The Great Qin Empire---Qin Li

"It was during the spring ploughing season. I went home on my day off to help plow the fields. My uncle, my brother, and my sister-in-law worked barefoot. After returning home, we washed the soil barefoot. Then I discovered that when standing side by side, my sister-in-law had the longest feet, followed by me, and my uncle had the shortest. The same was true for height. My sister-in-law was the tallest, a full eight feet, I was seven feet six inches tall, and my uncle was seven feet three inches tall."

"At this time, I suddenly had an idea and found a Qin ruler to measure the length of our feet and wrote the number on a wooden board. After returning to the pavilion, I repeatedly pondered but could not figure it out. Until last month, when there was not much official business in the pavilion, I found a counting stick in my spare time and tried to divide the height of the three people by their foot lengths. The result surprised me. The numbers I got were surprisingly consistent!"

"Six and three quarters! Gentlemen, this is the ratio of human height to foot length that I calculated!"

Hei Fu slowly recounted his "experience" of discovering this matter, and he spoke with conviction, as if it were true.

In fact, this was just an elective course called "Footprints" taught to him during his three years of undergraduate study at the police academy in his previous life. At least he attended every class and did not return all the knowledge to the teacher...

When he explained this matter, Xi, Nu, Le and Anpu listened attentively, and Hei Fu did not have to worry that they did not know what "division" and "fraction" meant. If they really thought so, they would underestimate the ancients.

The meticulous legal administration of the Qin State required a large number of officials who were proficient in mathematics, so the school had a special teaching "Book of Numbers". The petty officials in the Anlu County government, especially the warehouse and household officials, basically recited the Qin Dynasty version of the "Nine-Nine Multiplication Table", but they counted backwards from "Nine-Nine Eighty-One". There was no way, because their daily work was to calculate various grains and household registrations.

Moreover, in this era, there are already rules for fraction operations, including addition (fraction addition), subtraction (fraction subtraction), multiplication (fraction multiplication), reduction (fraction division), and even division (comparison of fraction size) and equal division (finding the average of fractions). Except for not using Arabic numerals, there is almost no difference from later generations.

After all, Li Si's fellow student, the great mathematician named "Zhang Cang", is now working in the Imperial Censorate in Xianyang, Qin State. Although the Nine Chapters on the Mathematical Art was written in the Han Dynasty, it was actually derived from the practical mathematics accumulation of Qin State for more than a hundred years...

Since everyone present has some basic knowledge of mathematics, it is not so tiring for Hei Fu to explain. He briefly threw out the number of six and three-quarters. The next thing to do is to verify whether this ratio is reliable.

Everyone still hesitated. After all, although the Qin State's historians recorded the size of footprints when handling cases, most of them were compared after catching the criminals, but rarely used footprints to arrest the criminals.

So Heifu said with a smile: "I have asked several people in Huyang Pavilion to try it these days. Without exception, they all got this number after dividing their height and foot length. If you have any doubts, why not try it too?"

"Okay, Heifu Pavilion Master, use the length of my foot to calculate my height!"

Wei Shi Anpu was the first to stand up. He took a Qin ruler, took off his boots, measured his feet, and reported his foot size: "No more, no less, exactly one foot and one inch!"

Le was the best at arithmetic among the few people, so he calculated with counting sticks, which were small sticks and were quite complicated to use.

Heifu saw that he had a hard time calculating, but he didn't rashly throw out the two things "Arabic numerals" and "vertical calculation". He knew that it was far from the time to offer them.

The Qin system is too special, different from all previous dynasties. Those things from later generations are only worth offering if they can maximize their benefits...

It took a while for Le to get the result: "Is Wei Shi seven feet and four inches tall?"

An Pu was a little unconvinced at first, but was slightly stunned when he learned the result: "Not much different!"

"Try mine!"

As a clerk, Nu has been dealing with footprints for so many years, but for the first time he learned that the height of the murderer can be inferred from footprints, and he couldn't help but be very interested.

Soon, the heights of Nu and Le were also calculated from the length of their feet, and they were indeed close to their original heights.

