In ancient times, we had a method of "carving wood to record the sun", that is, carving bamboo or wood to calculate the sun. For example, Party A and Party B have an appointment to meet somewhere in 10 days. How can we avoid making mistakes? When they agreed, they found a small piece of wood, carved 10 on it, and then cut it vertically in the middle, just like a "letter of introduction" and a "stub", with each party holding half. Every day, they cut off one grid, and when the 10 grid is cut off, that's when they meet. This original method of recording a day was later adopted by prisoners in prison. They often draw a line on the wall or on the ground every day to calculate the time spent.
When the ancients carved wood, there was an original method of "tying the rope to record the day": people tied a knot on a long rope to calculate the day. For example, if someone wants to go far away, he will tie a rope and tie a knot around his waist after leaving, that is, before checking in at night. When he walks, he ties a knot every day. When he arrives at his destination, he can know how many days he has walked this time from the number of knots on the rope, from which he can estimate the distance of this place. When he is ready to go home, he walks on the way back for a day to untie a knot. When all the knots on the rope are untied, he should go home.
The method of "tying a knot to commemorate this day" later evolved into a proverb: "Tie a knot in your pants-remember it."
In a longer period of time, the ancients counted the days by throwing stones into earthen pots. For example, whenever there are 10 knots on the rope, they throw a pebble (and untie the knots at the same time), so that they can finally calculate how many ten days have passed from the number of pebbles and knots. This method of stone-throwing commemoration was even used in some parts of China until the founding of New China. For example, in the Miao nationality areas in the southwest of China, the years were counted like this before liberation. When the moon is full, throw a pebble into the bamboo tube. When the number of pebbles inside has reached 12, throw them out and replace them with a big pebble-indicating that it has been a year.
Later, people not only noticed the rising and setting of the sun, but also slowly discovered the law of cold coming and summer going. The wind and snow in winter and the scorching sun in summer not only make them feel the change of environment, but also have a great influence on their gathering and hunting activities. After entering the agricultural society, people finally gradually realized the concept of "year". In China, phenology has been carefully observed for a long time, such as willows turning green and voles coming out of holes ... In the Wusuli River valley in northern China, the ancients couldn't figure out their age, but "ranked by generations" by eating marijuana and salmon several times. Because this delicious marine fish doesn't return to Wusuli River to lay eggs until September1October every year, people who eat fish for 40 times are definitely older than those who eat fish for 20 times and deserve more respect.
The ancients in northern China counted their ages by the number of times they ate fish. Because they live on the prairie and live on animal husbandry, they often take the decline and glory of the prairie as the year. They call how old you are "how green you are" or "how green the grass is". Extending the customs of Qiang people is described in China (Shu Wei) ancient books: "The customs are silent, and you can't remember the age until the vegetation flourishes and withers."
The Nile regularly overflowed, which helped the ancient Egyptians to determine the length of a year at the earliest. Around the 20th century BC, they found that the sun rose and fell 365 times on average between the two rises of rivers. So ancient Egypt set a year as 365 days long ago. But interestingly, the Egyptians used a fixed "calendar" of 12 months per year and 30 days per month. This calendar has only 360 days a year. So at that time, the last five days had no "status" in the calendar. During those five days, the Egyptians closed their doors, kept out of contact with others, and sent them away in a daze or deep sleep. ...
A day is a long time, but how to determine an hour? It is found that it is more accurate to judge the time according to the length of the shadow cast by the sun on the ground objects. Such as shadows of trees, houses and objects. In the morning, the shadow is longer; At noon, the shadow is the shortest; At night, the shadows grow again.
An ancient Egyptian wrote a letter to Princess Boloni, which said, "When your shadow grows to 16 step, Amassis will wait for you in the olive grove ..." In an ancient Greek comedy, an Athenian woman said to her husband, "When your shadow grows to 10 step, please come and eat sesame oil!"
What do you mean by shadow step 16 and 10? It turns out that in ancient Egypt and ancient Greece, stone tablets or monuments were built in many places. During the day, the sun rises and sets, and the monument casts shadows. People can know what time it is just by measuring the shadow with their feet.