Zhang Yiman and Hu Sanzi carefully opened a small wooden box, took out a wooden box from it and put it on the table in front of Yu Wenwen, and after the wooden box was opened, there was a glass rod lying in the brocade cloth inside.

The glass rod was about a foot and a half long and as thick as chopsticks, closed at both ends, with an iron hanging ring on one end and a string tied to it, and a glass ball at the other end, which was sealed with a pool of silver liquid, which extended about a quarter of the length of the glass rod along the thin pipes in the glass rod.

Thermometer, a thermometer that looks ordinary in the eyes of later generations, Yuwen Wen made his subordinates toss for half a year in the era of more than a thousand years ago, and finally made it, he glanced at this treasure that cost thousands of times and said: "Let's start, tell me how you made this thermometer." ”

Zhang Yiman and Hu Sanzi looked at each other and then opened their mouths to introduce the complete production process:

When Lord Lang first came up with the word thermometer, the two of them didn't know what it meant, temperature, Celsius, freezing point, and boiling point were explained by Lord Lang for a long time before he probably 'figured it out'.

The thermometer is 'very simple': first make a glass tube, this glass tube should have a thin glass hollow ball at one end, then pour mercury into the tube and seal it, and thirdly calibrate the freezing point and boiling point, and then divide it into 100 equal divisions between the two points.

Then this 'very simple' thing they spent half a year to make the real thing, the most headache is to make the glass tube, according to the requirements of the Lang owner, the smaller the 'inner diameter' of the glass tube, the better, must be straight and consistent from beginning to end thickness.

Zhang Yiman and Hu Sanzi thought of countless ways, and they didn't know how many hairs they had lost, and finally came up with a drum: use the iron pipe of the right size provided by Lin Youdi to connect the funnel to make an 'iron fan' for making glass rods, pull a taut copper wire at the center line of the iron pipe, pour the molten frit into the funnel, and wrap the copper wire in it while forming a glass rod.

When the glass is cooled and about to solidify, the copper wire is pulled out, leaving the thin pipe in the middle. But when to pull it out, there is a point in it. Too fast, no, otherwise the glass that hasn't solidified will flow and block the pipeline. If it is too slow, the thin copper wire will be wrapped too tightly, and when it is pulled out, the pipe will be twisted, and even the front and back will be of different sizes, which is not in line with the requirements.

With the glass tube, then heat one end and blow it into a thin-walled spherical or cylindrical cavitation, and after it is done, pour an appropriate amount of mercury into the glass tube, as for how to achieve 'vacuum' encapsulation, Zhang Yiman and Hu Sanzi really can't think of a way, or Yu Wenwen pointed out and gave a suggestion:

The closed section of the glass tube filled with mercury is vertically inserted into the hot rapeseed oil facing down, and after the mercury in the tube rises until it is stable, the glass tube at the mercury liquid level is burned and melted with fire, and the glass tube is taken out of the rapeseed oil and cooled, and the mercury in the tube is retracted, so the upper section of the tube is vacant, that is, the 'vacuum'.

"The temperature of the rapeseed oil that is almost boiling is more than 300 degrees, so when the mercury in the glass tube reaches this height, it can be melted and sealed to ensure that there is a range of 300 degrees, and it can also be simply made in a vacuum."

These are the original words of Lang Lord Yu Wenwen. They don't understand what more than 300 degrees mean, and they don't know what the range is, and the mysterious 'vacuum' is still half-understood, but it doesn't prevent them from making this thermometer according to Lord Lang's ideas.

At this point, we are almost finished, and finally the 'indexing' of the thermometer, first of all, the calibration of 'zero': the end of the thermometer ball is partially inserted into the dissolving ice, and when the mercury column falls to a certain stable point, a mark is used as the next fixed point, which is 'zero'.

