It is a four-wheeled carriage designed by Ben Gongzi himself, but after being carefully built by the skilled craftsmen of Chang'an, this four-wheeled carriage not only retains the lightness and airtightness of my design, but also increases the artistic level and appreciation style of the beautiful Chinese nation.

The driver sat in front of the four horses pulling the cart, and beside the driver, each sat a vigilant, heavily armed guard, and at the back of the carriage, two elite guards also watched vigilantly to keep the carriage safe.

Inside the carriage, everywhere is wrapped with beautiful and refined sheepskin, and in the seat, it is stuffed with down, so that the seat is moderately soft and hard, and there is no problem to sleep on as a bed, well, the car is about one meter eight wide, about two meters long space, in the center of the carriage, is a steaming iron stove, on each side can sit three people.

And now, Ben Gongzi was lying on the chair, his head resting on the round thigh of the Yaoguang girl, and he looked at the Yaoguang girl's exaggerated eyes with a funny look at the carriage she had never seen before.

"It's so comfortable...... Husband, how did you come up with it, and you can still see the scenery outside the car from the inside? This cushion is so soft, hey, husband, you are not allowed to make trouble......"

"What did I do to me? How, like the car? Ben Gongzi reluctantly withdrew the trembling twin peaks that sneaked into her chest, and said with a hippie smile.

"Well, yes, it's beautiful, and it doesn't feel as bumpy as it used to be in the car. Husband, when did you come up with it? Sister Yaoguang pinched the tip of my nose with a shy look on her face and asked curiously.

"You don't know what to do, do you? Hehe, this is a long way to go, and I have to start from the time when your husband and I got in touch with the Turks and started to trade wine and horses...... "This son held Yaoguang's slender hand that pinched the tip of my nose, put it on his lips and kissed it, and smiled.

The four-wheeled carriage was indeed conceived when Ben Gongzi began to trade wine and horses with the Turks, but there was a serious problem with the roads.

The advantage of a four-wheeled vehicle is that it has a large carrying capacity and runs smoothly. The disadvantage is that the four-wheeled carriage needs to be driven on a relatively flat surface. According to historical records, Roman carmakers discovered the Celtic four-wheeled chariot and reformed it with a rotating front axle to rotate the direction, a whole rim and hoop to increase strength, and a hub with metal edges to reduce friction. The performance of the carriage has been greatly improved. By the year 200 A.D., sturdy Roman four-wheeled transporters rumbled along the avenues, and horse-drawn mail wagons and coaches could travel 160 kilometers, or 320 miles, a day, stopping to change horses along the way.

In the centuries that followed, these vehicles were replaced by batches of stronger, lighter, more beautiful, and more efficient carriages. By the 17th century, four-wheeled public stagecoaches had taken on almost all long-distance passenger duties, bringing prosperity to overland travel, and elaborate private carriages had become a symbol of royal status. The most luxurious of these was built in 1763 for King Joe and has been described as "the most magnificent carriage ever".

By this time the speed of the carriage had reached a formidable level, and it took a fast stagecoach about twenty-three hours, or less than a day, to cover such a long distance of three hundred and seventy-six kilometers on the best roads of the time.

At its peak, the Roman Empire had nearly 80,000 kilometers of flat avenues, and the advantages of the four-wheeled carriage could be well reflected on such avenues, making this kind of four-wheeled carriage very popular. With the fall of the Roman Empire, the roads fell into disrepair over the centuries. In desperation, the four-wheeled carriage gradually reverted to a two-wheeled carriage because it was practical and could be driven in rough terrain conditions.

At the beginning of the wine and horse trade between Ben Gongzi and the Turks, there was no suitable way to drive such a carriage, so Ben Gongzi could only think about it. However, after I became the prefectural governor of Hanseong County, I finally began to have people study various equipment about four-wheeled carriages.

Of course, the carriage I wanted was no longer the original four-wheeled carriage, but one that had springs or steel plates as shock absorbers, and could be assembled and disassembled with screws for easy repair.

Nowadays, the cement straight road has spread throughout the Guanzhong area, and the number of horses in Guanzhong is also increasing rapidly, so the use of four-wheeled carriages naturally has perfect basic conditions.

Then, the Hancheng County Carriage Machinery Company, which has already developed a prototype, began to design and produce it as soon as it received the order of this son, well, it was originally used as my wedding car, but unfortunately, it was forcibly stopped by Fang Xuanling and others, and let this son sit in a six-horse carriage to greet his relatives, and this beautiful new car, naturally put it away first, after all, this son generally rides a horse when he goes out, unless he has to go a long way, otherwise he doesn't have the spare time to take the carriage.

