I suspect, if you ask any modern-day physicist who Jean-Augustin Fresnel was, he/she would know. Everyday folk, however, may not have heard of him. But anyone who drives an automobile, should thank Fresnel. He developed the science that makes car headlights work!
Fresnel, among other accomplishments, was the Father of Modern Wave Theory in optics. He was a gifted mathematician and engineer, and a person--no pun intended--who could "see the light." Perhaps most exciting for we lighthouse fanciers was his effort to produce a better lighting mechanism for lighthouses. His work, as all lighthouse fans know, revolutionized lighthouse illumination.
Today, May 10th, would be Fresnel's 229th birthday. He was born in Broglie, France on May 10, 1788. Only a year later, on July 14, the Bastille was stormed and the French Revolution began. His father moved the family to the quiet town of Mathieu during the Reign of Terror. Fresnel was just six at the time. He spent six more years in Mathieu as the oldest child in a family of achievers. All four Fresnel brothers gained fame, but the eldest, Jean-Augustine, became the most famous.
In case you're wondering, his name is pronounced Fray-nell. I've heard many docents, teachers, and speakers call him Frezz-nell. Yikes! It grates inside my head like chalk dragged across a blackboard. Please call him Fray-nell, oui???!!! Merci.
Like many geniuses, Fresnel had a slow start in the rigorous and tunnel-visioned education system of his time. Reportedly, he could not read until about age 8. Similarly, Albert Einstein is said to have eschewed speech until age 3, when he began speaking in profound statements. Isaac Newton was absolutely non-social for much of his life, perhaps somewhere on the Autism Spectrum.
What goes on in the brain of a genius, or any brain for that matter, remains mysterious. But what little limited research there is on the label "genius" suggests that very intelligent people have the two hemispheres of their brains well connected. You might call them superior in terms of corpus callosum--that broad band of nerve fibers connecting the left brain to the right brain. Imagine if we all could get logic and metrics and calculative ability to work in tandem with creativity and visual-spatial thinking! Woohoo! I want that!
Enough neuro-babble. Let's talk abut Fresnel's work on lighthouse optics. He surely began thinking about lighthouses as a young child when his father, an architect, was assigned to work on the great harbor at Cherbourg. Lights flashed all along the French coast at this time, perhaps mesmerizing the young Fresnel. But like other lighthouses around the world, the French beacons were feeble, barely reaching far enough at sea to prevent calamity. Their lights showed only a few miles, if that.
Young Fresnel was sent to the Ecole Centrale in Caen, France at the age of twelve, and at sixteen he began studies at the Ecole Polytechnique, due to his proclivity for mathematics. He wanted to be an engineer, which led to his acceptance at the prestigious Ecole des Ponts et Chausses. (Forgive my omission of diacritical marks for French words. I've yet to discover a way to type them on Blogspot.)
Fresnel graduated in only three years and was sent to Vendee to build roads for Napoleon, who wanted a massive military base at the town. In his free time, Fresnel experimented with his real fascination--light. This work began in 1814, but in 1815 he decided to join the King's army fighting against Napoleon, for whom he had no respect or liking. As a result, he was fired from his engineering job at Vendee. After Napoleon's "Waterloo," an unemployed Fresnel went off to Mathieu.
Biding time, he was able to work on a theory of light. Until this time, the scientific community had insisted that light was composed of particles, a "corpuscular theory" put forth by Isaac Newton. Fresnel believed light traveled in waves, and he set out to prove it. His work was much about "diffraction" and "polarization" of light. Though I took physics in college in 1971, I'm not able to articulate the science for you, so I'll simply say Fresnel's papers on the subject were met with acclaim, including an 1819 grand prize from the Academie des Sciences. If you need a more detailed description, go here for a layman's explanation of it all.
Soon after his award, he began work for the French Lighthouse Commission, trying to improve lighthouse illumination. Two of his younger brothers worked with him, Leonor and Fulgence, plus Jacques Tabouret, an excellent mechanical engineer. Saint Gobain Glassworks in France produced the prisms and other glass elements the men needed. The result was the fabulous Fresnel lens!
|An early Fresnel lens. This one was for Skerryvore Lighthouse in Scotland.|
Many of us know the rest of the story...how Fresnel experimented with mirrors and prisms, arranging them in a circle around a light source, making some into bulls-eye shapes of concentric prisms and others into huge bands of convex glass. We know how he forced light to bend and twist into parallel beams (this is called collimation) and intensify it without the volume of materials needed for conventional lenses of the day. He not only significantly improved the range (distance) of a light source, but he did it with an exceptionally compact, efficient, and splendid invention. Nothing compares in beauty to the shimmering glass and brass of a Fresnel lens!
|Lens of Point Arena Lighthouse, California.|
|Fifth-order lens at Point Robinson Lighthouse, Washington|
|A close-up of the prisms of Point Hueneme Lighthouse, California|
Sadly, Fresnel did not enjoy a long life. Plagued with ill health for much of his youth, he contracted tuberculosis in his twenties. He struggled throughout his career with fatigue and coughing. By 1827 the disease had taken a serious toll on his body. Sensing his eminent death, the Royal Society of Britain awarded him the Rumford Medal. On July 14, 1827 at the age of 39 he died at Ville-d'Avray. He was buried at Pere Lachaise Cemetery in Paris.
The Fresnel Lens went on to become the mainstay of lighthouse illumination almost everywhere. France and England began using it in the 1820s, but the penny-pinching lighthouse service in the United States waited until 1840 to test the lens and about 1852 to purchase and install the lenses in its lighthouses. Lens makers in France launched the manufacture of the optics, followed by a company in England called Cookson, and then Chance Brothers. The United States had a brief foray into Fresnel lens-making in Baltimore at the McBeth Evans Company, a predecessor to Corning Glass. Lens-makers always put their names on the base plate of their lenses. Unfortunately, some of these have been polished off by over-zealous lightkeepers and modern-day caretakers. Look for them when you visit a lighthouse or museum with a Fresnel lens.
Today, Fresnel's name is honored with schools, bridges, streets, and more. A bust of him by David D'Angers (below) is at France's National Museum of the Sea and also at Cordouan Lighthouse where his first Fresnel lens was installed and tested. Fresnel's name also is etched on the Eiffel Tower in Paris.
For more information on Fresnel, watch this YouTube video.
My fellow U.S. Lighthouse Society board member, Tom Tag, has a detailed (far better than mine) discussion of Fresnel and his work and its spin-offs here.
|Read this book!!! It's wonderful!|
For a real treat, you might consider seeing Joseph Smith's portrayal of Jean-Augustin Fresnel. Smith performed at a lighthouse conference I organized in April. The audience gave him a standing ovation!
Contact me at email@example.com if you like to know how to arrange a performance for your group.
|Joseph Smith portrays Jean-Augustin Fresnel. He even resembles Fresnel!!.|