My Portable Ming Dynasty

Chapter 158: Through Heaven and Earth
Su Ze explained his method to Huang Ji, and Huang Ji's eyes lit up as he listened.

Huang Ji's intelligence was undoubtedly exceptional, given that he was able to pass the imperial examinations to become a Jinshi (a successful candidate in the highest level of the imperial examinations), and then pass the selection process for Shujishi (a junior official in the Hanlin Academy) and Guanxuan (another official selection process).

During his time auditing the Crown Prince's accounts, Huang Ji discovered that he was quite talented in mathematics.

Su Ze also discovered his talent.

The Longmen Accounting Method that Su Ze taught Xiao Pangjun was actually just some basic accounting principles, since Su Ze hadn't seriously studied this kind of accounting method in his previous life.

However, Huang Ji was able to deduce a methodology for auditing accounts from these basic principles. There was a reason why Zhu Yijun valued Huang Ji so much among the many lecturers in the Eastern Palace.

Given this, Su Ze decided to guide Huang Ji and the Imperial Astronomical Bureau to compete, thereby promoting the calendar reform he needed.

After listening to Su Ze's method, Huang Ji looked at him with suspicion and asked:
"Is it really feasible?"

Su Ze said:

Whether it's feasible or not depends on Huang Hanlin.

Huang Ji thought for a moment and said:

"This trigonometric method sounds similar to the Pythagorean theorem, and with the addition of the tangent circle method, it doesn't seem too difficult."

"How should an equatorial theodolite be made?"

Su Ze said:

"I can ask the Ministry of Works to help make this."

Huang Ji then asked, "Is it really alright to privately test the constellations?"

"Huang Hanlin can ask the Junior Chamberlain, and we can also inform the Junior Chamberlain of our conversation today."

The Junior Chamberlain was Yin Shidan. Su Ze naturally knew about the relationship between Huang Ji and Yin Shidan, and he wasn't worried about telling Yin Shidan about it.

As mentioned before, the calendar is related to the legitimacy of a dynasty, and it has extraordinary significance for a feudal empire.

Throughout history, compiling history and compiling calendars have been essential tasks.

The deviation of the Datong Calendar had reached the point where it had to be corrected. If someone proposed to correct the calendar at this time, the emperor would certainly welcome it. How could he possibly suppress it by citing private study of astronomy?
In fact, the suppression of astronomy and divination in the early Ming Dynasty was mainly to suppress "divination," which refers to superstitious activities related to celestial phenomena.

Huang Ji thought for a moment, and then, remembering his pride as a Hanlin scholar, how could he allow himself to be suppressed by a mere official of the Imperial Observatory? So he said:

"Then please help me, Su Hanlin. I, Huang, will do my utmost!"

After seeing Huang Ji off, Su Ze returned to his study.

However, after Huang Ji's incident, he lost interest. Seeing Zhao Lingxian looking at the account books, he also sat down at his desk and started reading the letters that had arrived recently.

The study was filled with the rustling sound of pages turning, and the warm spring sun shone through, giving Su Ze a sense of cozy tranquility.

When her husband returned from meeting with guests and didn't tease her, Zhao Lingxian felt relieved but also inexplicably disappointed.

She quickly banished this idea from her mind, which was contrary to the standards of a lady from a prestigious family, but she couldn't bring herself to look at the account book at all.

Just then, a cooing sound came from outside the window. Su Ze walked to the bedside, and a fat pigeon flew in.

Zhao Lingxian recognized the pigeon; according to her husband Su Ze, the pigeon could travel between the capital and Dengzhou and Laizhou in a single day.

Zhao Lingxian didn't believe it at first, but the pigeon was released yesterday, and today she saw the message tube on the fat pigeon's leg. Could this pigeon really travel a thousand miles a day?
The fat pigeon stared at its mistress with its cross-eyed eyes. Zhao Lingxian couldn't hold back any longer. She picked up a rice cake from the table and gestured to it. The fat pigeon suddenly fluttered over and opened its beak to peck at the rice cake in the box.

Startled, Zhao Lingxian jumped up and instinctively threw herself into Su Ze's arms.

Holding his wife, Su Ze smiled slightly at the fat pigeon, but he still opened Tu Zemin's letter first.

Zhao Lingxian's cheeks were flushed, but she was held in her husband's arms. She was too weak to break free, and feeling utterly bored, she could only read the letter as well.

Tu Zemin's letter seemed to be seeking advice from her husband, but Zhao Lingxian could read all the words in the letter, yet she couldn't understand their meaning.

Zhao Lingxian also came from a scholarly family and had read a lot of books since childhood. This letter made her feel somewhat discouraged.

Sensing his wife's emotions, Su Ze casually remarked:

"Governor Tu's letter was a discussion with me about methods of maritime navigation."

"Methods of maritime navigation?"

