"Steam engine?" All three of them asked at the same time.

"Yes. This kind of machine can use steam to drive the wheels to rotate, can replace manpower and animal power, can pull the car to fly, drive the wheels to fly, and can do many things. He Zhiyuan said far away.

"Master, tell me about it. What does this machine look like? Wang Zhixue immediately became interested.

"It's not that easy to build a machine like this. The current steel quality is not up to the requirements, and the vapor tightness of the cylinder block is not up to the requirements, and there are many things to do. But you have to work in that direction now, and stop focusing on the steam cannon. He Zhiyuan taught them like a mentor.

"Master, can you draw another sketch of the steam engine?" Wang Zhixue asked hungrily.

"Yes, I can only draw a simple sketch, and as for how to make it, I have to figure it out. But it's not a machine that can be made in a few months, it's a very complex machine, and it uses a lot of tools. For example, the bolts and nuts you invented will be used in the manufacture of steam engines. However, it is no longer possible to use the casting method to make it, which is too slow and the scrap rate is too high. He Zhiyuan was inspired again.

"No casting? What's the best way to do it? Liu Xing's father and son asked at the same time.

"You can cut it with a lathe, and I'll draw another picture tomorrow for you to see." In order to make a steam engine, these tools had to be made first. He Zhiyuan said.

He Zhiyuan didn't expect a few of them to be able to build a steam engine, he just pointed them out the right way, and didn't want them to go astray on this road. As for how much they can do, he doesn't expect too much. The main reason is that there are too few talents, and there is too little money that can be taken out for their research, and it is a very money-burning thing to engage in research. This steam cannon alone cost him thousands of taels of silver. It is impossible to build a steam engine with the current financial and human resources.

After the test of the cannon, on the way home, He Zhiyuan said to Wang Zhixue: "Now that the steam cannon has been tested, the rest of the time can be done by Liu Xing and his son with the helpers." You have to focus on learning something new, and then you have exams in a while. How are you learning? ”

"Don't worry, master. I'm studying hard and I'm sure I'll do well in the exam! Wang Zhixue said confidently.

"Don't boast about it first, most of the knowledge talked about in physics is not physical, it is very abstract, can you see and understand?" The physics textbooks written by He Zhiyuan are basically based on the physics textbooks of later generations, and a lot of knowledge needs to be physically verified to understand, and he does not believe that Wang Zhixue can fully understand it.

"Some of them understand it, but there is no physical object, so it is difficult to verify." Wang Zhixue replied truthfully. Then he asked, "Master, you said that you can make convex lenses and concave lenses when you make glass, but when will you start making glass?" ”

"Now we have to open a cement workshop first, and we don't have the energy and financial resources to develop glass, and then the glass needs a very high furnace temperature, and the current refractory materials can't meet the requirements, so we have to wait. However, you can replace it with glasses, and the effect is the same. He Zhiyuan reminded.

"Can you use glasses?"

"Yes. If you take a closer look, if it is a convex lens, you can do an imaging test, and if it is a concave lens, you can do a sunlight focusing test. ”

"Oh, I see." Wang Zhixue replied thoughtfully.

Early the next morning, He Zhiyuan was still in bed and didn't get up, when he heard Wang Dejin, who lived in the front yard, scolding his son: "You bastard boy, stop for me!" Is it okay for you to run? ”

He Zhiyuan heard the scolding, and thought to himself that Wang Zhixue is very regular these days, why did he make his father angry today? So I got up quickly and wanted to go out to see what was going on.

At this moment, Wang Zhixue knocked on the door outside, shouting as he knocked: "Master, open the door quickly!" ”

He Zhiyuan thought to himself, it turned out that he had caused some trouble, and he came to me early in the morning to take refuge. He got dressed and got out of bed, opened the door, put on a straight face, and asked Wang Zhixue in a master's tone: "I heard the teacher scolding you in the front yard, why did you make the teacher angry?" Do you want to run away from me? ”

The Zhiwang Zhixue didn't answer him at all, but said: "Master, your physics textbook says that the convex lens can become an inverted image, and my experiment has proved that the convex lens can also become an upright image!" ”

At this time, Wang Dejin was scolding loudly, rushing from the front yard, Wang Zhixue didn't have a scared demeanor at all, and was still talking about his experiment.

He Zhiyuan asked: "Can you tell me why the teacher is still scolding you later?" ”

"I removed his glasses...... Wang Zhixue said indifferently.

"Ahh It turns out that you are doing an experiment with his glasses, so you go and hide in the house. He Zhiyuan hurriedly let Wang Zhixue into the house.

In the Ming Dynasty, the lenses were made of crystal, and a pair of glasses was expensive.

Wang Dejin took the glasses with lenses, walked to He Zhiyuan's door with a scolding, and asked angrily when he saw He Zhiyuan standing outside: "Have you seen Zhixue's prodigal play?" ”

"Why is the teacher so angry?" He Zhiyuan asked.

