Ancient Chinese hourglass

Because the sun clock such as the watch will not work on cloudy days or at night. Therefore, the ancient people invented instruments such as clepsydra and hourglass, oil lamp clock and candle clock to record time.
In the beginning, the method of engraving was used, but the water of the engraving was easy to freeze in winter, especially in the north, and the quicksand was used to drive it later. "History of the Ming Dynasty, Geographical Records" records that in the early Ming Dynasty, Zhan Xiyuan invented "five-wheeled hourglass". Later, Zhou Shuxue enlarged the quicksand hole to prevent clogging and used six wheels instead. The "Anthology of Song Xueshi" also records the structure of the hourglass, with the dimensions of the parts and the number of teeth in each gear of the reduction gear, and it is said that the shaft tip of the fifth wheel has no teeth, and is equipped with a viewing disc to indicate the time, which is now very complete.

Hourglass is also an ancient time measuring instrument. HourglassManufacturing principle and missing engraving Much the same, it measures time in terms of how long it takes for quicksand to leak from one container to another.
The most famous hourglass is the "five-wheeled hourglass" created by Zhan Xiyuan in 1360. The quicksand flows from the funnel-shaped sand pool to the sand bucket beside the primary wheel, drives the primary wheel, and then drives the mechanical gears at all levels to rotate. The last stage gear drives the middle wheel that rotates on the horizontal plane. There is a pointer on the axis of the middle wheel, and the pointer rolls on a scribed instrument disc to flash the time. This flashing method is almost the same as modern clocks. The surface structure is exactly the same. In addition, Zhan Xiyuan also wonderfully added a mechanical toggle device to the middle wheel to prompt the two wooden figures standing on the five-wheeled hourglass while cutting the drums. Every hour or quarter, the two wooden figures would come out on their own, cutting drums to tell the time. This hourglass is separated from the auxiliary geographical instrument and has become a mechanical clock structure independently. Because there is no water pressure constraint, the hourglass is more accurate than the leak.

while western Hourglass

< ;span style="font-size: 16px;">The earliest hourglass discovered in the West was about 1100 AD, which was later than the hourglass in our country.
The western hourglass is said to have been invented by Alexander in the third century, where they were sometimes carried around like a watch that people carry. It is estimated that it was invented in the 12th century, along with the advent of the compass, as an instrument for flying at night over the sea (during the day, sailors could estimate time based on the height of the sun).

The discovery with solid grounds is earlier than the 14th century, the earliest hourglass is a suitable government in 1338 The allegory of the fresco Ambronzetti appears in the written records of the same period speaking of the hourglass, it appears at the Listed Vessel Shop. The earliest extant record is a 1345 sales receipt by Thomas Stetesham, a clerk on the English vessel "La George".
From the 15th century, they were widely used at sea, in churches, in industry and in cooking. During Magellan's flight around the world, each of his ships stuck to 18 hourglasses. In the ship's paperwork, run the hourglass and then supply the time for the ship's logbook.

Before the Jesuits entered mainland China, foreign businessmen and missionaries living in Macau had brought medieval European bells to Macau. The Jesuits Michal Rvggier (1543~1607) and Matteo Ricci (1552~1610) came to China in 1581 and 1582 respectively. They not only carried clocks, but also accompanied watch repairers. The hourglass, the water clock (the water sundial) and the hammer-driven self-ringing clock widely used by Europeans were introduced to my country together. After the hourglass was introduced to our country, it was used as a timer in navigation. In the 23rd year of Qianlong's reign (1758), Zhou Huang wrote "The History of the Ryukyu Kingdom", saying that from Fuzhou to Ryukyu, the ship traveled "one to sixty miles", and used < ;a href="http://www.hcgy88.com/" target="_blank" style="font-size: 16px; text-decoration: underline;">hourglasstime,"every two and a half Zero is one more".