When it snows in Anlu in winter, many large families collect ice cubes and put them in ice cellars to cool off in the summer, and the Xiyang County Mansion is no exception, so the work of determining the zero degree was quickly completed, followed by the calibration of '100 degrees':

After boiling a pot of water for a period of time, the thermometer is inserted under the liquid surface, and when the mercury column rises and stops in a certain position, it makes a mark, which is the upper fixed point, that is, 'one hundred degrees', that is, the boiling point.

The distance between the two fixed points is the so-called zero to 100 degrees gauge distance, which divides this gauge into 100 equal parts. Each aliquot is divided into 1 degrees Celsius and marked with 0°C at the lower fixed point. The 100°C mark is marked at a fixed point, and the scale with the same spacing can be engraved below the zero point and above the boiling point.

"Master Lang, this small thermometer has already measured the temperature under the armpit, and the reading is between thirty-six and a half degrees to a little more than thirty-seven degrees."

The body temperature of the human armpit is about 36 to 37 degrees, and Yuwen Wen asked the two of them to measure their armpit temperature as a way to test the accuracy of the thermometer.

He carefully picked up the thermometer that had condensed the painstaking efforts of his men for several months and looked at it carefully, thanks to the previous craftsmanship of making 'glass jewelry' and 'glass mirror', this thermometer was 'good-looking' and well-made, and the scale on it was engraved according to the previous method, with a range of -10 °C to 300 °C.

'You can know whether it's warm or cold. Yu Wenwen said in his heart, "For you, I also spent a lot of effort."

Thermometers, chemical experiments and things that are needed in industry, agriculture, planting, and aquaculture, making this thing Yuwenwen also works part-time in science popularization in addition to 'investment': he gave Zhang Yiman, Hu Sanzi and Lin Youdi science popularization what is temperature, Celsius, freezing point, boiling point, inner diameter, vacuum and other 'scientific terms'.

Then he finally knew what it was to play the piano to the cow: he didn't understand it at all, the freezing point was the temperature when the water froze, the boiling point was the temperature when the water boiled, and it was easy to understand, and the Arabic numerals had been taught a long time ago and could accept it, but he didn't understand what vacuum it was.

The thermometer is not very useful for conquering the city, but it is very useful for people's livelihood, so Yuwenwen still got it out at any cost, and the other thing that Hu Sanzi took out next was also a thing that was used with the thermometer.

"Lord Lang, please take a look." Hu Sanzi opened a wooden box and took out a wooden disc with a pointer on it, and the tip of the needle was engraved on the disc with the same arc as the circumference of the pointer, and the scale was engraved on the arc.

Hygrometers, hair hygrometers to be exact. Yu Wenwen asked Hu Sanzi to make a hygrometer based on his memory when he was a 'science expert' in elementary school. The principle is simple:

Human hair has a peculiarity. The amount of water vapor it absorbs in the air increases with the increase of relative humidity, and the length of the hair is related to the amount of water it contains. This change can be used to create a hair hygrometer.

In order to ensure the sensitivity of the hair to humidity sensing, you can use alkaline water (lime water) to degreas, and several hairs are tightened in bundles, one end is fixed in a container and the other end is fixed at the end of the pointer, and when the hair expands or contracts due to humidity changes, the pointer will be pulled to turn directly on the scale.

When the air is completely dry, the position of the pointer is 0. When the water vapor in the air reaches saturation, the place pointed by the pointer is counted as 100. The principle and structure are very simple, so Hu Sanzi quickly made a hair hygrometer.

After having a hygrometer, the most important thing is to calibrate the scale, for this problem, Yuwenwen has no precise way, but to let Hu Sanzi soil method start: in a wooden box covered with lime, then put the hygrometer inside, cover the lid, open the reading after a while, at this time, the position of the pointer is humidity 0% RH.

As for the determination of humidity 100%RH, it is to make a wooden box with a side lid and how wet it is, put a basin of boiling water with steam, put the hygrometer in it, close the box, open the reading after a while, and the position of the pointer is 100%RH humidity.

