The non-rigid auto balloon ordered from Clément, and afterwards known as the _Clément-Bayard II_, was the masterpiece of that skilful designer, and occupied his best thought and energy for eighteen months, aided by his devoted and capable engineer, Sabathier. She was completed in the Clément-Bayard factory at Lamotte-Breuil in April, 1910, and during the next five months made thirty-two test ascensions and practice voyages. In particular she took a conspicuous part in the military maneuvers at Picardie during the early half of September, where with wonderful precision and airworthiness she made forced voyages in fair weather and foul, remaining, when so desired, in continuous communication with the land office by means of wireless telegraphy. Finally, on a fair day, September 16th, the tried and perfected vessel was brought forth from her hangar for the long contemplated voyage to London, her machinery and rigging in trimmest order, and her car furnished with supplies for twenty hours, or thrice the anticipated time of transit. The voyage was a glorious achievement for aëronautics, and for the enthusiastic constructor and his devoted aids. Starting at seven o’clock in the morning, with seven men aboard, including happy Clément, Sabathier, and an English delegate, the whalelike cruiser sailed directly to London with admirable regularity, covering the entire distance of 242 miles in six hours, or at the rate of forty miles an hour, which is better time than could be made by land and water. Enthusiastic cheers from the English spectators greeted the arrival of this French dirigible, built for the English government. Then quietly the English soldiers took the vessel in hand, as if performing a familiar duty, and housed her in the _Daily Mail_ hangar, at Wormwood Scrubs. Thus simply and without unusual incident terminated the first motor-balloon cruise between the two countries, and one of the finest voyages in the history of aëronautics.