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Hops

Hops are the flowers (also called seed cones or strobiles) of the hop plant Humulus lupulus, a member of the Cannabaceae family of flowering plants. They are used primarily as a bittering, flavouring, and stability agent in beer, to which, in addition to bitterness, they impart floral, fruity, or citrus flavours and aromas. Hops are also used for various purposes in other beverages and herbal medicine. The hops plants have separate female and male plants, and only female plants are used for commercial production. The hop plant is a vigorous, climbing, herbaceous perennial, usually trained to grow up strings in a field called a hopfield, hop garden (in the South of England), or hop yard (in the West Country and United States) when grown commercially. Many different varieties of hops are grown by farmers around the world, with different types used for particular styles of beer.

The first documented use of hops in beer is from the 9th century, though Hildegard of Bingen, 300 years later, is often cited as the earliest documented source. Before this period, brewers used a "gruit", composed of a wide variety of bitter herbs and flowers, including dandelion, burdock root, marigold, horehound (the old German name for horehound, Berghopfen, means "mountain hops"), ground ivy, and heather. Early documents include mention of a hop garden in the will of Charlemagne's father, Pepin the Short.

Hops are also used in brewing for their antibacterial effect over less desirable microorganisms and for purported benefits including balancing the sweetness of the malt with bitterness and a variety of flavours and aromas. It is believed that traditional herb combinations for beers were abandoned after it was noticed that beers made with hops were less prone to spoilage.

History
The first documented hop cultivation was in 736, in the Hallertau region of present-day Germany, although the first mention of the use of hops in brewing in that country was 1079. However, in a will of Pepin the Short, the father of Charlemagne, hop gardens were left to the Cloister of Saint-Denis in 768.

Not until the 13th century did hops begin to start threatening the use of gruit for flavouring. Gruit was used when the nobility levied taxes on hops. Whichever was taxed made the brewer then quickly switch to the other.

In Britain, hopped beer was first imported from Holland around 1400, yet hops were condemned as late as 1519 as a "wicked and pernicious weed". In 1471, Norwich, England, banned use of the plant in the brewing of ale ("beer" was the name for fermented malt liquors bittered with hops; only in recent times are the words often used as synonyms).

In Germany, using hops was also a religious and political choice in the early 16th century. There was no tax on hops to be paid to the Catholic church, unlike on gruit. For this reason the Protestants preferred hopped beer.

Hops used in England were imported from France, Holland and Germany and were subject to import duty; it was not until 1524 that hops were first grown in the southeast of England (Kent), when they were introduced as an agricultural crop by Dutch farmers. Consequently, many words used in the hop industry derive from the Dutch language. Hops were then grown as far north as Aberdeen, near breweries for convenience of infrastructure.

According to Thomas Tusser's 1557 Five Hundred Points of Good Husbandry:

The hop for his profit I thus do exalt, It strengtheneth drink and it flavored malt; And being well-brewed long kept it will last, And drawing abide, if ye draw not too fast.

In England there were many complaints over the quality of imported hops, the sacks of which were often contaminated by stalks, sand or straw to increase their weight. As a result, in 1603, King James I approved an Act of Parliament banning the practice by which "the Subjects of this Realm have been of late years abused &c. to the Value of £20,000 yearly, besides the Danger of their Healths".

Hop cultivation was begun in the present-day United States in 1629 by English and Dutch farmers. Before prohibition, cultivation was mainly centred around New York, California, Oregon, and Washington state. Problems with powdery mildew and downy mildew devastated New York's production by the 1920s, and California only produces hops on a small scale.

World production
Hops production is concentrated in moist temperate climates, with much of the world's production occurring near the 48th parallel north. Hop plants prefer the same soils as potatoes and the leading potato-growing states in the United States are also major hops-producing areas; however, not all potato-growing areas can produce good hops naturally: soils in the Maritime Provinces of Canada, for example, lack the boron that hops prefer. Historically, hops were not grown in Ireland, but were imported from England. In 1752 more than 500 tons of English hops were imported through Dublin alone.

Important production centres today are the Hallertau in Germany, the Žatec (Saaz) in the Czech Republic, the Yakima (Washington) and Willamette (Oregon) valleys, and western Canyon County, Idaho (including the communities of Parma, Wilder, Greenleaf, and Notus). The principal production centres in the UK are in Kent (which produces Kent Goldings hops), Herefordshire, and Worcestershire. Essentially all of the harvested hops are used in beer making.

