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This is an iHeart podcast.
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Audible Originals has a new title that our listeners are gonna love. An intimate full cast performance of Pride and Prejudice that's gonna have you falling in love with Jane Austen all over again. The cast for this version is absolutely incredible. It stars Marisa Abella as Elizabeth Bennett and Harris Dickinson as Mr. Darcy. Plus Marianne, John Baptiste, Will Poulter, Bill Nye, and Glenn Close as Lady Catherine de Bourgh. Whether you're a first timer to Pride and Prejudice or you just want to revisit a cherished favorite for a really spectacular experience, listen to the new Pride and prejudice@audible.com janeausten Life's messy.
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We're talking spills, stains, pets and kids. But with anibe, you never have to stress about messes again. At washablesofas.com, discover annabe sofas, the only fully machine washable sofas inside and out, starting at just $699. Made with liquid and stain resistant fabrics, that means fewer stains and more peace of mind. Designed for real life, our sofas feature changeable fabric covers allowing you to refresh your style anytime. Need flexibility? Our modular design lets you rearrange your sofa effortlessly. Perfect for cozy apartments or spacious homes. Plus, they're earth friendly and built to last. That's why over 200,000 happy customers have made the switch. Upgrade your space today. Visit washablesofas.com now and bring home a sofa made for life. That's washablesofas.com offers are subject to change and certain restrictions may apply.
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Listen to your elders, honey. You might know them from their viral videos. But now the old gays are pulling back the curtain with their new podcast, Silver Linings with the Old Gays, brought to you in partnership with iHeart's Ruby Studio and Veeve Healthcare. Hosts Robert, Mick, Bill and Jesse serve their lifetime of wisdom when it comes to love, sex, community and whatever else they've got on the gay agenda. So check out Silver Linings with the Old gays on the iHeartRadio app or wherever you get your podcasts at T. Rowe Price. Their experience helps them see investment potential differently. Instead of quick answers, they know that what really leads to confident investing is true curiosity. And since you're listening to this podcast, we know you value curiosity too. It's what drives them to ask the questions that really matter in our ever changing world, like can healthcare innovations create a healthier world? And how will AI be a part of a new tomorrow? Just like you, their curiosity runs deep and with it comes the power to help you invest more confidently. Better questions, better outcomes. T. Rowe Price. Learn more@t rowprice.com Curiosity welcome to Stuff you missed in History Class, a production of iHeartRadio. Hello and welcome to the podcast. I'm Holly Fry.
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And I'm Tracy Wilson.
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Hey. This is yet another instance of one episode tangentially inspiring another. That happens a lot.
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It does.
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Lately it happens a lot more than usual. I don't know why that is. I first came into contact with Fresnel lenses in college, but then because I worked, you know, I have a theater degree and they come up in lighting, which you had to do. Even though I was largely working in acting. I did a lot of set stuff as well. But then while I was working on our episode on TV remotes, Fresnel lenses came up again in relation to one of Eugene Polly's patents. And that, of course, reminded me of him, because Augustin Fresnel is pretty interesting to me. He did not live a long life, but in his relatively short life he contributed significantly both to the understanding of light and related to that, to the safety of coastlines. But what I love most about his story is that neither of the those accomplishments had anything to do with his chosen career, which we could talk about a little more behind the scenes, but we're going to talk about Augustin Fresnel today.
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Augustin Jean Fresnel was born on May 10, 1788 in Broglie, France, which sits roughly 75 miles or 120 kilometers west of Paris. His mother was Augustine Merime and his father was Jacques Fresnel, who was an architect. And, and Jacques was very successful. He took on projects like restoring and expanding chateau for the aristocracy. After Augustin was born, the Fresnels moved to Cherbourg, which sits on the northern point of the coastline bordering the English Channel. This was being built up as a port city and Jacques Fresnel was part of that expansion project.
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If you have ever seen the movie Parapluie de Charbours, which was a spectacular Catherine Deneuve vehicle, you like me hear that name and go, je t', aime, Guy. I can't help it. Forever. Forever. Augustin was born at a pivotal point in French history. He was still a baby, for example, when the Bastille was stormed in 1789, and he was not yet five years old when Louis XVI was beheaded and the Reign of Terror began. And although his parents were not directly involved in the revolution, the family was of course impacted by it. The most obvious result was that the work at Cherbourg stopped, and Jacques took Augustine and Augustin to live in a small village north of Caen called Mathieu. After the family moved there, Jacques and Augustine had two more sons, Leonard and Faugence.
