COMPASS, device for determining horizontal directions on the ground. It is used to determine the direction in which a sea, aircraft, land vehicle is moving; the direction in which the pedestrian is walking; directions to some object or landmark. Compasses are classified into two main classes: needle-type magnetic compasses, which are used by surveyors and tourists, and non-magnetic, such as gyrocompass and radio compass.
SPANISH MARINE COMPASS, 1853
Compass card. To determine the directions in the compass there is a rose (Fig. 1) - a circular scale with 360 divisions (corresponding to one angular degree each), marked so that the countdown is clockwise from zero. The direction to the north (north, N, or C) usually corresponds to 0?, To the east (Ost, O, E, or B) - 90?, To the south (south, S, or S) - 180?, To the west (west , W, or З) - 270 ?. These are the main compass points (cardinal points). Between them there are “quarter” points: northeast, or northeast (45?), South-east, or south-east (135?), South-west, or south-west (225?) And north-west , or NW (315?). Between the major and quarter points there are 16 “major” points, such as nord-nord-east and nord-nord-west (there used to be 16 more points, such as “nord-shadow-west”, which were simply called points).
MAGNETIC COMPASS
Operating principle. In the device indicating the direction, there must be some kind of reference direction, from which all the others would be reckoned. In a magnetic compass, this direction is the line connecting the North and South poles of the Earth. In this direction, the magnetic rod is installed by itself, if it is suspended so that it can freely rotate in the horizontal plane. The fact is that in the Earth's magnetic field, a rotating pair of forces acts on the magnetic rod, setting it in the direction of the magnetic field. In a magnetic compass, the role of such a rod is played by a magnetized needle, which, when measured, itself is set parallel to the earth's magnetic field.
Pointer compass. This is the most common type of magnetic compass. It is often used in a pocket-sized version. The needle compass (Fig. 2) has a thin magnetic needle that is freely installed at its midpoint on the vertical axis, which allows it to rotate in the horizontal plane. The northern end of the arrow is marked, and the card is fixed coaxially with it. When measuring, the compass must be held in hand or installed on a tripod so that the plane of rotation of the arrow is strictly horizontal. Then the north end of the arrow will point to the north magnetic pole Earth. A compass adapted for topographers is a direction-finding device, i.e. instrument for measuring azimuth. It is usually equipped with a telescope, which is rotated until it is aligned with the desired object, so that the azimuth of the object can then be read from the card.
Liquid compass. The liquid compass, or floating compass, is the most accurate and stable of all magnetic compasses. It is often used on sea-going vessels and is therefore called shipborne. The designs of such a compass are varied; Typically, it is a liquid-filled "pot" (Fig. 3), in which an aluminum card is fixed on a vertical axis. On opposite sides of the axis, a pair or two pairs of magnets are attached to the bottom of the card. In the center of the card there is a hollow hemispherical protrusion - a float that weakens the pressure on the axis support (when the pot is filled with compass fluid). The axis of the card, passed through the center of the float, rests on a stone thrust bearing, usually made of synthetic sapphire. The foot pad is fixed on a fixed disc with a "heading line". At the bottom of the pot there are two holes through which liquid can flow into the expansion chamber, compensating for changes in pressure and temperature.
Rice. 3. LIQUID (SHIP) COMPASS, the most accurate and stable magnetic compass of all. 1 - holes for overflow of compass fluid during its expansion; 2 - filling plug; 3 - stone thrust bearing; 4 - the inner ring of the universal joint; 5 - card; 6 - glass cover; 7 - heading line marker; 8 - the axis of the card; 9 - float; 10 - disc of the heading line; 11 - magnet; 12 - bowler hat; 13 - expansion chamber.
The card floats on the surface of the compass fluid. The liquid also soothes the rocking vibrations of the rose. Water is not good for a ship's compass as it freezes. A mixture of 45% ethyl alcohol with 55% distilled water, a mixture of glycerin with distilled water, or high-purity petroleum distillate is used.
The compass pot is cast in bronze and has a glass cover with a seal to prevent leakage. An azimuth, or direction finding, ring is fixed in the upper part of the bowler. It allows you to determine the direction to various objects relative to the ship's course. The compass bowler is fixed in its suspension on the inner ring of the universal (gimbal) joint, in which it can rotate freely, while maintaining a horizontal position, under conditions of rolling.
The compass bowler is fixed in such a way that its special arrow or mark, called the heading line, or a black line called the heading line, points to the bow of the boat. When the ship's course changes, the compass rose is held in place by magnets that invariably maintain their north-south direction. By displacement of the course mark or line relative to the rose, you can control the course changes.
LIQUID COMPASS
The man began to travel a long time ago. Even ancient tribes roamed from place to place in search of food. Developing, people began to move not only by land, but also by sea. With the advent of navigation, the question of orientation in space arose before travelers. Initially, this happened by the stars and by the sun, but in cloudy weather in the ocean there is no way to determine the direction. Many of the first sea voyagers lost their course. The man realized that without a special device he was doomed to a long search for the right path, and maybe to death. Now any child knows how to determine the correct direction using a compass. But not everyone knows who invented the compass.