Cultivation and harvest

Although hops are grown in most of the continental United States and Canada, cultivation of hops for commercial production requires a particular environment. As hops are a climbing plant, they are trained to grow up trellises made from strings or wires that support the plants and allow them significantly greater growth with the same sunlight profile. In this way, energy that would have been required to build structural cells is also freed for crop growth.

The hop plant's reproduction method is that male and female flowers develop on separate plants, although occasionally a fertile individual will develop which contains both male and female flowers. Because pollinated seeds are undesirable for brewing beer, only female plants are grown in hop fields, thus preventing pollination. Female plants are propagated vegetatively, and male plants are culled if plants are grown from seeds.

Hop plants are planted in rows about 2 to 2.5 m apart. Each spring, the roots send forth new bines that are started up strings from the ground to an overhead trellis. The cones grow high on the bine, and in the past, these cones were picked by hand. Harvesting of hops became much more efficient with the invention of the mechanical hops separator, patented by Emil Clemens Horst in 1909.

Hops are harvested at the end of summer. The bines are cut down, separated, and then dried in an oast house to reduce moisture content. To be dried, the hops are spread out on the upper floor of the oast house and heated by heating units on the lower floor. The dried hops are then compressed into bales by a baler.

Hop cones contain different oils, such as lupulin, a yellowish, waxy substance, an oleoresin, that imparts flavour and aroma to beer. Lupulin contains lupulone and humulone, which possess antibiotic properties, suppressing bacterial growth favoring brewer's yeast to grow. After lupulin has been extracted in the brewing process the papery cones are discarded.

Migrant labor and social impact
The need for massed labor at harvest time meant hop-growing had a big social impact. Around the world, the labor-intensive harvesting work involved large numbers of migrant workers who would travel for the annual hop harvest. Whole families would participate and live in hoppers' huts, with even the smallest children helping in the fields. The final chapters of W. Somerset Maugham's Of Human Bondage and a large part of George Orwell's A Clergyman's Daughter contain a vivid description of London families participating in this annual hops harvest. In England, many of those picking hops in Kent were from eastern areas of London. This provided a break from urban conditions that was spent in the countryside. People also came from Birmingham and other Midlands cities to pick hops in the Malvern area of Worcestershire. Some photographs have been preserved.

The often-appalling living conditions endured by hop pickers during the harvest became a matter of scandal across Kent and other hop-growing counties. Eventually, the Rev. John Young Stratton, Rector of Ditton, Kent, began to gather support for reform, resulting in 1866 in the formation of the Society for the Employment and Improved Lodging of Hop Pickers. The hop-pickers were given very basic accommodation, with very poor sanitation. This led to the spread of infectious diseases and led to contaminated water. The 1897 Maidstone typhoid epidemic was partly as a result of hop-pickers camping near the Farleigh Springs which supplied Maidstone with water.

Particularly in Kent, because of a shortage of small-denomination coin of the realm, many growers issued their own currency to those doing the labor. In some cases, the coins issued were adorned with fanciful hops images, making them quite beautiful.

In the United States, Prohibition had a serious adverse effect on hops production, but remnants of this significant industry in the western states are still noticeable in the form of old hop kilns that survive throughout Sonoma County, California, among others. Florian Dauenhauer, of Santa Rosa in Sonoma County, became a manufacturer of hop-harvesting machines in 1940, in part because of the hop industry's importance to the county. This mechanization helped destroy the local industry by enabling large-scale mechanized production, which moved to larger farms in other areas. Dauenhauer Manufacturing Company remains a current producer of hop harvesting machines.

Chemical composition
In addition to water, cellulose, and various proteins, the chemical composition of hops consists of compounds important for imparting character to beer.

Alpha acids

Probably the most important chemical compound within hops are the alpha acids or humulones. During wort boiling, the humulones are thermally isomerized into iso-alpha acids or isohumulones, which are responsible for the bitter taste of beer.

Beta acids

Hops contain beta acids or lupulones. These are desirable for their aroma contributions to beer.

Essential oils
The main components of hops essential oils are terpene hydrocarbons consisting of myrcene, humulene and caryophyllene. Myrcene is responsible for the pungent smell of fresh hops. Humulene and its oxidative reaction products may give beer its prominent hop aroma. Together, myrcene, humulene, and caryophyllene represent 80 to 90% of the total hops essential oil.

