Wang Defa, who was in the Bo Ni Kingdom, did ask a passing merchant ship to bring a letter to Zhang Guoan, the owner of the island. Pen | fun | pavilion www. ｂｉｑｕｇｅ。 ｉｎｆｏ

Now, the Bo Ni region has become an important trading area, and the number of passing sea vessels is increasing day by day...... Since the Da Song style sail is a longitudinal sail type, even if the wind direction is unfavorable, there are merchant ships traveling for profit, and it is nothing to suffer a little or slow down.

The Bo Ni Country area was originally a good stop and supply point, and the fresh water resources, fruits, and grains here are very abundant, and it is also a famous spice production area, so it is easy to develop.

After Wang Defa came here with a professional drilling team, related equipment, and a group of indigenous assistants, they first lived in the Liuqiu trading station for a period of time, and then began to look for oil fields.

The latitude and longitude of the oil wells in the world are all ready-made information, and Wang Defa can easily determine them with the help of a watch and a sextant.

They didn't carry a sextant with them, because as long as they knew the principle, it was easy to machine, and with their precision, it was easy to achieve an accuracy of 10 arc seconds.

The principle of a sextant is to determine latitude by measuring the angle between the horizon and the sun at noon, or by measuring the angle between the horizon and a fixed star.

The sextant designed by Wang Defa is a fan-shaped frame structure, which has a handle on the back for holding, and the frame is equipped with a movable arm, and the top of the movable arm is the indicator mirror.

On the left side of the sextant, in the center, directly opposite the telescope, a semi-reflective horizon mirror is installed.

It is also equipped with a filter next to it for measuring bright objects such as the sun.

When measuring the horizon height of a celestial body, simply hold a sextant to keep the telescope tube horizontal, and observe the image of the measured celestial body reflected by the horizon mirror from the telescope. At the same time, it is enough to adjust the movable arm so that the stars fall on the horizon as seen in the telescope.

It is indeed very simple, when the image of the object coincides with the horizon, the height of the object is equal to twice the angle between the horizon mirror and the indicator mirror.

Based on this, the scale on the arc scale can be properly designed, and the height of the celestial body can be read directly.

In order to improve the accuracy of reading, Wang Defa also added a drum wheel and vernier ruler to the movable arm of the sextant.

In this way, the accuracy of the sextant is relatively high, it can easily reach 10 arc seconds, and it is light and easy to use...... But there are two other important things here, one is to have an accurate time, and the other is to be able to see celestial bodies.

Only when these two points are present at the same time can the exact latitude and longitude be known...... There were sophisticated veteran sailors of this period, who could rely mainly on the height of the North Star to determine latitude, and this method was very applicable in the Northern Hemisphere.

The method of calculating the latitude by the height of the North Star was the most accurate and convenient method of navigation in the Great Song Dynasty.

In addition, it is also easy to determine the local latitude method by relying on the height of the sun.

Of course, the old sailors didn't have the concept of warp and weft, but they might have used some island as a landmark...... This can only be related to experience.

However, the measurement of longitude has always puzzled the navigators of the Song Dynasty, who did not have an accurate concept of time...... But knowing where it is is enough for them.

The navigation technology of this time and space is still a period when experience is greater than science, and it will continue to be for a long time.

After Wang Defa found the location of the oil well in that time and space, he thought that he should have processed the big grandfather clock earlier, which was not difficult in terms of technical content.

In that way, he can train the Great Song sailors to use the sextant------- but there is still time, so there is no hurry.

Wang Defa regretted that he found that a considerable part of the oil wells were located under the surface of the river!

It seems that it will take hundreds of years of vicissitudes before it can be fully revealed.

However, as long as there are one or two places, it should be enough for the current dosage.

Wang Defa also hired a number of indigenous laborers, and at that time, he immediately directed them to clear the weeds and trees at the location of the oil well.

At the same time, he arranged for people to light dried mugwort all around------ so that a special fragrance of Chinese herbs filled the surroundings.

The wells were located on the banks of rivers and were thriving with weeds and trees.

It took hundreds of them three days to clear half a square kilometer of work surface.

Wang Defa did not rush to drill oil wells, he first asked his assistants to build a panel house and a large tent, and the relevant materials were prepared a long time ago.

It is 30 kilometers away from the capital of the Boni Kingdom, and it is necessary to make a good home here.

While everyone was busy, the chickens and dogs were not idle, and the two of them had to take care of the five big buffaloes that helped dig the oil wells, rush to the river to graze, and rush back to the cattle pen to rest.

Wang Defa knew that there had never been any beasts here, so he was relieved that the two of them would go to herd cattle.

On this morning, the two of them drove their cattle further up the river.

The gnawing dog hummed a little song as he walked.

"I have a big buffalo, especially stubborn~~ I call it to the east and it to the west, never let it ride~~"

This is actually a small tune that can often be heard when herding cattle in the Liuqiu area, but the chicken rice can't learn it.

He then provoked the problem of gnawing the dog.

"You can see clearly, this is one, two, three, four, five, five big buffaloes, how is it one!

What does it have to do with it going east and west and not letting you ride! ”

The gnawing dog waved the rattan, squinted at the chicken, and said, "You miss Nana, right?" ”

"How do you know?!"

"You called her name when you went to bed last night!"

“------”

The gnawing dog said faintly: "I also want to ----- why do you say she is so beautiful?" More beautiful than a thousand thousands! ”

Ji Mi nodded and said, "Qianqian is too white, and she is too tall to look good." ”

It was already noon, the sun was almost high above their heads, and the smell of the endemic plants of the rainforest was dissipating into the air with the fierce rays of the sun, a bit like the vapor that immediately emitted when the steamer was opened.

The buffaloes found a place where the water and grass were abundant, and they happily ate the grass and frolicked happily in the water.

The two of them had plantain leaves on their heads, ready to find a good place to cool off, but everywhere was like a steamer, and they almost stuck out their tongues like dogs.

At this time, more than a dozen people came out of the jungle!

The two of them were startled, gods, these are savages!

Some of them held hardwood spears, some with bows and arrows, and one of them with a serpentine metal knife.

Both of them were frightened off their plantain leaves, and then took a common posture here, with their hands spread upwards to indicate that they had no weapons at all.

When those people saw this, they also slowly put away their weapons, and there was not much tension on their faces.

The guy with the serpentine metal knife was the strongest, and he said: "! @#￥%%……”

The chicken and the gnawing dog glanced at each other, it's over, it's not the language of the Boni region at all!

But body language, along with similar skin and physiognomy, still makes it easy for them to communicate.

The chicken took out the thick whale meat sausage, which was packed with shark fish intestines and dried naturally.

Due to the abundance of spices, the taste is quite good.

When the wild men took it, their expressions after tasting it illustrated it.

The gnawing dog took out a strip of bread, which had just been baked in the morning, and there was sugar in it.

Food is the best lubricant, and when the dozen or so people took them away, they didn't tie up the two of them, and their movements were still relatively gentle. (To be continued.) )