CHAPTER XIII
An Experiment with a Zeppelin
"LOOK slick!" hissed Detroit. "Don't stand there looking in the air."
The American's words roused Hamerton to action. Quickly he descendedbelow the level of the floor of the turntable, the flap fell with adull thud, and the two fugitives found themselves in darkness, savefor a faint circle of light where the exterior glare filtered throughthe narrow space between the round platform and the edge of the pitin which it stood.
Then came the tramp of many feet. Not knowing whether they had been"spotted" by a keen-eyed sentry, Hamerton and his comrade remained onthe thorns of expectancy. Alternate hopes and fears flashed acrosstheir minds in quick succession. Detroit was mentally bemoaning therashness that prompted Hamerton to suggest the exploration of theaircrafts' subterranean shelter instead of making for the base of thecliffs; while the latter regretted that he had not been able tocontinue his nocturnal tour of investigation.
Yet, although men were running hither and thither, none came acrossthe floor of the turntable. Trucks were rumbling along the tramlines, men were shouting in guttural tones, electric motors werewhizzing and buzzing. The place, hitherto practically deserted,resembled a gigantic beehive.
"They are not looking for us," whispered the Sub. "They are evidentlygetting one of the Zeppelins ready for a flight. I hope we won't bedisturbed. We may as well have a tour round our limited quarters, tomake ourselves acquainted with our hiding place."
"Go steady," cautioned Detroit.
"Trust me for that," rejoined Hamerton, "We don't want to electrocuteourselves, or start the turntable spinning round at the rate ofknots."
"Like a new form of joy-wheel," added the American. "It would be abit of a joke to see the soldiers attempting to reach the traphatchwith the platform spinning round at twenty miles an hour."
Their eyes were now getting accustomed to the gloom, for there was afair amount of reflected light that at first was almost unnoticeableafter the powerful glare without.
The place of refuge was certainly expansive, but much of the spacewas taken up with complicated machinery. The turntable itself workedon steel rollers set in a "race", the upper bearing surfaceconsisting of steel skeleton trestles, which in turn supported therevolving platform. Between the latter and the edge of the circularconcrete wall was a width of less than eight inches, insufficient toallow a man to crawl through. The only means of gaining the machinerychamber was by the two trapdoors.
"Shall we barricade the hatchways?" asked Detroit.
"No use," replied Hamerton. "It would only arouse suspicion. Then weshould either be starved out or run the risk of being potted, for thefloor is not proof against rifle fire. No, the best thing we can dois to keep quiet. Should anyone come we must endeavour to dodgebehind some of this gear."
"Guess I'm getting precious hungry," remarked the American.
"Now you mention it I begin to have a sinking sensation: a kind offamine and hunger strike rolled into one. But we can't go too strongin the provision line."
Six half-slices of rye bread, two small pieces of cold meat, andabout a pound of fish formed the sum total of the commissariat,barely sufficient, even with stringent economy, to last overtwenty-four hours.
The food, after reposing in their pockets, was not pleasing to theeye, but adverse circumstances settled all qualms. Both men ate withavidity, though sparingly.
At length daylight gained the mastery over artificial lighting, andthe arc lamps were extinguished. With the morning the rain ceased andthe wind dropped.
Peering through the gap between the turntable and the encirclingwall, Hamerton could see the sun shining upon the upper portion ofthe red sandstone cliffs that enclosed the vast artificial basin. Hisfield of vision was limited, but he was able to come to theconclusion that the floor of the airship sheds was nearly two hundredfeet below the surface of the tableland that comprised the major partof the island.
Between each pair of caverns constructed for the accommodation of theZeppelins was an iron ladder running perpendicularly up the sheerwall of sandstone. These were connected by an open lattice platformjust above the crown of the arch formed by the caves, and wereevidently for the purpose of facilitating the movements of theairships when entering or leaving their bases. Curiously enough, bothHamerton and Detroit had previously failed to notice these ladderswhen making a circuit of the basin.