Flavonoids

Xanthohumol is the principal flavonoid in hops. The other well-studied prenylflavonoids are 8-Prenylnaringenin and isoxanthohumol. Xanthohumol is under basic research for its potential properties, while 8-prenylnaringenin is a potent phytoestrogen.

Brewing

Hops are usually dried in an oast house before they are used in the brewing process. Undried or "wet" hops are sometimes (since c. 1990) used.

The wort (sugar-rich liquid produced from malt) is boiled with hops before it is cooled down and yeast is added, to start fermentation.

The effect of hops on the finished beer varies by type and use, though there are two main hop types: bittering and aroma.

Bittering hops have higher concentrations of alpha acids, and are responsible for the large majority of the bitter flavour of a beer. European (so-called "noble") hops typically average 5–9% alpha acids by weight (AABW), and the newer American cultivars typically range from 8–19% AABW.

Aroma hops usually have a lower concentration of alpha acids (~5%) and are the primary contributors of hop aroma and (nonbitter) flavour.

Bittering hops are boiled for a longer period of time, typically 60–90 minutes, and often have inferior aromatic properties, as the aromatic compounds evaporate during the boil. The degree of bitterness imparted by hops depends on the degree to which alpha acids are isomerized during the boil, and the impact of a given amount of hops is specified in International Bitterness Units. On the other hand, unboiled hops are only mildly bitter.

Aroma hops are typically added to the wort later to prevent the evaporation of the essential oils, to impart "hop taste" (if during the final 30 minutes of boil) or "hop aroma" (if during the final 10 minutes, or less, of boil). Aroma hops are often added after the wort has cooled and while the beer ferments, a technique known as "dry hopping", which contributes to the hop aroma. Farnesene is a major component in some hops. The composition of hop essential oils can differ between varieties and between years in the same variety, having a significant influence on flavour and aroma.

Today, a substantial amount of "dual-use" hops are used, as well. These have high concentrations of alpha acids and good aromatic properties. These can be added to the boil at any time, depending on the desired effect. Hop acids also contribute to and stabilize the foam qualities of beer.

Flavours and aromas are described appreciatively using terms which include "grassy", "floral", "citrus", "spicy", "piney", "lemony", "grapefruit", and "earthy". Many pale lagers have fairly low hop influence, while lagers marketed as Pilsener or brewed in the Czech Republic may have noticeable noble hop aroma. Certain ales (particularly the highly hopped style known as India Pale Ale, or IPA) can have high levels of hop bitterness.

Brewers may use software tools to control the bittering levels in the boil and adjust recipes to account for a change in the hop bill or seasonal variations in the crop that may lead to the need to compensate for a difference in alpha acid contribution. Data may be shared with other brewers via BeerXML allowing the reproduction of a recipe allowing for differences in hop availability.

Lately the dried pucks, extracts and pellets replace whole hops in brewing processes because of efficiency and cost.

Breeding programmes
There are many different varieties of hops used in brewing today. Historically, hops varieties were identified by geography, ie. from the towns of Hallertau, Spalt, and Tettnang in Germany, or the region writ large like the Neomexicanus hops of New Mexico. Others were named for the farmer who is recognized as first cultivating them, including Goldings or Fuggles from England, or by their growing habit like the Oregon Cluster.

Around 1900, a number of institutions began to experiment with breeding specific hop varieties. The breeding program at Wye College in Wye, Kent, was started in 1904 and rose to prominence through the work of Prof. E. S. Salmon. Salmon released Brewer's Gold and Brewer's Favorite for commercial cultivation in 1934, and went on to release more than two dozen new cultivars before his death in 1959. Brewer's Gold has become the ancestor of the bulk of new hop releases around the world since its release.

Wye College continued its breeding program and again received attention in the 1970s, when Dr. Ray A. Neve released Wye Target, Wye Challenger, Wye Northdown, Wye Saxon and Wye Yeoman. More recently, Wye College and its successor institution Wye Hops Ltd., have focused on breeding the first dwarf hop varieties, which are easier to pick by machine and far more economical to grow. Wye College have also been responsible for breeding hop varieties that will grow with only 12 hours of daily light for the South African hop farmers. Wye College was closed in 2009 but the legacy of their hop breeding programs, particularly that of the dwarf varieties, is continuing as already the US private and public breeding programs are using their stock material.

