Talk:Compass

Soundings

Prior to the introduction of the compass, wayfinding at sea was primarily done via celestial navigation, supplemented in some places by the use of soundings.

What kind of "soundings" are referred to in the article? None of the soundings listed in Wikipedia seem to be \DANIELLA ENVENTED COMPASSES O.K. bed could also be used as a means of navigation, but I don't know when this was first used. Billlion 22:59, 4 J countries and then to Europe sometime later in the 12th century. Which one is correct? —Simetrical 05:06, 30 Jan 2005 (UTC)

Well I have found different opinions but this article [1] states

 By the 10th century, the idea had been brought to Europe, probably from China, by Arab traders.

but we could do with a more respectable historical reference! Billlion 05:55, 31 May 2005 (UTC)

According to the Dictionary of the Middle Ages Volume 3 page 506, the compass was invented in Italy:

"The magnetic compass has been known and used in the Western world since the twelfth century. It is believed to have been invented in the Mediterranean region, probably at the Italian port of Amalfi, which was engaged in shipping magnetic ores from the mines of Elba."

MY 2c... Remove the history. The compass is likely one of those devices invented everywhere are the same time. Even the best research on this would likely be on shakey ground anyways. - Ravedave 03:40, 26 August 2005 (UTC)

I suspect it is a contensious, depending who you talk too. It might be good to frame it as such and list the various theories, rather than declare definitive knowledge. Stbalbach 03:54, 26 August 2005 (UTC)

Real apologies for this. I suspect it may have been me who changed the sentence (about the Arabs and the Europeans) although frankly it was a long time ago and I can't remember. In any case: the source I may (or may not) have used is as follows: 'The mariner's compass [...] was [first] deployed in Chinese ships around 1090....this was....the culmination of a series of Chinese innovations that stemmed back to 83 BC when crude compasses were invented, and even as far back as the Fourth Century BC, when .... 'lodestone' compasses were discovered. The Italians merely borrowed the compass, which had diffused across to ...Europe via the Muslims, from the Chinese.' (The Eastern Origins of Western Civilisation, J. Hobson, Cambridge University Press, 2004). The source given is: 'Hourani, G. Arab Seafaring in the Indian Ocean in Ancient and Early Medieval Times (Beirut, Khatats, 1963) pp108-109.. ISBN 0691000328 130.209.6.40 16:59, 20 February 2006 (UTC)

---

There is no evidence that the Italians were the first Europeans to use a compass. The first European to mention a compass was an Englishman, and since he did not mention specify an specific location for the sailors, the assumption be that he was talking about local sailors, i.e., English sailors. Had it been Italian or other foreign sailors, he would have mentioned the fact in his description.

Also The only supporting data for assuming that the Europeans learned the idea of the compass from the Chinese or Arabs is that use of the compass for navigation was first mentioned in writing little before the European. All other evidence points toward an independent invention. It is first mentioned by a northern European, not a southern European (i.e. Italian) or Arab who would have had the most direct contact with Chinese sources. And the European compass is always potrayed as pointing North, not South as in Chinese compasses. The closeness in time between European and Chinese sources can be explained that the 11th century seems about the time when steel needles became available in Europe. Before steel needles, it would have been hard to make practical compasses. Regular iron needles would loose their magnetism too quickly to be practical (iron do not retain magnetism as well as steel), and making the needles out of natural loadstone runs the risk of ruining the natural magnetism of the material. If you heat iron past its Curie point while making it into a needle, it will loose it magnetism. Using a fish or turtle shaped piece does not make a very practical compass for use on ships. The Ancient Romans and Greeks did not use steel needles, so evein if they were aware of the directional property of loadstone, they would not have found it practical to make compasses. —Preceding unsigned comment added by 66.51.147.97 (talk) 01:34, 17 December 2009 (UTC)

Lensatic?

I've been shopping for a compass, and many are described as "lensatic compasses" -- in particular, all military compasses I've found. What is a "lensatic" compass? This should be added to the article.

A lensatic compass has a lense (typically in the sight) so that when held to the eye to take a bearing you can read the dial. This is typically a military style field compass. If you get one maybe you could take a phot of it for the article. Billlion 05:45, 31 May 2005 (UTC)

Compass usage section

The section about using compass contains two images that are important part of the explanation. Any literature material on this topic has these two illustrations in one or another form and is not understandable without them. Please do not remove, these are not just images of the compass. Audriusa 09:40, 13 September 2006 (UTC)ffrrfr

Compass spoon

Oh my. At the risk of making a fool of myself: is there any chance that the line "[i]n China it seems that the convention was that the compass spoon (they used a spoon instead of a needle)", taken from History of the navigational compass, is not a vandalism? If it is, don't bother mocking me, just fix it. — Itai (talk) 23:38, 25 November 2006 (UTC)

accuracy of article

Since the Chinese used the compass in navigation, they had a practical mariner's compass. It may be possible to figure out the relative quality of early compasses, but I'm not able to do it.

The modern mariner's compass, as discussed in detail in the article, is not a compass needle in a dry box, but rather one that uses fluid to support the needle. I've adjusted the article. I specifically disagree with Ma's statement at the head of this page. The use of "true" in this sense is really ethnocentric. It's a loaded word, to be used only when there is no possibility of confusion. DGG 04:54, 27 November 2006 (UTC)

+++++++++++++++++ The above statement is not necessarily correct - simply becaused they used the compass in navigatoin, does not mean they had a practical mariner's compass. The term "mariner's compass" means a lot more than just a north pointing device. A mariner's compass does more than just point north - it also allows you to take specific bearings, and steer a specific course. A magnetic spoon spinning around on a plate may tell you the general direction of north, but it would not be practical for steering a specific course heading on a pitching boat.

The evidence is that the Chinese did not have a PRACTICAL mariner's compass. The only written evidence I have seen makes it clear that the compass was not a primary navigation tool for the Chinese, but only an aid used when other sources of navigation were not available (Phing-Chou Kho "in dark weather they look at the south-pointing needle"), and there is no evidence that Chinese navigation maps and charts had compass bearing directions on them. Nor do we find any evidence for a revolution in Chinese sailing practices as a result of the compass. This in direct contrast to the West, where the sailing practices thousands of years old in the Mediterranean Sea underwent a dramatic change at the time the mariner's compass was developed, and where portlan charts given specific sailing directions based on magnetic compass bearings. The mariner's compass was used as a primary navigation means in all weather, and not just when other sources were not available. Taking a compass reading on pitching and rolling deck on board ship with a needle floating in a bowl of water would not be practical. The dry pivot mounting of the needle used by European compasses would be less suspectible to the rolling and pitching of a ship, and the mounting of the compasses in a gimbal box, which the Chinese lacked, would make the compass even more practical. —Preceding unsigned comment added by 66.51.147.97 (talk) 20:11, 18 December 2009 (UTC)

The true mariner's compass

The term is not uncommon and can be also found in scientific literature, for example: Barbara M. Kreutz, "Mediterranean Contributions to the Medieval Mariner's Compass," Technology and Culture, Vol. 14, No. 3 (Jul., 1973), pp. 367-383. This justifies its use as opposed to the more colloquial "familar mariner's compass". Regards Gun Powder Ma 04:51, 27 November 2006 (UTC)

Ma, do not revert without discussing. You are here dealing with a technical subject, and it would be well for you --and me--to wait for comment.I have no intention getting into a revert war with you or anyone, here or elsewhere--though possibly some WP people would be tempted by this particular revert. But consider the word "true" in "true north" in this article--it has a meaning. How about true early European. It is undoubtedly true of early European compasses, just as it is false for current ones. DGG 05:11, 27 November 2006 (UTC)

True, dry or familiar compass are all accepted technical descriptions, as long as they fit the context, and one is not excluded on ideological grounds. That's why I say ok to your insertion in the entry (familiar), while I changed it in the text below to true again. "True" means in this context with a pivoting needle and a compass board which moves while the needle remains static in case the ship switches course. This "true" feature also remains with the late liquid compass. Gun Powder Ma 05:22, 27 November 2006 (UTC)

The supposed Olmec invention

I was unable to find the quoted article in the database of Revista mexicana de Fisica: http://www.ejournal.unam.mx/revmexfis/revmexfis_index.html

A.P. Guimaräes (2004) "Mexico and the early history of magnetism", in Revista mexicana de Fisica, v 50 (1), June 2004, p 51-53

Therefore, I cut the whole part out.