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This was a deeply religious family. The Fresnels were followers of the teachings of 16th and 17th century Dutch Catholic bishop Cornelius Otto Jansen, who led the Jansenist reform movement in the Roman Catholic Church. Jansenism focused on ideas of free will and God's grace and that the fate of humans is largely out of their hands, as those who God gives grace to will be saved by it, and those without it are doomed to sin. This faction of the Church was controversial. A lot of Catholics rejected it as not really being part of the denomination at all, although that sentiment may have had less to do with theology and more to do with power struggles within the Church. But the Fresnels were devout, and Augustin remained so for the rest of his life.
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As a young child, Augustin was educated at home, although he was not considered to be especially smart by his parents because he struggled with his studies and he actually couldn't read at all until he was about 8 years old. Other children thought he was absolutely a genius. All of the energy that he was not putting into his studies seemed to go into his own experiments and to sometimes building dangerous toys like projectile shooters for the village children. There's a story that he built them all cannons to play with, to the point that parents were like, oh my goodness, hey, frenels, can you control your kid?
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I was wondering when I read this, like, what kind of projectiles are we talking about here?
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Yeah, they weren't like fuselit cannons. They were more like, you know, simple machine type things that could shoot things. But yeah, he was apparently a little scamp in that regard. And when he was 12, he started studying at Cannes Eco Central School. And he got his first taste of science and mathematics there. And he really loved it. With subject matter that engaged his brain, he actually did very well in school. He pretty quickly decided that an engineering career was his goal, as it incorporated both of those things. So at the age of 16, he moved to Paris to study at the Ecole Polytechnique. He studied there for two years, and then he advanced to the Ecole des Pont et Chaussees, the school of bridges and roads. And he studied there for three years before receiving his credentials as a civil Engineer.
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In his mid-20s, Fresnel settled into a career path not dissimilar from his father's. He worked as an engineer on Public Works in 1804, the same year that Napoleon became Emperor of the French, he was hired by the Corps of Bridges and Roads to expand the country's roadways, starting in Vendee on the west coast of France. His first assignment was in La Rocheau, which was a town that Napoleon renamed after himself and then built up as an administrative seat of government in the region. And Fresnel's job was to create an infrastructure of roadways that would give La Roche Surroillon easier access to the rest of Vendee. And he hated it. He liked solving problems, but he was put in a position where he had to manage people, which is the last thing on earth that he wanted to do. So he kept himself busy studying various things that just tickled his fancy in his free time.
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Yeah, his writings back to his family are basically about how much he dislikes management, how he's one of those people that I suspect may not have been an amazing communicator of his ideas because he talks about often having to step in and do the work himself, which, listen, I have that same disease, so I understand it, but I think he just maybe wasn't always great at communicating what he was after. In 1812, Fresnel moved into another large scale public works project, this time building a roadway that would connect Spain and Italy, and it had to pass through France, particularly through mountainous areas. And this was once again a job assignment that came at the same time as a significant development in Napoleon's story. And that story impacts Fresnel. So we're going to quickly review a little bit of French history here. In the summer of 1812, the Emperor Napoleon, acting on fears that Russia was about to ally with England, invaded Russia after first parking his troops in Poland along the border for a while, this pretty famously did not go well. In the very simplest terms, the Russian army mostly refused to battle, which made Napoleon's entire effort look sort of foolish. There was only one major battle that happened as a result of this, at Borodino, which Napoleon did win, and that enabled the French to advance to Moscow. But the city had already been sacked by Russian forces, so that Napoleon's army would find nothing to gain there. Furthermore, Tsar Alexander I refused to negotiate with Napoleon. And as winter closed in, things got dire and Napoleon was forced to retreat to Paris, where he actually found rumors circulating that he was dead. He had, in returning to Paris, left behind most of his troops, which dwindled from a starting number estimated at 700,000 to a mere 100,000 by the end of the Russian campaign. Napoleon's failure was such a complete disaster that allies began to abandon him, and some of them actually joined forces with Russia. As countries expelled French troops and Napoleon's power shrank, he was eventually completely overthrown and the French monarchy was restored. With Louis XVIII as king, Napoleon was exiled to Elba in the spring of 1814.