And today, the Yaoguang girl is going back to the house, and my son will naturally take it out, show it to the soft girl, and by the way, I will also feel the comfort of this carriage, with me as the spokesperson, I believe that the carriage will definitely be sought after by the wealthy businessmen and magnates in Guanzhong in the future, and when the time comes, this son will be able to earn a lot of money.

Compared with the two-wheeled carriage, the biggest advantage of the four-wheeled carriage is its smoothness and comfort, especially suitable for long-distance travel, anyway, let me sit in such a carriage, put two beautiful girls in the car, let me stay for ten days and half a month I have no opinion, of course, the premise is that these two beautiful girls must be Sister Qingxia and Sister Yaoguang.

The carriage is indeed quite stable, and the shock absorption has been made, so sitting in the carriage, at most, you will feel a slight bump, as if sitting on a rocking chair, and even the shaking is not as large as the rocking chair.

And at this moment, the Yaoguang girl who has passed away is lying in my arms, her slender legs are placed on the soft cushion, and she enjoys it: "My husband is really smart, and he can always invent something unexpected, but very useful." ”

"It's like this carriage, it's not bumpy at all to sit on, and it's very spacious and soft, I'm afraid that the concubine can sleep while lying down."

"Of course, I don't want to think about who your husband and I are?" Ben Gongzi smiled very proudly. "In this world, only you can't think of it, and there is nothing I can't do."

"Cut, you just blow it, you have the ability, you take the moon off for me?" Sister Yaoguang pursed her lips disdainfully, hooked her finger at me, and said angrily.

"Uh, well, hey, what kind of expression do you have, don't think that you husband and I can't do it, but because the moon is so big, at least a quarter the size of the earth we are on, how to pick it? Even if you really pick it for your husband, you can't take it. "As an excellent traverser, my son can't see a beautiful girl so despised the most, especially if this girl is still my mother-in-law, then it's even worse.

"Really? No matter how I look at it, it's only a little bit, at most, that is, the size of the plate, how can it be so big? After changing into a more comfortable position in my arms, Sister Yaoguang raised her fingers and gestured towards the bright moon in the sky.

"That's because it's so far away from us, you know? It's at least ...... away from us 760,000 miles away. I mentally converted kilometers to miles and said.

Hearing this, the Yaoguang girl suddenly widened her eyes and whispered exaggeratedly. "Seven hundred and sixty thousand miles? God, how far does that have to go? Are you fooling me again? Hmph, definitely. ”

Ben Gongzi almost crooked his mouth in anger, and gently pinched her upturned breasts, and the tiger body was shocked. "How can a scientific person like Ben Gongzi, who has always been rigorous, fool you with such a simple fact?"

Yaoguang girl's breasts were attacked, and she quickly stretched out her hand to block it, but how could this son be so easy to deal with, and the devil's claws made Yaoguang's sister's resistance disappear without a trace.

"Badass! Then you haven't been to the moon, how do you know that the road is so far away? The Yaoguang girl pursed her lips stupidly, and her pink red lips looked so sexy and seductive.

Ben Gongzi swallowed his saliva, he must be serious in scientific research. At least in terms of expression, well, the hand continued to play with the bulging plumpness of the Yaoguang girl's chest lovingly, and I said rigorously: "Naturally, the answer is obtained after rigorous calculation." ”

"Really?" Yaoguang was completely attracted by the wisdom light emitted by the brain of my son, and she didn't notice what my hand was doing at all, perhaps, Yaoguang, who had given up resistance at the moment, actually acquiesced in my behavior in her heart, just to cover it up with doubts, worthy of my mother-in-law.

"Nature is true." I cleared my throat and began to speak: "Far away in the land of Western Qin, in the federal state of ancient Greece, there were scholars who calculated the distance from the earth to the moon. Of course, if you want to measure this distance, you must first have a suitable reference, after all, the distance and size of celestial bodies are difficult to measure, but as long as a starting point can be determined, then its various manifestations on the earth will be quantifiable......"

In the third century B.C., the Greek astronomer Cyradosenes first measured the radius of the earth. Because he found that on the day of the summer solstice, when the sun shone directly into the well (set as point S) in the city of Sai (which is now the city of Aswan in Egypt), the angle between the zenith of Alexandria (that is, the point where the plumb line extends infinitely upwards and intersects the "celestial sphere" of the sky) with the sun is 7. 2 degrees.

He thinks that these two places are on the same meridian, so that the central angle of the arc between these two places is 7. 2 degrees, and also knew that when the caravan traveled in the road, the distance between points A and S was about 5,000 ancient Greek li, and he calculated the radius of the earth as 4,000 ancient Greek li according to the relationship between the arc length and the central angle of the circle.