That may be true. The Olmec people of Mesoamerica may have discovered that a lodestone will align itself in a magnetic north-south position, and they are credited with developing a compass before 1000 BCE, centuries before the Chinese (American Indian Contributions To The World - 15000 Years Of Inventions And Innovations by Kay Marie Porterfield & Emory Dean Keoke, page 67; Lodestone Compass: Chinese Or Olmec Primacy? by John B. Carlson). Friendship & Rainbows (talk) 09:50, 14 July 2019 (UTC)

Good edit

Whoever mostly trashed my discussion of the US military dry compass; thanks! You know your stuff! But I carried a mini liquid-filled compass for some years, and the wear rendered it useless, so I did put back one sentence on that subject. Somebody might be trying to figure out what compass to carry for years; you never know. I politely refrained from suggesting outright that a dry compass with a needle lock might survive that treatment if water didn't get into it, which seems logical, and anyway, I don't personally know what treatment a really good liquid-filled compass will tolerate.

72.72.37.51 06:21, 7 January 2007 (UTC)Packer

Joseph Needham/Four Great Inventions of Ancient China

The change I made was:

• Joseph Needham attributes the invention of the compass to China in Four Great Inventions of Ancient China, but since there has been disagreement as to when the compass was introduced for the first time, it may be appropriate to list some important Chinese literary references leading up to its invention in chronological order:

From:

• Due to the place of its first appearance, most scholars credit the invention of the compass to China. Since there has been frequently confusion as to when a compass was introduced for the first time, it may be appropriate to list the important events leading up to its invention in chronological order:

The previous editor had deleted this line:

• It's included in Four Great Inventions of Ancient China (Si da fa ming) in one way or another.

This deletion makes sense as the information was redundant to the first line. ('inventions' pointed to 'list of chinese inventions' which itself points to 'four great inventions of ancient China.') Plus the line 'included' 'in one way or another' just isn't very specific. Add to that the vagary of 'most scholars credit the invention' and it just doesn't sound informative in a definite way. With the new edit there is a scholar listed by name along with his work that specifically credits the creation of the compass to China. Readers can then make there own inferences after reading all these articles as to whether they think the compass belongs to China or some other country. Aspenocean 09:51, 12 May 2007 (UTC)

"Readers can then make there own inferences after reading all these articles as to whether they think the compass belongs to China or some other country."

What? The compass was invented first in China, and then invented separately in Europe (where it was gradually improved). Period. End of story. Nothing more to discuss or "infer". Whether or not we can sit here and debate its diffusion from China to Europe is very trivial, considering how we have no evidence of its transfer (if it actually occurred in the first place), and quite possibly never will have such evidence. You have heard of common phenomena, haven't you?--PericlesofAthens 19:28, 16 May 2007 (UTC)

• You have heard of scholarly debate haven't you? If you were there at the time or otherwise have rock solid proof of the origins of the compass, the scientific community needs to hear from you right away. Aspenocean 20:31, 16 May 2007 (UTC)

Sure thing, bro! Just let me jump into my time machine really quick (lol). Following that brand of logic, I could also doubt if Alexander Neckham was truly describing the compass needle as well, about a hundred years later than Shen Kuo. Seriously though, this is a trivial pursuit. What evidence we have for the early compass in China is stated in the article, and valid for that matter.--PericlesofAthens 20:21, 19 May 2007 (UTC)

• In a recent edit the work of Joseph Needham attributiing the compass to China -Four Great Inventions of Ancient China- was removed and referred to as "plastering." I don't think the way to deal with controversy is to hide information. If you're going to bring up a controversial subject it should be lead in with a notable work by a notable author and that is why it is included here. Again, when there is controversy the reader can use information to make up their own mind. Aspenocean 03:14, 21 May 2007 (UTC)

And the controversey is what again? Yeah, Needham attributed the first discovery (or at least the first written reference) of the magnetic needle compass to Shen Kuo's Dream Pool Essays. The book isn't some big secret or conspiracy. When Shen Kuo was writing in the 11th century, he wasn't doing so to impress you and I, he was doing so to improve the knowledge of the known sciences in his day. You can argue all you want with Shen Kuo, the original source (and Needham for that matter), but I'm afraid you'll need a seance to do that. I wouldn't trust those spirit mediums though if I were you; instead I would just refer to historical texts.--PericlesofAthens 07:48, 22 May 2007 (UTC)

• My point exactly. I don't know what the problem is honestly. It was Gun Powder Ma that keeps trying to remove the reference to Four Great Inventions of Ancient China. I gather you've had conversations with this user in the past. This same user has in other edits removed referenced facts and more or less claimed he didn't like the reference because of its age. I hadn't intended on naming names, making accusations, or getting in the middle of anyone else's argument here; but was willing to assume good faith and believe there were editors who think there is a controversy. I do have an opinion of what's happening when an editor hides or obscures facts, but it has been discussed to death in other forums, and I dislike making too many assumptions. There are scholars who attribute the compass to China, and Four Great Inventions of Ancient China is a work by Needham. Just a plain fact and no reason to hide it away. Aspenocean 17:47, 22 May 2007 (UTC)

Ah yes, him and I are acquaintences from a history forum a while back (which I really don't visit anymore). He's a smart guy, with an honest and admirable interest in Western history, but when it comes to Chinese history he gets easily insulted by the notion that they could have done anything before a European had (which is unneccessary considering that the basis for the majority of global modern science, technology, mathematics, and politics comes from the European model, not Chinese). It's sort of upsetting and redundant to watch, especially in his misplaced loathing and distrust of anything labeled "Needham", even though Needham went to great lengths in his many books to accurately portray China in every field of study and statecraft. To say Needham's work is not credible is a challenge to his work that has to have some sort of grounds or evidence to show Needham was a 'fluke'. Besides questionable transfusion of technologies across the Eurasian world in the medieval period (which is hard to prove in the first place, and Needham never asserted he had direct evidence to show they had), the scientific community at large has nothing to refute in Needham's work. I don't care if the man wrote his books in the 50s, the 60s, or just last year, Needham is above and beyond a credible source.--PericlesofAthens 04:19, 23 May 2007 (UTC)

Updated Info, and one slightly disappointed Wikipedian

I made some new additions about China, the thermo-remanence compass, and the dry suspension compass.--PericlesofAthens 21:56, 27 May 2007 (UTC)

I also find it rather curious and questionable that someone would use Li Shu-hua's publication of 1954, in order to show that the method is still unknown of how the fish compass of 1044 AD would have worked. Clearly, someone was ignoring (unknowingly or intentionally) Wang Chenduo's work and Needham's publication made in 1962, which proved the Chinese used the weakly-magnetized thermo-remanence compass (which would have been inefficient, yes, but a compass needle nonetheless). It is also curious and questionable that no one mentioned the use of the Chinese dry suspension compass as early as the 12th century, and blatantly wrote that the only compass known in China before European influence was the wet compass placed in a bowl of water. To this I say: hogwash.--PericlesofAthens 22:15, 27 May 2007 (UTC)

Recent Reverts to the Thermo-remanence and Dry-needle compass

I have recently reverted the edits by Gun Powder Ma, who asserts that the existing sources contradict Needham's Volume 4 Part 1 of his Science and Civilization in China series, although I can't seem to find which contradictory source that would be. Gun Powder Ma, please point these sources out, as I do not think they exist.--PericlesofAthens 01:18, 29 May 2007 (UTC)

