Those Montgolfiers and their balloons

This weekend marks the 200th anniversary of the death of Joseph-Michel Montgolfier (26 August 1740–26 June 1810), who, with his younger brother Jacques-Étienne, succeeded in launching the first manned ascent in a hot-air balloon.

Some sources say that Joseph became interested in flight when his shirt (or possibly his wife’s dress) took off when placed in front of a fire to air. Others say that when someone threw a paper bag onto a fire he observed it to fill with hot air and fly up the chimney without igniting.

However, Joseph himself claimed that his urge to experiment was inspired by reading the French translation of Joseph Priestley’s book, ‘Experiments and observations on different kinds of air’.

During one early experiment, in November 1782, Joseph held burning paper beneath a small envelope of silk, which inflated and rose to the ceiling of his apartment.

At first the brothers did not appreciate the lifting power of hot air. They thought they had discovered a new gas, “Montgolfier air”, and experimented with various fuels, including old shoes and decomposed meat, to find the best way to make it.

Fortunately, as the fuel for the first public demonstration of their invention, they used a mixture of damp straw, chopped wool and rags soaked in spirits of wine. On 5 June 1783 an incredulous crowd watched as their balloon — made from panels of cloth lined with paper fastened together with buttons and buttonholes — soared soundlessly into the sky, landing gently about a mile-and-a-half away.

The news about Montgolfier’s experiments swiftly reached Paris, where some members of the Académie des Sciences decided to construct a rival balloon of rubberised silk filled with the “inflammable air” (later named hydrogen) discovered by Henry Cavendish. The Montgolfier brothers had tried but rejected this gas because it passed easily through their paper and cloth fabric.

On 27 August 1783, following a long struggle to generate sufficient hydrogen, the Académie’s balloon took off from near where the Eiffel Tower now stands. It landed about 15 miles from Paris, where terrified villagers tore it apart with pitchforks in the belief that a fearful monster had landed among them.

Then, on 19 September 1783, in the presence of King Louis XVI and Marie Antoinette, the Montgolfiers launched a balloon to which was attached a wicker cage holding a sheep, a duck and a cockerel. The balloon landed two miles away but, whereas the sheep and the duck arrived safely, the cockerel had a damaged wing. This caused some consternation among those who believed flying would be dangerous to human life. Fortunately several witnesses testified that the sheep had kicked the cockerel as the balloon took off.

The stage was set for the first manned flight. The king reluctantly agreed but only if the passengers were criminals. He even offered to pardon them in the unlikely (he thought) event that they could survive the experiment. Montgolfier’s supporters were outraged that the glory of making the first flight should go to such people.

The king relented and on 21 November 1783, just one year after those early experiments, two eager volunteers, Jean-François Pilâtre de Rozier and the Marquis d’Arlandes, made the first manned flight in a hot-air balloon. The first manned flight in the hydrogen-filled balloon took place 10 days later.