Why is the hottest day of the year called "dog days"? [sharing]

The first, middle and last three days are the hottest days in a year, so they are also called "dog days" and "dog days". According to Historical Records of Qin Benji, "(Qin Degong) for two years, he first descended to fight evil with dogs." In the Southern Song Dynasty, Pei Qian quoted Meng Kang as saying, "At the beginning of June, there is no week. So far, yes. " In addition, Zhang Shoujie's "Shi Yi" in the Tang Dynasty said: "The festival of June 3 began in Qin Degong, so the clouds fell first." Therefore, the saying of blessed days has a long history, which originated from the state of Qin. In addition, Guangya, written by the Three Kingdoms Shiyi, said: "Fu and Zang are also." And "Guang Yun": "V, Tibet also." This is the ancient explanation of "Fu", so what is "Fu Ri"? There are three kinds of statements. Yes, according to the "History of Li Ji", "Who lies down?" The day when the breath of gold lurks. The metabolism of the four seasons is mutual: spring wood replaces water, and aquatic wood begins; Long summer fire replaces wood and wood fire; Beginning of winter water substitutes gold, and gold produces water; As for beginning of autumn replacing fire with gold, gold is afraid of fire, so it will fall on Geng Day, and those who belong to Geng are gold, so it will fall. "This theory is based on the changes of the five elements and the four seasons. According to the theory of five elements, the ancients believed that spring belongs to wood, summer to fire, autumn to gold, winter to water, and four seasons alternate. Therefore, beginning of spring is the wood in spring, not the water in winter, the aquatic wood; In the long summer, spring wood replaced the summer fire, and the wood made a fire; Beginning of winter is the water of winter, not the gold of autumn. Gold gives birth to water, so it follows the five elements. The only difference is that in beginning of autumn, summer belongs to fire and autumn belongs to gold. Therefore, the transformation between summer and autumn is not based on five behaviors, but on mutual restraint, that is, fire belongs to gold and Geng belongs to gold. Therefore, Gengri is the day when the golden spirit will lurk, and the saying of "Furi" came into being. According to Records of Sacrifice to the Suburbs in the History of Han Dynasty, Yan Shigu pointed out: "Those who lie down say that Yin Qi will get up, but they are forced by the setting sun and cannot get up. So, it is hidden, and it is because of the name. "Because after the slight summer heat, it is followed by the concentrated rain, the hottest day of the year, and it is also the period when the yang suppresses the yin, so it is called' Furi'. He also said that Pei Zhi's "Xieji" in the Southern Song Dynasty quoted Meng Kang as saying, "Those who lie down will escape the summer. "People think that June in the solar calendar is the hottest season of the year, and it is suggested that people hide for the summer during this time, so it is called' Furi', which is easy to understand. Three volts is a general term for the initial, middle and final three volts, which is between mid-July and mid-August in the western calendar. From summer to the third Geng day in the future, it is a volt every ten days, which is divided into initial, intermediate and final volts. The dog days appear between the light summer heat and the heavy summer heat, and it is the hottest, humid and sultry day of the year. Days with direct sunlight are not the hottest in a year. After the summer solstice, the ground absorbs more and more heat from the sun, and emits less and less heat every day, so the heat on the ground accumulates more and more, getting hotter every day. After entering the dog days, the accumulated heat on the surface reaches its peak, so the weather is the hottest. The ancients used the method of "observing the day with heavenly stems and earthly branches" to record the day, and called every day with the word Geng "Geng Day." Gengzi ranks seventh in the ten-day work, and Gengzi Day is repeated every ten days. Therefore, since the beginning of summer, the third Geng day has been called the first autumn; The fourth Geng day is Zhongfu; The first Geng Day after beginning of autumn is the last day, which is called "dog days". For example, the Book of Yin and Yang said, "From the summer, the third watch is at the beginning, the fourth watch is at the middle, and beginning of autumn is at the back, which is called the dog days. "Usually, the first, middle and last three days are ten days each, but when there are four Geng days between the summer solstice and the beginning of autumn, the middle day is ten days, and when there are five Geng days, the middle day is twenty days. So sometimes it's ten days from the middle to the end, sometimes it's twenty days, and the first and last days are ten days. These dog days and dog days are the hottest thirty days (or forty days) in a year, so they are also called "dog days" and "dog days". Lying is hiding, so it is the hottest dog days, that is to say, in dog days, you should avoid the heat and summer heat by hiding, and don't over-expose yourself in the hot sun. You should pay attention to the hygiene of life, diet and daily life to prevent heatstroke or other diseases.