If Gun Powder Ma has a source (later than 1962) that contradicts this passage of the Wujing Zongyao (written in 1044 AD) featured in Needham's Volume 4, Part 1, then I would truly be astounded; here is the full excerpt from Needham's page:

"Actually, Khou Tsung-Shih was far from being the first to describe the water, or floating, compass. Until Wang Chenduo noted it, everyone had overlooked a passage in the great compendium of military technology, the Wu Ching Tsung Yao, edited by Tseng Kung-Liang and finished in 1044. Here the writer says:

When troops encountered gloomy weather or dark nights, and the directions of space could not be distinguished, they let an old horse go on before to lead them, or else they made use of the south-pointing carriage, or the south-pointing fish (chih nan yü) to identify the directions. Now the carriage method has not been handed down, but in the fish method a thin leaf of iron is cut into the shape of a fish two inches long and half an inch broad, having a pointed head and tail. This is then heated in a charcoal fire, and when it has become thoroughly red-hot, it is taken out by the head with iron tongs and placed so that its tail points due north. In this position it is quenched with water in a basin, so that its tail is submerged for several tenths of an inch. It is then kept in a tightly closed box. To use it, a small bowl filled with water is set up in a windless place, and the fish is laid as flat as possible upon the water-surface so that it floats, whereupon its head will point south.

Needham, Volume 4, Part 1, Page 252, illustration on 253.--PericlesofAthens 01:29, 29 May 2007 (UTC)

In fact, to contradict this, Gun Powder Ma would have to find a source later than 1995, since it was accepted by the scholarly community even by the time of Nathan Sivin's book Science in Ancient China, written in 1995, the part on the thermoremanence compass found on page 21 of section III.--PericlesofAthens 01:31, 29 May 2007 (UTC)

Furthermore, I would like to see the entire 373rd page of Barbara M. Kreutz's book Mediterranean Contributions to the Medieval Mariner's Compass,” Technology and Culture, Vol. 14, No. 3., in order to come to the conclusion if someone had not used her page as a means to post false information or omitting part of her writing to twist her intent. I say this because Needham, in 1962, quotes the passage of the Shi Lin Guang Ji (compiled in 1325 from material dating back to the 12th century), which says:

They also cut a piece of wood into the shape of a turtle, and arrange it in the same way as before (the south pointing fish), only that the needle is fixed at the tail end. A bamboo pin about as thick as the end of a chopstick is set up on a small board, and sustains the turtle by the concave under-surface of its body, where there is a small hole. Then when the turtle is rotated, it will always point to the north, which must be due to the needle at the tail.

Needham, Volume 4, Part 1, Page 255. Clearly, this is a dry suspension compass, it has nothing to do with water in bowls, and in craft is very different from dry European compass cards in box frames and with pivoting needles. More info from page 290 coming up...--PericlesofAthens 01:39, 29 May 2007 (UTC)

From the same volume, on pages 290 to 291, it shows illustrations of the suspension needle compass printed in Wang Zhenduo's book, and describes their use in China all the way up to the 18th century, despite the 16th century Italian compass-card being spread all over East Asia accompanied by the dry pivot. Needham also notes that dry suspension compasses were not as widespread in China as the floating type (both for navigation and popular in geomancy), but this does not mean it did not exist. I am guessing Barbara M. Kreutz's book (of 1973) notes that either

• the Chinese had the floating needle compass, and failed to mention the dry needle compass
• that since the dry suspension compass in China was not nearly as prominent or widely used as the wet floating bowl compass, mentioning the dry suspension compass wasn't worth mentioning in light of the European model of the dry box frame compass-card which prevailed
• or she made a terrible mistake at saying the only compass known in China was the wet one (I find stupid mistakes about China in tons of books, for example, refer to John Norris' book Early Gunpowder Artillery: 1300-1600, published 2003, which states that Wu Jing Zong Yao was a person who wrote a military treatise in 1044! Hah). I think I will be ordering her book soon, or see if it is available at my local library.--PericlesofAthens 01:53, 29 May 2007 (UTC)

With the evolution of the dry suspension compass in China (not the European dry compass-card type invented in the 14th century, and supposedly by one Flavio Gioja in Amalfi, Italy, around the year 1300 AD according to tradition, this date being asserted by historian Sylvanus Thompson, as Needham notes), by the 18th century the Chinese dry suspension compass used the following components (with illustration, as noted in Wang Zhenduo's work):

• a flat needle
• sharply pointed steel pivot
• inverted conical copper bowl
• glass cover
• copper ring
• ivory plate

--PericlesofAthens 02:22, 29 May 2007 (UTC)

Needle-and-bowl device

Could there be a confusion with static electricity? I cannot magnetize a needle by rubbing it with silk.Kinzele 16:10, 13 July 2007 (UTC)

Yeah, where did this come from? I know the Chinese rubbed needles with lodestone, and that did make them magnetic. But silk? That sounds kind of...stupid. Furthermore there's no citation for it.--PericlesofAthens 04:30, 18 July 2007 (UTC)

Why No Discussion Of Peter Peregrinus?

There is no detailed discussion of Peter Peregrinus, who described in detail two types of magnetic compass suitable for direction finding in 1269 A.D. He is also the founder of magnetic science. I can not understand the China bias in the invention of the compass and the subsequent lack of attention to European development. A separate section needs to be devoted to this and European development of compass. The current brief mentions are misleading to the reader. The European invention of the compass is one of the most important events in the history of the world. Since it allowed Europeans to discover America and open trade with India and China. In my view this is a major flaw. See [2]and [3]72.64.37.102 15:27, 19 July 2007 (UTC)

I'm Chinese, and I agree that there seems to be some bias in the article. There is no mention that the Olmec people of Mesoamerica may have discovered that a lodestone will align itself in a magnetic north-south position, and they are credited with developing a compass before 1000 BCE, centuries before the Chinese (American Indian Contributions To The World - 15000 Years Of Inventions And Innovations by Kay Marie Porterfield & Emory Dean Keoke, page 67; Lodestone Compass: Chinese Or Olmec Primacy? by John B. Carlson). Friendship & Rainbows (talk) 09:50, 14 July 2019 (UTC)

Reversal of Earth's magnetic field

This happens every few 100,000 years or so I read somewhere. This means a compass will point north due south (and vice versa). What would be a good discussion is to give the latest tehories on how this happens to the Earth's magnetic poles and when it is predicted to happen next on this here planet. Pomona17 13:03, 13 November 2007 (UTC)

Reversal of just the compass itself

Mention that one's compass might become reversed itself! Jidanni (talk) 00:59, 23 May 2010 (UTC)

“ Thrusting his head half way into the binnacle, Ahab caught one glimpse of the compasses; his uplifted arm slowly fell; for a moment he almost seemed to stagger. Standing behind him Starbuck looked, and lo! the two compasses pointed East, and the Pequod was as infallibly going West.

But ere the first wild alarm could get out abroad among the crew, the old man with a rigid laugh exclaimed, "I have it! It has happened before. Mr. Starbuck, last night's thunder turned our compasses—that's all. Thou hast before now heard of such a thing, I take it."

"Aye; but never before has it happened to me, sir," said the pale mate, gloomily.

Here, it must needs be said, that accidents like this have in more than one case occurred to ships in violent storms. The magnetic energy, as developed in the mariner's needle, is, as all know, essentially one with the electricity beheld in heaven; hence it is not to be much marvelled at, that such things should be. Instances where the lightning has actually struck the vessel, so as to smite down some of the spars and rigging, the effect upon the needle has at times been still more fatal; all its loadstone virtue being annihilated, so that the before magnetic steel was of no more use than an old wife's knitting needle. But in either case, the needle never again, of itself, recovers the original virtue thus marred or lost; and if the binnacle compasses be affected, the same fate reaches all the others that may be in the ship; even were the lowermost one inserted into the kelson.

