The Montgolfier Brothers

The Montgolfier Brothers

               













Joseph-Michel (August 26, 1740-June 26, 1810) and Jacques-Étienne (January 6, 1745-August 2, 1799) Montgolfier [mahnt gahl'fi er] were paper manufacturers who also had a lively and informed interest in scientific matters. Both were responsible for innovations in the paper-making process.
Joseph was familiar with the researches into gases that Joseph Priestley was currently undertaking in England. He was also aware of the discovery of hydrogen by Henry Cavendish in 1766, and of the implication that a gas which is 14 times as light as air could be made to lift a load if trapped inside an airtight membrane. The production of hydrogen in any quantity had not yet been achieved, however, and it was difficult to find a suitable leak-proof material. The brothers therefore concentrated on the hot-air principle, believing that gases in the smoke from a fire could cause a balloon to rise.
In November 1782, Joseph built a box-like chamber (3'x3'x4') out of thin wood and covered the sides and top with taffeta cloth. Under the bottom of the box he crumpled and lit some paper. The box lifted off its stand and promptly collided with the ceiling. Joseph then recruited his brother to help with his experiments. In December he repeated his experiment out of doors, with his entire family as witnesses. This time his box-like balloon went 70 feet into the air and remained aloft for a full minute.
Joseph and Jacques then set about building a contraption three times larger in scale. The lifting force was so great that they lost control of their craft on its very first flight, on December 14, 1782. The "balloon" floated about 1.5 miles before crash landing in the village of Gonesse. The alarmed inhabitants, thinking that it was the skin of a monstrous animal, attacked it with pitchforks and stones, destroying it.
Given these initial successes, the brothers were now prepared to make a public demonstration of their "balloon" in order to establish their claim to its invention. They built a globe-shaped balloon of sackcloth with three thin layers of paper inside that could hold almost 28,000 cubic feet of air. On June 5, 1783, they flew this craft at Annonay in front of a group of dignitaries. The flight covered about 1.5 miles, lasted 10 minutes, and reached an altitude of about 6,000 feet.
When news of the Montgolfiers' successful flight reached Paris, the Academy of Sciences immediately invited the brothers to set up a demonstration. In collaboration with a wallpaper manufacturer, the brothers constructed a 37,500 cubic foot envelope of taffeta coated with varnish and covered in bright colors. The craft was launched from the Palace of Versailles on September 19, 1783, before a huge crowd that included King Louis XVI and Queen Marie Antoinette. Because the effects of traveling in a balloon were unknown, the Montgolfiers decided to make a duck, a cock, and a sheep be the first passengers. The 41-foot-diameter baloon reached an altitude of 1,700 feet before descending gently into the forest about two miles away, after a flight of approximately 8 minutes. The animal passengers were unharmed, except that the sheep had kicked one of the cock's wings and damaged it slightly.
The way was now clear for a man to make the first balloon ascent. However, Pierre Montgolfier, father of the brothers, had given his permission for his sons to work on balloons rather than in the family paper-making business only on the condition that neither of the brothers ever go aloft in a balloon themselves. In addition, the king insisted that any passengers should be criminals whose lives were expendable. Fortunately, the king's historian, a young scientist named Jean-Françoise Pilâtre de Rozier, was able to overcome the king's decree and was chosen to be the passenger in a series of tethered test flights.
By now the fire was slung under the neck of the balloon in an iron basket, and could be controlled and replenished by the balloonists. The diameter of the balloon had grown to almost 50 feet. For the first untethered flight, which took place on November 21, 1783, Pilâtre de Rozier was joined by the Marquis d'Arlandes. In 25 minutes the two men traveled just over five miles. Enough fuel remained on board at the end of the flight to have allowed the balloon to fly four to five times as far, but burning embers from the fire threatened to engulf the balloon and the men decided to land as soon as they were over open countryside.
The Montgolfiers continued to improve their hot-air balloon, but the future of ballooning lay with the hydrogen balloon, invented and perfected by Jacques-Alexandre-César Charles in 1783.