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That same year, Fresnel started studying the area that would make his name famous, which was optics. He had some optics education at university, but it was pretty rudimentary, and to Fresnel, it seemed like the principles he was taught didn't really explain the behaviors of light very effectively. Newton's ideas about light were included. We'll talk more about those in a moment. But again, that felt limited to him. He did not feel compelled to start to do his own experimenting until the 18 teens. And he didn't actually start his scientific study as a hobby, working in light or optics. He kind of messed around with a few different things until he landed there. For a while he thought that light and heat transmission might happen through, quote, the vibrations of a special fluid. He wrote about this idea to his brother Leonor. He was just really excited. It seems to have projects that let him try to solve problems creatively. He eventually worked on various experiments to explain the behaviors of light, including reflection, refraction and polarization.
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And coming up, we're going to talk about exactly how Napoleon impacted Fresnel's work. But first we will hear from the sponsors that keep the show going.
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Picture it. 1852. A scandal erupts in Charleston not over politics, but over a ruined velvet settee. A guest spilled Madeira wine and tried to blame the dog. If only they'd had an Annabe Washable. Comfortable, practically drama proof. Annabe. A modern sofa for lives as messy as history itself. Built with machine washable covers, modular design and customizable comfort. It's made to survive every spill, splash and social mishap. Starting at just $6.99 and with up to 60% off right now, there's never been a better time to upgrade. So skip the scandal, head to washablesofas.com and relax, knowing history won't repeat itself in your living room. Shop Annabe today@washablesofas.com and get 60% off your new washable sofa. That's washablesofas.com youm can make a difference.
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- [14:23]
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Listen to your elders, honey. You might know them from their viral videos, but now the old Gays pull back the curtain on their brand new podcast Silver Linings with the Old Gays, brought to you in partnership with iHeart's Ruby Studio and Veeve Healthcare. With over 300 years of experience between them, hosts Robert, Mick, Bill and Jesse serve four lifetimes of wisdom when it comes to love, sex, community and whatever else they've got on the gay agenda. Listen in to these fabulous friends swap stories exploring how queer life has evolved over the decades and the silver linings they've collected along the way. Each episode dives into hot topics from safe sex and online dating to untangling Gen Z lingo, as well as insights on how music, art and fashion show up in queer culture. So check it. Check out Silver Linings, a show about how pride ages like fine wine. Available on the iHeartRadio app or wherever you get your podcasts. Wouldn't it be great to never buy gas again? EVs are as easy to charge as your phone and they are a perfect addition to your everyday life. Most people are only driving about 40 miles a day, and most EVs can handle 200 to 400 miles of range on a charge. And there are hundreds of EV models available today, so there's something perfect for every lifestyle and budget. I drive an ev. I've had it for a couple of years. It's my favorite car I've ever owned. It is so fun to drive. The pickup is incredible, it's super agile and it is easy to maintain. The way forward is electric. Learn more@electricforall.org When Napoleon returned from Elba suddenly in 1815, everything in the French government was upended, including public works projects. Fresnel was very dismayed when Napoleon landed at Caen on March 1, 1815. The exiled emperor had seven ships of soldiers with him and intended to reclaim France. Fresnel thought this was literally an attack on civilization, that is what he called it, and he left his job to go fight for the king. But Napoleon did manage to make his way to Paris with people joining his military as he passed through the country. And on March 20th he walked into Tuileries and began began his second rule, which of course famously lasted exactly 100 days.
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Because Fresnel had sided against Napoleon, his position as a civil engineer was of course no longer available to him, so he was unemployed and viewed as an Enemy of the state. And so he was also surveilled. He moved back to his village of Mathieu and took advantage of his unemployed free time to continue his study of optics. One of the things that he wanted to figure out was why the shadow around a thin edged object, like a knife, would have a fringed edge, or why light that passed through a slit in a card would have dark spots in it. He was after the cause of light diffraction. In some ways, he had to catch up to the contemporary discussions already happening in the science of light. He had no idea about the work and the controversy around Thomas Young and Young's wave theory of light.
