Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of UKEssays.com.
Baltz, Feldman, Wolfe
The compass is a navigational tool used for directional orientation. The compass shows directions relative to geographical cardinal directions, with the Compass Rose depicting a stationary North, East, South, and West, listed as depicted clockwise. In addition, midway marking points include Northeast, Northwest, Southeast, and Southwest. The compass is measured by degrees with North being 0 degrees. This allows the compassed to be used mathematically in bearings. The use of the compass extends over 2,000 years ago to the Han Dynasty of China between 300 and 200 BC. The invention was later used for navigation in the Song Dynasty. The first models of the compass were made using a naturally magnetized ore of iron called lodestone. Later models were used by taking needles of iron and magnetizing them using lodestone. In Medieval Europe by 1300 dry compasses became popular, however this was more commonly replaced with a liquid filled enclosed magnetic compass in the early 20th century. Prior to the invention of the compass, navigational tools consisted of significant and/or constant landmarks. This included natural or manmade structures, as well as celestial bodies such as the famous North Star. The Vikings were noticed during this time for their use of stars as navigational tools. The compass allowed for better reliability in navigation, as well as a sense of direction when weather conditions were less sufficient. In many instances, cloud coverage made star navigation difficult.
The first inventions of the compass existed in the Han Dynasty, where it was known as the “south-governor.” The early uses for these Chinese compasses did not exist in navigation, but rather fortune telling, geomancy, and other spiritual uses. The early Chinese magnetic compasses were made using lodestone and were used to harmonize architecture with the geomantic principles of feng shui. Lodestone is naturally magnetized pieces of the mineral magnetite, a naturally occurring magnet that attracts iron and naturally aligns itself with Earth’s magnetic field, causing the “south pole” of the lodestone to be attracted to the Earth’s north pole. The ancient Chinese discovered that when the lodestone was suspended it would point to these poles. The spoon-shaped instrument was placed on a cast bronze plate called a “heaven-plate” or diviner’s board that had the eight trigrams of the l Ching, as well as the 24 directions, and the 28 lunar mansions. The 24 directions were based on constellations whereas the 28 lunar mansions were based on the constellations dividing the equator. These early Chinese used this compass to choose suitable areas to build houses. In addition, the compasses were used to search and find rare gems that would pull the lodestone in a different direction than the natural poles. The first models of the early mechanical compasses are referenced the written records of the Chinese as well.
Compass, China, 220 BCE
The earliest explicit recorded use of a magnetic compass for marine navigation is found in Chinese writer, Zhu Yu’s book Pingchow Table Talks (èæ´²å¯è«‡; Pingzhou Ketan) and dates from 1111 to 1117. Pingchow Table Talks expresses this stating, “The ship’s pilots are acquainted with the configuration of the coasts; at night they steer by the stars, and in the daytime by the sun. In dark weather they look at the south pointing needle.” In China, the dry compass was a suspension compass, a wooden frame crafted in the shape of a turtle hung upside down by a board, with the lodestone sealed in by wax. When rotated, the needle at the tail would always point in the northern cardinal direction.
The Compass in Europe
The European Alexander Neckam reported the use of a magnetic compass for the region of the English Channel, with the account occurring roughly between 1187 and 1202, after he returned to England from France. Robert Southey, an English poet of the Romantic school, and noted historian, suggested that the Siete Partidas, a Castilian statutory code, contained a reference from the 1250s to the needle being used for navigation. In his well-known Epistola de Magnete, Petrus Peregrinus of Maricourt, described a floating compass for astronomical purposes as well as a dry compass for seafaring by 1269. In the Mediterranean, at first only known as a magnetized pointer floating in a bowl of water, the introduction of the compass, went hand in hand with improvements in dead reckoning methods and the development of Portolan charts, leading to more navigation during winter months in the second half of the 13th century. Prior to this development, the regular practice ancient times had been to curtail sea travel between April and October because of the lack of clear sky during the Mediterranean winter. As a byproduct of the invention of the compass, the prolongation of the sailing season resulted in a gradual, but sustained increase in shipping movement. By the time of 1290, the sailing season began as early as late January and ended as late as early December. This created an economic boost that allowed the Venetian convoys to make two round trips to Levant, as opposed to it’s usual one trip. Commercial travel in the Mediterranean to Europe increased heavily as a direct result.
