The Rong Mansion was really big in the past, so Uncle Wang brought his son back to celebrate the New Year.
Xiao Wang, who was almost sent to Xiaodao Liu Jingshen's operating room back then, has now been studying at Ding Haoliang's Beijing Chongshi School for more than a year.
According to the school's plan, he must study for at least three years before considering his next step.
Uncle Wang admired Li Yu very much and kept telling Xiao Wang to study Western learning hard.
It just so happens that there are students and people like Yu Heqin in the house right now. When I have nothing to do, I can help Xiao Wang with his homework in the evening.
Xiao Wang is very interested in modern science and enjoys learning.
Just like in later generations, many businesses will stop during the Chinese New Year.
Major departments of the imperial court were even "sealed" to prevent people from secretly getting involved in working overtime (someone did do this in the past, so the departments were sealed to give workaholics no place to use their energy).
But some things cannot be stopped, and the postal service has not been suspended. To be precise, the international mailing service has not been suspended, because there are still some foreigners who need to send letters.
Einstein's letter traveled across the ocean and finally reached Li Yu's hands.
Li Yu is in the capital, which is relatively nearby, otherwise this letter would have been delayed for nearly a month.
Zhao Qian goes to the Qing Post Office every day. This is a small daily task given to him by Li Yu. There is no other way. Now this is the fastest way.
Postman Cui saw Zhao Qian and immediately said to him: "There is a letter from your master, sent from Switzerland."
Zhao Qian knew that letters from foreign countries must be full of strange foreign characters, let alone foreign languages. He couldn't even read Chinese, so he asked: "Is it really from the master?"
Postman Cui said: "It's true, you are the only one who sent the mail from abroad and asked for the Chinese by name. Just wait, I will look for it."
There are many mailboxes in the post office, and international mail is sorted into boxes from different countries. Most of them are from Britain, France, Russia, and Japan, but there are really few from countries like Switzerland.
While looking for the letter, Postman Cui chatted with Zhao Qian: "We haven't seen each other for a long time, and you are already wearing such a good cotton-padded jacket."
Ordinary cotton-padded clothes cost half a tael of silver, but those with good quality like Zhao Qian's cost at least one tael of silver.
Zhao Qianliang took action and said proudly: "Not only do we have cotton-padded jackets, our master also gave us gloves!"
"Gloves?" Postman Cui raised his head, and sure enough he saw Zhao Qian wearing a pair of strange gadgets on his hands.
Although gloves have long been available in China, they are not very popular.
In the Qing Dynasty, the way to keep hands out of the cold was usually to put them in the sleeves on both sides, or in special "hands".
In addition, some clothing in the Qing Dynasty had a design called horseshoe sleeves, which were also designed to protect the hands from the cold.
Normally, the horseshoe sleeves are rolled up to the wrist; when going out in winter, they are lowered to keep the palms warm from the cold without affecting the flexibility of the fingers. From this function, we can see that the original design had combat needs.
Later, this design was incorporated into daily clothing. In the social life of the Qing Dynasty, dusting off the horseshoe sleeves has always been an important step when greeting elders.
You must have seen Qing palace dramas. Before officials bowed to the emperor, they often patted their sleeves on both sides. In fact, they were dusting off their horseshoe sleeves.
Starting from Huang Taiji, Emperor Taizong of the Qing Dynasty, this action has been designated as a regulation for officials to worship, and is called "Fang Wa Ha". "Wa Ha" is the Manchu name for horseshoe sleeves.
It was not until the late Qing Dynasty that gloves entered the public eye again with the arrival of foreigners.
It was discovered that both clergy and military officers in Europe like to wear gloves.
This is different from the living habits of wealthy people in the late Qing Dynasty. Rich people in the late Qing Dynasty liked to wear various finger rings or jade rings to show their status.
Perhaps this is also the reason why we have not paid much attention to gloves.
But now everyone sees that respectable Westerners like to wear gloves, and they follow suit.
Anyway, gloves are definitely a rare foreign item at this time.
Postman Cui was really envious when he saw it. It was a cold day at this time, and his hand reached out to find the letter for a while before it became extremely cold.
Postman Cui shook his hands and said, "I will also encourage the superiors to wear gloves for us from now on."
