"Discover the island!"

Almost as soon as the hour hand pointed to 11 o'clock at noon, the entire "New Hope" was filled with the sound of lookouts shouting from the top of the mast.

Looking in the direction of the fingers of the looking hand, I vaguely saw that when the island appeared on the horizon, ***'s face became a little strange, and even the gaze of Shi Yiwen changed.

He, how did he do it!

How could he know his position so accurately at sea, could it be that sextant?

In the face of such surprise, Shi Yiwen didn't even explain anything, he just smiled, and then unfolded the map and said to himself.

"It's still a bit of a gap in location."

Subsequently, Shi Yiwen drew a circle with a pen in Keelung and Tamsui in the north of Taiwan Island, and then muttered to himself.

"In the future, we can consider setting up bases in these two locations."

Actions speak louder than words!

In the face of Shi Yiwen's accurate "prediction", after decades of sailing experience was completely subverted, he also felt an unprecedented impact, but also had a strong interest in this new style of navigation. After all, he knew how important it was to be able to find his place at sea. Of course, the appearance of Penghu Island also made him no longer doubt this new navigation technology.

"General, can the Director-General really know where we are at sea?"

Wang Erxi asked with some curiosity.

"Well, you can ask him."

Looking at the two students who followed Shi Yiwen's side, *** said.

"I really should ask the Director-General for advice."

In fact, *** knew that he should apologize to the Director-General, of course, compared to this, he was more curious about how the Director-General knew the location of the ship at sea, and when he took the initiative to raise this question, Shi Yiwen took the sextant in his hand and said.

"This is a sextant."

This sextant was taken out of the library's exhibition room.

"A sextant is an optical instrument used to measure the angle between two distant targets. It is usually used to measure the angle between the Sun or other celestial bodies and the sea horizon or horizon at a given time, so as to quickly know the latitude of the position of the ship......"

The principle of the sextant was first proposed by Newton, and of course it has not yet been invented, so it is natural that it has become the invention of Edwin S.

“…… It consists of a small telescope, a translucent and semi-reflective fixed plane mirror, known as a horizon mirror, and an active mirror linked to the indicator, known as the indicator mirror. The scale arc of the sextant is 1/6 of the circumference. When used, the observer holds the sextant and rotates the indicator mirror...... It's like this,"

Shi Yiwen explained while operating the sextant.

"Make the celestial bodies that appear at the same time in the field of view coincide with the horizon. According to the rotation angle of the indicator mirror, the altitude angle of the celestial body can be read, and its error is about ±0.2°~±1°. The sextant is lightweight and can be observed on swinging objects such as ships. The downside is that you can't use ...... on rainy days"

Finally, Shi Yiwen looked at *** and said.

"How? Want to give it a try? ”

The answer is, of course, yes, when *** learned to use a sextant to measure latitude according to Professor Shi Yiwen's method, although his arithmetic was very good, he still couldn't substitute the formula for calculation for a while, and it could even be said that he couldn't figure it out at all, and finally *** had to give up.

"It's going to be useful, but even if it's measured, what's the use?"

Seeing ***'s dazed look, Shi Yiwen just smiled and said.

"General Li, measuring latitude with a sextant is inseparable from mathematics, in fact, learning navigation itself requires learning mathematics, Sun Jiuliang, you come and measure our latitude."

"Yes, sir."

Sun Jiuliang is a student of Shitaizhuang Social Sciences, although he has only studied mathematics for less than two years, but now he can skillfully use a sextant to calculate latitude, after all, he is a "professional" who has undergone "professional training", but only a few minutes later, he gave a latitude, facing the number he gave, *** asked puzzled.

"Director-General, what is this latitude?"

In the face of ***'s inquiry, Shi Yiwen explained to him, after all, most of the time in the future will be at sea, these are what he must learn, and to master good knowledge, in the next voyage, he is over forty years old, more often like a student, from Shi Yiwen learned about navigation, especially the measurement of latitude and longitude. Two days later, when he spent almost half an hour for the first time calculating the latitude of the ship with the help of a sextant, he asked again in joy.

"Mr. Shi, now that the latitude has been measured, do you know the position of the ship on the sea?"

"Is this just the first step? You see, it's like ......"

Pointing to the cloth on his sleeve, Shi Yiwen said.

"Just like these cloths, now that we know the latitude, we can't find out where we are, and if we want to solve this problem, we have to get the longitude, you see......"

Pointing to the warp and weft of the fabric, Shi Yiwen said.

"This vast sea is like a piece of cloth, as long as we get the latitude and longitude, we will naturally know where we are......"

After explaining the latitude and longitude to him in the simplest words, Shi Yiwen spent half a day and explained to him what the longitude is, and this knowledge can be said to be extremely novel in the Ming Dynasty of this era, even in Europe at the same time, it was just beginning to be studied.

In the face of these fresh knowledge, he is a reader, he is extremely curious, and he is eager to learn this knowledge, and he admires Shi Yiwen to the bone, after all, these knowledge of navigation are unheard of by him, which completely subverts his understanding of navigation.

The current "New Hope" is not so much an "adventure" as a "coach". The captain was there learning the new seamanship, and the crew also had to learn how to operate the artillery, after all, for them, operating the cannon was also a very new job, sometimes they would throw the empty barrel into the sea, and then concentrate the artillery fire on it, although most of the time, it was difficult to hit the barrel two hundred meters away, but it was certain that if it was a ship,

In this way, on the fourth day of sailing out of the Taiwan Strait, the land once again appeared in the sight of the lookout.

"Land!"

With the shouts of the lookouts, the sailors who had been sailing on the deep sea for 8 days all became a little excited, and when the gray-green land appeared in sight, Shi Yiwen muttered to himself.

"It's finally here!"