The German Government now made an offer of $500,000 for an airship which would remain continuously in the air for 24 hours, and be able to land safely. Count von Zeppelin immediately began work upon his No. IV, in the effort to meet these requirements, in the meantime continuing trips with No. III. The most remarkable of these trips was made in September, 1907, a journey of 211 miles in 8 hours. In October, 1907, the English airship “Nulli Secundus” was given its first trial. The gas envelope had been made of goldbeater’s skins, which are considered impermeable to the contained gas, but are very expensive. This airship was of the non-rigid type. It made the trip from Aldershot to London, a distance of 50 miles, in 3½ hours--an apparent speed of 14 miles per hour, lacking information as to the aid or hindrance of the prevailing wind. Several other trials were made, but with small success. The offer of the German Government had stimulated other German builders besides Count von Zeppelin, and on October 28, 1907, the Parseval I, which had been improved, and the new Gross dirigible, competed for the government prize, at Berlin. The Parseval kept afloat for 6½ hours, and the Gross for 8¼ hours. Meanwhile, in France, the Lebaudys had been building a new airship which was named “La Patrie.” It was 197 feet long and 34 feet in diameter. In a trial for altitude it was driven to an elevation of 4,300 feet. On November 23, 1907, the “Patrie” set out from Paris for Verdun, a distance of 146 miles. The journey was made in 6¾ hours, at an average speed of 25 miles per hour, and the fuel carried was sufficient to have continued the journey 50 miles further. Soon after reaching Verdun a severe gale tore the airship away from the regiment of soldiers detailed to assist the anchors in holding it down, and it disappeared into the clouds. It is known to have passed over England, for parts of its machinery were picked up at several points, and some days later the gas-bag was seen floating in the North Sea. [Illustration: The “Ville-de-Paris” of M. de la Meurthe.] Following close upon the ill-fated “Patrie” came the “Ville-de-Paris,” a dirigible which had been built by Surcouf for M. Henri Deutsch de la Meurthe, an eminent patron of aeronautic experiments. In size this airship was almost identical with the lost “Patrie,” but it was quite different in appearance. It did not have the flat framework at the bottom of the gas envelope, but was entirely round in section, and the long car was suspended below. At the rear the gas-bag was contracted to a cylindrical form, and four groups of two ballonnets each were attached to act as stabilizers. It was offered by M. de la Meurthe to the French Government to take the place of the “Patrie” in the army manœuvres at Verdun, and on January 15, 1908, made the trip thither from Paris in about 7 hours. It was found that the ballonnets exerted considerable drag upon the ship.