zur Förderung der Luftschiffahrt (Society for the Promotion of Airship Flight), contributing more than half of its 800,000 mark share-capital himself. Responsibility for the detail design was given to Kober, whose place was later taken by Ludwig Dürr, and construction of the first airship began in 1899 in a floating assembly-hall or hangar in the Bay of Manzell near Friedrichshafen on Lake Constance (the Bodensee). The intention behind the floating hall was to facilitate the difficult task of bringing the airship out of the hall, as it could easily be aligned with the wind. The LZ 1 (LZ for Luftschiff Zeppelin, or "Zeppelin Airship") was long with a hydrogen capacity of , was driven by two Daimler engines each driving a pair of propellers mounted either side of the envelope via bevel gears and a driveshaft, and was controlled in pitch by moving a weight between its two nacelles. The first flight took place on 2 July 1900 over Lake Constance. Damaged during landing, it was repaired and modified and proved its potential in two subsequent flights made on 17 and 24 October 1900, bettering the 6 m/s (21.6 km/h, 13.4 mph) velocity attained by the French airship La France. Despite this performance, the shareholders declined to invest more money, and so the company was liquidated, with Count von Zeppelin purchasing the ship and equipment. The Count wished to continue experimenting, but he eventually dismantled the ship in 1901. Donations, the profits of a special lottery, some public funding, a mortgage of Count von Zeppelin's wife's estate, and a 100,000 mark contribution by Count von Zeppelin himself allowed the construction of LZ 2, which made only a single flight on 17 January 1906. After both engines failed it made a forced landing in the Allgäu mountains, where a storm subsequently damaged the anchored ship beyond repair. Incorporating all the usable parts of LZ 2, its successor LZ 3 became the first truly successful Zeppelin. This renewed the interest of the German military, but a condition of purchase of an airship was a 24-hour endurance trial. This was beyond the capabilities of LZ 3, leading Zeppelin to construct his fourth design, the LZ 4, first flown on 20 June 1908. On 1 July it was flown over Switzerland to Zürich and then back to Lake Constance, covering 386 km (240 mi) and reaching an altitude of 795 m (2,600 ft). An