Experiment

A few mornings later, Joseph donned his formal attire once more. Accompanied by Napoleon, who was dressed in his military uniform, he boarded a light two-wheeled carriage to attend the experiment on the speed of light, scheduled for that evening at Burton Castle on the outskirts of Paris.

Burton Castle was a property of the Orleans Family, situated atop a small hill. It was said to have been a military fortress built in the twelfth century, though it had long since lost any strategic value. Furthermore, the very features that had once reinforced its defenses made it almost entirely unsuitable for living, leaving the castle in a state of semi-abandonment. However, it was an excellent location for an experiment; it was far from the city with few residents nearby, meaning there was virtually no light pollution. From the high castle ramparts, one could clearly see the firelight reflected from mirrors placed about four or five leagues away (one league being approximately four kilometers), which was crucial for the night's experiment.

The location was somewhat remote and quite a distance from Paris, with no public carriages traveling there, so Joseph had rented a light two-wheeled carriage for the trip.

The carriage traveled all morning, reaching the vicinity of Burton Castle around three in the afternoon. At the foot of the hill where the castle stood lay an estate belonging to the Orleans Family, where those participating in the experiment were currently staying. The carriage pulled up to the estate gate, and a servant stepped forward to inquire. Joseph identified himself, and moments later, the wrought-iron gates swung open. The carriage rolled along the stone-paved path and stopped in front of a large house with distinct Baroque features. A servant came to open the door, and as Joseph and Napoleon stepped out, a servant wearing a wig led them inside.

The servant guided them through the hall and into a small garden at the back, where a tiny glass greenhouse stood. While this might not be considered much in later ages, in this era, it was a luxury few families could afford. Several people were sitting inside, drinking tea and admiring the blooming roses. As Joseph walked over, he noticed Condorcet, Lavoisier, Laplace, and Monge were all present, though the host, Duke Charles, was nowhere to be seen.

"Ah, Joseph, come over, come over..." Lavoisier beckoned as soon as he saw him. Joseph stepped forward to greet them one by one, offering special thanks to Monge and Laplace for their recommendations. Of course, to Napoleon, this sounded as though they were thanking them for recommending his paper.

Joseph then introduced his brother: "This is my brother, Napoleon. He is currently studying at the Paris Military Academy. He has a keen interest in science, so I brought him along to broaden his horizons. By the way, why have I not seen His Grace the Duke?"

"The Duke was here earlier, but he was summoned by His Majesty the King not long ago... I am not sure what it was about," Lavoisier said. "However, the Duke left his steward, Mr. Will, to assist us. Everything is actually prepared; we are just waiting for nightfall."

Over the past few days, the members of the Academy, with the cooperation of the Orleans Family, had precisely measured the straight-line distance from the watchtower of Burton Castle to the two nameless hilltops nearby. To ensure a clear line of sight, they had even cleared all the trees from the tops of those hills—they were, after all, also property of the Orleans Family.

Now that everything was ready, they only awaited the darkness. With nothing else to do, the group began discussing various scientific problems. Monge and Laplace huddled together, debating the potential function representation of the gravitational component of celestial bodies on any external point mass. Napoleon listened in, though he did little more than listen; unlike Joseph, he could not chime in from time to time.

Just then, representatives from the Orleans Family arrived to invite everyone to dine. Since the experiment was to begin shortly, the dinner was essentially a working meal and, by the standards of the Orleans Family, could hardly be called lavish. Even so, there were many things that Joseph and Napoleon were tasting for the first time, such as truffle slices tucked into bread spread with foie gras, along with other items Joseph couldn't even identify.

After the meal, everyone boarded the carriages again and headed toward the nearby castle. The carriage wound its way up the twisting road, reaching the base of the castle shortly thereafter.

As they disembarked, the sun in the west was nearing the horizon, growing larger and redder by the moment.

Servants lit lanterns and led the men from the Academy into the ancient fortress.

To ensure defensive integrity, buildings like this castle typically featured incredibly thick stone walls and very small, inward-facing windows. Consequently, ventilation and natural light were poor; even without it being dusk, the interior would have been dark enough to require lamps even at noon. Thus, unless it was a time of war, nobles rarely chose to live in such castles. In the present day, due to the advancement of artillery, these old fortresses held no military significance, so nobles were even less inclined to live there, often refusing to pay for their upkeep, leaving them to fall into widespread disrepair. Gloomy and requiring illumination even during the day, these abandoned, dilapidated castles naturally became the settings for ghost stories. The very castle they were entering was said to have its own "castle ghost."