The Compass in Other Cultures
The earliest record of a fish or spoon like compass in the Middle East, such as the original Chinese models, occurs in a Persian book from 1232. In 1282, the earliest Arabic reference to a compass in the form of magnetic needle in a bowl of water, comes from astronomer Al-Ashraf and the Yemeni Sultan. Astronomer Al-Ashraf was the first to make recorded use of the compass for astronomical purposes. In 1300, another Arabic account of the compass was written by the Egyptian astronomer Ibn SimÊ¿Å«n and describes a dry compass used as a Qibla (Kabba) indicator” to find the direction to Mecca. Similar to Peregrinus’ compass, Ibn SimÊ¿Å«n’s did not contain a compass card. By 1400 Syrian astronomer Ibn al-Shatir incorporated a universal time-keeping device with the existing compass to address this, as well as to more accurately find the times of salat prayers. By 1933, the Egyptians had records of two types of compasses, the first being a dry compass and the second held the ideals of the Chinese compass. This compass contained willow wood or pumpkin in the shape of a fish, into which a magnetic needle is inserted and afterwards was sealed with tar or wax to prevent the penetration of water. In India, following Chinese design, the magnetic compass consisted of a magnet in the shape of a fish floating in a bowl of oil. The compass made it’s way into Eastern Africa via the Silk Road, which ended Somalia. It is suggested that the Swahili maritime merchants and sailors acquired the compass at some point and used it for navigation. Through increased travel and trade the compass made it’s way into deep Europe and then to the Americas.
Construction – Baltz
A magnetic bar is required while building a compass. This can be made by adjusting an iron or steel bar with Earth’s magnetic field and after that treating or striking it. Notwithstanding, this technique creates just a feeble magnet so different strategies are favored. For instance, a charged pole can be made by over and over rubbing an iron bar with a magnetic lodestone. This charged pole is then put on a low grating surface to permit it to unreservedly rotate to adjust itself to the magnetic field. It is then named so the client can recognize the north-indicating from the south-guiding end; in cutting edge tradition the north end is ordinarily set apart somehow.
On the off chance that a needle is rubbed on a lodestone or other magnet, the needle gets to be distinctly charged. When it is embedded in a stopper or bit of wood, and put in a bowl of water it turns into a compass. Such gadgets were all around utilized as compass until the innovation of the crate like compass with a “dry” rotating needle at some point around 1300.
Initially, many compasses were checked just with regards to the heading of magnetic north, or to the four cardinal focuses. Afterward, these were isolated, in China into 24, and in Europe into 32 similarly divided focuses around the compass card. For a table of the thirty-two focuses, see compass focuses. In the present day period, the 360-degree framework grabbed hold. This framework is still being used today for non military personnel guides. The degree framework spaces 360 equidistant focuses found clockwise around the compass dial. In the nineteenth century some European countries received the “grad” framework rather, where a correct edge is 100 grads to give a circle of 400 grads. Separating grads into tenths to give a circle of 4000 decigrades has often been used in various armed forces.
Most military strengths have received the French “millieme” framework. This is an estimate of a milli-radian, in which the compass dial is dispersed into 6400 units or “mils” for extra exactness when measuring points, laying mounted guns, and so forth. The incentive to the military is that one precise mil subtends roughly one meter at a separation of one kilometer. Supreme Russia utilized a framework inferred by isolating the outline of a circle into chords of an indistinguishable length from the sweep. Each of these was partitioned into 100 spaces, giving a circle of 600. The Soviet Union isolated these into tenths to give a circle of 6000 units, generally interpreted as “mils”. This framework was received by the previous Warsaw Pact nations, like the Soviet Union or East Germany, usually counterclockwise is still being used in Russia.
Since the Earth’s magnetic field’s slant and power change at various scopes, compasses are frequently adjusted during creation so that the dial or needle will be level, taking out needle drag which can give wrong readings. Most producers adjust their compass needles for one of five zones, running from zone 1, covering a large portion of the Northern Hemisphere, to zone 5 covering Australia and the southern seas. This individual zone adjusting anticipates over the top hanging of one end of the needle which can bring about the compass card to stick and give false readings.
A few compasses highlight an exceptional needle adjusting framework that will precisely demonstrate magnetic north paying little respect to the specific magnetic zone. Other magnetic compasses have a little sliding stabilizer introduced on the needle itself. This sliding stabilizer, called a ‘rider’, can be utilized for counterbalancing the needle against the plunge brought on by slant if the compass is brought to a zone with a higher or lower plunge.