"Yes, my wife, think about it. On the vast ocean, even if you have a compass to help you find your way, how would you determine your location?"

Zhao Lingxian is from Sichuan and has never seen the sea, but after imagining the boundless wilderness, she shook her head and said:
Zhao Lingxian then said, "Looking out at the vast expanse of misty waves, one can recognize one's hometown by the birds flying at dawn. So, we can only rely on seabirds to find our way?"

Su Ze glanced at his wife in surprise, not expecting her to be so accomplished in poetry and so intelligent.

He said quickly:
“My wife is exceptionally intelligent; that’s what our ancestors thought.”

Zhao Lingxian looked bewildered, and Su Ze explained:
"The sea is vast. During the reign of Emperor Chengzu, when Zheng Linggong sailed to the Western Ocean, he sailed along the coast. As long as he did not deviate from the coast, he could naturally sail to the place marked on the nautical chart, and then return by going against the course."

Seeing that she had answered correctly, Zhao Lingxian smiled smugly.

Su Ze continued:

"Of course, Lord Zheng had more than one method."

Su Ze pulled a Western nautical chart from his desk and continued:

"If we divide the nautical chart horizontally and vertically, dividing it into parallels of latitude and longitude, then any point on the chart can be determined by its corresponding latitude and longitude values."

Zhao Lingxian's mind was completely blank. She tried to follow Su Ze's train of thought and said:

"The same principle applies to looms?"

Su Ze looked at his wife in shock, and Zhao Lingxian said:
“I have also learned how to use a jacquard loom. If you want to weave the corresponding pattern, you have to position the warp and weft according to the master’s method.”

Su Ze suddenly realized, "So that's how it is!"

Yes, warp and weft are originally textile terms. The concept of warp and weft was probably introduced by translators who associated it with the principle of jacquard looms, hence the use of the two characters "warp and weft"!

The Shu brocade produced in Sichuan uses extremely complex looms to weave exquisite patterns.

Looms with fifty warp threads have fifty foot pedals (operated by foot control panels). By simultaneously operating the shuttle and the foot pedals, complex patterns can be woven.

In addition, there is the pattern book, which is a program on the jacquard loom that stores pattern information. It is woven from the warp threads and weft threads according to the pattern requirements.

After the pattern book is prepared, you can simply follow the procedure to operate the loom and weave the pattern book's preset design.

This is also why Zhuge Liang was able to use Shu brocade to plunder the wealth of Cao Wei and Eastern Wu, and support the Northern Expeditions.

The Shu brocade was so exquisite that even though Cao Pi knew that buying it was aiding the enemy, he still wrote "Ode to Shu Brocade" to praise it.

That's true. His wife can operate the loom, so understanding latitude and longitude isn't difficult for her either.

Su Ze continued:

“Since you know the latitude and longitude, things will be much easier.” “Latitude is actually quite easy to calculate. The Big Dipper hangs high in the sky, unchanging since time immemorial. We only need to measure the angle between the Big Dipper and the latitude to determine the latitude.”

Su Ze said:

“When Zheng Linggong sailed to the Western Ocean, he used a star chart to observe the stars and then combined it with a nautical chart to determine the latitude.”

Su Ze wasn't so clueless as to explain the calculation process of trigonometric functions. If it was just about understanding the concept, Zhao Lingxian quickly figured it out.

"And what about longitude?"

Su Ze sighed and said:

"Longitude is the most difficult."

"The Earth revolves around the sun, and this longitude is actually the difference in time."

Su Ze, fearing his wife wouldn't understand, added:

"Back then, Lord Zheng discovered that sometimes the sun would not set for a long time while sailing, while at other times it would set suddenly. This is because the time is different at different longitudes, and ships sail across longitudes."

"To determine longitude, you can take the noon time when the capital is located as the 'normal time', and then measure the 'normal time' of a place. The time difference between the two is the longitude."

At this point, Zhao Lingxian's mind was completely blank.

Su Ze, much like those straight-laced STEM guys in later generations explaining science to their liberal arts girlfriends, continued speaking to himself:

"But how can we determine if the capital is in peacetime when we are sailing thousands of miles away? There are two methods."

"One method is the celestial clock method, which involves observing celestial phenomena and finding a celestial time independent of sunrise and sunset. Once you arrive at a place, as long as you determine the local time, you can observe celestial phenomena to obtain the celestial time, and the difference between the two is the longitude."

"Another method is the clock method, which involves creating a perfectly accurate clock, checking the clock against the local time, and then calculating the difference to get the time."

"Clocks?"

Seeing his wife's puzzled expression, Su Ze remembered that Western clocks only entered the Ming Dynasty during the Wanli era.

He said:
"A clock is a clepsydra, and a gnomon is a sundial."

Although Zhao Lingxian didn't understand, she still smiled, giving Su Ze a great deal of emotional value.

Su Ze didn't continue, as the calculation of latitude and longitude was still a bit beyond his scope.

