Chongzhen revived the Ming Dynasty

Chapter 159 Jiajing Teeth Ruler
The Qintian Supervisor was in charge of astronomy, calendars, predictions, and steps. It was the only yamen in the Ming Dynasty that was qualified to study astronomy.

After Zhu Youjian assigned this yamen to the inner court, he never had time to manage it. Just let the eunuchs in charge of the Lingtai who have astronomical responsibilities monitor the situation in the Qintian Prison.

Now it was necessary for Qintian to monitor the length of the quantum meridian, so Qintian Supervisor officials were finally called over.

Qin Tian Jian Zheng Ye Zhenchun, Wu Guan Zheng Ge Fengnian, doctors Yang Yuanqing and Zhou Changgeng were all excited when they heard the emperor's call, thinking that this was a good opportunity to change the fate of Qin Tian Jian.

In the Ming Dynasty, although the Qintianjian officials were hereditary, they did not receive as many preferential treatment as the hereditary officers. Instead, they were very hardworking——

Because although they have been able to serve as officials in Qintian Prison for generations, and even formed a family inheritance, the place of suffering is also here.

According to the edict issued in the sixth year of Hongwu's reign, Qin Tian Jian personnel are never allowed to move, and their descendants are only allowed to learn astronomy and calendar calculations, and are not allowed to learn other professions. He was not a scholar, so he sent troops to Hainan.

It can be said that they have been imprisoned in Qintian Prison for generations and can only learn astronomy and calendar. Even going to the funeral only lasted three months——

Of course, going to mourn for three months is no longer exclusive to Qin Tianjian, and it cannot be said to be treated harshly. Zhu Youjian invented the additional title of Qin Tianjian, so that other officials could attend the funeral for three months like the Qin Tianjian officials. This system was also given a name, called Year by Month.

Nowadays, officials who are allowed by the emperor to attend the three-month funeral are not only not treated harshly, but can even be said to be valued. Only officials valued by the emperor received this treatment.

Moreover, using the term "Yue Yi Nian" also avoids criticism from outsiders. After all, using the month to change the year sounds similar to using the sun to change the month. Those who oppose the use of the month to change the year are opposing the emperor's use of the sun to change the month. Therefore, attending funerals for three months cannot be called unfilial.

Qintianjian is the only yamen that is allowed to attend the three-month funeral. If other officials want to have the same treatment, they must add the title of Qintianjian. This has improved their status a lot and made them more respected.

Moreover, Zhu Youjian has changed many systems since he came to power. The officials of Qin Tian Jian hoped that the emperor would lift the ban so that their children could take part in the imperial examinations and become civil servants.

Especially after the establishment of the Mingshuan Division, the various families in Qintianjian were even more excited, wishing that the emperor would lift the ban and allow their children to participate——

These people believe that no one can compare to the disciples of Qin Tianjian in terms of calculation. As long as they can get the Juren status, they will definitely be able to pass the Ming Shu Science Examination.

The only pity is that the emperor did not set up a system to recruit talents for the imperial examination. Their children still need to study the Four Books and Five Classics, and may be stopped in the exam before becoming a Jinshi.

It would be better if the county examination, prefectural examination, hospital examination, and township examination also set up a calculation department. The children of Qin Tianjian can definitely pass the exam without any obstacles.

Of course, these are all their imaginations. Now that Zhu Youjian has not lifted the ban, no matter how many ideas they have, they cannot realize them.

Moreover, after meeting the emperor, before they could think of how to speak, Zhu Youjian's first question stumped them:

"From the North Pole to the equator, the length of this meridian is determined by me to be twenty thousand miles."

"Can you figure out how long this li is and how different it is from the li we use now?"

They had never considered such a thing before. The officials of Qintian Prison looked at each other in confusion. In the end, Ye Zhenchun, the supervisor, said:
"This dynasty has never measured the length of the meridian. I read in ancient books that monks from the Tang Dynasty once measured it."

"If the length of the meridian is used to determine the length, there may be deviations."

This unit is too commonly used here, and it is related to the well-field system that is hotly discussed in Beijing. Ye Zhenchun couldn't bear the responsibility of randomly changing the Li system, so he could only answer truthfully.

The Qintian Supervisor official said this, and Zhu Youjian had nothing to do. He knew that he could force the Qintian Supervisor officials to measure it, but if the measured mileage length was inaccurate, how could he determine the weights and measures?
So Zhu Youjian could only say:
"Find some people to test it first, and it will eventually come out."

"Which yamen is in charge of measurement matters, and who determines the kilo and liter?"

Dr. Zhou Changgeng from Qin Tianjian said:
"Your Majesty is talking about weights and measures, which are under the control of the Department of Water Resources of the Ministry of Industry."

"All measurements and trade-offs are collated and issued by the Department of Water Resources."

