At noon, when the shadow of the sun was at its shortest, Zhang Yu and his companions were observing the sundial, which was the most effective way for them to obtain local time. Pen? Interesting? Pavilion wWw. ｂiquge。 ｉｎfo

They set the three grandfather clocks they had brought with them to the local time, and the three grandfather clocks used pendulums, but they had not been running since they set off from Xiyang, in order to avoid structural damage caused by the turbulence at sea.

obtained the local time, then you can compare with the time of the big clock on the flagship, the five big clocks, now only two have the same time, that is to say, three of the five have been bumped so that the time is not accurate, and the time of the two big clocks is the same as the time of Xiyang.

In terms of minutes, the time here is about 80 minutes faster than that of Xiyang, which means that it is 12 o'clock at noon, and it is still about 10:40 in the morning in Xiyang.

Zhang Yu took out his pocket watch, which was also used after landing, and the time on it was the same as the time of the ship's big clock, and the hands now show that it is 10:40.

"It's... Is the time really different in different parts of the world? ”

Some people were amazed, and Zhang Yu then explained: "Of course, the sun rises from the east, first shines on the Wa Kingdom in the East China Sea, and then shines on the West Sun in the Central Plains, and the time here must be faster." ”

"Then how far is it from Xiyang?"

"How far? We waited for a boat from Xiyang to Guangling for no less than 1,500 or 600 miles, crossed Guangling into the sea, sailed on the Heishui Ocean for nine days and arrived at the Tsukushi Island of the Wa Kingdom, according to the speed of the ship, this is about 2,000 li, and the total is almost 4,000 li. ”

"It's so far..."

Everyone was sighing, and Zhang Yu calculated the number in his heart, according to what Lord Lang said, for every longitude difference between the east and west, the time difference is about four minutes, and the time of the Wa Kingdom is about an hour faster than that of Xiyang, and the difference between here and Xiyang is about eighty minutes, which is exactly in line with the statement.

So pushing back backwards, isn't this about twenty degrees of longitude east of Xiyang? Although the accuracy of the clock carried by Zhang Yu is not enough, and the error should not be small, it is really exciting to personally confirm Lord Lang's statement.

"Did you measure the latitude?"

"It's measured, and compared with a few places in that table, it's about a few points higher than the latitude of Chang'an, and about the same as Luoyang." The man who observed the shadow of the sun with a projector said, and then added:

"The latitude is about four degrees and a minute higher than that of the western sun."

"Write it down, and remember it along with Hakata's latitude and time difference."

Sailing on the endless sea, there is no reference, if the latitude (abscissa) of the fleet is different from the latitude of Hakata, it means that the direction is wrong, high means that the course is northerly, and low means south.

Using the ship's water platform, the approximate time of the position observed by a sundial on a sunny day is faster than Hakata's time, indicating that it is east of Hakata, and vice versa, indicating that it is west of Hakata.

So theoretically, by observing the shadow of the sun and observing the local time difference, you can get the current latitude and longitude, and then compare the latitude and longitude of Hakata, you can know where you are.

When you compare yourself to Hakata, you know exactly where your ship is and whether you should continue to go east or north, and you know in your heart.

Of course, this is a secret hidden in Zhang Yu's heart, and it is Professor Yu Wenwen, the master of Lang, and it cannot be leaked easily, because the more people who know, the greater the possibility of the secret being leaked.

In these years, most of the voyages were coastal routes, and there were land references to judge their approximate location, and even so, the traditional route to the Wa Kingdom was too time-consuming, so Zhang Yu went to the Wa Kingdom according to Yu Wenwen's plan to take a new route.

A skilled boatman can sail with a starry sky, and he can also distinguish his own direction on the Black Water Ocean, such a boatman is not nothing, but Zhang Yu and others do not have such ability, so they have to find another way.

Sailing eastward from the mouth of the Yangtze River, keeping the latitude unchanged, about seven or eight days later, you can reach the large island of Tsukushi in the Wa Kingdom, that is, directly across the Black Water Ocean, without any reference along the way, and normal boatmen will not and dare not go.

This is isodimensional sailing, the principle is simple, but it is also very risky, in case of a storm on the way, or when sailing on a cloudy day, it is easy to unknowingly deviate from the course.

It's okay to say that it is not good to go to the north, but once the course deviates to the south, after a few days, it is very likely to pass through the sea area on the south side of the Tsukushi Island in the Wa Kingdom and enter the depths of the ocean.

Without any references, I don't know if I've gone too far, and I'm stupid enough to continue to go east, this is a road of no return, so when sailing on the vast sea, you have to rely on longitude to save your life, and judge whether you have "gone too far".

