The balloon frame was divided into seventeen compartments, each of which held a ballonet filled with hydrogen gas. The purpose of this was similar to the practice of dividing a ship's hulls into compartments. If one or more of the ballonets, for any reason, were injured the remainder would keep the ship afloat. The space between the ballonets and the outer skin was pumped full of air to keep the latter taut and rigid. Moreover it helped to prevent the radiation of heat to the gas bags from the outer envelope whose huge expanse, presented to the sun, absorbed an immense amount of heat rays.
Two cars were suspended from the frame of the Zeppelin, forward and aft, and a corridor connected them. A sliding weight was employed to raise or depress the bow. In each car of the first Zeppelin was a sixteen-horse-power gasoline motor, each working two screws, with four foot blades, revolving one thousand times a minute. The engines were reversible, thus making it possible to work the propellers against each other and aid materially in steering the ship. Rudders at bow and stern completed the navigating equipment.
In the first Zeppelins, the corridor connecting the two cars was wholly outside the frame and envelope of the car. Later the perilous experiment was tried of putting it within the envelope. This resulted in one of the most shocking of the many Zeppelin disasters. In the case of the ship L-II., built in 1912, the corridor became filled with gas that had oozed out of the ballonets. At one end or the other of the corridor this gas, then mixed with air, came in contact with fire,--perhaps the exhaust of the engines,--a violent explosion followed while the ship was some nine hundred feet aloft, and the mass of twisted and broken metal, with the flaming envelope, fell to the ground carrying twenty-eight men, including members of the Admiralty Board, to a horrible death.
But to return to the first Zeppelin. Her trial was set for July 2, 1900, and though the immediate vicinity of the floating hangar was barred to the public by the military authorities, the shores and surface of the lake were black with people eager to witness the test. Boats pulled out of the wide portal the huge cigar-shaped structure, floating on small rafts, its polished surface of pegamoid glittering in the sun. As large as a fair-sized ocean steamship, it looked, on that little lake dotted with pleasure craft, like a leviathan. Men were busy in the cars, fore and aft. The mooring ropes were cast off as the vessel gained an offing, and ballast being thrown out she began to rise slowly. The propellers began to whir, and the great craft swung around breasting the breeze and moved slowly up the lake. The crowd cheered. Count von Zeppelin, tense with excitement, alert for every sign of weakness watched his monster creation with mingled pride and apprehension. Two points were set at rest in the first two minutes--the lifting power was great enough to carry the heaviest load ever imposed upon a balloon and the motive power was sufficient to propel her against an ordinary breeze. But she was hardly in mid-air when defects became apparent. The apparatus for controlling the balancing weight got out of order. The steering lines became entangled so that the ship was first obliged to stop, then by reversing the engines to proceed backwards. This was, however, a favourable evidence of her handiness under untoward circumstances. After she had been in the air nearly an hour and had covered four or five miles, a landing was ordered and she dropped to the surface of the lake with perfect ease. Before reaching her shed, however, she collided with a pile--an accident in no way attributable to her design--and seriously bent her frame.
The story told thus baldly does not sound like a record of glorious success. Nevertheless not Count Zeppelin alone but all Germany was wild with jubilation. Zeppelin I. had demonstrated a principle; all that remained was to develop and apply this principle and Germany would have a fleet of a๋rial dreadnoughts that would force any hostile nation to subjection. There was little or no discussion of the application of the principle to the ends of peace. It was as an engine of war alone that the airship appealed to the popular fancy.
But at the time that fancy proved fickle. With a few repairs the airship was brought out for another test. In the air it did all that was asked for it, but it came to earth--or rather to the surface of the lake--with a shock that put it out of commission. When Count Zeppelin's company estimated the cost of further repairs it gave a sigh and abandoned the wreck. Thereupon the pertinacious inventor laid aside his tools, got into his old uniform, and went out again on the dreary task of begging for further funds.