Unexpectedly, it was the Capital Water Department, the yamen of the Ministry of Works in charge of water conservancy. Zhu Youjian heard this strangely, and then thought of the land ruler used by the Ministry of Household Affairs to measure acres, and asked:
"Are the weights and measures issued by the Department of Water Resources recognized by other departments?"

"Why have I heard that in addition to construction rulers, there are also tailoring rulers and floor measuring rulers?"

Zhou Changgeng didn't know why the emperor was so concerned about this point, but he still replied seriously:

"The construction ruler is an official ruler, while the tailoring ruler and the floor measuring ruler are for private use."

"This dynasty used rulers from the Song dynasty, which were aligned with the ink edge of treasure banknotes." "The length of the tailoring ruler was aligned with the edge of paper on treasure banknotes."

"The length of the measuring ruler is between the two."

Zhu Youjian really has a headache with this complex scale. Although the Ministry of Industry has issued a construction ruler, some people have to use other standards. There are naturally errors in the measured pieces of cloth and acres of land.

Thinking of the Ming Dynasty's scale alone, there were three lengths, and even more lengths due to errors in actual execution. Zhu Youjian made up his mind to unify these measures and formulate a standard ruler.

After the standard ruler is determined, one mile is calculated as three hundred steps and one step is calculated as five feet, which is fifteen hundred feet. The length of the li can also be determined and used to determine the well field.

Thinking of this, Zhu Youjian ordered:
"Come here with some precious coins and get the building ruler from the palace."

When the eunuch of Qianqing Palace heard this, he hurriedly found some treasure notes, and then went to the imperial prison to get a dental ruler.

When Zhu Youjian saw this tooth ruler, especially the words "Ming Jiajing Year System" on it, he felt happy and knew he had found the answer.

Because he realized that this was the Jiajing tooth ruler he had seen in later generations. The ruler was 32 centimeters long. The Palace Museum wrote it very clearly.

With this reference, the length of the meter can be determined. According to the calculation of one meter, three feet, and one mile, 500 meters, the lengths of feet and miles can also be determined.

The only thing that makes him doubtful is that he doesn't know how stable the ivory is. From the Ming Dynasty to later generations, whether the length will change due to thermal expansion and contraction -

If the current Jiajing dental ruler is not 32 centimeters, but a little longer or shorter, then there is an error.

When Zhu Youji realized this, he immediately asked someone to measure and use a Jiajing tooth ruler to determine the length of one decimeter. Then he prepared clean water and measured whether one cubic decimeter of water would be one liter.

Because he clearly remembered that the market liter is the liter, and the two units are the same. The liter is a metric unit, but the city liter is still used. Therefore, the liter in the Ming and Qing Dynasties is similar to the liter in later generations, and the deviation will not be too big.

If one cubic decimeter determined with the Jiajing tooth ruler was similar to one liter, he decided to use this length and set the decimeter length, as well as the standard liter and kilogram.

Confused by the emperor's orders, the Qintianjian officials had to obey orders.

For a 32-centimeter dental ruler, it is very easy to determine one centimeter. Just cut a piece of paper or a piece of wire to the length of the ruler and keep folding it in half.

Then use one centimeter to determine the length of ten centimeters, which is one decimeter. Then use this one decimeter to create a container of one cubic decimeter.

Zhu Youjian asked different people to measure several times. After determining the length of one decimeter, he asked the Internal Affairs Supervision and Construction Department to build several containers based on this length. He measured which length was the most accurate and chose which one to use to measure the volume.

After struggling like this for a long time, I finally created a container of one cubic decimeter, compared with the standard liter. The volume of the two is indeed not much different, which is surprising.

This didn't stop yet. Zhu Youjian asked someone to measure the weight of one liter of water, and then compared it with the kilogram used by Daming. Look at the weight of a pound. Is it about three-fifths of a liter of water?

Because he remembered that the so-called Sima Jin was about six hundred grams.

Sima Jin and Sima Liang were used from the Ming and Qing Dynasty Jin Liang. If this deviation is not large, then it can be determined that the Jiajing dental ruler's 32 centimeters have basically no error.

The final measurement result made Zhu Youjian very happy, because the weight of one pound is about 596 thousandths of a liter of water. Compared with Sima Jin in later generations, the difference can be said to be very small.

This allowed Zhu Youjian to confirm that the Jiajing dental ruler in his hand was thirty-two centimeters. Even if there is still an error, the deviation will not exceed one millimeter.

For him at this time, this ruler can be used as a reference to transfer the metric system of weights and measures from later generations without any changes:

"Even if officials from the Qintian Prison were to measure the meridian, there would probably be errors in the determined miles and meters."

"Even when the metric system was first established, the meridian length measured in France had errors, so the earth's meridian circle was not the standard 80,000 miles, but a little longer."

"There is no need to insist that one mile must be one eighty thousandth of the Meridian Circle, as long as it is close."

"You can use the Jiajing tooth ruler to determine the length of meters and miles."

(End of this chapter)