One morning, a few days later, Joseph, once again dressed in formal clothes, took Napoleon, in uniform, to a light two-wheeled carriage to attend an experiment on the speed of light to be conducted tonight at the Château de Bourdon outside Paris.

Château de Bourdon was the property of the Orléans family, a castle built on a hilltop. The castle is said to have been built as a military fortress in the 12th century, but it has long since lost its military value. When the castle was first built, it was made almost completely uninhabitable to strengthen its defenses. So now the castle is almost in a semi-abandoned state. But for experiments here is very good, here far from the city, the nearby residents are few, there is almost no light pollution. On the top of the castle, you can see the light of the fire reflected from the reflector about four or five furlongs away. This is crucial for the night experiments.

But the place was a bit isolated and far from Paris, and no public carriage would come to it, so Joseph rented a light two-wheeled carriage to go there.

It took the carriage all morning and until about three o'clock in the afternoon to arrive near the Chateau de Bourdon. At the bottom of the hill where the castle was located, there was a manor house of the Orleans family, where all the people who came to participate in the experiment were staying at that time. The light carriage stopped at the entrance of the manor. An attendant came up to ask questions. Joseph identified himself to the attendant, and in a moment, the iron gate of the manor was opened, and the carriage entered the manor along the stone-paved road and stopped in front of a large house with obvious baroque style. A waiter came up and opened the door, and Joseph and Napoleon got down from it, and a messenger in a wig led them in.

The attendant led them through the hall to the little garden at the back, and in that little garden, there was a little glass greenhouse. This was not much in later times, but in these times, it was not something that ordinary people could afford. At this time several people are sitting inside while drinking tea and watching the roses in bloom inside. Joseph walked by and noticed that Condorcet, Lavoisier, Laplace, and Monge were all there. But he didn't see his master, Duke Charles.

"Ah, Joseph, come here, come here ．．．．．．" As soon as he saw Joseph, Lavoisier waved to him. Joseph went up to them, greeted them one by one, and thanked Monge and Laplace in particular for their recommendation. This thanks, of course, meant to Napoleon that he thanked them for recommending his thesis.

Then Joseph introduced his brother to them: "This is my brother Napoleon. He is now studying at the École Militaire in Paris. He is also very interested in science, so I brought him here to open his eyes. By the way, why didn't I see His Grace the Duke?

"His Royal Highness was also here. But a while ago, he was summoned by His Majesty the King ．．．．．． I don't know what's going on." But the Duke has asked his butler, Mr. Will, to stay here to help us, and now everything is ready for the night.

In the days, the men of the Academy, with the cooperation of the Orleans family, measured the distance from the watchtower at Fort Burton to the top of the two unnamed hills nearby. To ensure the line of sight, they also cut down all the trees on top of the two nameless hills - which were also the property of the Orleans family anyway.

Now everything is ready, only the darkness. There was nothing to do at this time, so we discussed various scientific issues together. Monge and Laplace got together to discuss the expression of the potential function of the gravitational component of a celestial body concerning any point of mass outside it. Napoleon also listened, but only to listen. Unlike Joseph, he was able to interrupt from time to time.

At this time, the Orléans family came to invite everyone to dinner. Because the experiment will be conducted soon, the dinner is a working meal, according to the standards of the Orleans family, it is not at all sumptuous. But even so, there are many things that Joseph and Napoleon ate for the first time. For example, the truffle slices that were stuck in the bread with foie gras and some other things that Joseph didn't know what were in his mouth.

After the meal, everyone got back on the carriage and drove to the castle not far away. The carriage curved up the winding road, and soon arrived at the bottom of the castle.

Everyone got off the carriage, and by now the sun was nearing the horizon in the west, growing bigger and redder.

The servants lit the lanterns and led the men from the Academy into the castle.

Castles, to ensure the defensive power of such buildings, usually have very thick stone walls, and very small, and usually inward windows. So this kind of building ventilation and light will be very poor, not to mention that it is already evening, is noon, the castle inside is also dark enough to need to light the light. Therefore, unless the war era, the nobles are still less willing to live in the castle. Nowadays, because of the progress of artillery, these ancient castles no longer have military significance, the nobles naturally will not live here, and even continue to take care of their expenses are not willing to pay, so these ancient castles are generally in disrepair. Eerie, even in the daytime need to light the ancient fortress, coupled with the decay of no one, these ancient castles have become the stage for ghost stories one after another. Including this castle, they entered today there is also the "ghost of the castle" legend.