”

—Herman Melville: Moby Dick. 1851.CHAPTER 124: The Needle. (continued)

—Pawyilee (talk) 11:04, 31 May 2014 (UTC)

Tritium replaced by Luminova

PLease include informataion that Tritium is now replaced by Luminova in compasses. See this article and this one

I couldn't actually see any refernce to the material used to make a compass readable at night. However, I'm confident that it usually wasn't/is't tritium. A luminous substance was painted onto the needle, used to mark the numbers and graduations, give an aiming arm for taking bearings. My understanding is that it was usually radium based. The key point is that it was luminous not illuminating. Tritium light sources are used to illuminate, ie like a light bulb, not as a paint, and were introduced in the 1960s, however, they only replaced luminous paint in some instances. Nfe (talk) 04:26, 5 June 2008 (UTC)

Besides battery illumination, there are not two, but THREE current methods of illuminating compass needles and dials for use in darkness or low light (unencapsulated radium-containing paint hasn't been applied for YEARS - for reasons why, see Madame Curie). The first is the old standard 'luminous' or phosphorescent paint, zinc sulfide (ZnS) - which has been around for years. It's not very bright. The second method has been called 'self-luminous', since it uses an encapsulated radioactive isotope of tritium for illumination. Tritium is found on several military models of compass that are sold to civilians (Silva of Sweden, Suunto, and Cammenga all make tritium models). Unlike radium-base paint, tritium gas emits only low energy beta particles (electrons) that are unable to penetrate the borosilicate glass walls of its capsule. This makes their use relatively safe. The third method is well-known to sailors who have purchased modern hand bearing compasses, though perhaps not to others. This third material is strontium aluminate(SrAl), aka LumiNova, which acts like a photoluminescent phosphor, and is typically called (in the compass trade) photoluminescent. Due to its bright blue-green glow, most people can usually tell right away when a compass part has an SrAl coating. Because SrAl is MUCH brighter than ordinary ZnS luminous paint, and because it is NOT a radioactive isotope, may see increasing use of SrAl on recreational compasses used for land navigation in years to come Article. Special:Contributions/Don01 (talk) 21:54, 26 November 2008 (UTC)

History of compass too long?

I think it's time to split off the History of compass section into another article. Comments? If there are no objections, I will do it next week.lk (talk) 08:20, 4 May 2008 (UTC)

Admittedly, it is fully 50% of the article. However, barring unexpected new discoveries, I don't see any part of the article ever getting much bigger...

I wouldn't be the one to revert it, as long as you craft a suitable wikilinked summary of the history to remain behind in the original article. I simply do NOT see a need.

Badly Bradley (talk) 18:48, 4 May 2008 (UTC)

The article is 60 kilobytes, which does put it in the running for splitting. The "History of compass" section would be a good choice: it includes a deal of speculation (referenced speculation, but all the same), whereas the sections starting "Modern compasses" are more definitely factual. Many users coming to this article are liable to be GPS owners, hikers, sailors, who are wondering "What is this thing, and how can I understand it better?" For them, the historical background is huge and rather inconclusive. Piano non troppo (talk) 17:49, 29 November 2008 (UTC)

Semi Protection for this page?

I've been watching this page for about a month, and it seems that every few days, this page is vandalised. Looking at the page history, it seems that this has been happening for a long time. I think it happens because school kids regularly look up compass for their school projects. Should this page be semi-protected? Any admins watching? lk (talk) 06:19, 21 May 2008 (UTC)

Liquid filled compasses

The statement that liquid filled hand held compasses were invented in 1936 is nonsense. Liquid filled hand held lensatic and prismatic compasses were available from several (4 or 5) suppliers(eg JH Steward & Son) in UK (mainly London)during World War 1, they were advertised for sale in military magazines. It's a less clear if they were also UK official service issue or when they first appeared. Perhaps similar compasses were also available in France and Germany.Nfe (talk) 04:11, 5 June 2008 (UTC)

I've removed the section on the invention of liquid compasses in 'history'. Do you have any references on when liquid filled compasses were invented? lk (talk) 18:55, 6 June 2008 (UTC)

No but it was before 1918, I've also got a copy of a 1918 British magazine article that states 'there are 4 well-known types of liquid compasses on the market, and these vary mostly in their method of reading the bearing'. These include JH Steward (prismatic), 'Blacker' type of wrist compass by Creagh-Osborne, Creagh-Osborne artillery pattern, the picture suggests its prismatic, and a lensatic compass with no manufaturer's name given.

I also have a advert by JH Steward Ltd, 406 Strand, London for a 'Lensatic Liquid Compass, Luminous', price five pounds and five shillings. Which was probably about a weeks pay for a working man in those days. I think this advert is from 1917/8 Nfe (talk) 08:03, 7 June 2008 (UTC)

If you ever find more information or a citation about when the liquid filled compass was invented, please do update the pages. Thanks. lk (talk) 17:29, 8 June 2008 (UTC)

Other aspects

Another type of compass used in late 19th and early 20th century was the 'trough compass'. This was used with plane tables. Another matter was/is compass 'dip', this seems to mean the tilt of a magnetic compass needle from the horizontal and varies depending where it is.Nfe (talk) 05:10, 6 June 2008 (UTC)

I believe the issue of 'compass dip' is addressed in the section titled 'balancing the compass'. lk (talk) 17:29, 8 June 2008 (UTC)

Lacking info about modern compasses

This page needs more history concerning about liquid filled, prismatic, lensatic and surveyors compasses. Also needs more info about the new electronic compasses that are sometimes built into watches and GPS devices. If anyone knows anything about these devices, could he/she please add to the page. Thanks. lk (talk) 17:29, 8 June 2008 (UTC)

A few comments about the U.S. military lensatic compass are in order. While I own one myself, and realize it is beloved by many, this design is frequently oversold. It is not 'more rugged' than most other compasses (including acrylic protractor compasses used by many more military forces than the U.S. Army/Marines). First, it does not have an airtight capsule filled with liquid or inert gas, so it's NOT waterproof, despite claims from the manufacturer(s) over the years (remember what happens to binoculars that are sealed with ordinary air?). Water can enter, despite the seal, and humid air can also condense inside the capsule and corrode or freeze up the dial. It happens! Second, it is NOT shockproof. The military lensatic has a long pivot due to its deep well design, so it is vulnerable to bent pivots when dropped on hard surfaces, like a rock, or on concrete. Most people don't realize that the U.S. military drop tests random samples of military lensatic compasses by dropping them onto plywood tables covered with 10 cm (4 inches) of plastic-covered dry sand from 90 cm (3 feet) heights! Remember, the test is NOT "does the card still rotate", but rather "does it still read within a degree of magnetic north". In fact, the baseplate compass is better able to withstand drops with its light weight, short pivot, and liquid-damped capsule. It also tends to require less frequent servicing, unit for unit. The British Army noted this years ago when they adopted the baseplate design. Third, while some baseplate compasses can be read to 1-degree, the lensatic still has a compass card design dating to the 1930s, with only five-degree markings. It takes a very skilled individual to interpolate 1-degree splits with a standard Cammenga. One could use the mils and convert, of course, but what's the point of trying? - the military only requires 40 mil (2.25 degree) inherent accuracy from a brand-new lensatic compass anyway. So the claim of 'most accurate' doesn't begin to apply to this model in comparison to several other designs (Brunton M2, Brunton 54LU (Silva 54), Suunto KB-14.LK (talk) 15:59, 5 December 2008 (UTC)

History: Sorting by type of compass

Sorting the history section by the different types of compasses does the complicated subject more justice, and is certainly more convenient for the reader than a confusing patchwork of geographical subcategories. I also tried to verify sources given and corrected those I had access to. Regards Gun Powder Ma (talk) 03:41, 11 September 2008 (UTC)

I ordered the compasses by type and function, so that the structure of the article is now more sound and reader friendly. If there are any objections to a systemically ordered history section, they should be brought forward here, not by making unexplained reverts. The more so, since the user does not seem to have read the sources cited, and blindly double posted material from the astronomy section in that about the Islamic world. Regards Gun Powder Ma (talk) 01:17, 3 January 2009 (UTC)

I Invite the user again to explain his enigmatic edits to a wider audience. Gun Powder Ma (talk) 16:50, 8 January 2009 (UTC)

POV pushing in the lead

The invention of the compass deserves a place in the lead. The knowledge of magnetism in Ancient Greece does not. This is similar to editing the article on the internal combustion engine to emphasize the discovery of petroleum in the ancient Middle East and leaving out the invention of the engine in Germany in the 19th century. lk (talk) 07:53, 11 September 2008 (UTC)

That isn't POV pushing; that is cruft. --Una Smith (talk) 16:52, 5 October 2008 (UTC)

Is this article protected?