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Thomas Young was an English physician and physicist, originally from Somerset, England. And Young achieved a lot of noteworthy things in his life. He could easily be an episode in the future. But germane to Fresnel's story is his wave theory of light. He developed this theory through an experiment that involved sunlight passing through two small slits in a card. And when Young observed the light that had passed through the card onto the wall beyond it, he noted that it appeared not as two spots of light, but as a series of vertical lines. And that evidenced an interference pattern. And that was important because it supported the idea that light traveled in waves. This challenged the idea that had been put forth by Sir Isaac Newton, that light traveled as a particle. What was known as the corpuscular theory.
- [18:41]
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The corpuscular theory of light came about as the scientific world was struggling to get a handle on what exactly light was and how it moved throughout the world. In 1704, Sir Isaac Newton proposed the corpuscular theory. Newton's take on light was that it was made up of tiny particles, what he called corpuscles. These particles were emitted from various sources, obviously the sun, but also things like candles, stars, et cetera. Different luminous objects produce differently sized corpuscles, and that accounts for different colors of light. And per Newton's theories, these particles moved at a very high velocity and always in a straight line. So if one hit an opaque object and could not pass through it, it would be reflected away at an angle and continue to travel in a straight line. That's reflective light. But if light hits a medium, it can pass through. These particles are attracted at the surface. And if the medium is denser than the medium that the light had been traveling through, like traveling from air into a prism, the denser nature of the prism will speed up the light and cause the directional shift. And in this theory, vision is explained as light hitting the eye to produce the imagery.
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Yeah, so that was Isaac Newton's take. Obviously some of that is incorrect. We'll talk about that some more. Fresnel had started his own experiments in this area even before he knew about Jung's work. He wasn't entirely flying blind, though. He was basing his experiments on the work of another scientist, Danish mathematician and astronomer Christian Huygens, who he had learned about in school. Huygens principle regarding wave motion states, quote, every point on a wavefront is in itself the source force of spherical wavelets which spread out in the forward directions at the speed of light. The sum of these spherical wavelets forms the wavefront. And Fresnel eventually expanded on Huygens, adding that these secondary wavelets would then interfere with one another. Where Huygens had described those secondary wavelets as enveloping the initial wave and carrying it forward, Fresnel's explanation suggested that they overlapped and interfered with one another and that that was what formed the wavefront. This, by the way, I should say, is my very rudimentary understanding. Holly is not a physicist, but this amended version of Huygens work came to be known as the Huygens Fresnel principle.
- [21:18]
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Fresnel also worked on explaining the dark spots that appeared in pools of light. Sometimes he came to the conclusion that two light waves that perfectly lined up peak to trough would yield darkness as they interfered with one another. But if they were lined up peak to peak and trough to trough, they would amplify into a larger wave. The earliest of these ideas was put into an essay which got lost, but through an uncle, Augustin was introduced to Francois Arago, who would become an important collaborator and friend.
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But Fresnel did not get to work on his special interest projects forever because he got his job with the Corps de Pont et Chasses back after Napoleon was exiled for the second time to the island of Saint Helena and Fresnel was sent to Rennes to resume work on the roads. This slowed Fresnel's scientific work quite a bit. His work in optics was relegated to the small amounts of free time that his work afforded him or to times when he took vacation or leave. And he made a lot of requests for time off, each time heading to Paris to continue his scientific studies. These frequent leaves from work would not have been approved had it not been for high ranking members of the scientific establishment like Francois Arago, advocating with the Bridges and Roads department on his behalf. Because Fresnel had a strong mathematical background, he was able to back up a lot of his ideas about light wave theory with it. But it also took A lot of time, as we mentioned, he worked out a lot of his early ideas and formulas before he even knew about other scientists working on the problem of light. The thing about Fresnel's work that was unique was that a lot of it, or work closely related to it, had happened already. So in a way, this young public works engineer was actually working in his spare time to verify earlier theories and experiments without even knowing it. And that was a huge challenge. He believed that elementary waves were generated all along the arc of the wave and interacted with one another. Okay, to a layperson, that kind of makes sense. I'll be frank. It's easier when you look at diagrams, but for me, and probably a lot of listeners, imagine having to come up with the math that supports that idea. To me, this seems like superhero stuff. I can't even fathom it. And Frenell, who was very good at math, still needed months to puzzle it.
