The great ship with her nine tons burden was to have sailed from Bitterfeld to Frankfort, for the Aëronautical Exposition, but owing to excessive gales, she was sent by rail. Once there, she made many excursions, at times carrying passengers at a schedule rate, reported to be 200 marks for a voyage of one to two hours. In October she made an inter-city excursion covering a distance of nearly 500 miles, during which she passed four nights in the open air, finally returning in good form to Frankfort. On October 27th she made a farewell tour about Frankfort, then voyaged along the Main and down the Rhine valley to Cologne, there to participate in the aëronautic military maneuvers, together with the _Parseval I_, the _Gross II_ and the _Zeppelin II_. Having passed creditably through these and other operations in the autumn, she was eventually stationed at Tegel, as a part of the national fleet. The fourth _Parseval_, a smaller vessel, was built for the Deutscher Aëro Club early in 1909. Her hull cubed 113,000 feet, and her framing was made of the strongest materials, carefully hollowed, to eliminate undue weight. At the rear of the car, on either side, were two 100-horse engines, driving two _Parseval_ propellers at a common speed, whether both engines were in operation, or only one. In many respects she resembled her immediate predecessors, and her little successor _Parseval V_ of 1,200 cubic meters capacity and 30 meters length, built for the Imperial Automobile Club. The maneuvers at Cologne constituted the first grand demonstration of the new fleet of military dirigibles, and proved a severe test of the powers of the air ships, even when manned by experienced crews and commanded by regular military officers. Two companies of the balloon corps battalion were in attendance. Large provisions of hydrogen loaded on wagons, each carrying 100,000 cubic feet, were kept in readiness to be attached to an express train and rushed at the first alarm to any balloon in need of replenishing. On Sunday, October 31, three of the dirigibles representing each type, _Zeppelin IV_, _Parseval I_, _Gross II_, left Cologne together, by official order, and returned after flights of 7, 10 and 11 hours respectively, covering in the aggregate 930 miles. Again, leaving Cologne shortly before noon on November 3d, they went down the Rhine, simulated a concerted attack on the great fortress of Eherenbreitstein, and returned in the evening, each having covered 155 miles. And so on for many days they continued to execute maneuvers under military orders and in severe forced marches. CHAPTER VI DEVELOPMENT OF RIGID DIRIGIBLES