When I display the article, it shows a Semi-protection icon on the upper right side. However, we seem to have been suffering a spate of vandalism attacks from anonymous IPs. How is that possible if the article is semi-protected? Anyone know what is going on? LK (talk) 04:27, 13 January 2009 (UTC)

It seems that the semi-protection for the page has expired. I'm going to request that it be reinstated, since as soon as it expired we have been experiencing about 1 vandalism per day, and almost all the edits since are either vandalism or reverts of vandalism. If anyone objects, please do so below. Remember, silence implies consent. LK (talk) 16:34, 18 January 2009 (UTC)

2 of the arguments against independent European invention of the compass are false

At least 2 of the arguments in the article against independent European invention of the compass are wrong. In the first case, the earliest European to mention a compass talks about a dry mounted compass (see Neckham's 'De Utensilibus'.) Nowhere does he mention a floating compass.

Second, the ancient Greeks knew about magnetism, so the Europeans would likely know about magnetism. All our sources from the ancient Greeks came from either Medieval Europeans copying ancient Greek works, or from Arabic sources later transllated into Latin during the middle ages.

Glenn Beard, Michigan. —Preceding unsigned comment added by 66.51.147.97 (talk) 21:27, 14 March 2009 (UTC)

Awesome, now you just have to find sources for this information and edit the page! 174.49.43.243 (talk) 06:23, 27 May 2009 (UTC)

Wrist and small clip compasses

In Ski-O and MTB-O small compasses attached to the mapboard or the wrist exists. A short sections about these modern compasses are needed. An example product here.--Kslotte (talk) 12:23, 1 July 2009 (UTC)

pliny the elder

• The lack of evidence of prior knowledge in Europe of magnetism or how to induce it in an iron rod.

CHAP. 42.—THE METAL CALLED LIVE IRON. We shall speak of the loadstone in its proper place,1 and of the sympathy which it has with iron. This is the only metal that acquires the properties of that stone, retaining them for a length of time, and attracting other iron, so that we may sometimes see a whole chain formed of these rings. The lower classes, in their ignorance, call this "live iron," and the wounds that are made by it are much more severe. This mineral is also found in Cantabria, not in continuous strata, like the genuine loadstone, but in scattered fragments, which they call "bullationes."2 I do not know whether this species of ore is proper also for the fusion of glass,3 as no one has hitherto tried it; but it certainly imparts the same property as the magnet to iron. The architect Timochares4 began to erect a vaulted roof of loadstone, in the Temple of Arsinoë,5 at Alexandria, in order that the iron statue of that princess might have the appearance of hanging suspended in the air:6 his death, however, and that of King Ptolemæus, who had ordered this monument to be erected in honour of his sister, prevented the completion of the project.

1 B. xxxvi. c. 25.

2 Properly "bubbles," or "beads."

3 See B. xxxvi. c. 66. In the account of the loadstone referred to above, he informs us that this mineral was employed in the formation of glass.—B. Beckmann is of opinion that Manganese is here alluded to. See Vol. II. p. 237.

4 Another reading is "Dinochares," or "Dinocrates," for an account of whom, see B. v. c. 11, and B. vii. c. 38.

5 Wife and sister of Ptolemy Philadelphus. See B. vi. c. 33, and B. xxxvi. c. 14.

6 Some accounts state that the statue was to be of brass, and the head of iron. It is said that the same thing was attempted with respect to the statue of Mahomet, in his tomb at Medina.—B. The Natural History. Pliny the Elder. John Bostock, M.D., F.R.S. H.T. Riley, Esq., B.A. London. Taylor and Francis, Red Lion Court, Fleet Street. 1855.

this shows magnets were known in classic timesJ8079s (talk) 02:54, 4 July 2009 (UTC)

Critique of Compass Article

The article is well written and easy to read. The facts are well researched and accurate. The sources are complete, authoritative and cover a wide time frame of publishing. It is good to not only use older sources, but the most recent source included was published in 2007. The images and descriptions were good and added to the article. They were relevant and not just distracting. The subject was covered throughly without many inaccurate contributions. It would be interesting to add more about the argument on wether the compass' technology migrated from China to Europe or if by chance it was also invented in Europe with a similar design. There is not much about that in the article. Also, there is a ton of information about the history of the compass in China and then in contrast the European history with the compass was a very brief summary spanning a long period of time. It also does not address the argument of wether the compass was invented or shared, but just says it was reportedly used starting in 1187. These few improvements would help this article. —Preceding unsigned comment added by Nrobbin1 (talk • contribs) 14:37, 4 October 2010 (UTC)

gyrocompass does not sense magnetic field!

"fibre optic gyrocompass, which detects the magnetic directions" -it's a bluff. Gyrocompass is a gyroscope, be it mechanical or fiber optic. It DOES NOT detect magnetic field of Earth, and points to true North. Magnetic North could be calculated, if longitude and latitude are known.

Gyrocompass has a drift, and should be corrected periodically, while magnetic compass does not need this kind of correction.

Proofs: http://www.britannica.com/EBchecked/topic/407011/navigation/61207/The-gyrocompass#ref363677 http://www.hnsa.org/doc/gyromk14/index.htm — Preceding unsigned comment added by 95.26.163.85 (talk) 23:15, 25 May 2011 (UTC)

Critique of deletions

Someone has seen fit to delete a few statements I put in the article. I contend that the deletions are unjustified.

The article says that a compass is a navigational instrument. I changed that to say that the compass is frequently used for navigation, and sometimes for other purposes. My change has been undone. But I know amateur astronomers who use compasses to set up telescope mounts, real-estate agents who carry compasses so as to be able to show clients which windows of a house face south, Muslims who use compasses to find in which direction to pray, interior decorators who use compasses to find studs in walls (the magnetic needle responds to the presence of nails in the wall). I myself have a compass attached to the base of a portable heliostat. I use it to help in setting up the machine in a new location. I am not suggesting that a long list of the uses of compasses should be put in the article, but I do think the implication that a compass is purely for navigation should be avoided.

To a paragraph that states some historical facts about the magnetic compass, I added a couple of sentences about the history of the gyro compass. I just copied them from other articles here in Wikipedia. For some reason, they have been deleted.

I put in a few sentences about using a wristwatch to find the compass directions. This is something that is known by every Boy Scout in Britain. (I know. I was raised there.) I said that it works better in high latitudes than in low ones. (Britain is almost entirely north of 50 deg. N latitude.) In the tropics, it is useless, and in the southern hemisphere it has to be done a bit differently. I included a link to a (British) video that shows how to do it. However, this has all been deleted...

The person who did the deletions suggested that I had written the results of personal research. No. I wrote what is common knowledge in many parts of the world.

I'm not going to undo the deletions. That kind of battle can get silly. But if other people see fit to undo them, I won't object!

