It is normal for Li Ciyu to be inexplicable, and the problem of the base system is very common, such as the old scale of sixteen taels and one pound, shoes, socks, etc., but there is this term in ancient China, and Li Zubai found this problem very sensitively at this time.

The abacus is a commonly used method of the quintal system, but no one will consider the base system problem if they are used to it, or no one will be aware of this problem. The abacus began to replace the calculation from the Song Dynasty, which was a huge progress, which was promoted by the developed commodity economy of the Song Dynasty, but it was only simple and convenient to use, and no one seriously studied why the calculation efficiency of the abacus was so high, which was a problem of the way of thinking.

Li Zubai saw the opportunity from here, so he asked Galileo for advice: "Mr. Galileo, I am very interested in the 'quintal system' you just mentioned, can you explain to us the knowledge of the base system?" ”

Galileo smiled and said: "This question is very simple, it's just that you are not used to this way of thinking, in fact, there is this kind of problem in your "Nine Chapters of Arithmetic", and the base system is just a noun. Specifically, it is to take different quantities as a unit of measurement, for example, this abacus, the lower beam five beads on the top of the upper beam a bead, whenever the lower beam is enough to make five, use the upper beam a bead instead, if written down is 1, 2, 3, 4, 10, 11, 12, 13, 14, 20, this counting method is the quintal, but here 10 is the decimal 6, which needs to be marked. ”

This kind of knowledge is very new to Li Ciyu, he is a family heirloom of arithmetic, for Galileo such an unreserved explanation of the system of the system of entry he was very surprised, this in the Ming Dynasty is a unique science, in the traditional habits will only teach the son-in-law, but here is an open research, no wonder the emperor Zhu Youxiao to vigorously develop the school, it turned out to change everyone's mode of thinking, let everyone take out the family heirloom of the school.

Drawing inferences from one another, Li Ciyu naturally thought of why many selling sesame oil on gourds or marked good scales, it turned out that they had already been calculated by the shopkeeper, and the calculation method was the "Jin Scale Slip" formula, he was familiar with this problem, and many novices who did business had come to ask for advice, but they were all taught in secret, and they were not allowed to teach others. It seems that the knowledge of arithmetic is still very profound, and his own knowledge is still much worse.

In the next topic, Li Ciyu humbly asked Galileo a lot of questions about arithmetic, and even on the "Nine Chapters of Arithmetic" and Galileo had a different method of calculation competition, the two had a feeling of sympathy, and finally Li Ciyu finally understood that he had studied arithmetic for so many years, called mathematics in Europe, and studied the knowledge of "number", which is a new concept, and he must start from scratch to study the knowledge of "number" in essence.

After getting along for many days, everyone got along with Galileo very happily, whether it was Li Zubai or Li Ciyu, they all got a lot of new learning experiences, even Gu Yanwu, Huang Zongxi, and Chen Zilong also felt that they had benefited a lot. Galileo was also very happy, he also learned a lot of knowledge from these foreign scholars, enriched his own knowledge, and it should be said that he achieved a win-win goal.

Galileo was delighted, and also introduced more European scholars of this era to Xu Xiake and his entourage, such as mathematicians Descartes, Dezag, Mason, etc., especially Mason, he is a very special person, although Mason is committed to religion, he is an ardent supporter of science, and has done a lot of work in the church to defend the cause of science. He defended Descartes' philosophical ideas against criticism from the Church and translated some of Galileo's writings.

However, Galileo lamented to tell everyone that his favorite mathematician, Descartes, had returned to Paris and was now unable to meet with everyone, and if he was interested, he could lead everyone to Paris to find him.

Xu Xiake and Li Zubai were of course very happy, and Xu Xiake offered to take charge of all the expenses of Galileo's activities, because this was Galileo's initiative to help him, and Galileo's current conditions were not very good, even if he wanted to go to Paris to meet with the scholars he admired, it was also an opportunity for in-depth exchanges.

