Seven days have passed in a blink of an eye, and Zhang Tian will be beaten by his father every morning.

Fortunately, after gradually getting used to it, he was no longer in a coma, although the healing medicine given by Zhang Yi had a wonderful effect, it made him grin in pain every time.

But no matter how miraculous this medicine is, it still takes some time to fully recover from the injury, which also seriously slows down Zhang Tian's time to develop new products.

But fortunately, he got six bottles of quenching body fluid from the emperor, and in addition to being beaten every day, his swordsmanship and cultivation have improved significantly during this time.

With his current swordsmanship, not to mention how powerful he is, at least the opponent of the same level, he no longer cares about it!

Finally, half a month later, Zhang Tian sent someone to invite Li Sitong's sister and brother, intending to show his research results in the past half a month.

During this time, they had already completed the handover of the factory and shop with the people sent by the royal family, but they didn't expect that the person sent by the royal family to be in charge of this matter was actually His Royal Highness the Fifth Prince!

originally thought that they would be troubled, but they didn't expect the five princes to be extremely friendly to the two, which flattered them.

After the handover, the two of them went from being busy all day long, and suddenly became home-free, and they were almost crazy!

Li Dabao couldn't help but want to go to Zhang Tian several times, but was stopped by Li Sitong.

She knew that Zhang Tian must not be idle at home, and she didn't let Dabao bother him recklessly.

When the two of them saw that Zhang's subordinates came to invite, they were immediately overjoyed and hurried to Zhang Tian's courtyard in a hurry.

Seeing the two of them walking into the small courtyard, Zhang Tian hurriedly got up from the rocking chair, "Haha, welcome, welcome!" I'm sorry for the delay in calling you over for so long..."

Li Sitong was wearing a lilac gauze skirt, and her phoenix eyes had a hint of resentment, as if she was making a silent accusation.

And Li Dabao wiped the sweat from his forehead and muttered, "My brother Tian, you can be regarded as thinking of us, I am almost a bird at home!" I ate and slept all day long, slept and ate, and I lost weight! ”

"Hehe, I'm not afraid of being late for a good meal, I'm sure to surprise you today!" Zhang Tian scratched his head and said.

"Okay, let's talk about it, what treasures have you figured out in the past half a month?" Li Sitong gave him a blank look and hurriedly asked.

She was already impatient, how could she have the time to listen to the two of them talking about idle days here.

After letting the two of them sit down, Zhang Tian smiled and took out a silver metal cube from his pocket, about half the size of a palm.

I saw that with a flick of his fingers, he opened the lid above, and pressed the roller with his thumb, and a spark came out, instantly igniting a wisp of orange and yellow flames!

Li Dabao and Li Sitong's eyes widened suddenly, their faces were full of disbelief, in this world where flint and steel, fire sickles or fire folds are still used to ignite fires, this is simply a miracle!

"It's... Can this thing ignite in an instant?! Li Sitong was surprised.

Li Dabao stood up suddenly, obviously shocked by this scene, "What is this?" It's amazing! It looks so delicate, how did it light the flame?! ”

Zhang Tian waved his hand, "Sit down, sit down, it's just a basic operation!"

This thing is called a lighter, no matter when and where, as long as it is not blistered, it can be ignited instantly! You say this thing, can it be sold? ”

"Yes! That's great! This lighter is so magical, it is definitely a hot seller! Li Dabao sat back in the chair, his face full of surprise, and he slapped his thigh excitedly.

Ordinary people can only use flint and steel or fire sickles to light a fire, and it doesn't take half a day.

Only the wealthy can afford to use the fire fold, but although it can preserve Mars, it can be as short as a few hours or as long as a few days, and it will be extinguished, which is not very convenient.

Li Sitong's beautiful eyes sparkled, "This thing is so exquisite, it takes a lot of work to manufacture, right?" ”

"Well, if you want mass production, of course it won't be so fine, just make it with ordinary brass!" Zhang Tian nodded.

