Louis Blériot of 1909. Like some of the other prizes offered by the paper, it was widely seen as nothing more than a way to gain cheap publicity: the Paris newspaper "Le Matin" commenting that there was no chance of the prize being won. The English Channel had been crossed by an unmanned hydrogen balloon in 1784 and a manned crossing by Jean-Pierre Blanchard and John Jeffries followed in 1785. Blériot, who intended to fly across the Channel in his Type XI monoplane, had three rivals for the prize, the most serious being Hubert Latham, a French national of English extraction flying
Hot air balloon course) stated in the previous section. Liftoff would require a slightly greater temperature, depending on the desired rate of climb. In reality, the air contained in the envelope is not all the same temperature, as the accompanying thermal image shows, and so these calculations are based on averages. For typical atmospheric conditions (20 °C, 68 °F), a hot air balloon heated to (99 °C, 210 °F) requires about 3.91 m³ of envelope volume to lift 1 kilogram (62.5 ft³/lb). The precise amount of lift provided depends not only upon the internal temperature mentioned above, but the external temperature, altitude above