Like any magnetic gadget, compasses are influenced by close-by ferrous materials, and also by solid neighborhood electromagnetic strengths. Compasses utilized for wild land route should not be utilized as a part of closeness to ferrous metal articles or electromagnetic fields as that can influence their exactness. Compasses are especially hard to utilize precisely in or close trucks, autos or other automated vehicles notwithstanding when amended for deviation by the utilization of inherent magnets or different gadgets. A lot of ferrous metal consolidated with the on-and-off electrical fields brought about by the vehicle’s start and charging frameworks by and large outcome in critical compass blunders.
Adrift, a ship’s compass should likewise be remedied for mistakes, called deviation, brought about by iron and steel in its structure and gear. The ship is swung, that is turned about a settled point while its heading is noted by arrangement with settled focuses on the shore. A compass deviation card is arranged so that the pilot can change over amongst compass and magnetic headings. The compass can be revised in three ways. Initially the lowlife line can be balanced so it is adjusted to the course in which the ship ventures, then the impacts of changeless magnets can be rectified for by little magnets fitted inside the instance of the compass. The impact of ferromagnetic materials in the compass’ surroundings can be remedied by two iron balls mounted on either side of the compass binnacle. The coefficient a0 speaking to the blunder in the loafer line, while a1b1 the ferromagnetic impacts and a2b2 the non-ferromagnetic segment. A comparable procedure is utilized to align the compass in various aircraft, with the compass deviation card frequently mounted for all time simply above or beneath the magnetic compass on the instrument board. Fluxgate electronic compasses can be adjusted involuntarily, and can also be customized with the right neighborhood compass variety in order to show the genuine heading.
How to use it – Baltz
A magnetic compass focuses to the Earth’s magnetic north pole, which is around 1,000 miles from the genuine geographic North Pole. A magnetic compass’ client can decide genuine North by finding the magnetic north and after that redressing for variety and deviation. Variety is characterized as the edge between the heading of genuine north and the course of the meridian between the magnetic poles. Variety values for the majority of the seas had been computed and distributed by 1914. Deviation alludes to the reaction of the compass to neighborhood magnetic fields brought about by the nearness of iron and electric streams; one can incompletely make up for these via cautious area of the compass and the position of remunerating magnets under the compass itself. Sailors have long realized that these measures don’t totally scratch off deviation; henceforth, they played out an extra stride by measuring the compass orientation of a historic point with a known magnetic bearing. They then directed their ship toward the following compass point and measured once more, charting their outcomes. Along these lines, redress tables could be made, which would be referenced when compasses were utilized when going in those areas.
Sailors are worried about getting exceptionally exact estimations; be that as it may, easygoing clients require not be worried with contrasts amongst magnetic and genuine North. But in regions of outrageous magnetic declination change, this is sufficient to shield from strolling in a significantly unique bearing than anticipated over short separations, gave the landscape is genuinely level and perceivability is not impeded. Via painstakingly recording separations and magnetic direction voyaged, one can plot a course and come back to one’s beginning stage utilizing the compass alone.
Compass route in conjunction with a map requires an alternate strategy. To take a map bearing or genuine bearing to a goal with a protractor compass, the edge of the compass is put on the map so it interfaces the present area with the craved goal. The arranging lines in the base of the compass dial are then pivoted to adjust to real or genuine north by adjusting them to a stamped line of longitude, overlooking the compass needle completely. The subsequent genuine bearing or map bearing may then be perused at the degree pointer or course of-travel line, which might be taken after as an azimuth to the goal. In the event that a magnetic north bearing or compass bearing is wanted, the compass must be balanced by the measure of magnetic declination before utilizing the bearing so that both map and compass are compatible.
In the given illustration, the huge mountain in the second photograph was chosen as the objective goal on the map. A few compasses permit the scale to be changed in accordance with make up for the nearby magnetic declination; if balanced accurately, the compass will give the genuine bearing rather than the magnetic bearing.