Particular hop varieties are associated with beer regions and styles, for example pale lagers are usually brewed with European (often German, Polish or Czech) noble hop varieties such as Saaz, Hallertau and Strissel Spalt. British ales use hop varieties such as Fuggles, Goldings and W.G.V. North American beers often use Cascade hops, Columbus hops, Centennial hops, Willamette, Amarillo hops and about forty more varieties as the US have lately been the more significant breeders of new hop varieties, including dwarf hop varieties.

Hops from New Zealand, such as Pacific Gem, Motueka and Nelson Sauvin, are used in a "Pacific Pale Ale" style of beer with increasing production in 2014.

Noble hops

The term "noble hops" is a marketing term that traditionally refers to certain varieties of hops that became known for being low in bitterness and high in aroma. They are the European cultivars or races Hallertau, Tettnanger, Spalt, and Saaz. Some proponents assert that the English varieties Fuggle, East Kent Goldings and Goldings might qualify as "noble hops" due to the similar composition, but such terms are not applied to English varieties. Their low relative bitterness, but strong aroma, are often distinguishing characteristics of European-style lagers, such as Pilsener, Dunkel, and Oktoberfest/Märzen. In beer, they are considered aroma hops (as opposed to bittering hops); see Pilsner Urquell as a classic example of the Bohemian Pilsener style, which showcases noble hops.

As with grapes, the location where hops are grown affects the hops' characteristics. Much as Dortmunder beer may within the EU be labelled "Dortmunder" only if it has been brewed in Dortmund, noble hops may officially be considered "noble" only if they were grown in the areas for which the hop varieties (races) were named.

 * Hallertau or Hallertauer – The original German lager hop; named after Hallertau or Holledau region in central Bavaria. Due to susceptibility to crop disease, it was largely replaced by Hersbrucker in the 1970s and 1980s. (Alpha acid 3.5–5.5% / beta acid 3–4%)
 * Spalt – Traditional German noble hop from the Spalter region south of Nuremberg. With a delicate, spicy aroma. (Alpha acid 4–5% / beta acid 4–5%)
 * Tettnang – Comes from Tettnang, a small town in southern Baden-Württemberg in Germany. The region produces significant quantities of hops, and ships them to breweries throughout the world. Noble German dual-use hop used in European pale lagers, sometimes with Hallertau. Soft bitterness. (Alpha acid 3.5–5.5% / beta acid 3.5–5.5%)
 * Žatec (Saaz) – Noble hop, named after Žatec town, used extensively in Bohemia to flavour pale Czech lagers such as Pilsner Urquell. Soft aroma and bitterness. (Alpha acid 3–4.5% /Beta acid 3–4.5%)

Noble hops are characterized through analysis as having an aroma quality resulting from numerous factors in the essential oil, such as an alpha:beta ratio of 1:1, low alpha-acid levels (2–5%) with a low cohumulone content, low myrcene in the hop oil, high humulene in the oil, a ratio of humulene:caryophyllene above three, and poor storability resulting in them being more prone to oxidation. In reality, this means they have a relatively consistent bittering potential as they age, due to beta-acid oxidation, and a flavor that improves as they age during periods of poor storage.

Other uses

In addition to beer, hops are used in herbal teas and in soft drinks. These soft drinks include Julmust (a carbonated beverage similar to soda that is popular in Sweden during December), Malta (a Latin American soft drink) and kvass. Hops can be eaten; the young shoots of the vine are edible and can be cooked like asparagus.

Hops may be used in herbal medicine in a way similar to valerian, as a treatment for anxiety, restlessness, and insomnia. A pillow filled with hops is a popular folk remedy for sleeplessness, and animal research has shown a sedative effect. The relaxing effect of hops may be due, in part, to the specific degradation product from alpha acids, 2-methyl-3-buten-2-ol, as demonstrated from nighttime consumption of non-alcoholic beer. 2-methyl-3-buten-2-ol is structurally similar to tert-amyl alcohol which was historically used as an anesthetic. Hops tend to be unstable when exposed to light or air and lose their potency after a few months' storage.

Hops are of interest for hormone replacement therapy and are under basic research for potential relief of menstruation-related problems.

Toxicity
Dermatitis sometimes results from harvesting hops. Although few cases require medical treatment, an estimated 3% of the workers suffer some type of skin lesions on the face, hands, and legs. Hops are toxic to dogs.