"They are naval airships," announced the Sub, for men were swarmingup and down the ladders with a seeming recklessness that only seamandare show, and they were wearing the uniforms of the German ImperialNavy.
"Here she comes," said Detroit, as the huge bulk of a Zeppelinemerged slowly yet steadily from its resting place.
"What a superb target!" commented the Sub. "A dose of shrapnel wouldknock the whole concern to smithereens, while one of our seaplaneswith a one-pounder automatic gun would make rings round her."
"I don't know so much about that," said Detroit. "Just look at thealuminium body just abaft the 'midship car. It's been holed at onetime, and they've put a patch on it."
"An accident, perhaps," rejoined Hamerton. "The airship looks ratherold."
Over the heads of the two watchers passed the unwieldy craft. Nowthey could hear the jar of the framework as it settled on theturntable. Then, with hardly a sound and barely a tremor, theplatform began to move until the bows of the Zeppelin pointed in thedirection of the great incline. The six propellers began to revolve,and the airship, gathering way, rose rapidly and steadily, keepingalmost parallel with the slope. Then, gaining an altitude of nearlyfive hundred feet, she circled slowly and disappeared beyond thelimits of the vision of the two spectators in the pit.
Within a quarter of an hour of its leaving the cave the Zeppelinreturned to earth. Anchored fore and aft it strained and staggered inthe still strong wind. The officers and crew descended by means of arope ladder, then the holding ropes were cast off and the aircraftbounded upwards. Hamerton could see that it was still connected withthe ground by a flexible steel rope. The propellers were revolvingand the rudders set hard over, consequently the Zeppelin wasdescribing circles in the air at a height of a little over fivehundred feet.
"What's the game?" asked the Sub.
The words were hardly out of his mouth when the sharp, rapiddetonations of a pom-pom were heard. Almost simultaneously with thescreech of the projectiles sinister dark marks appeared on thealuminium cover of the Zeppelin; yet to the Sub's surprise theone-pounder shells without exception did not burst, neither did theairship appear to lose its reserve of buoyancy.
For nearly fifteen seconds the firing continued. Nearly four timesthat number of projectiles had been fired, many of the shot-holesoverlapping each other.
Upon the conclusion of this severe test the Zeppelin was broughtdown, and, controlled by about fifty men holding guide ropes, wastaken down the incline.
As it neared the turntable Hamerton was able to come to someconclusion as to the nature of the self-closing material surroundingthe ballonettes. In one place the havoc wrought by the concentrationof several projectiles had completely torn off a strip of aluminiummeasuring roughly two feet six inches by two feet. Within the cavitycould be seen the inner lining of aluminium, which had been badlyperforated, thus releasing all the hydrogen from that particularballonette. At the edges of the perforations a substance resemblingdirty cotton waste had been forced out. Only the width of the fissureprevented the closing up of the textile fabric.
As the Zeppelin was being guided on to the turntable a fragment ofthe plugging material fluttered to the ground. A breeze caught it andswept it towards the edge of the turntable pit. There it stopped,provokingly out of reach even if the Sub had dared to stretch out hishand to grasp it.
Just then one of the sailors manning the trail ropes kicked the pieceof packing. It fell literally into Hamerton's hands.
Hamerton and his comrade exchanged glances of satisfaction. Theydared not speak. They realized that they had made a great discovery.
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Directly the experimental airship was safely housed the men inattendance were marched off, presumably to breakfast, and theoccupants of the machinery pit were able to discuss their find.
"It's cotton waste, right enough," said Hamerton.
"And asbestos fibre," said Detroit, plucking out a piece of core. "Isuppose that renders the waste non-inflammable?"
"Hardly," replied the Sub. "Besides, how do you account for the stuffbeing gas-proof? It's as porous as a sponge."
Detroit put a small quantity of the stuff between his teeth.