By determining the two endpoints of the arc on the dial and dividing them into 100 scales, a 'crude' hair hygrometer is now complete, and now it can be measured with the rough environmental elements of a working thermometer and a hygrometer: temperature and humidity, which is very useful for some work.

For example, in sake brewing, the temperature reading of the sake is much more intuitive when it is cooked, cooled, and fermented, and the specific temperature can only be felt by experience, and experience can only be taught by the master. There are no direct physical and chemical parameters, which can only be passed on from generation to generation, and once the intermediate natural and man-made disasters will be broken.

Another example is silkworm raising, in order to have high yield and high quality of silkworm cocoons, then in the process of silkworm raising, master and adjust the appropriate temperature and humidity of silkworms of all ages. Yuwenwen doesn't know anything about this, but after the thermohygrometer is popularized, at least farmers can sum up the lessons and control the temperature and humidity at the appropriate stage.

"Well done, go to the account room tomorrow to receive the reward." Yu Wenwen said with satisfaction, although the two boys in front of him were his servants, he still did not hesitate to reward the 'technicians'.

"Thank you, Lord Lang."

"The production of thermometers should be improved, the smoother the inner wall of the glass tube, the straighter the better, the simpler the production, the better, and the lower the cost, the better!"

The biggest key to the practical application of a technology from the laboratory is the cost, Yu Wenwen's glass workshop is now really a 'cottage workshop', which is basically handmade, because the problem of insufficient numbers also restricts the output, so he decided to appropriately increase reliable manpower to Zhang Yiman and Hu Sanzi.

The last person to come in to report was Lin Youdi, the small workshop he led had been busy for several months, and the 'pneumatic cavalry gun' was mass-produced with 20 strokes worth 200 strokes per stroke, and the failure rate was extremely high, and this thing had been ruthlessly sentenced to death by reality.

"There is land, except for the kind of handcuffs used in this communal use, the rest of the guns are suspended." Yu Wenwen was a little unwilling, but he was still helpless, before the air tightness was solved, the failure rate of this gas gun was too high, and it could only be used as a hidden weapon for self-defense. "There are also rainstorm pear flower needles and cloud-piercing arrows that have been suspended, and the cicadas will continue."

Seeing that Lin Youdi was a little uneasy, he said with a smile: "Don't think about it so much, this hydraulic drilling machine is not wasted, Zhang Yiman and Hu Sanzi use iron pipes to blow glass, and the things you make come in handy." ”

"Don't cry with a sad face, in a few days, my father will let the glass workshop make some things and I will need your help."

"Master Lang, that small pressure gauge still can't figure out how to do it." Lin Youdi still said the problem that he had been entangled for a long time, and Lord Lang asked him to find a way to make something to measure the approximate air pressure in the gas tank, but he and several of his subordinates couldn't come up with it after thinking about it for several months.

"It's okay, it's not in a hurry." Yuwenwen didn't pay attention to it, the pressure gauge is another bottleneck that restricts the development of the gas gun, the reason is very simple: the power of the gas gun comes from the high-pressure gas tank, the air pressure is low, the power is not enough, the air pressure is high, there is a danger of bursting the tank, and the sealing is not good, it is easier to leak.

The pressure gauge was very common in later generations, but even he didn't know much about the principle inside, not to mention the people of this era, without the pressure gauge, the filling of the gas tank could not be quantified at all, and from a wider range of uses, pressure vessels and pipelines must have a pressure gauge to ensure safe production.

Now they rely on stupid methods to solve the pressure problem: look at the number of pumps, but the number of hundreds of times often forget how much they play, so before this problem is solved, the gas gun can really only be used as a hidden weapon.

"I'll talk about this later, I have something new for you to do."

"What does Lang do?"

"The Japanese will give you the drawings in a few days, and after reading it, you will say what you need." (To be continued.) )