- Brand: Freewind
- Item: 00936
- made in China
- Price tag: 56
- Sports & Outdoors items: biking mountaineering camping hiking upstream tourism
- Time to market: Spring 2014
- Purpose: to point navigation
- Whether the water:
- Whether shockproof: Yes
- Whether luminous display: Yes
- Carrying options: Handheld
- Display: Analog
"Name"Hardcover compass compass
"Material"Copper shell, 14K gold plating
"specification"Diameter 57mm, height 12mm
"weight"About 70 grams
※ precise pointing direction, position the pointer back to the other low cost fast process of a few dollars difference compass when the compass is rotated, the pointer to swing around several times before stabilizing point.;
※ Built-in damping oil, better stability, more suitable for sports, rugged environment;
※ brass shell: the average thickness of 0.6 mm, durable;
※ pointer with a luminous design, after absorbing light, clearly visible in the night;
※ glass mirror, better transparency, more wear-resistant;
※ compass attached to the back of the pile, better adhesion, placed on a smooth surface, do not slip;
※ Compass clear, excellent workmanship, shell plating 14K gold, highlighting the grade can be used as gifts.
"Instructions for use"
E S W N representing the four cardinal points
Arrow pointing to 'North' direction
Rotation of the compass, so the letter 'N' coincides with the arrow (pointing in the same), then the other letters corresponding to the compass direction is the actual geographical location
※ use in a horizontal state, in order to try to ensure that accurate;
※ In order to avoid the occurrence of needle disorder, please use to maintain a certain distance (such as power lines, generators, sound, magnets, etc.) and barbed wire, as well as objects containing magnetic;
※ Can not beat or slapped compass, so as not to affect the measurement accuracy;
※ maintaining housing and mirror finish, do not use a dirty cloth, hand to wipe;
※ put away when not in use into the box, do not place near ferromagnetic materials, in order to avoid loss of magnetism.
Compass refers to the geographic South Pole is the geomagnetic North Pole
Compass is a simple instrument for determining the orientation of the compass, formerly known as Ian, one of the four ancient Chinese invention. The main components are mounted on a shaft free to rotate the needle. Needle under the earth magnetic field can be maintained in the tangential direction of the magnetic meridian. Antarctic geographic north Pole pointing the needle, take advantage of this performance can be a sense of direction. commonly used in navigation, geodesy, travel and military affairs.
Invention of the compass is our working people, resulting in long-term practice of magnetic object awareness. As production of labor, people contact with the magnetite, and began to understand the magnetic properties. People first discovered the nature of the iron magnet cited later also we found a directional magnet. through experiments and research multi-party, and finally invented the compass can be useful.
[Principle] compass pointing direction
Earth is a big magnet, the magnetic south pole near the geographic North Pole, the geomagnetic north pole near the geographic South Pole.
Compass effect by the magnetic force of the Earth's magnetic field, it will end one end of guide refers to the North.
Compass of 'four great inventions' one, was removed after was introduced to Europe to play in the discovery of a large sailing irreplaceable role, but historians of science is clear, first to answer 'why the compass can guide' is not the Chinese people's problems, but British scientist Gilbert. then, after the Chinese invented the compass of the compass theory for what kind of explore? Gilbert's theory is timely spread to China? Ming and Qing Dynasty 'Western Learning', but also on our compass theory which of the development impact? Professor of the History of Science and Philosophy of Science Department of Shanghai Jiaotong University off additions from 2003 began to study these issues basically blank.
'Chinese compass theory, is based on the theory of yin and yang on the basis of' induction say '' Off additions introduced mid-11th Century when the great scientist Shen Kuo also on the compass was incredible, his "Dream Pool Essays" describes compass manual the method of magnetizing the magnetic declination compass discovery and erection, but why the compass guide but had no concept - 'magnet of the original Guide ...... Mo its reasoning can!' then, literary scholars depart from the yin and yang theory ., when it was combined with the shape of the earth understanding, put forward various theories such as compass, a book in the late Song Dynasty "tube's geography means Mongolia", first put forward the following logic:
'Needle is ground into iron, iron is a gold, according to the five elements, said gold water, while the north is water, so the water north of the gold sub-iron produced in the magnet, the magnet is nurtured by yang arising yang is a fire, in the south, it is equivalent to the mother of the needle of the South. In this way, the needle will visit both the mother, but also nostalgia children would naturally point to the north-south direction. '
Off enlargement he said that from the viewpoint of modern physics, 'Montessori theory' totally fantastic, but the properties of things starting to explain their behavior, in the history of Eastern and Western science is a common practice in ancient China yin and yang theory prosperity, with the yin and yang theory Interpretation compass guides and "ordinary Differential easterly 'principle, is the most natural thing in particular, the theory that different sections have different attributes magnet that determine the needle point, this argument is easy to inspire people to find magnet poles and further associate the relationship between the magnetic pole and the needle point, in order to find possible ways to correct understanding of the problem.
Southern Song Dynasty compass principle remains that the 'compass of the meaning that lies yang', just around the phenomenon of magnetic declination, arguments based on more steering geographic azimuth coordinate system - Chinese ancients believed that the earth is flat limited size, so there must be a center of the surface, over the center piece of the meridian is the only north-south direction. Song had three different people and so that, once the measure is not in this place north-south line, the compass is pointing naturally 'less partial 'to the Ming Dynasty, someone who works false Tuonan Tang pointed out, the needle guide being determined by the orientation of the earth system, and the azimuth angle divided by the celestial system decision. off build that such statement' reflects the traditional theory of yin and yang induction compass existence theory and magnetic declination in front of this contradiction manifested distress'.