- [23:51]
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In 1816, Frenell published his first paper about this work. But he acknowledged that he was still in the early stages of working everything out and included a plea to readers to understand the situation. And he also, for a while, joined forces with Francois Arago, who was two years older than Fresnel and was the chair of Analytic Geometry at the Paris Ecole Polytechnique. Together, the two of them studied interference as it applied to polarized light.
- [24:23]
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Fresnel may have continued to focus on polarized light, had a high profile opportunity to show his work in light waves not have come up. But he learned that the Academy of Sciences was going to make diffraction the topic of their 1819 Grand Prix. And as we just mentioned, he had worked a long time on the mathematical side of this theory, and he really believed that his work was solid. So he hustled to get an entry ready. He wrote, quote, I think I have proved that light is propagated by the undulations of an infinitely subtle fluid diffused in space. And it is to the demonstration of this great principle that I have been particularly attached. It is the end towards which I have directed all my efforts. Though Arago had tried to promote the work of Fresnel to the scientific establishment in both France and England, most of the people who heard about what this young civil engineer was doing assumed that he was just copying Thomas Young. And they really didn't give his work a whole lot of additional attention.
- [25:24]
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1819 would prove to be a big year for Augustin Fresnel. And we will talk about why after we pause for a sponsor break.
- [25:35]
D
Picture it. 1852 A scandal erupts in Charleston, not over politics, but over a ruined velvet settee. A guest spilled Madeira wine and tried to blame the dog. If only they'd had an annabe Washable Comfortable, practically drama proof. A modern sofa for lives as messy as history itself. Built with machine washable covers, modular design and customizable comfort, it's made to survive every spill, splash and social mishap. Starting at just $6.99 and with up to 60% off right now, there's never been a better time to upgrade. So skip the scandal, head to washablesofas.com and relax, knowing history won't repeat itself in your living room. Shop Annabe today@washablesofas.com and get 60% off your new Washington washable sofa. That's washablesofas.com.
- [26:36]
C
Youm can make a difference in someone's life, including your own with a job in home care. These jobs offer flexible schedules, healthcare, retirement options, and free training. They also provide paid time off and opportunities for overtime. Visit oregonhomecarejobs.com to learn more and apply apply. That's oregonhomecarejobs.com.
- [27:06]
B
Listen to your elders, honey. You might know them from their viral videos, but now the old Gays pull back the curtain on their brand new podcast, Silver Linings with the Old Gays, brought to you in partnership with iHeart's Ruby Studio and Veeve Healthcare. With over 300 years of experience between them, hosts Robert, Mick, Bill and Jesse serve four lifetimes of wisdom when it comes to life, love, sex, community and whatever else they've got on the gay agenda. Listen in to these fabulous friends swap stories exploring how queer life has evolved over the decades and the silver linings they've collected along the way. Each episode dives into hot topics from safe sex and online dating to untangling Gen Z lingo, as well as insights on how music, art and fashion show up in queer culture. So check out Silver Linings, a show about how pride ages like fine wine. Available on the iHeartRadio app or wherever you get your podcasts. Wouldn't it be great to never buy gas again? EVs are as easy to charge as your phone, and they are a perfect addition to your everyday life. Most people are only driving about 40 miles a day, and most EVs can handle 200 to 400 miles of range on a charge. And there are hundreds of EV models available today, so there's something perfect for every lifestyle and budget. I drive an ev. I've had it for A couple of years. It's my favorite car I've ever owned. It is so fun to drive. Drive. The pickup is incredible. It's super agile and it is easy to maintain. The way forward is electric. Learn more@electricforall.org In 1819, Augustin Fresnel presented his work with light waves and diffraction to France's Academy of Sciences under the title Nature simplex et facunda Nature simple and fertile. And this offered 25 cases of ways diffraction might appear, along with mathematical formulas to explain each of those cases. This competition was intended to bring the smartest minds in the country's science community together to discuss the true nature of light. But because Fresnel's work ran counter to the widely accepted work of Newton, there was a lot of resistance to what he presented.
