Jinling is beautiful, but it is not worthy of Song Che's nostalgia. On the morning of August 16, Song Che chartered a passenger ship and returned to Hangzhou alone.

Tang Hulu and other merchants still stayed in Jinling, probably because they wanted to find more opportunities to make a fortune at the feet of the Son of Heaven.

On the afternoon of August 18, the passenger ship arrived in Hangzhou. In the days that followed, everything went into normal. The affairs of the family and the business outside are all well taken care of by the women.

In addition, this autumn's bumper harvest, a large amount of foreign capital inflow, the original financial deficit due to the war in the north has also been made up, the government has money, so there is no need for Song Che to pay for blood transfusion to them, moreover, many refugees from the north have voluntarily joined the army, the desire to drive out the Tartars, restore the Central Plains is very urgent, now, the money is available, there are enough people, just wait for the horses from the northwest, the weapons and armaments are sufficient, you can wave the army to the north.

Song Che was a little distressed - the fierce fire oil refined from Shedao was very successful, and a single can could burn a house, but the problem was that there were firearms but no vehicles to launch; Usually the army's use of fire oil is trebuchet, canning or applying oil to stones, igniting and throwing it out to achieve a certain distance of killing, but this method of combat is too clumsy, the trebuchet must be pushed very close to have a chance to play an effect, but if it is pushed too close, if the enemy uses a strong bow and a crossbow, and then carries a rocket, it is easy to shoot, in case the fire oil is in his own camp

"Blowing up", but you will be in big trouble. Since Song Che developed artillery, the trebuchet has almost been eliminated by the army, but the fierce fire oil is a liquid, and it cannot be pushed out with gunpowder like a solid cannonball.

On the day of "Alas......", Song Che sat in the study as usual, staring out the window with his cheeks in his hands, thinking hard.

"Whew-" The study door was pushed open.

"Sir, it's windy today, and the ladies are calling you to fly kites!" Coco hugged the kite and rushed into the study in high spirits.

Song Che shook his head, where did he still have the heart to fly a kite? Ay? Kite? Fly a kite to the sky!

If you want to ask about fluid bombs like fierce fire oil, the best way to throw them is

"Airdrop"? But how do you send a bomb into the sky and apply it to the battlefield with precision?

Is it possible for me to build an airplane? He can't live on this thing. The aura that had just flashed was denied by him shaking his head, and sighed lightly: "Go play by yourself, I'm really not in the mood to ......" At this time, Lin Yue rushed into the study, dragged him off the chair, and dragged him out: "Oh, you lock yourself in the study all day long, go out to move your muscles!" ”

"Yes, yes, we have prepared a sky lantern tonight, and the wind is so strong today that it will definitely be able to fly to the clouds." Coco said.

"Sky lantern!" Song Che's freshly broken aura was renewed again. Sky lanterns? Kong Ming lantern? Balloon!

If you can't build an airplane, you may want to try a hot air balloon!

"Coco! Go and get the sky lantern for me to see! ”

"Huh? But, sir, the sky lantern should be lit at night to look good, right? ”

"You go and get it, I'll be of great use!" Song Che urged. Coco didn't ask any more questions, and soon fetched all kinds of sky lanterns.

The structure of the sky lantern is divided into two parts: the main body and the bracket, the main body is mostly made of bamboo strips, the lampshade is made of cotton paper or light oil paper, and the fuel is mostly burned animal ointment, and the burning flame increases the temperature of the surrounding air, and the density decreases and rises, so as to discharge the original air in the lamp, so that its own gravity becomes smaller, and it is held up by air buoyancy.

Hot air balloons can think of it as:

The "giant sky lantern" usually uses sandbags and fuel to control the rise and fall, as for the direction and speed, it requires more complex processes, such as thrusters, spoilers, etc., ancient warfare, the requirements do not need to be too high, as long as the fierce fire oil can be transported to the sky, and then thrown to the enemy.

"Haha! Coco, you're such a clever little ghost! Song Che laughed, got on his bicycle, and rushed to Yunshuifang.

Coco pouted: "People will be sixteen years old soon, not a little clever ghost...... "...... Although the principle of hot air balloon is the same as that of sky lanterns, the material and structure are not the same.

The main material of the sky lantern is cotton paper, as the height rises, if it encounters strong air currents, it will be easily blown off, so if you want to make a hot air balloon, you must first find a tougher, lighter material, the last fair, Yunshuifang from the hands of the merchants, collected a lot of characteristic cloth, maybe you can find the favorite one.

"Hurry up, I need a kind of cloth now, the texture needs to be light, not too breathable, and the toughness should be high!" Song Che rushed into Yunshuifang and shouted loudly.

The big proprietor wanted something, the clerks didn't dare to slack off, and soon, Qin Ruo came over with three pieces of fabric, and she introduced them in turn: "This is 'rainproof cloth', this is 'light rob', and this is 'Ziyun yarn', all of which are Xinping launched in the market, do you see if there is one that meets your needs?" Song Che unfolded the three fabrics in turn and checked them, the rainproof cloth has good toughness, but it is too heavy and the air permeability is too low; The texture and breathability of the light rob are satisfied, but the toughness is too poor; Although the texture and toughness of Ziyun yarn are good, the air permeability is too high...... Song Che shook his head and asked, "Can you combine the toughness of the rainproof cloth, the breathability of the light cloth, and the texture of the purple cloud yarn to weave a new kind of cloth?" Qin Ruo pursed her lips,

"The rainproof cloth is made of fine cotton sateen, the light cloth is made of fine linen, and the purple cloud yarn is made of silk, the process and material of these three fabrics are different, alas, it seems that it is not easy to combine them, well...... It's not easy. Song Che said with a smile: "Wrong, there is nothing difficult in the world, only afraid of people with hearts, our workshop is full of talents, there must be a way to make it." Qin Ruo said: "I'm not good at textile technology, but I can go to Suzhou to find Lu Mushroom to try, she may have a way to ......" Song Che said: "I also went to Suzhou to find her to do something, and directly invited all the experienced weaver girls in the head office, I want this batch of cloth soon, the sooner the better!" ”

"What the hell do you want this cloth for? This strange cloth is not suitable for summer clothes, winter clothes, and even more suitable for private rooms, even if it is woven, it is not easy to sell well on the market. "Qin Ruo and the clerks couldn't understand it.

Song Che was full of enthusiasm and interest, and pointed to the sky and said, "I want it, heaven!" ”

"Huh? Big...... Big boss, don't think about it! ”

"Stupid, when I say heaven, I am flying into the sky, riding the clouds and the wind, and competing with the birds for freedom!" ……