After a few minutes, he finally found a thick letter. The letter was wrapped in a delicate envelope, and the seal was covered with thick wax. At first glance, it looked like a typical Western letter.
"That's probably this one. It's pretty thick. Let me look at the stamps. 70... francs?"
Zhao Qian asked: "What is a franc?"
Postman Cui said: "I don't know what it is specifically, but generally a letter sent from the UK costs close to 3 pounds. I think it might be similar in Switzerland."
Postman Cui has been exposed to many Western letters and has a preliminary understanding of European geography.
"The British pound is amazing!" Zhao Qian was also very proud of his master, and felt that he had a very respectable face, "Our master can have high-level exchanges with foreign adults."
Postman Cui said with a smile: "That's not true. Mr. Li is the emperor's master after all."
Zhao Qian collected the letter and asked, "Do I need to pay more money?"
Postman Cui said: "No, this Swiss man named Shorty Stan has already paid for it. It's a 70-franc stamp."
"Short Stan?" Zhao Qian wondered.
Postman Cui said: "Don't you know, there are many people in foreign countries called Stan."
Zhao Qian said: "It's really weird for foreigners to have names. Short ones? How can anyone be called this?"
It was not something he could understand now. Zhao Qian collected the letter and returned to the mansion.
As soon as he left, a young man stepped out and turned out to be Xiao Zuoxiang brought by Konoe Akiyuki.
Xiao Zuo Xiang and Postman Cui exchanged glances. Postman Cui leaned out and looked outside, then said, "Come inside and talk."
Coming to the back room, Xiao Zuo Xiang asked: "The Empire of Japan values you very much. I hope you won't let us down."
Postman Cui said: "Looking at what you said, the little one will definitely not dare."
Xiao Zuoxiang continued to ask: "How do you think about the things we entrust you to do?"
Postman Cui murmured: "I am not the head of the post office. Some things are really inconvenient to operate."
Little Zuo Xiang raised his voice and said, "What's so difficult about this?"
"I..." Postman Cui said, "After all, Mr. Li and I have no grievances..."
Little Zuo Xiang said: "Of course you have no enmity with him, but we can be kind to you."
Postman Cui said: "I..."
Little Zuo Xiang snorted: "How much money can you make as a shabby postman? As long as you complete a small task for us that is easy for you, you will get a lot of money."
Postman Cui asked: "Do you really mean what you say?"
Little Zuo Xiang glanced at the direction Zhao Qianyuan was going and said: "Not only money, do you also want to have gloves and cotton-padded jackets like that? He is just a little slave, and he is better off than you. Can you stand it?"
Postman Cui swallowed and finally said, "I want it."
Xiao Zuo Xiang laughed and said: "Isn't this right? Those who know the current affairs are heroes! I will come to you again after a while."
Postman Cui sighed: "I understand, little one."
Xiao Zuoxiang patted him on the shoulder: "Serve the Empire of Japan, and the Emperor will not forget your benefits."
——
At Li Yu's house, when he got Einstein's letter, he didn't expect it to be so thick. When he opened it, he found two papers.
The first article is relatively thin, and its name is "A New Method for Determining the Size of Molecules." This article may be less famous, but it is also one of Einstein's miracle years. This paper actually analyzes and proves the molecular
existence.
Yes, at this time, the scientific community still cannot fully believe in the existence of molecules; or some people believe it, but cannot prove it.
The second article is thicker and is titled "An Instructive Viewpoint on the Generation and Transformation of Light". It is also an article about using the light quantum hypothesis to explain the photoelectric effect. Einstein's only Nobel Prize in Physics was based on this
papers.
Einstein also appended an additional letter:
"Dear and respected Mr. Li Yu,
"There is a sacred silence between us thousands of miles away. This is the absolute distance in time and space. If I break it with insignificant words, I think it would be a kind of blasphemy.
"In view of our previous communication that was full of whimsical ideas and insight into the truth of the universe, I wrote the following paper - of course, it is not just that.
"The first paper is about a recent thought experiment of mine. I had previously read the 1901 paper by Mr. Jacobs Vantoff that won the Nobel Prize in Chemistry. He mentioned that particles in solutions are similar to those in gases.
.
"So I thought if the same thing happened in a liquid, wouldn't it be like a magical sugar cube dissolving in coffee, where water molecules surround the glucose molecules and separate them from the sugar crystals.
