Later, as they began making cloth balloons, they observed that by launching progressively larger balloons, they were able to achieve higher altitudes and they could lift additional payload. In June 1783, from the public square in Annonay, they released the largest balloon they had built to date. It floated skyward for about ten minutes before descending to earth.
With that achievement, they concluded that it was time to launch a balloon that carried people. First, though, in September 1783, thousands of spectators gathered at Versailles to witness the release of a balloon with a rooster, a duck, and a sheep on board. All three survived the eight-minute flight with no ill effects. Shortly thereafter, on November 21, 1783, the first flight with humans on board was attempted. Louis XVI was persuaded to allow two noblemen to have the honor. They were launched from Château de la Muette and floated over Paris for about five miles [8 km]. After about 25 minutes, they made a forced landing when the balloon caught fire.
About this time, the Academy of Sciences in Paris showed interest in this invention. Professor Jacques Charles, one of the best-known physicists of the day, collaborated with two clever mechanics, Charles and M. N. Robert, and built the first hydrogen-filled balloon, testing it on August 27, 1783. It floated for 45 minutes, covering about 15 miles [24 km], and became known as a Charlière. This type of balloon remains in use to this day in almost its original form.