It is also a short distance from Venice to Paris, but there are so many interesting people who still don't feel lonely together, especially Gu Yanwu, Huang Zongxi, and Chen Zilong, who were originally thinkers and writers in history, but with the arrival of Zhu Youxiao, they have now changed their original development process, and are now learning mathematics, physics, and astronomy, and they are the best in their studies. During this long journey, they were full of passion, exoticism, and quaint rural scenery, all of which aroused their interest, and their casual poetry or witty remarks also made Galileo feel as if he was a few years younger, and everyone was very happy along the way.

Finally, in the excitement, I came to Paris, which had developed to both sides of the Seine, with churches and buildings abounding, and became the political and cultural center of the West at that time. The University of Paris is a well-known university in Europe, one of the oldest universities in Europe, formerly the Sorbonne, founded in 1257, but even earlier dates back to 1150-1160. The University of Oxford was founded in 1167 by teachers and students who returned to England from the University of Paris. In the 13th century, there were tens of thousands of students at the University of Paris, many from its European neighbors, and for a long time the University had a special relationship with the Pope and the King, which made him feel like a fish in water.

Galileo took Xu Xiake and his entourage to the University of Paris, both the scale and the number of students in the university surprised Li Zubai, especially when Li Zubai knew that the University of Paris had a history of nearly 500 years, and Li Zubai felt that this time it was the right time, and he must study the development process of this university and put forward better suggestions for the development of Daming University.

In a quaint courtyard, Galileo and Daming met Mason, whose full name was Marin Mason, and Mason and the Parisian mathematicians Descartes, Fermat, Robois, and Medogs used to meet once a week at Mason's residence to take turns discussing mathematics, physics and other issues, and this kind of non-governmental academic organization was known as the "Mason Academy".

But today Mason is obviously not in a very good mood, when Galileo introduced each other's identities, found that he was a little absent-minded, which made Galileo feel a little unhappy, Zi said: There are friends from afar, I am very happy! Will his attitude make Galileo happy?

However, the eldest here is Xu Xiake, his experience can be described as very rich, and he is also good at observing words and feelings, from the first glance of the meeting, it can be seen from the expression that Marin Mason is sincerely welcoming the arrival of Galileo, as for the depressed mood, it must not have much to do with their party. Oriental people like to talk after dinner, but Westerners will not inquire about other people's privacy except for their relatives and friends, so Xu Xiake is very interested in taking Daming and his party to say goodbye to Marin Mason, by the way, he will come to visit when it is convenient for him, and it will be troublesome for a few days.

Galileo is a scholar, he respects the guests of the Ming Dynasty, Marin Mason's attitude makes him very unhappy, and he doesn't know how to observe the communication skills of words and colors, and he is not upset when he sees Marin Mason's somewhat cold attitude, as an old friend, he still can't help but express his dissatisfaction, and without waiting for Xu Xiake to turn around, he asked bluntly: "Mr. Mason, are you a little unhappy about my presumptuous visit?" These guests are famous university scholars in the Ming Empire! Or do you have something unpleasant to deal with today? ”

Hearing Galileo's displeasure, Marin Mason smiled wryly and said to Galileo: "Mr. Galileo, how can I be unhappy about your arrival? It's too late for me to welcome you, these scholars from the Ming Empire have traveled thousands of miles to discuss with us, and we should be even more happy! But I'm very sorry today, I'm in my own home has some problems, I'm a little upset, and I have to deal with it quickly, so it's a little slow to treat you, I apologize a little bit, please wait a day or two, let me finish the family affairs, gather more friends and we discuss the study together, okay? ”

Hearing that there was something going on at his friend's house, Galileo was naturally polite as a friend, and asked, "I don't know if Mr. Mason has something at home, I'm sorry, can we help?" ”

Marin Mason said: "Probably not. My wife is breastfeeding, three or four days ago suddenly started a high fever, today the fever is terrible, I want to go to the doctor as soon as possible, so I am a little slow, please Mr. Galileo's understanding. ”