"Although it's not exactly the same, it's very close. Captain Heifu, you've discovered another amazing method of solving cases..."

Xi watched from the side for a long time. While confirming Heifu's discovery, he couldn't help but sigh: "If this method had been known earlier, many of the cases I've handled over the years would have been solved faster, and there would have been fewer vicious thieves who escaped and committed crimes again."

Since Heifu's "footprint method" has been proven to be reliable, the next step is to call up the "Sealing Clinic Method" recorded by Nu that day to see the footprints left by the murderer.

At this time, Anpu asked again that although the height can indeed be calculated based on the length of the foot, if the person is wearing shoes, will there be deviations?

Hei Fu looked at An Pu's deerskin boots for riding horses and said with a smile: "Wei Shi, those criminals are not comparable to officials. They can't wear good shoes, let alone xi and boots. They can only wear hemp shoes."

It turned out that the shoes of this era mainly included xi (xì), boots, and lu. Xi was a wooden-soled shoe sewn with brocade and embroidery, and only nobles who did not work wore it. Boots were made of leather. They became popular after the Warring States Period with the Hu clothing and riding and shooting, and were commonly seen among officials and riders.

Most of the soldiers and soldiers still wore straw shoes and cloth shoes, which were generally called lu. Since lu is a kind of shoe that only binds the foot, the error between the shoe print and the foot length is relatively small.

The "Fengzhenshi" was quickly taken. According to the record of that day, the footprint was one foot and two inches long...

"According to the Qin system, one foot is equal to 23.1 cm. The thief is a person who can wear size 44 shoes. What a pair of big feet..." Hei Fu complained in his heart.

On the other side, Le also calculated the height of the thief and said in surprise: "I calculated it. After multiplying it by six and three quarters, the thief's height is about eight feet and one inch!"

"1.87 meters, even in the future with better nutrition, he can be called a sturdy man..."

The truth came out, and Hei Fu couldn't help but whistled. It was easy to find people of this height in Anlu County, and there would be no more than fifty people of this height!

The height of the Qin people is not like the Terracotta Warriors, each of them is nearly 1.8 meters. Maybe that is the standard height of the people in Guanzhong?

Anyway, in Anlu County, Hei Fu found that his height of 1.75 meters was already outstanding. Most men in the county were below 1.7 meters. In rural areas, many people with poor nutrition were only 1.6 meters tall.

This is not surprising, after all, the standard for adulthood in Qin is "six feet and seven inches", about 155 centimeters...

After calculating the height of the "murderer", Le was overjoyed. The mystery that had been stuck in a bottleneck for a long time finally made a breakthrough.

Wei Shi Anpu was also ready to take the county soldiers to search for people with tall height and body and wearing swords. Even if the man threw away the scabbard and the sword inside, it would be useless. With their methods, they would definitely find the flaws.

Nu looked at Hei Fu with more and more admiration, and even felt ashamed that he had been a Lingshi for so many years, but Hei Fu had repeatedly proposed new methods. He subconsciously felt that whether it was protecting the scene or the footprint method, it should be recorded and reported to the county government and the court, so that they would become routines, or even laws, and spread throughout the country!

Only Xi was very cautious. He took Le's counting chips and calculated it again. He found that the number "eight feet and two inches" was correct, but he was not happy but worried, and his brows frowned even tighter.

"In this case, there is a new problem."

He stared at everyone and said:

"How can a man who is eight feet two inches tall jump into a window that is only three feet wide and kill people with such agility?"

Hei Fu also discovered this flaw at this time, and suddenly broke out in a cold sweat, realizing that he had overlooked an important issue.

The footprints were very fresh, and they were indeed left on that day, but were they really left by the murderer?

If not, why didn't the murderer leave his own footprints when he climbed up to the window from the mud?

Everyone was like being poured with a bucket of cold water, and the excitement just now was gone, and they all frowned and thought hard.

"There is another possibility."

Hei Fu's mind turned quickly, and he blurted out: "We thought this case was too simple before."

"The murderer may be more than one person!"

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