"And as you add more sugar, the coffee gets sweeter and sweeter.
"Then I thought that if I could calculate the osmotic pressure, I could calculate the accurate Avogadro's constant, thus proving that molecules really exist."
After Li Yu read this, he understood why Einstein was truly the greatest physicist of the 20th century. His thought experiments were ridiculously powerful. The starting point was so simple, but the truth was so profound!
After drinking coffee, I thought about how to prove the existence of molecules.
Li Yu immediately guessed that he should have encountered some mathematical difficulties and experimental difficulties.
You can try to calculate Avogadro's constant, but this paper involves the field of thermodynamics, so it must be obtained through experiments to be convincing.
It is not easy for most experimental physicists to measure such ultra-super astronomical numbers at the level of 10 to the power of 23.
Li Yu had no choice but to hope that Jean Perrin from the University of Paris in France would speed up the progress.
After all, this constant is indeed critical and useful.
In mathematics, Li Yu has some ideas.
Li Yu unfolded the letter and continued reading:
"Mr. Li Yu, you know, there are not many people who believe in the molecular or atomic hypothesis. I have contacted many university professors, but they are not willing to accept or review my papers. And I remember that you have used Bohr many times.
Professor Zeman's theory, so I know that you believe in the existence of atoms and molecules. And in mathematics, your achievements are as tall as a thousand-year-old tree, so I hope you can help me correct some mathematical errors.
"With your name, physics journals will be happy to publish my paper.
"And this paper is related to whether I can get a doctorate from the University of Zurich."
Einstein indeed relied on this paper to obtain his doctorate. Li Yu did not expect that he could be of help.
Einstein's thesis is actually very complete, but there are still some minor omissions in mathematics.
Fortunately, the mathematical content involved was within Li Yu's ability.
Li Yu turned to the second page of Einstein's letter:
"The second paper is about a demonstration of the photoelectric effect. The most critical point is Mr. Planck's quantum theory. I know that this contradicts the 'infinite divisibility hypothesis of energy' in the academic world of physical systems, but I found that
It can best explain the results of Mr. Leonard's photoelectric experiments.
"You must understand that how to explain the mysterious Planck constant proposed by Mr. Planck is the key to the problem, because my formula just uses it. But Mr. Planck thinks that this constant is just a method used in mathematics.
, has no physical meaning. But I think I discovered the truth hidden behind it.
"You have used profound mathematics to perfectly demonstrate Mr. Planck's theory, so I think you can also be the most suitable reviewer.
"...
"Einstein, written in Bern, Switzerland."
Li Yu closed the letter and opened the two papers.
The first article about proving the existence of molecules is actually not difficult to handle. Although Avogadro's constant cannot currently obtain an accurate value through experiments, a rough value can be estimated temporarily using mathematical methods.
——In fact, Li Yu knew the specific value in his heart.
Einstein was somewhat rusty in mathematics because he had been a patent clerk for two years, but his talent in physics was really unreasonable.
The errors in the paper are not particularly serious and can only be corrected slightly.
As for the paper on the photoelectric effect, I need to answer a letter carefully.
Li Yu spent a whole day carefully reading and revising the paper, and then wrote a telegram and sent it first:
"Dear Mr. Einstein,
"Thank you for your trust! I have completed the revision of the papers, and they will soon be on the passenger ship bound for Europe.
"As for what you said about Planck's constant, I think it can be understood this way.
"Just as any periodic function in mathematics can be decomposed into a sine wave using Fourier series, the frequency of the sine wave can only take discrete values such as ω, 2ω, 3ω (ω is related to the period T),
"Planck's constant is very similar in meaning. After expanding Professor Planck's blackbody radiation formula, the energy of frequency v can only take discrete values such as hv, 2hv, 3hv, h (h is Planck's constant)
It can be considered as the expansion coefficient after expanding the blackbody radiation function.
"So it can indeed be regarded as a unit of quantity. Even for physical thinking, its specific amount is not important. It is enough to know that it is a very small positive number.
"Because this does not affect your interpretation of the photoelectric effect.
"..."
What Li Yu said was very basic, but for Einstein, physical thought was more important, so what he said was enough.
With a brain of Einstein's level, there is no need to talk nonsense. He was just too ahead of his time. He was inevitably hesitant, and the times were also resisting his ideas.