But her glory was short-lived. In the course of the Government trials, while some 900 feet aloft, the huge vessel suddenly exploded and was burned in the air, a mass of broken and twisted metal-work falling to the ground. Of the 28 officers and men, including members of the Admiralty Board who were conducting the official trials, all but one were killed outright, and the solitary exception was so terribly burned as to survive the fall for only a few hours.
The accident was remarkable and demonstrated very convincingly that although Count Zeppelin apparently had made huge strides in aerial navigation through the passage of years, yet in reality he had made no progress at all. He committed the identical error that characterised the effort of Severo Pax ten years previously, and the disaster was directly attributable to the self-same cause as that which overwhelmed the Severo airship. The gas, escaping from the balloons housed in the hull, collected in the confined passage-way communicating with the cars, came into contact with a naked light, possibly the exhaust from the motors, and instantly detonated with terrific force, blowing the airship to fragments and setting fire to all the inflammable materials.
In this airship Zeppelin committed an unpardonable blunder.
He had ignored the factor of "internal safety," and had deliberately flown in the face of the official rule which had been laid down in France after the Severo disaster, which absolutely forbade the inclusion of such confined spaces as Zeppelin had incorporated. This catastrophe coming so closely as it did upon the preceding disaster to the pride of the German aerial fleet somewhat shook public confidence in these craft, while aeronautical authorities of other countries described the Zeppelin more vehemently than ever as a "mechanical monstrosity"and a "scientific curiosity."
The Zeppelin has come to be feared in a general manner, but this result is due rather to stories sedulously circulated, and which may be easily traced to Teutonic sources. Very few data of a reliable character have been allowed to filter through official circles. We have been told somewhat verbosely of what it can accomplish and of its high degree of efficiency and speed. But can credence be placed in these statements?
When Zeppelin IV made its unexpected descent at Luneville, and was promptly seized by the French authorities, the German War office evinced distinct signs of uneasiness. The reason was speedily forth coming. The captain of the craft which had been captured forgot to destroy his log and other records of data concerning the vessel which had been scientifically collected during the journey. All this information fell into the hands of the French military department, and it proved a wondrous revelation. It enabled the French to value the Zeppelin at its true worth, which was by no means comparable to the estimate based on reports skilfully circulated for the benefit of the world at large.
Recently the French military department permitted the results of their expert official examination to be made public. From close investigation of the log-book and the diagrams which had been prepared, it was found that the maximum speed attained by Zeppelin IV during this momentous flight was only 45 miles per hour! It was ascertained, moreover, that the load was 10,560pounds, and the ascensional effort 45,100 pounds. The fuel consumption had averaged 297 pounds per hour, while the fuel tanks carried sufficient for a flight of about seven hours. The airship had attained a maximum height of about 6,230 feet, to reach which 6,600 pounds of ballast had to be discarded.
Moreover, it was proved that a Zeppelin, if travelling under military conditions with full armament and ammunition aboard, could carry sufficient fuel for only ten hours at the utmost, during which, if the slightest head-wind prevailed, it could not cover more than 340 miles on the one fuel charge.
This information has certainly proved a revelation and has contributed to the indifference with which the Parisians regard a Zeppelin raid. At the outbreak of war the Zeppelin station nearest to Paris was at Metz, but to make the raid from that point the airship was forced to cover a round 500 miles. It is scarcely to be supposed that perfectly calm weather would prevail during the whole period of the flight, so that a raid would be attended by considerable risk. That this handicap was recognised in German military circles is borne out by the fact that a temporary Zeppelin hangar was established at a point considerably nearer the French capital, for the purpose of enabling a raid to be carried out with a greater possibility of success.
The capture of Zeppelin IV revealed another important fact. The critical flying height of the airship is between 3,300 and 4,000feet. To attempt a raid at such an altitude would be to court certain disaster, inasmuch as the vessel would have to run the gauntlet of the whole of the French artillery, which it is admitted has a maximum range exceeding the flying altitude of the Zeppelin. That the above calculation is within reason is supported by the statements of Count Zeppelin himself, who has declared that his airships are useless at a height exceeding 5,000 feet. Confirmatory evidence upon this point is offered by the raid upon the British East Coast towns, when it is stated that the aircraft were manoeuvring at a height not exceeding 2,000 feet.