The principle of measuring longitude led to the need for extremely accurate clocks, and today's so-called marine clocks are not very accurate, but they are enough to judge the approximate position of the moment, so the time of Hakata must be ascertained.

Don't seek to be accurate to the second, it doesn't matter if it's a minute, at least it can make people have a number in their hearts, Zhang Yu's trip is to do experiments and familiarize himself with this novel navigation method as soon as possible.

Their crossing of the Black Water Ocean this time was very smooth, but it does not mean that it will be like this every time in the future, Zhang Yu had seen the storm at sea back then, and knew that the power of heaven and earth was beyond the power of manpower, so there was one more means, so there was a little more hope of survival.

"The matter on the side of the Wa Kingdom has been negotiated, everyone is ready, and we will go to Boduo in a few days."

"Are you leaving?"

"What, can't bear to be here?"

Zhang Yu smiled, and the man touched his head: "How come!" Where is Xiyang here? ”

"Homesick?"

"Yes, of course."

"Everyone is homesick, but what needs to be done has to be done, right?"

Zhang Yu beckoned his subordinates into the room and began to study the drawings, which were the sketches of Hakata Bay that they had drawn when they were staying in Hakata, there were more than ten of them, and with their excellent sketching skills, these sketches were very realistic.

"Minister Soga has agreed to assign a piece of land to us in Hakata, of course, this land is still nominally the territory of the Soga clan, and this is also to facilitate trading, so how to choose a site is what we have to do next..."

Doing business is indispensable for the store, warehouse, so Zhang Yu and others are now for their own store (including docks, manors) to choose the site, Hakata Port is located in a large bay, the choice is particular.

First of all, of course, it must be suitable for ships to moor, and there should be no reefs and shoals near the fairway; The second is safety, which is also very important, neither in the port area nor too far away.

The fleet of the King of Xiyang, who came to the Wa Kingdom to take a new route, could greatly shorten the time spent between Hakata and the Central Plains, and it was necessary to keep it as secret as possible, so the safety of the crew had to be guaranteed.

The crew here refers to the navigator or fleet manager who knows how to observe the latitude, so together with other crew members, try to avoid contact with outsiders, so that the accommodation after going ashore should not be too close to the idle people.

But it can't be too far away, the fleet will inevitably carry a lot of valuable cargo when it arrives in Hakata, which can easily attract the covetouss of outlaws, and if the house is in a secluded corner of Hakata Bay, it is easy to be isolated if something happens.

There are robbers on the ground and pirates on the sea, and if hundreds of pirates attack the mansion directly from the sea one night, it will be a headache.

If the address of the mansion is too remote, it will take too long for the Japanese officials and troops of Hakata Port to arrive for reinforcements, and the guards of the manor itself will not be able to survive at that time, and the goods will be robbed, and the person who knows how to measure the latitude will be killed if he is caught.

If the shipping route is exposed, other maritime merchants will make a fortune with it, and the pirates will also come to business: they can choose to wait outside the mouth of the Yangtze River, or wait in the waters on the southwest side of Chikushi Island.

At that time, a route that was finally opened up will be wasted, and a good end of a financial road will be gone, so the achievements of everyone's hard work and hard work will be empty in the end.

"Since Lord Lang has entrusted us with the heavy responsibility, then everyone must do things well!" Zhang Yu said confidently, "Let the world know that our Xiangyang Navy is not just tossing in the rivers!" ”

While Zhang Yu and others were discussing planning matters, someone was also discussing something in another part of the city.

"The Buddha statue carved by Zhan Tan is so generous, what is the origin of this group of people?"

"I don't know, the owner of Sima Village is very tight-lipped, and Duosunai is also tight-lipped and can't ask anything, but these people are probably from the Central Plains."

"Central Plains? It can only be the Central Plains, so many expensive incense medicines, could it be the maritime merchants of the Southern Dynasties? ”

"It is very likely that the maritime merchants of the Northern Dynasty and the Zhou Kingdom have sent some Buddha statues and Buddha passages in the past two years, and they have actually done it at a loss, hum."

"Don't be careless, Minister Su and I want to promote Buddhism in the Japanese country, which is a great thing, but if the Central Plains country is allowed to intervene, it will not be good."

"What do you mean?"

"The relationship between the Wa Kingdom and our Baekje cannot be alienated by others!"

"Do you have to do it? The gang came home with a lot of money, and it's worth a try. ”

"Don't mess around, they are the distinguished guests of Minister Su, if the matter is leaked, it will not be good, don't lose a big one because of a small one."

"What then?"

"Let's see what happens."