"Ugh!" he exclaimed. "There's alum in it, and gum arabic in a viscousstate, only this piece has got slightly dry. I guess I see the trick.They pack the space between the outer and inner skins with the stuffunder pressure. There is not sufficient resistance to cause the shellto explode, therefore the projectile passes completely through,making only a small aperture that instantly closes behind. They madea severe test, for the Zeppelin was practically a captive balloon.Had she been travelling at from thirty to fifty knots at an uncertainrange it would have been a difficult matter to get a shot home."
"Do you know what they were firing with?" asked Hamerton.
"A pom-pom, I should imagine."
"Yes, firing a one-pound shell, almost the identical weapon we mounton our seaplanes. Every blessed experiment these Germans make seemsdirected solely against the recognized means of offence adopted bythe British Government."
"Shrapnel's the thing."
"Aye, coarse-charged with irregular pieces of metal in the place ofthe bullets used in shells when directed against troops. TheseZeppelins, with their non-explosive hydrogen and their fireproof,shot-closing envelopes will be a tough nut to crack in the next war,I fancy. Look here, Detroit, old man, this stuff's worth keeping.We'll divide it into four parts, and wear it in our shoes like corksocks; then, if we are collared, we may stand a chance of keeping itin our possession."
While the two friends were thus engaged the dull boom of a gun firedthrice in quick succession struck their ears. This was followed by abugle-call that Hamerton recognized as the "Assembly" of the GermanArmy. This was taken up in other parts of the island till the wholegarrison was aroused.
Hamerton glanced at his watch. It was just after seven o'clock, atwhich hour their jailers were wont to bring in the prisoners'breakfasts.
"They've discovered we've broken ship," he said. "Hans and companyhave found that our cells are empty. Now comes the fun."
It seemed as if the caves in the sandstone cliffs surrounding theZeppelin station disgorged human beings, for within a few seconds ofthe alarm being given two hundred men were drawn up in divisions,while their officers were discussing amongst themselves the probablereason for the unexpected summons.
Up ran a portly sergeant-major. He was almost out of breath, yet hespoke in such a loud voice that the Sub was able to interpret everyword.
"A message has just come through on the telephone, Herr Major," heannounced; "those rascally English spies have escaped. The generalorders are that all commanding officers shall post double sentriesover all confidential posts; the rest of the men are to be employedin the search. No leave is to be granted until the spies arerecaptured."
The major shrugged his shoulders. He was not at all pleased with thetelephone message, since he had arranged to spend the followingSunday at Flensburg.
"Why have we not turned out the bloodhounds, sir?" asked a captain."The scent must be hot."
"Ach, I know not!" was the reply.
"All the dogs were taken across to Sandinsel yesterday, Herr Major,"announced another officer, a tall, fair-haired subaltern. "ColonelDietrich wished to try the hounds on a trail laid on the sand."
"And, as a result, we have two English spies roaming over theisland," added the major. Then, giving the order to march, he led thefour companies under his command up the steep incline. "Now the funcommences," observed Detroit, when all seemed quiet once more. "Thankgoodness they have no suspicions that we made our way here!"
"And it's lucky for us that the bloodhounds are away," rejoinedHamerton. "One never knows; they might be able to follow a trail inspite of a couple of ounces of pepper."
Before Detroit could express his opinion a deep baying sound camefrom the heights above.
Both men looked at each other as if to say: "We counted our chickensbefore they were hatched;" then, without a word, they made their wayto a different part of their place of concealment whence they couldcommand a view of the summit of the artificial cliffs.
Standing out clearly against the white drifting clouds were fourlarge hounds. With their noses almost touching the ground they moveddeliberately and unhesitatingly, while behind them walked a number ofofficers and men, the latter armed with rifles and bayonets.
The bloodhounds, keeping close to the brink of the abyss, graduallyapproached the spot where the inclined plane met the level ground ofthe tableland. Here they paused but for a brief instant; then theybegan to trot straight towards the fugitives' hiding place.
"They've tracked us right enough," muttered the Sub dejectedly.