Under the puzzled gazes of the crowd, Alok installed the gears in front of the alchemical instrument that emitted light beams, and placed a piece of strange-looking glass between them.

Lin En finally explained. "This is a half-mirror! It is different from ordinary glass. As the name suggests, only one side can let the light beam pass through!"

Glenn looked back and forth in amazement. He could see the scene behind him clearly on one side, but it was blurry on the other side.

"This experiment is also very simple. This alchemical instrument emits a beam of light. When the gear is stationary, the light passes through the gap between the teeth and hits the reflector on the opposite side. It will then reflect back along the same path and hit the side that is not transparent, forming a larger light spot for us to see directly!"

As he spoke, Lin En turned on the alchemical instrument, and two beams of light immediately appeared in the air.

Just as he said, the light passed through the semi-transparent mirror, crossed the gap between the two gears, accurately hit the reflector in the distance, then turned back, passed through the gap between the teeth again and hit the semi-transparent mirror.

"But if this gear starts to rotate... then the light that passes through the teeth may be blocked on its way back." Lin En paused, his mind moved, and under the drive of the [Mage's Hand], the gear slowly turned.

Lin En didn't need to explain too much. Everyone could see that the light beam behind the huge gear began to appear and disappear from time to time, and the light spot on the half-mirror also began to flicker. That was because the light might just pass through the teeth when returning, or it might be blocked by the gear...

Just as the wizards were frowning and thinking about this phenomenon, Lin En's words came again.

"Theoretically, if the gears rotate fast enough, the light will pass through the first tooth gap and return across a distance of eight kilometers, and then pass through the second gear gap. Then..."

Before Lin En could finish, Glenn said in shock as if he had thought of something. "In this way, every light element that can pass through the tooth gap will definitely return from the second tooth gap. There is no possibility of being blocked, and the light beam and light spot will become extremely obvious!"

Glenn's words were like a huge rock thrown into a calm lake, and the wizards present were immediately in an uproar.

"This is really... a genius idea!" Raphael said with a trembling voice.

He had been wondering what method this magic star would use to measure the speed of light, but he didn't expect that the other party could do it with just a small gear!

The key to this experiment is to synchronize the time it takes for the gear to rotate one section with the time it takes for the light to be emitted and returned.

The subtlety lies in the fact that light needs to travel a full distance of eight kilometers, while the relative gear only needs to rotate slightly to reach the second tooth gap!

In other words, each tooth on the gear represents a distance of eight kilometers traveled by light. If there are a total of one thousand teeth, and they rotate once, light must travel a distance of eight thousand kilometers. Ten rotations would be eighty thousand miles!

The wizards who also understood this couldn't help but gasp. This tiny gear was like a super amplifier!

The speed of light may be incredibly fast, but the speed of gears can also be increased to an extremely fast level...

"This is the speed of gears competing with light!" Harof also said with an exclamation.

It’s just that Lin En is very unethical. For the gear to move five millimeters (the distance of one tooth), the light must run eight kilometers... a difference of hundreds of thousands of times!

Finally, you just need to know the distance the gear has traveled multiplied by this multiple difference - that is, look at the number of teeth separated on the gear and the number of circles the wheel rotates in one second, and you can reversely calculate the speed of light!

No wonder Lin En was so confident that he could measure the speed of light...

He was convinced. What kind of brain could come up with such an idea?

However, there were also many wizards watching with confused expressions on their faces.

What are you talking about? I don't understand...

But in order to maintain his dignity as a wizard, he nodded pretentiously and then said a few words of praise.

"As expected of the Magic Star..." "That's a good idea! I knew he would have a solution!"

Amidst the praise, there were also many opposing voices. Athos and others insisted that the speed of light was infinite, and no matter how fast Lin En could accelerate the gears, it would be in vain!

"Dean, can we start?" Lydia shouted loudly.

Lynn nodded and asked the halfling girl to start the internal combustion engine and increase the speed of the gears.

Under the gaze of everyone, the 720-tooth gear in front of them slowly began to turn, and then the speed became faster and faster, five circles per second, ten circles, fifteen circles... and soon it turned into an afterimage.

The light beam and the light spot on the half-mirror are also flickering constantly, with the frequency getting faster and faster, because the light is always switching back and forth between passing through and not passing through...

"So fast..." Witch Nancy muttered to herself. She could no longer see the speed of the gears. "At this speed, can light really distinguish the tiny gaps between the teeth?"

You have to know that the distance between each tooth gap is only 0.5 cm, which will become a sharp cutting instrument at high speed. What if the light element can't find the tooth gap when passing through? Then they can't see it? "We may not be able to distinguish, but light can!" Lin En said confidently.

"Look, the frequency of the flashing light beams and light spots seems to... be starting to slow down!" Raphael hurriedly reminded.

He was not the only one who noticed this, because the change was so obvious that it could not be an illusion. After the speed of the gears increased again, the wizards present suddenly showed expressions of fear on their faces...

"The light spot actually...disappeared!"

Sanchez's eyes widened as he saw an extremely strange scene in front of him. The tiny light beam emitted from the alchemical instrument stopped on the gear when it returned, but the light beam from the gear to the half-transmitter suddenly disappeared. It no longer appeared and disappeared like before, and there was no light spot on the half-transmitter.

This is exactly the opposite of what Lynn said...

"What is going on?" Raphael almost pulled his beard off, his mind full of confusion.

"That's because the light that passes through the teeth just happens to hit the tooth joints when it returns. This shows that the speed of light is limited. We are already halfway successful!" Lin En's words rang in everyone's ears.

(End of this chapter)