The advanced hand-held protractor compass dependably has an extra course of-travel bolt or marker engraved on the baseplate. To check one’s advance along a course or azimuth, or to guarantee that the question in view is surely the goal, another compass reading might be taken to the objective if noticeable. Subsequent to indicating the heading of-travel bolt on the baseplate at the objective, the compass is situated so that the needle is superimposed over the arranging bolt in the container. The subsequent bearing showed is the magnetic bearing to the objective. Once more, in the event that one is utilizing “genuine” or map bearings, and the compass does not have preset, pre-balanced declination, one should also add or subtract magnetic declination to change over the magnetic bearing into a genuine bearing. The correct estimation of the magnetic declination is place-subordinate and changes after some time, however declination is every now and again given on the map itself or possible online from different destinations. On the off chance that the explorer has been taking after the right way, the compass’ revised shown bearing should nearly compare to the genuine bearing beforehand acquired from the map.
A compass should be set down on a level surface so that the needle just lays or holds tight the bearing interlaced to the compass bundling – if used at a tilt, the needle may touch the bundling on the compass and not move energetically, along these lines not showing the appealing north exactly, giving a broken reading. To check whether the needle is especially leveled, look at the needle, and tilt it imperceptibly to check whether the needle is impacting side to side straightforwardly and the needle is not achieving the bundling of the compass. If the needle tilts to one heading, tilt the compass to some degree and carefully to the limiting course until the compass needle is level, the long way. Things to keep up a vital separation from around compasses are magnets of any kind and any equipment. Appealing fields from equipment can without a lot of an extend disturb the needle, shielding it from acclimating to the Earth’s alluring fields, making misguided readings. The Earth’s magnetic qualities are astonishingly weak, measuring at 0.5 Gauss and appealing fields from family contraptions can without a doubt outperform it, overpowering the compass needle. Introduction to strong magnets, or appealing impedance can now and again cause the alluring posts of the compass needle to differentiate or even switch. Avoid press rich stores while using a compass, for example, certain stones which contain appealing minerals, like Magnetite. This is consistently shown by a stone with a surface which is dull and has a metallic sparkle, not all alluring mineral bearing rocks have this sign. To check whether a stone or a range is realizing deterrent on a compass, escape the locale, and check whether the needle on the compass moves. If it does, it infers that the range or shake the compass was at that point at is bringing on impedance and should be avoided.
How the Compass works – Wolfe
Compasses were first invented in China, between 300 and 200 BC, and has been used as a tool of navigation ever since. A compass is a navigational instrument with a magnetized pointer, which points to the Earth’s magnetic north. The Earth is a magnet, and because of this, it is able to interact with other magnets. All magnets have a north pole and a south pole, and Earth is no different. The geographic north pole is at 90 degrees latitude, 0 degrees longitude, which is about 1,000 miles away from the magnetic north pole. For navigational purposes, a compass is best used with a map, and for the most effective use, a map with with the magnetic north and south lines drawn onto it.
The first step of using a compass is determining what direction you are traveling. Then, place the compass on the map, with the long connecting the location you are traveling to and the location you are at, with the heading arrow facing the destination you are headed to.
Then, holding the compass in place on the map, turn the compass turntable to make the north-south lines on the compass parallel to the north-south lines on the map. In some cases, you would need to adjust the compass turntable when considering declination, which is the angular difference between true north and the horizontal trace of the magnetic field.
Third, hold the compass in your hand, making sure the base plate is horizontal, and the heading arrow is pointing straight ahead. Rotate yourself until the north-south lines line up with the compass needle, and the compass needle is pointing the same direction as the heading arrow. This will show you the direction of where you are traveling to.
Modern Compasses – Wolfe
Most modern compasses consist of either a magnetized needle or dial inside a capsule, which is completely filled up with a liquid, such as oil or ethyl alcohol. The purpose of the liquid in the compass is to dampen the movement of the needle, making the needle have less oscillation and more stability. The end of the north needle also has self luminous materials, making the tip of the needle glow.
Many pieces of technology in today’s world use compasses, such as naval and aircraft in the United States Military. Another device that uses a compass is the cell phone. Most smartphones have a magnetometer, which measures the strength and direction of magnetic fields. The compasses used on naval and aircraft are known as gyrocompasses. Gyrocompasses are a different form of compass, which are non-magnetic, and is instead based on a fast-spinning disk, and the Earth’s rotation, which automatically finds geographical location.
 Colin A. Ronan; Joseph Needham. The Shorter Science and Civilisation in China. Cambridge University Press. pp. 28-29.
Cite This Work
To export a reference to this article please select a referencing stye below:
Related ServicesView all
DMCA / Removal Request
If you are the original writer of this essay and no longer wish to have your work published on the UKDiss.com website then please: