Jacques Charles

French inventor

• Born: November 12, 1746; Beaugency, France
• Died: April 7, 1823; Paris, France

A French mathematician and physicist who flourished during the end of the Enlightenment, Jacques Charles invented or improved several scientific instruments and formulated a law governing the behavior of gases. He is best remembered for designing and piloting the first hydrogen-filled hot air balloon.

Primary field: Physics

Specialties: Hydrology; thermodynamics

Early Life

Jacques Alexandre César Charles was born on November 12, 1746, in Beaugency, a community on the Loire River in France. He received a general education typical of that time, which gave him a rudimentary working knowledge of mathematics, chemistry and natural sciences, and language skills. Despite his rural roots and perfunctory studies, Charles was highly intelligent and curious, with a natural ability in mathematics.

After completing the equivalent of high school in the early 1760s, Charles relocated to Paris, where there were greater opportunities for employment. In the French capital, he was eventually hired to work with the Controller-General of Finances. On the job, Charles’s facility at manipulating numbers and his polite, courtly demeanor likely stood him in good stead. It is probable that as a royal civil servant, Charles became a trusted assistant to a succession of Controllers-General. As high-level cabinet members, the Controllers-General maintained offices at the monarch’s residence in the sprawling palace at Versailles, and Charles may have accompanied his superiors when participating in financial councils that reported directly to the king of France.

In 1774, Louis XVI ascended to the throne. Though the French economy was still a shambles following the Seven Years’ War (1756–63), the young king made two financial decisions that directly influenced his fate and indirectly changed the course of Charles’s life: he funded several expensive scientific and geographic expeditions, and he backed the American Revolution against France’s long-time rival Great Britain.

Life’s Work

One of the scientific expeditions of Louis XVI—a three-year voyage around-the-world begun in 1785 underthe command of Jean François de Galaup, comte de Lapérouse—turned into a disaster when both of Lapérouse’s ships vanished in the Pacific in 1788. The king had better luck supporting the American fight for independence (1776–83), though the success of the venture would provide inspiration for the French Revolution (1789–99), during which Louis lost his head on the guillotine. As a new ally, the United States sent Benjamin Franklin as ambassador to France, a post he served from 1776 to 1784. Franklin was not merely a statesman, but also a well-known scientist and inventor of such items as the lightning rod, bifocals, the Franklin stove, and the glass harmonica. In visiting the French court, Franklin may have encountered Charles and influenced his decision to begin a career in science.

Whether or not he was influenced by Franklin, Charles during the late 1770s turned completely away from finance. He converted his office in Versailles into a laboratory, and with the approval and encouragement of the king, immersed himself in physical science. He read about and duplicated Franklin’s experiments. He became fascinated with scientific gadgets and built an impressive collection of meters and measuring devices. While tinkering with his gadgets, he invented an aerometer to measure the density of gases and a hydrometer to measure the density of fluids; built a reflecting goniometer to gauge the angles of crystals; and made improvements to existing heliostats to better reflect sunlight onto his projects.

By 1781, Charles had become a popular public lecturer, demonstrating scientific principles to enthusiastic audiences of ordinary citizens. To help illustrate his points, and to impress the crowd, he used a magic lantern–like device of his own making, the megascope—a precursor of the modern motion-picture projector—to display magnified images on a screen.

On June 5, 1783, brothers Joseph-Michel and Jacques-Étienne Montgolfier made history by launching the first unmanned hot air balloon. Their success initiated a frenzy of creating lighter-than-air craft, in which Charles, with encouragement from the king, enthusiastically joined. The Montgolfier brothers next sent up several animals in September 1783; they took the first tethered human flight a month later. On November 21, 1783, François Pilâtre de Rozier—later the first ballooning fatality—and François Laurent, marquis d’Arlandes, became the first humans to ascend into the sky untethered. The flight of their Montgolfier balloon lasted approximately twenty minutes. Just ten days later, on December 1, 1783, Charles joined these aeronautic firsts. He and one of his balloon engineers, Nicolas-Louis Robert, became the first to ascend in a balloon filled with hydrogen gas. The flight lasted approximately two and a half hours and covered twenty-five miles.

