In order to restore industrial civilization, even if it is only a partial industrial civilization, precision is one of the necessary foundations, so it is imperative to find a unified benchmark for weights and measures.

In this regard, there is not much problem with using the original scale units, but the commonly used rulers may not be able to achieve the accuracy required by human beings today.

For example, millimeters are already the smallest commonly used units of length in life, but at this time, 1 millimeter is about the diameter of a human fist, and it is obvious that such accuracy is far from enough.

But further down, the silk meter and the humi are units that are almost not used, and few people know about them, but they are smaller microns, which are used more frequently in scientific research.

It's just that no matter which unit, when it reaches below the millimeter, ordinary measuring tools have become ineffective.

Chen Du looked at the first completed house, and his thoughts gradually diverged to this aspect.

"What do you think?"

Tang Jing saw that he didn't move for a long time, and asked a little curiously.

Chen Du said his thoughts.

Tang Xueba said with a smile: "You still know Simi and Humi." ”

"I don't know where I heard two terms, but I don't understand anything." Chen Du has always been very modest in front of Tang Jing, even if he says something he happens to understand, he will not show it, but mainly listen.

"100 meters = 10 silk meters = 1 millimeter, but these two units are basically no longer used." Tang Jing said.

"But I've heard that some old workers will use the silk unit."

"The silk often said in machining, is not silk rice, in fact, it is Hu Mi, that is, 0.01 mm, but it is also a non-standard statement, I remember which national seminar, someone once proposed to re-popularize the silk rice and Hu Mi two units, but it is said that it is because of the fear that the silk and silk rice commonly used now will make people confused, after all, it did not pass."

Chen Du nodded: "Actually, I think these two units are very suitable for us now." ”

"Indeed, it's a pity that most people don't know, if it's just for our own use, it's okay, it's just that the habit of weights and measures is not so easy to popularize, you see, many places in the United States are still using the anti-human imperial system." Tang Jing spread his hands, as if joking.

Chen Du said: "In fact, popularization is still secondary, the main thing is, even if these units are used, what means do we have to measure them?" The rulers that can be found in the school can only reach millimeters at most, and vernier calipers are estimated to be difficult to find. ”

"The accuracy of vernier calipers is generally 0.05 and 0.02 mm." Tang Jing thought for a while and continued: "Further down, the spiral micrometer, I remember that there is a physics laboratory on the third floor of the teaching building, with an accuracy of 0.01 mm. No matter how small it is, you have to use optical instruments, which you definitely don't have in school.

"It's just that even if these can be obtained, with our current size, it is difficult to carry and use, and these tools need to be well maintained, otherwise they will not be allowed to use it a few times, and our current conditions are better to forget it......"

"So, I can't help it for the time being." Chen Du spread his hands.

"In fact, in the short term, even if we want to build some equipment, we only need relative accuracy, not such a high absolute accuracy, and in the future, maybe someone will awaken the ability to measure?" Tang Jing seems to be optimistic.

Chen Du glanced at her and said in her heart that you are quite similar.

However, although he had some guesses, since Tang Jing didn't take the initiative to say, he wouldn't ask, not to mention Tang Jing's condition, even if he had awakened, it was by no means a simple measurement ability, and he was about to catch up with a supercomputer.

Regarding Tang Jing's extraordinaryness, Chen Duan was aware of it from the beginning, because it was obviously beyond the scope of erudition.

But if Tang Jing had really awakened some kind of brain-strengthening ability, there seemed to be no reason to hide it.

Taking a step back, if she really wanted to hide it, she could use a more subtle way to help everyone, and I am afraid that Chen Du would not notice her strangeness, but now, it is obvious that even Dong Junwei and He Ying and others have doubts.

However, in Chen Du's eyes, Tang Jing seemed to want others to be suspicious of her, but she refused to tell the truth herself.

I feel that this girl has some major secrets, and after she wraps this secret in a layer of dispensable paper, she reveals it in front of everyone without any scruples, without explanation, without evasion, as if she wants to be seen through, but she is very confident that she will not be seen through.

This is also the reason why since the disaster, Chen Du admires Tang Jing very much, but always has a little estrangement from her.

So much so that sometimes Chen Du would deliberately pretend to be stupid in front of her, in order to let Tang Jing perform more, maybe he could reveal some secrets.

And Tang Jing seems to have realized this, and in turn is still cooperating with him.

This is what makes Chen Duan speechless.

Of course.

He still trusts Tang Jing very much.

Because with her mind, whether she is awakened or not, it is estimated that it is not difficult to harm these people who want to harm herself.

Her weirdness probably has something to do with her abilities as well.

It's just that there's no way to know yet.

The question of measurement can only be put to an end.

In fact, this is also Chen Dui's side-knock on Tang Jing, but Tang Jing still didn't respond.

……

After the first house was built, with the template in place, the rest was much simpler.

Four rectangular bungalows rise from the ground in a row.

The bottom of the house and the ground are firmly glued together, plus twenty-four buckles to ensure that they will not be overturned when attacked, and the thickness of the exterior wall is nearly 1 centimeter, and even a rat will have to work hard to break it.

And the biggest improvement of these houses compared to the previous ones is that Chen Dui dug a tunnel on the indoor ground for four people to hide, and equipped it with a flap.

The replica is made of stainless steel, fits the floor, and has a deadbolt on the inside, so if you dodge inside, even if a rhino breaks in, it will hardly hurt - unless it directly crushes the concrete floor.

Authentic ideas, Chen Du had it very early.

It's just that the ability at the beginning was insufficient and was not put into practice.

Since the end of the world, he has had so many things to do, and he has hardly rested, so that Dong Junwei, Tang Jing and others sometimes have good ideas, and they can't bear to bring them up immediately.

Of course.

At present, the tunnel can only be Tibetan, to be precise, it is a cave, and it is still far from opening another exit.

Change the shape of the object, but cannot affect the volume.

Therefore, digging a tunnel is in principle the same thing as digging with a shovel.

He had to constantly transport the excess cement blocks, which was the most troublesome thing for Chen Du, whose strength was still just an ordinary person, so he had to constantly alternate with Wei Dalei, and the efficiency was naturally much lower.