Joseph, with Napoleon in tow, followed an attendant with a horse lamp up the winding stone steps. The attendant, while shining his horse lamp on the steps, warned, "Sir, the castle is very humid, and the stone steps are mossy and slippery.

"Thank you, we'll take care of it," Joseph replied with his head down, staring at the stone steps under his feet.

Soon they came to the uppermost lookout of the castle. This is a small platform about 20 meters long. At one end of this small platform, there is a firewood pile, which is piled with whale oil poured wood. When this fire pit was lit, it could emit a brighter fire compared to the general flame. In the dark conditions, this fire can be seen even from nine furlongs away. And at the other end of the platform, there is a set of eight mirrors that can be rotated.

There was also a telescope on the platform. Looking through the telescope, you could see that a set of reflectors had been installed on the top of the hill.

"Have these reflectors been tested? Joseph asked.

"They've been tested. They reflect the light accurately on the other side of the eight-sided mirror. Monge replied in a low voice.

The sun was getting lower and lower, finally sinking below the horizon. Only a lavender glow remained in the western sky. Star after the star appeared in the darkening sky, and in a short time, the sky was filled with jewel-like stars.

Seeing that it was dark enough, Lavoisier said, "Well, it's time to begin.

An attendant lit a large fire with a torch in his hand, and then a firework went up from the top of the hill there. This was to show them that the fire on that side of the hill could be seen from there.

After receiving this response, everyone focused on the other side of the eight-sided mirror. Because according to the experimental setup, the firelight from the side of the rotating eight-sided mirror to another reflector on the hill, and then reflected. If the mirror happens to rotate a mirror angle during this time, then the reflected light can be seen from the other side of the mirror.

There is no reflection in that direction. The eight-sided mirror turned faster and faster, but still no firelight.

"Faster, faster, faster." Joseph stared at the spinning mirror and said.

The mirror continued to spin faster and faster, and finally, the flashing fire began to flicker on the side everyone was staring at.

"Hold on, hold on to the rotation speed. Yes, yes! Quickly, record the speed!" Monge shouted.

An assistant hurriedly recorded the speed.

As soon as the data came out, Joseph, Laplace, and Monge immediately gathered around. By the light of the fire, they began to calculate. Laplace came up with the answer first, then Monge also calculated it, and Joseph, when they all calculated it, Joseph had only completed about two-thirds of his calculation.

"Hahaha, Joseph, your calculation ability is not good enough, you are so slow. Monge burst out laughing.

Napoleon's face was also full of gloating smiles. Looking at his eyes, Joseph knew that this guy was thinking: "My stupid brother, you are also despised sometimes.

"In my older days, I would have solved such complicated calculations by knocking a carriage return, who would do it manually? I'm already very good at this speed, but it's not good. Joseph thought this and replied with a bitter smile, "My calculations are not good, I can't get up to speed, and when I speed up a little, I make mistakes. I can't help it."

The people next to me laughed together.

Amid the laughter, Joseph also finished his calculation. The three of them compared the results of their calculations and they were the same. Joseph silently converted the number into kilometers and concluded that it was very close to the speed of light measured by the next generation.

"It's that fast?" Laplace murmured, "If the light is indeed a wave, what kind of strange properties the Ether should have. It's unimaginable! But if the light is a particle, what about double-slit interference and Bonaparte's bright spot? ．．．．．．"

"If the propagation medium of light is not a substance as we usually think, but space itself? Napoleon on the other side suddenly opened his mouth.

"Space itself? Light is the fluctuation of space? Condorcet immediately said, "Ah, Napoleon, you have a philosophical talent. But if this idea is a scientific conjecture, it is obvious that there is not enough evidence. Science requires evidence, like your brother's conjecture, at least a set of mathematical models to support it. But this view, but really ．．．．．． Unfortunately, we don't have any available research methods for space itself.

And Napoleon's words also took Joseph by surprise. He knew, of course, that although the light ether or whatever does not exist, light is not the fluctuation of space. There can be fluctuations in space, but they are not light, they are gravitational waves.

"This guy, this guy has some imagination. If we cultivate him seriously, can we make him crooked and eventually become the emperor of physics? Joseph could not help but think so.