DOwenWilliams (talk) 03:44, 31 July 2011 (UTC) David Williams

Your arguments all rely on personal experience, and thus constitute original research, which is not appropriate for Wikipedia. LK (talk) 11:32, 4 August 2011 (UTC)

Ultimately, everything anyone writes relies on personal experience. Excluding it from Wikipedia essentially excludes everything. Take a look at my user and user talk talk pages to see some stuff I wrote a while ago about the usefulness, or otherwise, of citations. DOwenWilliams (talk) 02:00, 10 August 2011 (UTC) David Williams

I disagree with you when you write "everything anyone writes relies on personal experience", but I agree that your content could be a valuable part of the article, IF it can be sourced. And I reckon sources could be found for at least some of it. HiLo48 (talk) 07:41, 10 August 2011 (UTC)

Well that's pretty easy. For example the Geography Fieldwork site shows the use of the watch (and from Barcelona, not exactly northern Europe). Don't be put off by this "original research" argument. Just find the necessary confirmation for everyday knowledge. Chris55 (talk) 10:13, 10 August 2011 (UTC)

I still contend that it's silly to insist on quotations to support facts that are everyday knowledge. For example, don't we all know that a compass can be used for purposes other than navigation? As I wrote on my user page, citations are sometimes just plain wrong, even if they were written by experts in the field. Other facts are difficult to support by citations, because they are so well known that nobody would bother to write learned papers about them. Citations should, in my opinion, be *one* of the tools by which the validity of statements in Wikipedia articles should be judged, but they should certainly *not* be the only one. DOwenWilliams (talk) 02:23, 12 August 2011 (UTC) David Williams

Watch as compass (again)

Getting back to the use of a watch to find the compass directions: Basically it assumes that the azimuth (bearing) of the sun changes at a rate of 15 degrees per hour (the speed of the earth's rotation) throughout the day. As seen from the North Pole, this is true, but from lower latitudes it is not. For example, I now live in Toronto, Canada, at latitude 43.5 deg. N. (This is also roughly the latitude of Barcelona.) At the summer solstice at noon, the sun is about 70 degrees above the horizon, or only 20 degrees from the zenith. As the sun moves westward, even a small movement causes its azimuth to change substantially. The rate of change of azimuth at this time is far more than 15 degrees per hour. Actually, the maximum rate of change is proportional to the secant of the angle of elevation of the sun. Sec(70deg) is close to 3, so the rate of change of the sun's azimuth at noon is close to 3x15 or 45 degrees per hour.

Think of an extreme example. (This is often a useful trick.) Suppose you're on the equator, at an equinox. The sun rises exactly in the east, ascends vertically up the eastern sky, with no change in its azimuth, until noon when it is exactly overhead. At that point, its azimuth abruptly changes by 180 degrees, and the sun then descends vertically down the western sky until sunset. Obviously, a watch could not be used in the standard way to tell which way is north.

Chris55 tells us that he found a reference to the use of a watch as a compass in Barcelona. Frankly, I suspect that whoever wrote it didn't really know what he was writing about. In Barcelona, especially in summertime when the sun is highest, the watch would often be hopelessly wrong if used as a compass. So why did the author write what he did? My guess is that he relied on something that had been written much further north, maybe in Britain. He found something to cite, and assumed it was true. Bad mistake.

Relying on citations is no substitute for real knowledge.

DOwenWilliams (talk) 22:21, 12 August 2011 (UTC)

Determination of latitude

According to the subsection Navigation prior to the compass, the observation of celestial bodies together with a compass "enabled the calculation of latitude." While this statement is strictly true, its inclusion and placement in the History section strongly implies that this technique was used prior to the 17th century. No compass is needed on a clear night; the latitude is the elevation of the pole star as well as the declination of whatever star is directly overhead. During the day, when the stars are invisible, one can determine latitude from the sun's elevation, its compass bearing, and the date; a citation is necessary, however, to support any contention that medieval mariners actually performed this rather complex calculation or had an analog device to do it for them. Peter M. Brown (talk) 17:43, 31 August 2011 (UTC)

Sentence in need of attention in "Limitations of the magnetic compass", and some expansion.

Doing the expansion first, the sentence: "Local environments may contain mineral deposits and human sources such as MRIs." could profitably have added to it far more common sources such as "..., loudspeakers, computer hard drives, magnetic door catches, magnetic door seals (such as on refrigerators), television and computer monitors, and a variety of common household tools and appliances that contain electromagnets or electric motors. High-current domestic appliances, such as electric welders and the whole gamut of electric cooking and heating devices, can create significant temporary magnetic fields whilst in operation".

The above sentence (in the protected) article now mentions "electric engines"! Could this, please, be corrected to "electric motors".

The sentence : "Vehicles may contain ferrous metals, which may pick up their own fields." seems to be in need of some attention. Perhaps something along the lines of: "Vehicles may contain ferrous metals, which may influence the direction and strength of the local magnetic field. These metals can themselves become magnetised, which may influence the local field even further".

Anyone have any problems if I make these changes? Old_Wombat (talk) 09:48, 9 October 2011 (UTC)

No physical evidence

All of the supposed evidence of the Chinese inventing the compass lies in single sentences in books. There are no physical compasses from or near the time of invention or even drawings. What is the Chinese character for magnet or compass and when were they first created? That would give a clue to when or if the Chinese first invented the compass. — Preceding unsigned comment added by 98.111.29.207 (talk) 10:07, 30 December 2011 (UTC)

Recent edits late April

I've reverted them; these are cited info and changing cited info to fit something is OR and rather bad for the text-source integrity. Also, I can't find the added info in the reference, which was provided with this edit [4]. Meaning this source by Schmidl, Petra G. (1996–1997). "Two Early Arabic Sources On The Magnetic Compass". Journal of Arabic and Islamic Studies. 1: 81–132. {{cite journal}}: Invalid |ref=harv (help) http://www.uib.no/jais/v001ht/01-081-132schmidl1.htm#_ftn4 --Cold Season (talk) 02:20, 28 April 2012 (UTC)

Does this make sense?

"Since opposite poles attract ("north" to "south") the North magnetic pole of the Earth is actually the south pole of the Earth's magnetic field."

What now? — Preceding unsigned comment added by 69.117.238.130 (talk) 00:33, 18 May 2012 (UTC)

Misleading edits

The consensus among technology historians is that the first textual evidence of the navigational compass, a compass used as a device for direction finding, appears in China in 1040-44, in Europe in 1187-1202, and in the Middle East in 1232. The direct quote from Kreutz, the historian cited in the article, is that "barring the discovery of new evidence, it seems clear the first Chinese reference to" the compass "antedates any European mention by roughly 150 years" (page 367). This edit removes the sourced figure that was taken directly from the text, replacing it with a 50 year figure that appears nowhere on the page being cited (page 370). Page 370 does mention that the first mention of the compass in the Middle East is attributed to a Persian text dating to 1232, but rounding up from 30 to 45 years to "50" is ridiculous, and does not justify the removal of the original figure, which actually appears in the source. The edit also removes mentions of the diviner's compass, an important historical predecessor of the navigational compass, much like alchemy was the historical predecessor of modern chemistry. Questions of diffusion through the Middle East are legitimate, and are addressed in the article, but this shuffling of words is clearly trying to push a certain viewpoint.--Ninthabout (talk) 06:46, 27 May 2012 (UTC)

I have a feeling we're going to get into a semantics debate over navigation. There was an earlier discussion on this, but navigation, if used in the military sense of the word, does include land navigation.--Ninthabout (talk) 04:54, 30 May 2012 (UTC)

I'm still waiting for the user to comment. Although s/he said in the edit summary that s/he "adressed" these issues, but the user did not even reply on the talkpage here or the above section of April... Facts should be supported by refs; info should not be re-worded just enough to change the meaning like s/he did. The date 1117 does specifically mention its use on sea, I guess. --Cold Season (talk) 15:21, 30 May 2012 (UTC)

I have read what you have said here, but you (CS) have only accused me of "misrepresenting" things even though I have backed everything with the sources, especially in my latest edit. In other words, you have provided next to no constructive criticism regarding my edits. R3venans (talk) 20:40, 30 May 2012 (UTC)