Charles’s study of and experiments with hydrogen led him to explore the properties and nature of gases. In 1787, he refined the earlier work of Robert Boyle and others by demonstrating with hydrogen, nitrogen, and oxygen that the volume of gases under constant pressure increases in direct proportion to temperature. Charles’s important discovery remained unpublished during his lifetime; due to his lack of formal scientific education, he published very little except on mathematical topics. Repeating the experiment early in the nineteenth century, French chemist and physicist Joseph Gay-Lussac gave credit to Charles, and today the fundamental concept is known alternately as Gay-Lussac’s Law, Charles’s Law, or the law of volumes.

For his body of work, Charles was elected as a member of the Académie Royale des Sciences in Paris in 1795, where he served as president of the experimental physics division after 1816. He also was appointed professor of physics and librarian at the Conservatoire National des Arts et Métiers (National Conservatory of Arts and Crafts), where he remained until the end of his life.

In 1804, at the age of fifty-seven, Charles married a twenty-year-old Creole woman, Julie Françoise Bouchard des Hérettes. Despite the great disparity in their ages, the couple lived happily together for a dozen years before Julie succumbed to tuberculosis. Charles outlived his young wife, dying in Paris on April 7, 1823, at the age of seventy-six.

Impact

Widely known and respected in France between the late 1770s and the early nineteenth century, Charles fell into obscurity after his death, and facts about his life became scarce. Extrapolation from what is known suggests he was a charming, adaptable individual. He persevered through frequent changes in the Controller-General’s office, and during the French Revolution he survived an assault of peasants on Versailles by distracting them with colorful reminiscences of his balloon flights. Capable of absorbing great amounts of arcane information in a short period of time, he was able to simplify what he learned to make presentations for public consumption, and as such he was a pioneer in the popularization of science.

Handicapped by a lack of formal training, the largely self-taught Charles was not an original thinker. Most of his work in mathematics and physics, including the development of the law governing the behavior of gases that bears his name, consists of expansions upon the work of others. Some of his collection of scientific instruments was absorbed into the Paris Musée des Arts et Métiers (Museum of Arts and Crafts). Likewise, the majority of his inventions have been housed in that museum. Most of these inventions featured slight improvements upon existing apparatus and were in turn rendered obsolete by later refinements.

The one area in which the name of Charles is still revered is in the sport of ballooning. His design of the enclosed gas balloon envelope, called a Charlière in his honor, has remained essentially unchanged since 1783. The modifications Charles developed to better control lighter-than-air flight—filling mechanisms, gas-releasing valves, and vents—are still in use today.

Bibliography

Hallion, Richard P. Taking Flight: Inventing the Aerial Age, from Antiquity through the First World War. New York: Oxford UP, 2003. Print. A compendium of diaries, memoirs, and other sources accompanied by photos and drawings, covering the gamut of humanity’s attempts to fly.

Holland, Geoffrey, and James Provenzano. The Hydrogen Age: Empowering a Clean-Energy Future. Layton, Utah: Gibbs, 2007. Print. Covers the history of hydrogen from its discovery, details early experiments with the gas such as Jacques Charles’s balloon, and discusses hydrogen’s potential as a future fuel of choice.

Pickover, Clifford A. The Physics Book: From the Big Bang to Quantum Resurrection, 250 Milestones in the History of Physics. New York: Sterling, 2011. Print. Illustrated survey of some of the most significant discoveries in the field of physics. Includes Charles’s Law governing the behavior of gases.

Rousseau, George Sebastian, and Roy Porter, eds. The Ferment of Knowledge: Studies in the Historiography of Eighteenth-Century Science. Cambridge: Cambridge UP, 2008. Print. A collection of scholarly essays that explore the state of scientific fields during the period in which Jacques Charles worked, when experimentation and empirical evidence became the norm.