Wang Zhixue raised the glasses in his hand and said, "Look at the good things that this loser has done, he borrowed them from me last night, and I didn't give them to them." He actually stole and folded it, did a night of experimentation, and smoked the candle with that lens, and completely ruined it! ”

It turned out that Wang Dejin was presbyopia, and he had been reluctant to buy it before, but now that he has money, he was willing to spend twenty taels of silver to buy glasses.

He Zhiyuan hurriedly apologized: "Oops, teacher." Yesterday I was talking about the physical test, and I said that I could use glasses instead of a convex lens for imaging tests, but I didn't expect him to really do it, and he broke your glasses. This is my fault for not being strict with my disciples. I'll pay you today. ”

When He Zhiyuan said this, Wang Dejin was a little embarrassed, and hurriedly said: "That can make you compensate, it was the evil beast who demolished it, and he should be compensated." ”

"Wang Zhixue, you come out! Tell me how you broke your teacher's glasses. He Zhiyuan took out the majesty of being a teacher and said to the room.

Wang Zhixue had to come out of the house at this time, looked at his father and said, "Father, I didn't mean to, I just wanted to do that experiment too much." I thought I could put it on if I removed it......"

Wang Dejin didn't want to beat and scold anymore in front of his students, but said sharply: "Why are the lenses blackened?" ”

"That's because the candle is too close to the lens." Speaking of this, Wang Zhixue said excitedly: "But I found a phenomenon that the teacher didn't talk about in his textbook......"

He Zhiyuan saw that he was about to deviate, and hurriedly interrupted: "Don't talk about this first, fix the teacher's glasses today." Then he said to Wang Dejin: "Teacher, today we will go to the city to help you repair it, and ensure that it is exactly the same as the original." You don't have to be angry, he is eager to experiment, and with his spirit of exploration, he will definitely have great achievements in the field of science in the future. The bolt and nut he invented was a very important invention, and it may be written down in history in the future. ”

Wang Dejin listened to He Zhiyuan praise Wang Zhixue, and his anger was almost gone. took his glasses and went back with Wang Zhixue.

After their father and son left, He Zhiyuan thought to himself, why not invent the telescope together while going to the city this time. A simple telescope is not complicated, only two lenses are convex and concave, so I decided to make a monocular first. So, he came to Carpenter Wang's house early in the morning, told him to make a retractable wooden tube, and told him the size, and he would use it when he came back in the afternoon.

Then, he and Wang Zhixue went to the city in a carriage. Walking on the road, Wang Zhixue was also excitedly talking about the experiment last night: "Master, when I did the candle imaging experiment last night, I found that when the candle was very close to the lens, the image on the opposite side was gone, and then I found that the image ran to the same side, and it was upright." Why is that? ”

He Zhiyuan looked at Wang Zhixue like a child with 100,000 whys in his heart, hungry for knowledge, and said: "There is no pen and paper here now, I will draw a light map for you when I go back, and you will understand." Today, let's go to the city, in addition to repairing glasses, we will also make another telescope for the teacher to open your eyes. ”

"Telescopes?" Wang Zhixue asked, "What is this?" ”

"A telescope is a mirror that can see things far away, and use it to look at distant things as if they were right in front of them." He Zhiyuan explained.

"And this kind of feature? Wouldn't that become clairvoyance? Wang Zhixue asked suspiciously.

"Yes, it's like the myth of clairvoyance."

They chatted about the telescope all the way, and He Zhiyuan simply explained the principle of the telescope to him. Since there is no paper and cannot draw, Wang Zhixue only seems to understand but does not understand. But I was looking forward to the telescope.

When they arrived in the city, they came to a shop called Ren Kee Glasses. He Zhiyuan entered the optical store for the first time since he crossed. As soon as I entered the store, a young man of fifteen or sixteen years old stood in front of the counter, and an old man was polishing the lenses with a grinding wheel on his feet in the counter. When the guy saw a guest coming, he hurriedly stepped forward and asked, "Guest, do you want to buy glasses?" ”

Wang Zhixue took out his glasses and said, "Do you think these glasses can be repaired?" ”

The guy took his glasses and looked at them and said, "You can fix it, but it costs two taels of silver." ”

"So expensive?" Wang Zhixue was a little distressed.

Taking advantage of the time when Wang Zhixue and his men were bargaining, He Zhiyuan began to observe the furnishings in the store. Daming's optical shop was not as brightly lit as later generations, and the glass counters were spotless. On the contrary, the store is a little dark, with ropes pulled up on the cabinets, glasses frames hanging from the ropes, and pairs of lenses of different sizes and shapes placed on the counters.

He Zhiyuan asked the guy: "Do you have myopia lenses here?" ”

"Myopia?" The guy asked rhetorically with a confused expression. Apparently he hadn't heard of the term.

He Zhiyuan thought to himself, didn't this word exist in the Ming Dynasty? He explains: "It's the opposite of these lenses, which are thin in the middle and thick on all sides. ”

"Oh, you're looking at the lenses." It dawned on the man.