The history of the compass
About 3 thousand years ago, a person noticed that a magnetized iron arrow always points to the north. Presumably, the first prototype of the modern compass appeared in ancient China during the reign of the Song dynasty. But this information is not accurate. According to some reports, the compass was invented much later - 100-200 years BC, however, also by the Chinese. Of course, the ancient device was far from modern devices. But he performed his functions regularly. By the way, the ancient Chinese used a compass to navigate the deserts. A little later, the sailors began to take him on a voyage with them. Already in the XI century A.D. the Chinese invented a device with a floating arrow in the form of a fish. The new invention was very much liked by the Arabs, who began to use the compass on their merchant ships.
In Europe, the compass appeared rather late. Traders from Eastern countries introduced the Europeans to him. It was only in the 12th century that the first primitive device began to be used by the Spaniards and Italians for navigation. The European compass was a magnetized iron strip that was attached to a cork floating in water. Then, the arrow began to be fixed on a thin hairpin, which was installed on the bottom of a vessel. Soon, not a single navigator went out to sea without this device.
Around the 14th century, Italian jeweler and inventor Flavio Gioia figured out how to improve the compass. He divided it into 16 points of 4 for each of the cardinal points. The new device made it easier to navigate in space. Immediately after that, shipping began to develop at a rapid pace in Portugal and Spain. Now the sailors calmly set off on long voyages, not afraid to get lost in the vastness of the ocean. Already by XVIII century the compass is becoming a rather complex device, indicating not only direction, but also time.
Modern compass
Modern devices have received many new functions, and their appearance bears little resemblance to ancient brethren. Their principle of operation is no longer based on a magnetic needle, but on complex electronic circuits with which the earth's magnetic field is determined. Many instruments are oriented via satellites. Now even in simple phone models there are GPS receivers, which, via satellite, determine the exact location of a person with an accuracy of a degree.
The idea of creating satellite navigation arose back in the 50s of the last century, immediately after the launch of the first artificial satellites. But this idea was put into practice only in 1973. Initially, the GPS satellite navigation system was developed exclusively for the military. But gradually she came into civilian life. Modern systems navigation in navigation and aviation are inconceivable without satellite communication and orientation systems. Such systems are used in other areas as well. For example, in geodesy and cartography.
The creation of the compass and its widespread implementation gave impetus not only to geographical discoveries, but also made it possible to better understand the relationship between electric and magnetic fields. New industries began to emerge after the compass began to be used. scientific knowledge.
A compass with a magnetic needle opened to mankind not only the globe, but also physical world in all its diversity.
The primacy in the discovery of the properties of the compass is disputed by several: Indians, Arabs and Chinese, Italians, and British. Today it is very difficult to reliably determine who the honor of the invention of the compass belongs. Many conclusions are made only on the assumptions put forward by historians, archaeologists and physicists. Unfortunately, many of the evidence and documents that could shed light on this issue have not survived or have survived to this day in a distorted form.
Where did the compass first appear?
One of the most widespread versions says that the compass was in China about years ago ("From astrolabe to navigation systems", V. Koryakin, A. Khrebtov, 1994). Chunks of ore, which had a wonderful property of attracting small metal objects to themselves, were called by the Chinese "a loving stone" or "a stone of mother's love." The people of China were the first to notice the properties of the magic stone. If it was given the shape of an oblong object and hung on a thread, it would occupy a certain position, pointing one end to the south and the other to the north.
It was surprising that the “arrow”, which had been deflected from its position, returned to its original position after hesitation. Chinese chronicles contain indications that the property of a magnetic stone was used by travelers to determine the correct position when moving through the deserts, when the daylight and stars were not visible in the sky.
The first Chinese compass was used when caravans moved through the Gobi Desert.
Much later, the magnet began to be used for orientation in navigation. According to Chinese sources, around the 5th-4th centuries BC, sailors began to use a metal needle rubbed with a magnetic stone and suspended from a silk thread. It is surprising that at that time the compass did not reach India and Europe, because then there was already a communication between China and these regions. But the Greek writers of those times did not mention the compass.
It is believed that the compass came to Europe not earlier than the 3rd century BC through Arab sailors who plowed the waters of the Mediterranean Sea. But some researchers do not exclude that this useful device was re-invented by Europeans, who independently discovered the effect produced by a magnetic arrow suspended on a thin thread.
Instructions
The idea of creating a compass belongs to the ancient Chinese. In the 3rd century BC. one of the Chinese philosophers described the compass of that time as follows. It was a magnetite pouring spoon that had a thin handle and a well-polished ball-shaped convex part. The spoon rested with its convex part on the same carefully polished surface of a copper or wooden plate, while the handle did not touch the plate, but hung freely above it. Thus, the spoon could rotate around its convex base. On the plate itself, the cardinal points were drawn in the form of zodiacal signs. If you specifically push the handle of the spoon, it began to rotate, while, stopping, the handle always pointed exactly to the south.
