In the exhibition hall of "Long Wind and Waves: 500 Years of World Navigation" exhibited at the Museum of Naval Warfare, there is a 19th-century British sailing ship copper cover magnetic compass.
Navigating in the vast sea, to maintain the correct course, you need to have navigation technology, how to locate ships at sea before the advent of GPS? The wise ancients invented several methods to locate ships, such as sky surveying, land beacon positioning, navigation instruments, and track calculation. In the 17th century, human beings invented and created navigational instruments such as sextants, nautical astronomical clocks, magnetic compasses, towed meters, wheel meters, and water blocks, making the dream of global navigation finally come true.
Today we will talk about the story of the compass, a navigational instrument.
19th century British seafaring ships with copper cover magnetic compass
19th century British sailing ships with a copper cover magnetic compass, length 25.5 cm, width 20 cm, height 53 cm, weight 5824 grams, wooden floor-to-ceiling base, the base bears the logo with the words "sestcee hendy bdowne & son station works barking essex type 'a'". The upper is a theodolite with a copper cover, a glass observation window, and small boxes on both sides, and lamps placed for easy viewing at night. There are round handles on both sides, painted red and green respectively, which are convenient for correct judgment of direction.
The origin of the compass
The compass is the compass, and an iron needle running through the center of the disk always points due south and north, which is now called the compass. Geography scholars attributed the invention of the compass to the Yellow Emperor, and said that King Wen of Zhou made the compass into a compass to check the positioning of qi and observe the heavens and the earth. The compass is mainly used for navigation, helping us to navigate, determine the direction, and determine our position during navigation to ensure the correctness of the route.
compass
Storytelling: How was the compass invented?
In the Warring States period, people have been able to polish jade into utensils of various shapes, and a jade mining worker made a spoon from the jade he collected, and he put the spoon inside the plate to turn and play, and found that the handle of the spoon always pointed south. He was happy to find that he often had to go far away and get lost when he went out to quarry jade, and wasn't this spoon just right to point the way? After continuous evolution, people carved directions and scales on the plate, named "Sinan". Si Nan was later introduced to Europe and evolved into a compass and became an important positioning tool in maritime activities.
compass
History
Compass classification: magnetic compass and electric compass. In early human navigation, the guidance of the course was the use of a magnetic compass. In the late nineteenth century, steel ships gradually replaced wooden ships, magnetic compasses could not guarantee their accuracy, and near the poles, magnetic compasses would fail, people began to look for azimuth indicators that could replace magnetic compasses. In 1908, the German Anschutz and the American Sperry in 1909 successfully developed the gyrocompass, opening a new chapter in ship navigation. The gyrocompass is also known as the electric compass, and then the electric compass appears. This article focuses on the use of the magnetic compass.
British copper compass in 1914
Basic construction
The magnetic compass, which is an essential instrument for navigation, is an instrument made according to the principle of the compass to indicate the direction, also known as the magnetic compass. The magnetic compass is usually composed of three parts: a compass cabinet, a compass basin and an azimuth meter. The magnetic compass is mainly composed of two parts: the compass basin and the compass cabinet. A compass basin is a bowl-shaped copper basin or other non-magnetic material with a compass pointing system, and the upper part of the basin is an airtight glass lid.
16th century magnetic compass
Structural principle
The north and south poles of geomagnetism do not coincide with the north and south poles of geography, and the direction pointed by the free-hanging magnetic needle has a deviation angle from the direction of the geographical north and south (true meridian), that is, the magnetic declination angle (also known as magnetic difference). The compass is mainly through the cooperation of the compass and the circumferential ruler, which changes with its own position, so as to determine the direction of the ship's operation. The magnetic compass is a traditional navigation pointing instrument, and its working principle is to use the geomagnetic field and sensitive components such as magnetic needles to attract and act on each other, and the magnetic needle of the compass always points to the magnetic north pole of the earth.
The compass is used in navigation and is an all-weather navigation tool, which makes up for the shortcomings of astronomical navigation and creates a new era in maritime history.
As a nautical pointing instrument, the magnetic compass can not only indicate the direction of the ship, but also locate and navigate the ship.
How the disk works and structure
Usage
Do you know when the compass was used for navigation? The world's first maritime navigation using the compass was the Northern Song Sea ship at the turn of the 11th-12th centuries. Zhu Yu's "Pingzhou Can Talk" written in 1119 first recorded this matter. The book says: "The boat master knows geography, the night is stargazing, the day is watching the sun, and the obscurity is observing the compass." This is the first recorded voyage in the history of world navigation using a compass needle.
Zhu Yu's father, Zhu Fu, served as Zhizhou of Guangzhou from 1101 to 1103, and Zhu Yu recorded what he saw when he was in Guangzhou with his father, so Chinese the earliest floating compass used around 1103. Chinese wisp suspension compass used shortly after the floating compass. Chinese use more floating compass needles.
Chinese earliest floating compass used around 1103
Chinese wisp suspension compass used shortly after the floating compass
Chinese use more floating compass needles
Chinese documented method of making a water-flotating guide fish
Rise knowledge \ The world's first use of a compass needle was Chinese
The magnetic compass is made by using the characteristics of the magnetic needle pointing north, and the compass is the primary stage of the magnetic compass, that is, the original type of magnetic compass. The compass was invented in China, and the application of the compass to ships also began in China. The earliest records are Zhu Yu's "Pingzhou Can Talk" and Xu Jing's "Xuanhe Fengjing Goryeo Tujing" during the reign of Song Xuanhe. The use of the compass in navigation not only solved the problem of sea direction seeking in bad weather, but also opened the way for instrument navigation, and human beings have truly freed themselves from the shackles of the coast and galloped on the wider ocean. After the introduction of marine magnetic compasses to Europe through Arabia in the 12th century, European seafarers also began to use it. The magnetic compass commonly used on ships now is the navy-type magnetic compass improved by the British scientist Kelvin at the end of the 19th century.
Ancient Chinese compass
Zheng He's voyage to the West was a maritime voyage during the Yongle and Xuande years of the Ming Dynasty, the first voyage began in the third year of Yongle (1405) and the last voyage ended in the eighth year of Xuande (1433), a total of seven voyages. Zheng He's voyage to the West was the largest and longest sea voyage in ancient China, with the largest number of ships and seafarers, and the largest series of maritime expeditions in world history before the voyage of the great geographical discoveries in Europe at the end of the 15th century. In the history of world navigation, he opened up direct shipping routes between the western Pacific Ocean and the Indian Ocean, proving that the shipbuilding and navigation technology of the mainland at that time had reached a high level.
Zheng He went to the West
The compass used by Zheng He to go to the West
DIY small production \ teaches you to make a super simple compass
When it comes to homemade compasses, many children raise their hands: I will! Rub the steel needle for sewing clothes twice on the magnet to become a magnetic needle, and then use the suspension method, the water float method or something, you can make a simple compass.
But the method we introduced here does not even need a magnet!
Take a steel needle and rub it on the hair a dozen times
Then cut a small piece of foam, stick a steel needle on it, and float in a bowl of clean water
At this time, you will find that the steel needle automatically points north-south, which is a compass!
This method of making a compass is super simple and is described in some wilderness survival manuals. Find a steel needle, or a pin or a short piece of wire, you can make it. It's just that the magnetic needle made by this method is very weak in magnetism, and it needs to be constantly magnetized.