the cabin and dropped to the ground below, but instead an almost naked and primitive warrior, armed with hunting knife, spear, a bow and arrows, and the long rope which Tarzan always carried, for in the hunt he preferred the weapons of his youth to the firearms of civilization.
Tarzan at the Earth's Core p-4 Page 2