Fiction
Hops and hops picking form the milieu and atmosphere in the British detective novel, Death in the Hopfields (1937) by John Rhode. The novel was subsequently issued in the United States under the title The Harvest Murder.

title: Hops


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Talk:Historical linguistics/Archive 1

Holger Pedersen invented the term Nostratic in 1903, although one source said 1931.

Google Search: holger pedersen nostratic Address: http://www.google.com/search?q=holger+pedersen+nostratic Historical linguistics also describes the changes that have taken place within individual languages and, at times, reconstruction of missing words and forms.

The Nostratic hypothesis was first proposed in Holger Pedersen's 1931's book ''The Discovery of Language: Linguistic Science in the 19th Century", of which I own a copy. The relevant section starts on page 334 in my edition (1st Ed., Harvard University Press). -- Paul Drye

 * Wup, never mind. I looked in the bibliography of it and found he was quoting himself in an earlier reference -- 1903 it was after all. -- Paul Drye

Sinai vs Yemen
"Additionally, it contradicts genetic evidence that suggests the first humans migrated from the Horn of Africa into Yemen, rather than across the Sinai peninsula." How so? As the article stands, that looks to me like a complete non sequitur. - Mustafaa 06:08, 29 Apr 2004 (UTC)
 * Seconded the question -- how so? Jorge Stolfi 05:11, 4 May 2004 (UTC)

Perhaps because the Horn of Africa was once connected with the Arabian peninsula and Yemen, before ancient geologic events (Red Sea spreading, creation of great rift valley, etc.)? But I can't say what the writer meant. I thought those events were supposed to have happened long before "humans" in their present form evolved. 172.165.13.58

Historical linguistics is not philology
It strikes me as odd to make this a redirect to Philology. --Brion

Agreed. Stephen C. Carlson

English language
What about English- its history hasn't been mentioned...
 * Uh, it has been on the English page. I don't think there is a particular need do discuss the history of English on this page. Although examples drawn from the history of English would be an excellent way to improve the article.

Wesley Holt, June 2007.

Merge with "Historical-comparative linguistics"
There is another page Historical-comparative linguistics which seems like it should be merged with this one. Anyone disagree? Dduck 12:28, 13 Nov 2003 (UTC)

I agree. Opus33 19:18, 13 Nov 2003 (UTC)

They're now together. At last! ;) Dduck 09:52, 14 Nov 2003 (UTC)

Validation
''Use of the comparative method is validated by its application to languages whose common ancestor is known. Thus, when the method is applied to the Romance languages (which include French, Spanish, Portuguese, Italian, and Romanian), the reconstructed common ancestor language comes out rather similar to Latin--not the classical Latin of Horace and Cicero, but something perhaps more akin to the Latin that must have been spoken in various dialects during the Dark Ages, following the breakup of the Roman Empire. ''

what is this? Spoken Latin was different from the written latin. Since allways!!! There was a latin that was spoken, and a latin that was written both were used in the today's latin countries and IN ROME! just, the spoken latin suffered local chanches. And the "classical" latin were also official. At least in Portugal classical latin was the officially used language till 1290!Pedro 01:10, 16 Mar 2004 (UTC)
 * IIRC, the divergence between spoken and written latin is attested only by the end of the 1st century BC, when the Roman empire and the city had already grown much beyond the original town, where classical Latin was born. It seems highly unlikely that the written language differed from the spoken language in the 4th century BC, when Rome was just a small kingdom. Moreover, the "Latin" that gave origin to Romance was the language of the Roman army, which was largely made up of people who were not native of Rome. So it was probably some sort of lingua franca that Scythian soldiers could use to talk to Iberian soldiers; distinct not only from the classical written Latin, but also from the Latin spoken in Rome. Jorge Stolfi 17:38, 24 January 2006 (UTC)

The 10,000 year limit
You know, it occurs to me that the only way I can think of to justify a bald claim like that there will be no detectable similarities after 10,000 years is glottochronology, which is rightly pretty discredited. Is that where this claim comes from, or does someone know of a different argument for it? - Mustafaa 06:49, 29 Apr 2004 (UTC)

Linguistic landscape in 500 years
Please somebody make a page talking about what we will all be speaking in e.g., 500 years.