This thing was made by Zhang Tian according to the flint lighter on the earth, and he made some adjustments to the place where the flint was stored, replacing it with flint cut into small pieces.

It took Zhang Tian a lot of effort to design this thing, and he originally wanted to design it the same size as the one on earth.

But that was too small, and even if he could make it, he wouldn't be able to make it mass-produced.

So I had to double the size of the lighter, and I tested it for several days before it finally succeeded.

Zhang Tian handed over the lighter to Zhao Dabao, and he immediately used it in the same way as Zhang Tian, looking at the beating flames in amazement.

"You also sell this thing like lipstick, in high and low grades?" Li Sitong calmed down a little, looked at Zhang Tian and asked.

"No, just let the craftsman make it by pouring the mold."

Zhang Tian shook his head, there is no shortage of those three melons and two dates now, just make a few exquisite ones and give them to friends to play with occasionally.

Li Sitong laughed, although she was calm on the surface during this time, she had always felt very uncomfortable in her heart, and now she was really relieved when she saw this magical lighter.

"I plan to sell this thing for one or two pieces of silver, and let the craftsman make a mold, pour copper paste, and produce it in batches.

It's just that the flint used in it has some limitations, and it can be a bit troublesome. Zhang Tian said with a smile.

"Well, flint is easy to find, there are ore veins near the Imperial City, I will find a way." Li Sitong said.

Zhang Tian pulled the Xingxing Dabao who was playing, "Don't study the lighter yet, I'm showing you something else." ”

Li Dabao was stunned, "And?" ”

"Hey, it's a must! Wait, I'll take it out for you! ”

After saying that, Zhang Tian ran into the house, hugged a big one and a small one, and walked out with two strange-shaped guys.

Zhang Tian put the things on the stone table in the courtyard, and the two hurriedly surrounded them, staring at them with big eyes, and they didn't understand it after looking at it for a long time.

The two things were about the same length, the larger one was about two feet high, with four oval pieces of copper stuck at the top, and a long wooden cylinder the thickness of an arm, attached to the base, and on the base protruded something that looked like a handle.

"What is this? How does it look weird? Li Dabao wiped the Han and said suspiciously.

"Hey, hey, you turn the handle underneath and try it!" Zhang Tian smiled mysteriously.

Hearing this, Li Dabao held the handle and turned it slightly, only to see the four thin copper sheets on it spinning rapidly, and the whirring cool breeze blew on his face.

Li Sitong, who was standing on the side, was also blown upright, the purple gauze was fluttering, and he was suddenly very comfortable, and his eyes were suddenly surprised.

"How? Isn't it cool? Zhang Tian smiled with a smile.

"Cool! Much cooler than a fan! What's this thing called? Zhao Dabao asked in surprise.

"I named it, Fan!"

In the scorching summer, Li Dabao sat at the stone table and gently shook the handle, feeling the cool wind blowing in his face, and Li Sitong also leaned forward.

"Sitong, you try this small one, you can use it in your hand, it's light." Zhang Tian smiled and handed the other one over.

Li Sitong took the smaller fan and turned the handle, and the green silk blowing in the breeze also blew away the good fragrance on her body.

Zhang Tian looked at the beauty holding the fan, smelling the fragrance in his nose, which was very pleasant.

"Brother Tian, why did I only gently turn the handle once, but the copper leaf on it turned several times?" Li Dabao asked suspiciously.

"I added gears of different sizes to the inside, and by using the gear difference, I was able to increase the rotational speed." Zhang Tiandao.

Only the blades and the internal construction of this fan are made of copper, and the rest are all made of wood, which is much lighter and less difficult to make.

"Wonderful! Brother Tian, I'm convinced! How can you think of anything!? Although Li Dabao didn't understand, he still praised it.

Zhang Tian scratched his nose and blushed, these are the wisdom of others on the earth, he just borrowed it.

But he can't explain it, he can't say that he came through time.