The three refs of R. Merill, W. Lowrie, and J. Needham specifically mentions "compass" with a lodestone needle and dial which was invented during 2c BC - 1c AD in the Han dynasty. You haven't "backed everything with sources" to your OR claims, you have merely rearranged excisting refs and reworded the info (now not supported by ref) to fit your original research. Which is evident, since you even have attributed your OR info to someone who states that it's invented in the Han dynasty. --Cold Season (talk) 21:02, 30 May 2012 (UTC)

I think we're approaching a consensus, but I have a few remaining quibbles. The diviner's compass used during the Han dynasty was certainly not a needle. That transition did not occur until the 4th or 10th century. The source is in French, so I'm unable to verify its claims, but English translations of the text do not mention a needle, only a lodestone that points south. And the use of the word "probably" is problematic. Scholars are mostly in agreement that the diviner's compass preceded the navigational compass. The only dispute is whether the divination compass was invented in the Han dynasty or later on, but there is evidence of its use from alchemist texts dating to the 4th, 2nd-6th, 3rd-5th, 8th, and 10th centuries. It's also against the Manual of Style to use words like "alleged" or "probably." And as for whether or not the diviner's compass is a compass, a device that is functionally a compass, even if the compass was used for "the search for gems and the selection of sites for houses," is still a compass.--Ninthabout (talk) 07:29, 31 May 2012 (UTC)

I believe I've figured out the discrepancy. The quote, "A lodestone attracts a needle," may come from the text, but it is not used by historians, supportive of the theory, as evidence of a Chinese compass, although it does show the Chinese observing magnetism. It's this line, "But when the south pointing spoon is thrown upon the ground, it comes to rest pointing at the south," that is used as evidence of a Han Dynasty compass.--Ninthabout (talk) 10:06, 31 May 2012 (UTC)

I think I'm mostly content with the current version, but is there any evidence of the han dynasty device being a "magnetic compass"? Is that what the sources claim? The first actual mention of a "magnetized needle" is only from the 11th century. What the about the part "according to Kreutz, scholarly consensus is that the Chinese invention [of "the compass"] predates the first European mention by 150 years"? Doesn't that suggest that at least according to that expert, most experts who know and write about the subject agree that the song dynasty wet compass is the first known true "compass"? The supposed han dynasty invention of "the compass" seems to be a minority viewpoint, and should not be included in that part of the article, at least not without reservations. R3venans (talk) 21:40, 31 May 2012 (UTC)

Hence the phrasing, "as early as the Han dynasty." Among historians, there is a consensus that the compass was used for divination in China prior to being used for orienteering and marine navigation. The only disagreement is on when this began. Chen-Cheng Yih writes that the "device described by Wang Chong has been widely considered to be the earliest form of the magnetic compass," but the Han dynasty text by Wang Chong is not the sole textual evidence of a compass. There are other texts, dating to later centuries, used as evidence for the divination compass. Some argue that the compass was invented as early as the Han dynasty, some argue that the compass wasn't widely used by alchemists until the 5th-6th centuries, or until the 10th century. I wouldn't object to the addition of a footnote to clarify this point.--Ninthabout (talk) 07:48, 1 June 2012 (UTC)

All Magnetic Compasses Points East

I was just reading this article and there is much reference to the compass pointing due north on the Types of Compass section for a magnetic compass. All magnetic compasses points east and true north is set by the second hand to the NNW or West North.

I dont believe most people dont know how to use a coooompass.

What is with the iPhone plug?

Someone who worked on this article seems to be an Apple junkie, because the Android phone shown was just labeled as "smartphone", and they specified the brand name of "iPhone", not to mention proclaiming advanced features like 3-axis accelerometer and 3-axis teslameter.

I'm not arguing that you should add "Android" to the other caption, but just pointing out that you are advertising for Apple somewhat in the way that you write things. — Preceding unsigned comment added by EbedYahweh (talk • contribs) 17:33, 18 September 2012 (UTC)

It seems more like an indirect plug for the app itself. I mean... the uploader did make a small accompanying article Geological compass including a section dedicated to the app (~ june/july '12). It isn't hard to see the COI... --Cold Season (talk) 03:11, 14 May 2013 (UTC)

Redirected from "lenstatic compass" yet no discussion of what a lenstatic compass is

Subject pretty much says it all. I came here looking for what the difference(s) is between a regular magnetic compass and a lenstatic compass and no where in the article is it mentioned and the search term "lenstatic compass" automatically redirects here. If you are going to redirect a specific type of compass to this article, you should at least mention it.70.197.195.158 (talk) 02:28, 7 March 2013 (UTC)aka uts

Bearing reading notations

Shouldn't the "use" section in this article explain the different notations of compass bearings which are recorded or used on charts? In particular:

• Decimal degrees versus degrees, minutes and decimal-seconds.
• Quadrant bearings vs azimuthal bearings vs rose bearings. For example: 112.5° = ESE = S67°30'E. [5]
• Magnetic bearings vs grid bearings vs true bearings (including local differences).

Cesiumfrog (talk) 01:14, 6 July 2013 (UTC)

Incorrect Image Labelling

The image labelled "Pivoting compass needle in a 14th-century copy of Epistola de magnete" is clearly a picture of the alidade of an astrolabe, not a compass needle. Note the labelling of degrees around the circumference, which give degrees of elevation, not degrees of bearing. Edrowland (talk) 18:55, 8 July 2013 (UTC)

two types of compass?

Overall I like this entry for compass, and I have a suggestion for improvement. The paragraph that starts "gyro compass" needs to be verified by someone with a good knowledge of physics, I believe it is in serious error and misleading. I went to the Wikipedia entry for gyrocompass and came away even more confused! Were both written by the same person? This is all that needs to be said:

"A gyrocompass uses a motor driven gyroscope to provide a stable platform that is aligned with the earth's axis of rotation and so indicate directions relative to true north and south. It is used as a navigation instrument. Unlike the magnetic compass it is not affected by magnetic metal in the vicinity, for example, the steel hull of a ship."

This short statement has the advantages that it stays on topic and does not stray into the physics of precession, which belong elsewhere, and which I believe to be misstated here.

Perhaps the editor of this entry will consider my suggestion and act appropriately.

Ted 216.6.141.200 (talk) 21:45, 12 November 2013 (UTC)

North at the top?

In the illustration "Pivoting compass needle in a 14th-century copy of Epistola de magnete of Peter Peregrinus (1269)." north is at the bottom. When didi it become the convention to put north at the top? 87.113.37.38 (talk) — Preceding undated comment added 10:48, 2 April 2014 (UTC)

magnetic navigation

this article is a redirect of the term magnetic navigation, amongst others for animals (birds, insects, etc). However, the article is entirely anthropocentric.

Therefore, either the article should include info on magnetic navigation for other creatures, or the redirect should be changed to magnetic navigation (human), as currently it is inappropriate.--Wuerzele (talk) 05:24, 31 August 2015 (UTC)

External links modified

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high latitudes

the real problem at high latitudes is that the horizontal component of the Earth magnetic field is small and thus may be overriden by atmopsheric/solar perturbations, also because the poles should be the preferren incoming directions of the charged particles of the solar wind (please check the physics)

87.3.202.110 (talk) 13:43, 13 January 2017 (UTC)as a matter of fact, the Lund-Lunfqvist book on the PQ-17 convoy describes the compass of a merchantman rotitating without rest

i can recover the reference if felt useful

pietro

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A Commons file used on this page or its Wikidata item has been nominated for deletion

The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for deletion:

• Compass render.jpg

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Semi-protected edit request on 1 October 2020

The first magnetic compass picture should be changed to this one https://ae01.alicdn.com/kf/Hfa674ca684344ed2893e68e99ec7f5a3C.jpg because the one that exists now is upside down. VerifiedEditor1 (talk) 19:14, 1 October 2020 (UTC)

 Not done. First of all, we can't just pull random pictures that are likely not freely licensed. See WP:IUP for the gory details. But also, the picture in lead isn't "upside down". It shows a perfectly normal compass. –Deacon Vorbis (carbon • videos) 02:09, 2 October 2020 (UTC)

Needle tilts near the poles

Regarding this sentence: "Also, the needle starts to point up or down when getting closer to the poles"

It would be clearer, and more correct, to say "Also, the needle starts to tilt up or down when getting closer to the poles".

