World of Chemistry on Jacques-Alexandre-César Charles
Jacques-Alexandre-César Charles is famous for his contribution to ballooning, (the science of aerostation). He was the first to use hydrogen ("inflammable air") instead of hot air in an aeronautical balloon, and designed and developed almost all the essential components of a balloon so perfectly that few changes or additions have been made in the ensuing 200 years of ballooning.
Charles was born in Beaugency on November 12, 1746. The only information surviving about his childhood is that he received a liberal education with no scientific focus. When he moved to Paris, he worked at the bureau of finances and in 1799 became interested in nonmathematical, experimental physics. By 1781, he began giving public lectures and experimental demonstrations, attracting a large number of attendees, among them people who had already achieved considerable notoriety. He was ultimately appointed a resident member of the Académie de Sciences in 1795. He also became professor of experimental physics and librarian at the Conservatoire de Arts et Métiers and, in 1816, president of the Class of Experimental Physics at the academy. In 1804, he married Julie- Françoise Bouchard des Hérettes, who died in 1817 after suffering from a long illness.
Charles' association with ballooning began when, in 1782, Joseph Montgolfier (1740-1810) discovered that hot air entering a paper bag held over an open fire made the bag rise to the ceiling. He and his brother, Étienne (1745-1799), experimented with larger "envelopes" and, on April 25, 1783, launched a balloon large enough that it was considered capable of carrying a person. On June 4 they successfully launched, from Annonay in France, a manned balloon made of linen covered with paper. Their creation, called montgolfières, consisted of an open fire hanging in a cage under the basket. The fire had to be fed by the pilot for the balloon to remain afloat.
News of the Montgolfier's experiment quickly reached Paris and the French Academy of Science assigned Charles the task of studying the invention. He had already learned of a recent scientific discovery by British scientist Henry Cavendish of a gas 14 times lighter than air and which was being called "flammable air." (It would ultimately be named hydrogen.)
Hydrogen was probably first produced by alchemists in the fifteenth century. Although the element itself was unknown, alchemists were aware of metal/acid reactions that, according to Phillippus Aureolus Paracelsus caused "air to arise and break forth like the wind." French chemist Antoine-Laurent Lavoisier, continuing Cavendish's experiments, became the first to produced both hydrogen and oxygen in a laboratory by dissolving metals in acid. He named them "flammable air" and "life- sustaining air" respectively.)
Charles either assumed Montgolfier's balloon utilized this new gas, or simply decided to use it in his own ballooning experiments. Regardless, on August 27, 1783, he launched his first balloon from the Champs de Mars in Paris (the site on which the Eiffel Tower was ultimately constructed), creating the gas by pouring sulfuric acid over scrap iron. Among the spectators at this launch was the American ambassador to France, Benjamin Franklin. The balloon descended after about 45 minutes, landing in a field where terrified farmers attacked the "monster" with pick axes and shovels, "inspired by the beast's behavior to sigh and groan and emit a horrible smell."
Charles' creation included almost all the essential components still used in ballooning. He constructed the balloon sack of silk, coating it with a solution of rubber dissolved in turpentine to prevent the gas from escaping. At the top of the sack was an apex, open tube through which expanded gas could escape to prevent the balloon from exploding. A network of ropes covering the sack attached to a wooden hoop holding a wicker basket suspended below the sack. This basket would ultimately hold pilot and passengers. Charles also invented a valve line, allowing the pilot to release gas to initiate descent.
In December 1783, Charles, along with Nicholas Marie-Noel Robert (1761-1826), one of two brothers who helped in the design of the balloon sack, entered the basket and launched his creation called Charlière. This was the first manned gas balloon flight. Leaving Tuileries, the two aeronauts travelled for about two hours, landed in the village of Nesles-la- Vallée, and Charles then ascended alone to soar for another half hour. For some reason, this was the only flight Charles made, even though he lived until 1823.
Because of Charles' success with hydrogen, hot air balloons quickly disappeared, and it was not until recent times have they made a resurgence in popularity.
This is the complete article, containing 743 words
(approx. 2 pages at 300 words per page).