Ming Dynasty (AD 1573 ~ 1620), missionaries brought Western compass theory, the Earth theory and related scientific and technical knowledge. Under its influence, Chinese scholars began to explore a new perspective compass theoretical issues in this process , continued to play down the role of yin and yang, analytical mechanics angle increases, but scientific theories Gilbert in 1600 proposed by Western scholars did not even unity, let alone the White East soil. missionaries, arrived in China in 1658 Belgian Jesuit Ferdinand Verbiest compass systems theory, but he decided that the needle points to the geographic north and south poles of the earth itself, the theory is still limited to the range of ancient science, unlike Gilbert recognized that the Earth itself a magnet . Ferdinand Verbiest influential theories in China until the mid-19th century, scholars still use it to explain our compass problems. by this time, the late Qing Dynasty missionaries have started to Western knowledge of modern magnetism introduced to the Chinese.
 Found that magnetic phenomena
Qin era of our ancestors have accumulated a lot of awareness in this area, often encountered in the search for iron ore magnetite, which magnet (main ingredient is iron oxide). These findings have long been documented down. " pipe "in several articles described in these findings:" the mountain has a magnet, their under gold and copper. 'other ancient books such as "Shan Hai Jing" also has a similar record iron absorption properties of magnets have long been found. " Lu "chapter nine volumes have proficient: 'Chi move iron, or also cited the' at that time called 'magnetic' to 'chee' they attract a magnet to attract iron seen as mother of their children and said: 'stone's mother is iron, but do not Shiyou Ci Ci two, loving stone to attract his children, not been kind to the stone can not be attracted.' it is said that Qin Shi Huang, the repair Fanggong near Xianyang Palace there is a door with a magnet made, if someone wearing armor, the hidden weapons, to assassinate the palace, the door will be a magnet sucked. this story tells us that the ancient working people have long mastered the knowledge of magnetism.
People used to write Han magnet do 'Tsz stone', it is the meaning of love stone.
Since the magnet can attract iron, so if you can attract other metals do? Our ancestors did a lot of attempts, not only can not find a magnet to attract gold, silver, copper and other metals, can not attract the bricks and the like items. When the Western Han Dynasty it has been recognized that a magnet can attract iron, but not attract other items.
When the two magnets close to each other when put together, and sometimes attract each other, sometimes mutually exclusive. Now people know that the magnet has two poles, one said N pole, called a S pole. Like poles repel each other, mutually opposite pole attract. At that time people did not know the truth, but this phenomenon can still perceived.
To the Western Han Dynasty, there was a big alchemist named Luan, he used the nature of magnet do something like two pieces, by adjusting the mutual position of the two polar pieces, sometimes two pieces attract each other, sometimes mutually exclusive. Luan Great call 'fighting game'. he dedicated this novel stuff Han Dynasty, and the spot demonstrations. Han Emperor marveled, dragon heart big Yue, Feng Luan much actually "five of General Lee 'Luan big advantage of magnets nature, produced a novel stuff deceived the Han Dynasty.
Earth is a big magnet, and its two poles are near the geographic South Pole and the geographic North Pole, so the magnet surface of the earth, when free to rotate, it will same-sex repulsion due to the magnet, an indication of the nature of the opposite sex attraction north and south. The reason enough to understand the ancients, but they know this phenomenon.
[Compass ancestor - Ian]
Compass ancestor occurs approximately in the Warring States Period. It is made with natural magnet. Looks like a spoon, round, can be placed on a smooth 'turf' and keep the balance, and can rotate freely. When it is stationary when the spoon handle will point to the south of the ancients called it 'Ian', when the book "Han Fei" in there: "first Wang Sinan to end overnight. '' end of the day and night 'is the positive square, fixed orientation means." Guiguzi "recorded in Ian's application, when Cai Yu Zheng who took Ian to ensure that it does not get lost.
Spring and Autumn Period, people have been able to hardness of 5 degrees to 7 degrees nephrite and jadeite refined into various shapes apparatus, and therefore can only hardness of 5.5 degrees to 6.5 degrees lodestone made Sinan. Eastern Han Wang Chong in his the book "on balance" in the shape and usage of Ian made a clear record. Ian is pondering made dippers, spoon handle guide pole with a piece of lodestone through, and the center of gravity of the whole spoon spoon bottom just fell middle, spoon into a smooth among sites, site foreign inner circle, surrounded by carved Lunar four-dimensional, synthetic twenty four-way. this design is carefully observed by many ancient nature of phenomena related to magnetism, and accumulated a lot of knowledge experience, after long-term research was completed. Ian is the emergence of people magnet refers to the actual application of polar knowledge, but Ian also has many flaws, natural magnet is not easy to find, in the process vulnerable to strikes, heat and loss of field. so Ian magnetic relatively weak, and it is in contact with at the site to be very smooth, otherwise they will be rotational friction is too large, and difficult to rotate and can not achieve the desired effect guide. and Ian have a certain size and weight, very convenient to carry, it Ian is probably the main reason for the long-term has not been widely used.
Sinan magnetic spoon bronze plate and natural magnet made from the composition of twenty-four-way engraved bronze plate, spoon set in a magnetic disk center circle surface, stationary, spoon tail pointing south.