Joseph led Napoleon, following a servant carrying a lantern, as they climbed the winding stone stairs. The servant illuminated the steps with the lantern and offered a warning: "Sir, the castle is very damp, and these stone steps are covered in moss and quite slippery. Please be careful as you ascend."

"Thank you, we will be careful," Joseph replied, his head bowed as he watched his feet on the stone steps.

Soon, they reached the watchtower at the very top of the castle, a small platform about twenty meters long. At one end of the platform sat a pile of firewood soaked in whale oil. Once lit, this brazier would produce a flame significantly brighter than an ordinary fire, visible in the darkness from as far as nine leagues away. At the other end of the platform stood a rotating eight-sided mirror.

A telescope was also mounted on the platform, and through it, one could see the set of reflecting mirrors already installed on the distant hilltop.

"Have these mirrors been calibrated?" Joseph asked.

"They have. They can accurately reflect the light onto the other face of the eight-sided mirror," Monge replied in a low voice.

The sun sank lower and lower, finally dipping below the horizon, leaving only a pale purple afterglow in the western sky. One by one, stars began to appear in the darkening firmament, and soon the sky was studded with jewel-like constellations.

Seeing that it was sufficiently dark, Lavoisier said, "Very well, we may begin."

A servant lit the large woodpile with a torch, and shortly after, a firework rose from the distant hilltop, signaling that they could clearly see the light from this side.

With that confirmation, everyone focused their attention on the other face of the eight-sided mirror. According to the experimental design, the light would travel from one face of the rotating mirror to the reflector on the other hill and then bounce back. If the eight-sided mirror rotated by exactly one facet angle during that interval, the reflected light would be visible on the opposite face.

There was no reflection in that direction. The eight-sided mirror spun faster and faster, yet the light remained unseen.

"Faster, it needs to be faster," Joseph said, staring at the rotating mirror.

The speed of the eight-sided mirror continued to increase until, finally, a flickering light began to shimmer on the face they were watching.

"Steady, hold the rotation speed! Good, excellent! Quick, record the speed!" Monge shouted.

An assistant hurried to record the rotation rate.

As soon as the data was available, Joseph, Laplace, and Monge immediately crowded around. By the light of the fire, they began their calculations. Laplace arrived at the answer first, followed by Monge. As for Joseph, by the time they had finished, he was only about two-thirds of the way through his own calculation.

"Haha, Joseph, your calculation skills are not quite up to par; you are surprisingly slow," Monge laughed heartily.

Napoleon's face was also filled with a gloating smile. Looking into his eyes, Joseph knew exactly what the boy was thinking: My foolish brother, even you have times when you are looked down upon.

In my past life, such complex calculations would have been solved with a single tap of the 'Enter' key; who would ever do it manually? My speed is already impressive enough as it is—if it were anyone else, they might not even be halfway done, Joseph thought to himself, while offering a wry smile in response: "My calculation skills are indeed lacking; I can never seem to get the speed up, and if I try to rush, I make mistakes. I can't help it."

The others laughed along.

Amidst the laughter, Joseph finished his calculation. The three men compared their results, which were essentially identical. Joseph silently converted the figure into kilometers, concluding that it was already very close to the speed of light measured in later generations.

"Is it truly that fast?" Laplace murmured. "If light is indeed a wave, what strange properties must the aether possess? It is truly unimaginable! But if light is a particle, how then to explain double-slit interference and the Bonaparte spot..."

"Let us be bolder. What if the medium for the propagation of light is not some substance as we usually assume, but space itself?" Napoleon suddenly interjected.

"Space itself? Light is actually a fluctuation of space?" Condorcet asked immediately. "Ah, Napoleon, you have a great talent for philosophy. However, as a scientific hypothesis, it clearly lacks sufficient evidence. Science requires evidence, much like your brother's conjecture, which at least has a mathematical model to support it. Still, this perspective is truly... unfortunately, we have no available research methods for space itself."

Napoleon's remark had given Joseph quite a start. He knew, of course, that while the light-aether did not exist, light was not a fluctuation of space. Space could indeed have fluctuations, but those were not light—they were gravitational waves.

This guy, this guy really has some imagination. If I cultivate him carefully, could I lead him astray and eventually turn him into the Emperor of Physics? Joseph couldn't help but think.