- [29:28]
A
The next figure who's important to this particular part of the story is a man named Simeon Denis Poisson. Poisson was a mathematician who had become known for his work in probability, and he was very influential on France's scientific education system. He was also one of the competition judges for the Academy of Sciences, and he thought Fresnel was talking absolute nonsense.
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One particular example in Fresnel's paper really rankled Poisson, and he pointed it out as proof that this person didn't know what they were doing. This was an instance where Fresnel suggested that the shadow of a circular disc would actually have a bright spot of light in the center. And Poisson was adamant that this just simply could not happen. But Arago, who really believed in his friend and saw that there was bias against his work, managed to get the right instruments to do the experiment there with the competition judges so that they could see if Fresnel was correct and he was. The shadow that he produced had a bright spot in the center. And although the judges who favored the Newtonian theory of light didn't exactly believe in Fresnel's work, it had proven out, and they couldn't deny that, and so he won the prize.
- [30:45]
A
As an aside, eventually it was recognized that elements of both Newton's corpuscular theory and Fresnel's work were true. Regarding nature of light, Corpuscular theory is kind of the proto version of our understanding of photons. Newton's take had some incorrect ideas, specifically, different sized light particles causing color difference, light levels traveling faster in denser media, and the idea that media could attract or repel light. That also didn't offer an explanation for things like polarization or diffraction. Eventually, humans came to understand that Diffraction was the result of light waves passing through a small opening the size of or smaller than the wavelength. Or when a light wave bends and spreads as it passes around an obstacle. Today the idea of wave particle duality is accepted to understand the nature of light. That means that sometimes it does travel like a particle, a photon in a straight line, but at other times it behaves like a wave, enabling it to bend. A thing that I remember from physics class.
- [31:56]
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I don't remember a whole lot from physics class. We can talk about what a weak physics student I was on Friday if you like. Fresnell still longed for a position where he could work on his scientific studies full time so he wouldn't have to juggle it in his free time alongside a public works engineering job. Job that he just clearly did not like. And starting in 1819, Fresnel did begin working alongside Francois Arago in a national project that was intended to improve upon the lighthouses of France. First by working to perform a series of tests on them. And this project was precipitated by the ongoing problem of shipwrecks being caused by vessels simply running aground unexpectedly or slamming into rocks that were near the land. France had been abuzz after a high profile shipwreck of a French ship off the coast of Africa. And this had led to a high level of interest in fortifying their own coastline against similar accidents.
- [32:57]
A
At this time there were a number of ways that lighthouses provided light. Lighthouses have been around since at least 285 BCE, maybe even longer. That example is one of the seven wonders of the World built in Alexandria, Egypt. There were Roman lighthouses spread throughout Europe during the time of the Holy Roman Empire. Early lighthouses used beacon fires. Some of these fires were protected by a roof and others were in the open air. Eventually coal and then candles and then oil lamps replaced the fires in the 12th century. Lighthouses became more common as the Dark Ages ended and new trade routes were established. Established fostering a need for near shore lights. The earliest modern lighthouses appeared sometime around the beginning of the 18th century. In 1780, Amy Argand invented a clean burning oil lamp that became standard in lighthouses. These were sometimes combined with reflectors that consisted of large glass discs with spherical coatings to reflect the light. A glass cutter from London had actually created a lighthouse lens in the 1780s that was 21 inches across and five and a half inches thick. That glass cutter. Thomas Rogers implemented these lenses in a couple of lighthouses. But they were made of green glass and had some imperfections. So they did not really throw the light as far as was hoped. Then there were developments that led to rotating parabolic reflectors, a couple of which were combined with lenses. But the lenses actually made the lighthouse less effective, and they were abandoned.
- [34:42]
B
I kind of want to do a history of lighthouses. It's on the list. Yeah, there's a lot of interesting stuff there and a lot of science. So we'll see if my brain can handle it. Because Fresnel had already done so much study of light, he was kind of the perfect man for this challenge. And as he had been helping Arago perform tests on the existing lighthouse setups in the country, he immediately began to brainstorm the ways that they could be improved. Although, to be clear, that was not a task he had been given. At that point, Fresnell realized that reflective mirrors could be replaced with lenses that bent the light instead of reflecting it. And this was something that had been tried. We just mentioned it in some of those efforts. But Fresnel tried to figure out ways to fix the problems that previous lenses had. At one point, he actually considered something I found quite charming, which is creating a lens by filling a glass contain with wine. Obviously that would be a white wine, but he abandoned it. And then he had the idea to create a giant lens that did not have to be impenetrably thick in the middle. Instead, it would have a series of prisms that could bend and focus the light into a beam. And he called his design lentil a echelon, or lenses by steps.