The compass needle always points somewhere. Having it tilt off the horizontal (as happens near the poles) is an undesirable thing, and that's the point being made here. — Preceding unsigned comment added by 60.242.15.164 (talk) 11:58, 3 December 2020 (UTC)

Vectors

See this diff. A vector has direction and magnitude. A compass only shows azimuth; it is not a rangefinder, so it cannot show vectors. Just plain Bill (talk) 13:06, 16 April 2021 (UTC)

@Just plain Bill: As always, my main interest relates to the grammar in the leads. This time your edit achieves perfect grammar but involves substantive error. You're right that a compass only shows azimuth and it isn't a rangefinder. Yet, virtually all compasses have a compass rose that entails vectors, which show the magnitude (i.e. a degree) of azimuth as cardinally indicated by 0° (i.e. north), 90° (i.e. east), etc., and points in between. Sure, some compasses have chevrons rather than vectors; some have needles rather than true vectors, but that's all beside the point (no pun intended) of concision regarding the lead. For someone who professes to champion simplicity, your edit is a wordy and technical disappointment.

Technically speaking, the Earth's magnetic field, i.e. a vector field, doesn't have a "horizontal component." It has polar components that key a compass. (By contrast, the Earth itself has horizontal components.) I leave it to you to change your edit to "A compass is a magnetometer that shows the geographic cardinal directions (or points) used for navigation and orientation relative to Earth's magnetic field." I admit that lead is technically incomplete. For scientists, it should be: "A compass is a magnetometer that shows azimuth as geographically represented by cardinal directions (or points) and intermediate directions used for navigation." But, this isn't a scientific encyclopedia. It's for plain Janes and plain Joes. For them, the "With correction applied for local variation" verbiage is just plain turgid, turbid, awkward writing needless and obfuscatory and just plain murky. --Kent Dominic·(talk) 16:57, 16 April 2021 (UTC)

Don't be obtuse. The local bit of the earth's magnetic field detectable by a compass certainly does have a horizontal component. You went so far as to link Euclidean vector, which has nothing to do with the markings in and around the capsule of a compass, and you have confused the magnitude of an azimuthal angle with the scalar magnitude of a vector.

I agree that the present state of the lead is a cluster of jargon, stiff, opaque, and awkward. Your suggested verbiage is no better in that regard. My immediate aim was to get rid of the "vector" link.

I am working on some simpler, clearer text to replace it, which will demote "magnetometer" to a much later paragraph, or remove it entirely. The most common type of compass remains a magnetized needle on a pivot. (Gyrocompasses are common enough on the instrument panels of aircraft, and have nothing to do with magnetism.) When I have something in presentable shape, it will show up on this talk page. Just plain Bill (talk) 17:43, 16 April 2021 (UTC)

For now, I've restored the version after you dealt with a dangling modifier, but before you linked "vector". FWIW, while I do favor the eschewal of obfuscation, brief mention of magnetic variation (or declination) deserves early mention, being a core part of interpreting a compass reading. Just plain Bill (talk) 18:14, 16 April 2021 (UTC)

Let's agree to disagree about the relevance of vectors. (Check out the magnetic field article FRIW re. vectoring.) I just deleted the redundant "direction relative to direction" verbiage." The lead is now bare bones simple. Stuff later in the article can clarify vector versus needle versus chevron or whatever. P.S. In engineering, a Euclidean vector is represented by a mechanical arrow (or needle) such as the ones used in a compass, in avionics, etc. In meteorology, a Euclidean vector is represented by an arrow showing wind direction, weather front directions, high/low pressure directional movement, etc. A Euclidean vector isn't limited to math. --Kent Dominic·(talk) 19:58, 16 April 2021 (UTC)

In engineering, a vector may be represented by an arrow whose length is significant because it represents some scalar value. Wind, for example, has direction and speed. Just because something is drawn as an arrow does not mean it is a vector; to claim otherwise is approaching the realm of a cargo cult, where the superficial forms (e.g. vocabulary) mimic the real thing, but the substance is missing. Just plain Bill (talk) 20:14, 16 April 2021 (UTC)

Anyway, "A compass is..." --Kent Dominic·(talk) 21:36, 16 April 2021 (UTC)

Proposed lead section

Here it is, drastically reduced from the present version, in the spirit of William Strunk's "Omit needless words." I believe the history paragraph at the end can be removed entirely, with that info appearing in the article's body.

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A compass is a device that shows the geographic cardinal directions used for navigation and orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with magnetic north. Other methods may be used, including gyroscopes, magnetometers, and GPS receivers.

Compasses often show angles in degrees: north corresponds to 0°, and the angles increase clockwise, so east is 90°, south is 180°, and west is 270°. These numbers allow the compass to show azimuths or bearings which are commonly stated in degrees. If local variation between magnetic north and true north is known, then direction of magnetic north also gives direction of true north.

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Your comments? Just plain Bill (talk) 00:15, 17 April 2021 (UTC)

Vast improvement! So that you know, if you didn't already, I basically edit just the leads of certain articles here and at Wiktionary only in instances where I've hyperlinked my textbook to certain definitions. My textbook contains about 498,000 original definitions, but technical ones that invite the need to show a picture (e.g. compass) aren't worth my effort to define myself. Yet, I refuse to hyperlink definitions that have grammatical flaws since my textbook relates to English composition. Quite honestly, I was unhappy with my own mention of "vector" in the lead because - although I STILL think it's accurate - the talk of azimuth and vector and magnetic field, etc. is beyond what most people want to know when glossing the definition of "compass." In fact, I'd changed my textbook's definition from "A compass is a magnetometer..." (who the heck uses magnetometer in everyday life?) to "A compass is a device..." but I'd hyperlinked the definition to Wikipedia nonetheless. So, yes, your draft reflects my thinking. Its second sentence, with "needle" instead of vector, is great. Technically, the needle represents a vector, but - right or wrong - who cares? Normal people say "compass needle" regardless, so good work. --Kent Dominic·(talk) 11:20, 17 April 2021 (UTC)

One slight change: I'd recommend "A compass is a device that shows the cardinal directions used for navigation and geographic orientation." Why? Grammatically speaking, it's inadvisable to accrete attributive items (i.e. geographic cardinal directions) especially when rewording can accomplish a clearer intent. --Kent Dominic·(talk) 11:29, 17 April 2021 (UTC)

P.S. I've just updated my textbook according to that last iteration. MUCH better than anything that came before. --Kent Dominic·(talk) 11:34, 17 April 2021 (UTC)

"shows the cardinal directions... geographic orientation" is an improvement, to be included when this text goes into the article. If nobody else chimes in within the next few days, I intend to make the bold change, and sort things out from there. Just plain Bill (talk) 13:03, 17 April 2021 (UTC)

I don't foresee people lining up to riot over any of this. --Kent Dominic·(talk) 14:14, 17 April 2021 (UTC)

Definition needed

Lensatic compass redirects here, but isn't defined (unless I overlooked something). ZFT (talk) 07:50, 4 September 2024 (UTC)

Would it be acceptable to insert Merriam-Webster's definition into the article? ZFT (talk) 07:55, 4 September 2024 (UTC)

ZFT, it's already in there under the Design section, including a picture of a lensatic compass ^~Hydronium^~Hydroxide^~(Talk)~ 02:27, 21 October 2024 (UTC)

Earth inductor compass

Can somebody add Earth inductor compass to the See Also section? I can't because I seldom login to edit. Confessfletch (talk) 02:19, 21 October 2024 (UTC)

Confessfletch, added to the Variants section ^~Hydronium^~Hydroxide^~(Talk)~ 02:37, 21 October 2024 (UTC)