early ballooning in the USA
Charles hydrogen balloon
Napoleonic military balloons
balloons in the US civil war
Military balloons 1850 - 1900
Santos Dumont
Henri Giffard
the Baldwin dirigible
balloons in World War 2
balloons to the stratosphere
record balloon flights
balloons and meteorology
science research and balloons
airships today

the hot air balloon

While some were dreaming of flying like a bird, others preferred to take it one step at a time and simply try to lift into the air. The idea of using Archimedes’ buoyancy principle to rise in the atmosphere by creating an object lighter than the air it displaces had been introduced in 1670 by a Jesuit priest, Father Francesco de Lana of Brescia, Italy. De Lana suggested (in print) that copper could be used to create spheres thin enough to be light- weight yet strong enough to be evacuated of all air, thereby making the total sphere lighter than the air the sphere displaced. The theory was sound, but producing sufficiently light spheres that would not collapse under the pressure of the air proved too difficult. In 1766, the British scientist Henry Cavendish discovered hydrogen gas (as the product of mixing iron, tin, zinc shavings, and sulfuric acid) and found it to be one-tenth the weight of air. This should have stirred someone to realize that hydrogen gas could be used to fill a balloon and the result would be a lighter-than-air object. Inexplicably, it did not, and the first balloons to fly were filled with hot air.

Barthelmy-Laurent de Gusman’s flying boat, from a 1709 engraving.  The craft was to be kept aloft by magnets in the two globes fore and aft. How this was to be accomplished was never explained.

Adding sulphuric acid to iron filings creates hydrogen, as illustrated by this eighteenth-century drawing.

In the mid-1770s, Joseph and Etienne Montgolfier, brothers who worked in their father’s paper factory in Annonay in South-Eastern France, noted that paper rose in the updrafts of the factory’s chimney, and occasionally a sheet would fold into a dome and continue rising even after leaving  the immediate area of the chimney. They conducted some simple experiments with silk bags and soon became convinced that a large bag with heated air inside would rise. In actuality, this effect had already been demonstrated nearly seventy-five years earlier by the Brazilian priest C Bartolomeu de Guasmao, who conducted a spectacular demonstration in the court of King John V in Lisbon, Portugal. But the Montgolfiers knew nothing of this demonstration, and they knew little about the reason their balloon rose into the air. They believed that the balloon was filled with a gas they called “Montgolfier gas” that had a special property they called “levity.” They did not even associate heated air with Montgolfier gas—they believed that the levity was contained in the smoke. Still, the Montgolfiers conducted their experiments and trials with care and learned much from each trial run.

After experimenting with smaller models, they constructed a large balloon of linen covered with stiff paper—prints of the time show a large blue ovoid, brightly decorated and held together with buttons—and conducted many trials, beginning on April 25, 1783 (the first known date), and culminating in a public demonstration in the town square of Annonay on June 5. Etienne was immediately summoned to Paris to address the Academy of Sciences about the brothers’ invention. Even before Etienne arrived, the French physicist Jacques Charles, mistakenly believing the Montgolfiers had used hydrogen in their ascent, hastily constructed a balloon of varnished silk, filled it with hydrogen (an expensive chemical procedure on such a large scale), and launched it from the Champs de Mars, Paris, on August 27. It rose through heavy rains that fell that day and was carried away by the storm to the village of Gonesse some fifteen miles (24km) away, where it finally came to rest.

The superstitious peasants of the village, believing the balloon to be a monster that was attacking them from the sky, proceeded to rip it to shreds with scythes and pitchforks. The flight of the first “Charliere,” as hydrogen-filled balloons  were to be called for many years afterwards, had therefore been a qualified success. The Montgolfier brothers then built an even larger balloon—some seventy feet (21m) high—equipped with a circular gallery for the aeronauts. Two adventurers, Jean-Francois Pilatre de Rozier and Francois Laurent, Marquis d’Arandes, volunteered for the flight, which was prepared for and anticipated with the same nail-biting nervousness that characterized the first manned rocket launches of modern times.

Tests were conducted with animals to determine what possible ill effects there might be on living beings, and then, beginning on October 15, tethered flights with humans were conducted from the courtyard of the Palace of Versailles. On November 21, the same pair made a free (un-tethered) flight in their Montgolfier, landing about ten miles (16km) away about twenty-three minutes after launching. That event is often considered the first time humankind flew.

The Charles hydrogen balloon, which was launched on August 27, 1783, was ripped to shreds by the fearful townsmen of Gonesse

On December 1, Charles and his associate, Nicolas Robert launched a new hydrogen balloon from the Tuileries Gardens. They landed twenty-seven miles (43.5km) away after a flight of two hours, and except for the fact that the balloon took off again with Charles when Robert abruptly jumped out of the gondola after their first landing (only to land several miles away), filling a balloon with hydrogen was quickly seen as the superior method: it did not require constant attention to a heat source to warm the air (and anyway, the heat source was a smoky mess since the Montgolfiers refused to accept Charles’ instruction that it was merely the heated air that was carrying their craft aloft and not the smoke). The explosive nature of hydrogen was not to become important until years later, when very large volumes of hydrogen were placed in close proximity to flames and sparks.

The throng that gathered to watch the historic flight of Montgolfier’s crewed balloon on November21 was less superstitious.

The French wasted no time exploiting the new technology. Eleven years later, in France’s war with Austria, tethered balloons were used in the siege of Mainz and were decisive at the Battle of Fleurus. The captain of the Company of Aerostiers was a man named Coutelle, a shadowy figure who was ridiculed for espousing the use of balloons on the battlefield. After France’s victory, he became a national hero. De Lana had foreseen the possible military uses of his flying evacuated copper globes, and feared flight for “the disturbance it would cause to the civil government of men.” It took more than a century, but his words proved prophetic.