- [36:01]
A
But the lighthouse commission was kind of ho hum on this idea and compared it to a similar one created by another person some years earlier. But Fresnel really thought he was onto something. He knew, though, that he would have to make it to show them what he was talking about. He did manage to get some grant money from the commission to help with the cost of construction. Like any prototype, this one had some problems. But Fresnel worked with craftsmen to refine them. A specialist named Francois Soleil was crucial to the construction of a glass panel that looked like a square containing a bullseye with concentric rings formed around a central circle to form a polygonal lens. It had 97 different pieces of glass in it. In an actual functioning lighthouse, he planned for there to be eight such panels combined together in an octagonal shape surrounding the light source course. But for this test, one would have to do. He combined it with a lamp that used several small wicks instead of one large one. And when he tested it in front of the commission, those in attendance were, in Fresnel's account, dazzled.
- [37:15]
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But while a full version of this design was requested, Fresnel was not getting a full green light to go ahead with this project. Two other people were also presenting fully assembled, attempted solutions to the lighthouse problem. Both of those other competitors used reflectors, and the final test of these three models was public. It was held at the Paris Observatory, and Fresnel was the very clear winner by a mile. Nobody could deny that what he had achieved far outshone, not to be punny, the work that everyone had been doing with reflectors. From there, he was commissioned to build a lens for France's oldest continuously operating lighthouse house, which was known as Cordoin.
- [37:59]
A
Between the successful test of that lens and its final installation, which was postponed due to winter weather, Fresnel continued to work on his work in light theory and refining and formalizing any theoretical points that had been involved in his earlier work with mathematics. He also wrote an entry on refraction for Encyclopedia Britannica at the behest of none other than Thomas Young. When the winter was over, the final installation of the lens at Cordoin was completed, and Fresnel's place in French scientific history was cemented.
- [38:34]
B
For all of his work, Fresnel became an elected member of the Academy of Sciences in 1823. He also received the French Legion of Honor. And the Royal Society of London inducted Fresnel as a member in 1824. And that same year, he was assigned to France's Lighthouse Commission.
- [38:53]
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The French government was so pleased with Fresnel's lenses that it developed a plan to illuminate the entire French coastline. With them, Fresnel himself created a map of a planned 51 lighthouses for the country that would create a continuous network of light. He also improved on his lens design as he worked.
- [39:13]
B
Yeah, at that time, there were 13 of those 51 lighthouses that existed. So a huge number were going to have to be built from scratch, and those 13 were going to have to be significantly updated. In 1827, Fresnel received the Rumford Medal. That's a medal bestowed by the Royal Society of London, quote, for important discoveries in the field of thermal or optical properties of matter and their applications. For some reason, just if you go looking the Royal Society site, say this happened in 1824. That is the year he was inducted. But based on ratings of other people involved in the nomination and the award itself, this did happen in 1827.
- [39:53]
A
Fresnel had not been especially healthy at any point in his life. But as he got into his late 30s. He declined really rapidly all through his life. He'd been one of those people who worked constantly up to and through the point of exhaustion. Many biographies cite his deeply held religious faith as the source of his drive. He believed his service to society was important, and he pursued it to the exclusion of everything else. Sometimes he's characterized as being aware that he probably wouldn't live a long life, and consequently he felt compelled to do as much as he could in whatever time he had. Just as his scientific work was taking off, he was warned against overworking and had to prioritize what projects he felt were the most important.
- [40:40]
B
And Frenell did have a short life. In the summer of 1827, he was ill and was taken to a family property in Vie Davray in the hopes that fresh air would help his health improve. His friend Arago traveled there to see him and to give him the Rumford Medal he had been awarded. And Arago was quite distressed at just how sick his friend was regarding the medal. Fresnel, who was incredibly weak, is said to have told Arago, quote, the most beautiful crown means little when it is laid on the grave of a friend. Friend. He died of tuberculosis on July 14, 1827. His mother was with him when he died and he was 39. His brother Leonor continued his work on the lighthouse project. The Fresnel lens quickly became the standard in lighthouses around the world.
