His name is Maxwell.

The very same Maxwell who wrote Maxwell's Equations, laying the foundation for the modern electromagnetic field theory, without whom there might not even be mobile phones, and whose personal ethics are considered exemplary, the ultimate boss.

Late 19th century.

When Maxwell was invited to establish the Cavendish Laboratory, he personally discovered twenty bundles of mysterious manuscripts in a box left by Cavendish.

Of course.

Some people later added a mysterious touch by describing the box as if it was a puzzle box that required solving certain problems to open.

For decades after Cavendish's death, only Maxwell could solve this mystery.

However, it's a pity.

Maxwell's method of opening it wasn't so mystical; he just used some physical means:

He broke the lock with an axe.

These manuscripts are currently housed in Room 6 of the Percival David Collection at the British Museum, and years ago, the Louvre even argued over it with the British Museum.

At that time, the Louvre believed these manuscripts were discovered by Maxwell and should therefore be collected by the Louvre.

The British Museum retorted that an artsy museum like them couldn't understand a single thing about physics manuscripts, rejecting the request.

According to the manuscript records.

Between 1772 and 1773.

Cavendish conducted an experiment called the concentric spheres experiment.

This experiment was the first to accurately measure the relationship between electrical force and distance, with an index deviation of no more than 0.02.

Later, the French Coulomb verified his discovery through experiments, thus the law of interaction between charges was named Coulomb's law.

Compared to Coulomb's torsion balance experiment, Cavendish's concentric sphere experiment was not only earlier but more accurate.

Although later measurement accuracy reached the magnitude of 10^-16, Cavendish's experimental principles were still used.

If he had published these findings, what we know today as Coulomb's law might have had a different name.

Additionally.

Cavendish was the first to propose the concept of electric potential, noting the proportional relationship between electric potential and current.

Since there were no instruments at the time to measure current, Cavendish used his body as an experimental instrument.

He estimated the strength of the current based on the numb feeling in his body, discovering that the electric potential (difference) across the conductor is proportional to the current passing through it.

This is also what we know as Ohm's law in our physics textbooks.

Meanwhile, Cavendish, along with Faraday, advocated that:

The capacitance of a capacitor changes with its medium and is affected by the material inserted between its plates.

Based on this, he proposed the concept of dielectric constant.

And because he conducted so many electrical experiments, he also proposed that around every charged object there exists "electricity," which is very close to the concept of electric field theory.

Impressive, right?

But that's not all:

In one accidental experiment, Cavendish unexpectedly discovered a situation:

Some metals, when reacting with acid, produce a "flammable air."

This "flammable air" is hydrogen.

But at that time, there was no common understanding of this gas produced by the reaction, and Robert Boyle referred to all produced gases collectively as "artificial air."

However, Cavendish disagreed.

He insisted it was a new substance.

So he used the now common method of water displacement to collect some hydrogen.

After drying and purification processes, he successfully determined the density of hydrogen.

Of course.

The most important part of this experiment wasn't determining the density of hydrogen, but discovering that mixing two gases surprisingly produced water.

This caused quite a stir at the time because the chemical community widely believed that water was one of the elements that composed all things:

The then "four elements" theory included water, earth, air, fire, believing water couldn't be decomposed further.

Because of this, Cavendish was even stripped of some knighthood honors, and his annual income suddenly dropped to the equivalent of fifty or sixty million today.

Yes, fifty or sixty million.

Quite a sad story—Cavendish was born into a large family and, due to choosing the right side, was virtually a financial giant, which allowed Cavendish to conduct so many experiments.

What was even more unexpected was this:

Cavendish also found that about 1/120 of the air consists of a gas that almost doesn't react, which are the rare noble gases.

When were noble gases truly discovered?

The answer is more than a hundred years after Cavendish's passing:

In 1895, Ramsey discovered argon using yttrium uranium ore, confirming Cavendish's genius conjecture from back then.

Aside from the numerous contributions above.

Cavendish was most famous for the torsion balance experiment.

But interestingly enough.

It's precisely this most famous torsion balance experiment of Cavendish's that has been misunderstood by the world.

The torsion balance he used was actually designed by Michel, that previously mentioned Father Michel, and Cavendish was not the true inventor.

After Michel's death, the device changed hands several times before it finally reached Cavendish.

Then Cavendish made several meticulous modifications to the device and began a lengthy measurement that lasted 25 years.

Also worth mentioning:

What he measured with the torsion balance was not any gravitational constant.

He actually intended to measure the Earth's density and mass to assist the popular astronomical research at the time and, in doing so, verify the existence of gravity.

The operation of this experiment wasn't complicated:

First, in a stationary state, light was shone on a small mirror, and the light would be reflected to a faraway place.

Then immediately mark the position where the light spot appeared after being reflected.

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