However, latitude and longitude, especially the calculation of longitude, is the most important technology for ocean voyages.

In fact, the current voyages, including those of Spanish and Portuguese merchants that came to the Ming Dynasty, were not "ocean-going voyages," but rather, like Zheng He's voyages to the Western Ocean, they traveled along the mainland and circled around to the Ming Dynasty.

If the ship is far from the mainland, it will quickly lose its way, and then it will only be a matter of luck to find the mainland or an island.

Tu Zemin's letter was actually about this very thing.

A merchant ship belonging to the Denglai Maritime Trade Office encountered a storm after leaving port and was blown off course, disappearing into the vast ocean.

This merchant ship was merely heading to Japan for trade.

In later times, merchant ships departing from Shandong would only need to sail southeast, passing Jeju Island to reach Nagasaki.

However, ships can no longer sail far from the mainland, so there are two routes to Japan, one to the south and one to the north.

The northern route runs along the Korean Peninsula, from Laiju northward to Liaodong, then all the way to Busan, and finally through the Korea Strait to the edge of Japan.

Another southern route starts from Fujian, goes to Ryukyu, and then heads north to Kagoshima.

The northern route is blocked by ice floes along the coast in winter, while the southern route is suspended due to the typhoon season in summer.

In short, even though Japan is so close, there are so many dangers in ocean voyages.

Therefore, developing maritime trade, especially long-distance ocean trade, cannot be solved simply by announcing the opening of the sea.

It is essential to be able to build ships that can cross oceans and possess navigation technology capable of locating positions at sea.

The former is actually not so bad. Nowadays, ships from both the East and the West can sail far away. Once people know about the lucrative profits of ocean trade, they will naturally research better and faster ships.

However, navigation technology is not something that ordinary people can master.

In the history before Su Ze's time travel, the measurement accuracy was a competition between the celestial clock method and the clock method. Galileo and Newton devoted a great deal of effort to this longitude battle, and countless astronomers, mathematicians, and engineers also participated in this competition.

Britain, which ultimately solved the problem of longitude measurement, relied on this navigation technology to eventually become the British Empire.

All of this ultimately comes down to astronomy.

The foundation of calendars is the observation of celestial phenomena, and the celestial clock method for longitude problems also requires the observation of celestial phenomena.

Calendar timekeeping is essentially a matter of the Earth's rotation and revolution, while the celestial clock method is also a matter of celestial calculation.

Astronomy is the cornerstone of navigation. In this era, the role of astronomy is to lead humanity out of the land and into the open ocean.

None of this could be accomplished by private individuals. The British longitude war was also a result of the government establishing the Longitude Commission, heavily funding scientific research, and taking a hundred years to finally reach a conclusion.

Thinking about this, Su Ze became somewhat excited.

In this era, the war of longitude has not yet begun. In fact, there is no significant technological gap between East and West. Even the Datong Calendar currently used by the Ming Dynasty is still advanced.

Of course, this was still because Guo Shoujing was too strong.

Guo Shoujing, an astronomer in the Yuan Dynasty, led a team to conduct surveys across the four seas, carrying out astronomical measurements at multiple locations throughout the entire Yuan Dynasty territory.

Historical records state: "The officials in charge of the survey set out in different directions, reaching as far east as Goryeo, as far west as Dianchi Lake, as far south as Zhuya, and as far north as the Tiele, surveying the four seas, totaling twenty-seven locations."

Based on the results, Guo Shoujing combined ancient calendars and Hui arithmetic to calculate a tropical year as 365.2425 days. This figure differs from the actual time it takes for the Earth to revolve around the sun by only 26 seconds.

Su Ze also had another ambition: to start with the calendar, restart the Four Seas Test, set up observatories across the world to map the stars, and then use this data to calculate and find the celestial clock, thus developing longitude measurement technology.

As for the clock method, that's a different path altogether, the path of mechanical engineering.

This path is equally important. The precise concept of time gave birth to the concept of industrialization. Only when time can be accurately measured and unit output can be strictly calculated can we truly say that we have moved from the agricultural era to the industrial era.

The ticking of clocks is the sound of the industrial age, and this is not just a saying.

As for this path, the water-powered hammers at the Denglai Mint and the weapon upgrades that Suze is preparing to undertake are following this path.

Su Ze picked up his pen and wrote a letter to comfort Tu Zeming. He explained that ocean voyages are never smooth sailing, and that these unexpected losses had already been factored in when calculating the profits. Su Ze suggested that Tu Zeming study Western sailing techniques and hire some Western sailors to teach him how to operate the sails.

After writing his reply, Su Ze picked up his wife and hugged her tightly.

Ellipsis.
-
On March 2nd, Su Ze returned to the history museum after his honeymoon, and Shen Yiguan rushed in and said:

"Huang Ji and the Imperial Observatory are fighting!"

(End of this chapter)