- [41:31]
A
One of the ways that Fresnel contributed to the world of science beyond his specific work in light waves and lenses, was that his approach to his work helped to establish the ways in which questions the of. Of physics would be examined. Going forward, the idea of physics as a branch of science hadn't really solidified yet. When Fresnel was conducting his experiments and developing his formulas, the word physics was kind of a nebulous term that referred to almost any study of the natural world. There were efforts in the decades leading up to Augustine, Fresnel's birth and beyond to try to formalize a more specific definition, but it had been problematic in some ways. Other specialties had managed to carve out their own identities. And physics was made up of the science that was unclaimed by the other disciplines. There were two branches of physics that developed. General encompassed things to do with the mechanics of the world and universe as it was understood at the time. So things like gravity, inertia, movement, etc. Particular physics dealt with the various characteristics of matter, like heat, light and magnetism. Former podcast subject Antoine Lavoisier had introduced the idea of physics as a recognized branch of science to the Academy of Science just three years before Fresnel was born. But Fresnel's very careful methodology of performing experiments and then developing the math to both verify and explain the results was a huge step forward and it set the bar for physics theory and proofs. Yeah, he's interesting.
- [43:07]
B
I feel like we left so much out, but I honestly can't parse a lot of his work. Don't ask me to explain the math. I love math and theory. I'm just bad at it. I have a listener mail that I hope won't make me cry, but it might because it's quite beautiful. This is from our listener Jen who writes hi Holly and Tracy. I recently listened to your behind the scenes episode on Spray Paint and I think it was Holly who was saying in her youth there was an area that it was a rite of passage for the young people to tag with spray paint and that it would periodically get painted over. It reminded me of my small town growing up. We actually had a rather high level of deaths of high school students. For the size of our town, death is always hard to process, but especially for kids and especially when it is someone so young. Anyway, there was a barn in the area that was unused and after a death the friends of the student would go out there and paint a eulogy of sorts, obviously sometimes more artistically than others, depending on who was present. But the point wasn't really the art of it as the grief processing it allowed. The memorial would stay until the next high schooler died and then it would be covered by the next group. It was a haunting, beautiful reminder each time you drove by. The barn continued to fall into disrepair over the years and it has now been torn down. But I sometimes wish something similar everywhere to allow for this kind of public and personalized memorial and a way for young people to work out some of their grief. Grief as Pet tax. I have attached a short video of my 3 year old son rolling around with our 7 year old rescue mutt Scuttlebutt. Thanks to the podcast. I always enjoy it. This is such a beautiful thing. Yeah, I get very choked up over it. It's so lovely and it is very insightful about people trying to process loss. So Jen, thank you. I'm crying. It's lovely. If you have an email that you would like to make me cry with, feel free. Take it as a challenge. It's not a very hard one. You can do that@historypodcastheartradio.com you can also subscribe to the show. Wherever you listen to your favorite podcasts, including the iHeartRadio app.
- [45:15]
A
Stuff youf Missed in History Class is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.
- [45:30]
C
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- [46:31]
A
For years, everyone thought Verizon had the best network because they did. But now the best mobile network in the US is T Mobile. T Mobile's network has the most advanced 5G with more towers, and their signal reaches further than ever. So you can text an insta talk and say, you won't believe where I am.
- [46:52]
B
T Mobile has the best mobile Network in the US based on analysis by.
- [46:55]
A
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- [46:59]
B
Network @t Rowe Price, their experience helps them see investment potential differently. Instead of quick answers, they know that what really leads to confident investing is true curiosity. And since you're listening to this podcast, we know you value curiosity too. It's what drives them to ask the questions that really matter in our ever changing world, like can healthcare innovations create a healthier world? And how will AI be a part of a new tomorrow? Just like you, their curiosity runs deep, and with it comes the power to help you invest more confidently. Better questions, Better outcomes. T. Rowe Price Learn more@t rowprice.com Curiosity.
- [47:36]
C
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A
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- [48:05]
A
This is an iHeart podcast.