All in the same China in the XI century came up with a floating compass needle. They made it out of an artificial magnet, usually in the shape of a fish. She was placed in a vessel with water, where she swam freely, and when she stopped, she also always pointed her head to the south. Other forms of the compass were invented by the Chinese scholar Shen Gua in the same century. He proposed to magnetize the usual sewing needle about a natural magnet, and then attach this needle in the center of the body to a silk thread using wax. So it turned out less when turning the needle than in water, and therefore the compass showed a more accurate direction. Another model, proposed by the scientist, involved fastening not to a silk thread, but to a hairpin, which is more reminiscent of the modern form of a compass.
Almost all Chinese ships in the XI had floating compasses. It is in this form that they spread throughout the world. They were first adopted by the Arabs in the 12th century. Later, the magnetic needle became known in European countries: first in Italy, then in Portugal, Spain, France, and later in England and Germany. At first, the magnetized needle on a piece of wood or cork floated in a vessel with water, later they guessed to close the vessel with glass, and even later they guessed to place the magnetic needle on the tip in the center of the paper circle. Then the compass was improved by the Italians, a coil was added to it, which was divided into 16 (later - 32) equal sectors pointing to the cardinal points (first 4, and later 8 sectors for each side).
Further development of science and technology made it possible to create an electromagnetic version of the compass, which is more perfect in the sense that it does not provide for deviations due to the presence of ferromagnetic parts in the vehicle on which it is used. In 1908, the German engineer G. Anschütz-Kampfe created a prototype gyrocompass, the advantage of which was the indication of the direction not to the magnetic north pole, but to the true geographic one. For navigation and control of large sea vessels, it is the gyrocompass that is almost universally used. The modern era of new computer technologies has made it possible to come up with an electronic compass, the creation of which is associated primarily with the development of a satellite navigation system.
Modern people have no problems in determining their location with high accuracy - you can, for example, use devices equipped with a GPS or GLONASS sensor. However, in ancient times, when traveling long distances, people had problems. It was especially difficult to navigate when traveling through deserts or sailing on the open sea, where there were no known landmarks. As a result, travelers could easily get lost and die. Already after the beginning of the era of great geographical discoveries in the 16-17 centuries. sailors often lost the already open islands or mapped them several times, let alone the ancient navigators.
Of course, even in antiquity, people still found ways to determine the cardinal points, this was helped primarily by observing the Sun and the stars. It has long been noticed that, although the stars change their position, one of the stars, namely the North Star, is always in the same place. From this star, they began to determine the direction to the north. But what if the sky is covered with clouds, and neither the Sun nor the stars are visible? The direction of movement cannot be determined, the ship goes astray and may sail away completely in the wrong direction. Therefore, distant expeditions were very dangerous business until the compass appeared, and it was no coincidence that only after navigators began to use it, all corners of our planet were discovered and studied. And when and by whom was the compass invented?
The principle of the compass is based on the fact that the earth has a magnetic field and is like one large magnet. The compass, on the other hand, has a magnetic needle, which, in the earth's magnetic field, always indicates the direction to the magnetic poles that are not far from the geographic ones. Thus, using a compass, you can determine the direction to the cardinal points. There is a material in nature that has magnetic properties, namely magnetite (magnetic iron ore).
magnetite
The property of pieces of magnetite to be attracted to each other, as well as to iron objects, has long been noticed by people. For example, the ancient Greek philosopher Thales Milesiky wrote about this in his works in the 6th century. BC e., however, he did not find magnets practical application... And the Chinese found him.
It is not known for certain when the Chinese invented the compass, but the first description of it that has survived to this day dates back to the 3rd century BC. NS. The ancient Chinese compass was something like a magnetite spoon mounted on a polished copper plate. It looked like this:
ancient chinese compass
The spoon was untwisted and after a while it stopped so that its end pointed to the south. Moreover, initially the compass in China was not used at all for navigation, but in the mystical Feng Shui system. In Feng Shui, it is very important to correctly orient objects to the cardinal points, for this they used a compass.
It took a long time before the compass was improved and began to be used in travel, first on land and then at sea. Instead of a piece of magnetite, they began to use a magnetized iron needle, which was suspended on a silk thread or dipped into a vessel with water, where, floating on the surface, it turned in the direction of the magnetic pole. Important improvements to the compass, as well as the description of magnetic declination (i.e. deviation of the direction to the magnetic pole and geographic), were made by the Chinese scientist Shen Gua in the 11th century. It was after this that the Chinese navigators began to actively use the compass. From them the compass became known to the Arabs, and in the 13th century. the famous traveler Marco Polo brought the compass from China to Europe.
In Europe, the compass has been improved. The arrow began to be installed on a hairpin, a scale was added, divided into points to more accurately indicate the direction. In later versions, the compass began to be installed on a special suspension (the so-called gimbal) so that the rocking of the vessel would not affect the readings.
vintage ship compass
The advent of the compass gave a huge impetus to the development of navigation in Europe and helped European sailors to cross the oceans and discover new continents.