I.e., will we all be speaking English? No page I can find on Wikipedia discusses what the linguistic landscape will look like in 500 years. Jidanni 21:50, 13 October 2007 (UTC)

Wikipedia is not a crystal ball. --189.31.60.216 (talk) 10:29, 23 March 2008 (UTC)

Monogenesis
"Not all scholars believe that such a language even necessarily existed, since some models of human evolution may allow the independent appearance of human speech in several parts of the world, resulting in several linguistic families with no common ancestral language"

This sounds rather...avant-garde. It's been my impression that no one is really opposed to monogenesis, only that's it's thought to be undemonstrable.

Can anyone provide a cite? If someone has a theory advocating heterogenesis, I should like to hear about it.

Timothy Usher 24 apr 2005

 * Partly my fault.... The previous version of the article (as I undestood it) said simply that the *existence* of a common ancestor to all languages was not universally accepted by linguists.  I tried to clarify that statement, and the only alternative to monogenesis I could think of was multigenesis. I know that the same issue exists with regards to the origin of modern Homo sapiens. The mainstream theory is that the species appeared in Africa, as a small population, then spread to the entire world, overwhelming other preexisting Homo-like species that got there in previous eras. But there are those who believe that the older species evolved in parallel throughout the world into modern Homo sapiens, by gradual gene diffusion.  For these scientists, there is no "common ancestral population" to all mankind --- at least not a Homo sapiens population. I just presumed that the "non-monogenetic" theory of language evolution was similar. Greenberg's number presumably comes from the monogenetic theory of modern humans' evolution and the assumption that the ancestral tribe of all modern humans already had language.  In that case he probably got the date wrong; IIRC the current estimate is closer ot 100,000 years ago.  Of couse no one knows when language was "invented", but it seems a reasonable bet that it is at least as old as modern humans. Jorge Stolfi 17:38, 24 January 2006 (UTC)

 * Well, there is still monogenesis under the candelabra theory, it's just that the root node is Homo Erectus. The real question there is, how much similarity is due to horizontal factors, how much to vertical descent?  And to that degree, is the heirarchal model of descent appropriate?  Some linguists do have similar inclinations, like Dixon, but that's not really multigenesis (though if anyone will propose this, it will likely be him if not Johanna Nicols).  Multigenesis  asserts several root nodes.  Say, one group heard the other talking and it seemed like a good idea, so they made up a languahe, or just that people came up with it independently, like the Mayan writing system. - Tim

Historical linguistics = comparative linguistics?
Is indeed "historical linguistics" the same thing as "comparative linguistics"? By logic, the latter term should include both diachronic (historical) and synchronic comparative linguistics. Jorge Stolfi 16:39, 8 February 2006 (UTC)

 * There are two problems here. The first is the false equation of comparative and historical linguistics - but comparative linguistics is only about establishing genetic relationships. That would be fairly easy to deal with by rewriting the opening para. But the second problem is that almost the entire content of the page relates solely to comparative linguistics. Perhaps ideally this page should be renamed "Comparative linguistics" and linked from a page on "Historical linguistica", but admittedly that's quite a bit of work. Pfold 17:33, 4 March 2006 (UTC)

Books on comparative linguistics
I was wondering, do anyone here know the best books to buy to get a general overview of comparative linguistics, particularly Indo-European and Afro-Asiatic, and as well as of the current discussions in the field. I've looked around for a number of books, but I'm not sure what the best ones to get are, and the German ones listed doesn't help me too much, as my knowledge of English is far greater than that of German. Any help is accepted. Thanks in advance. Satanael 13:19, 18 February 2006 (UTC)

I would recommend Anthony Arlotto's "Historical Linguistics" for a good general overview. Theodora Bynon's "Historical Linguistics" is more comprehensive but also a much heavier read and assumes a little more in linguistics background. Dixon's "The Rise and Fall of Languages" is a very interesting read but he does directly espouse certain theories and decry others, so it might not be the best start if you're looking for a completely objective overview. Beyond that, I would say that most introductory Linguistics texts (eg. O'Grady and Dobrovolsky) worth their salt give a good general overview of historico-comparative Linguistics. Hope this helps. Susan W

Please, please, can an expert (which excludes me) write a section on recommended readings for beginners? For example, should we recommend Hock, Campell, etc (in addition to the texts mentioned by Susan W). What about introductory books by McWhorter and others? This should be separate from a general bibliography. Also, what are the standard textbooks used in contemporary graduate programs in linguistics? Wesley Holt. 30 June 2007.

Cut comparative material
Since there is now an independent page on comparative linguistics (replacing the old redirect) and there are existing pages on comparative method, glottochronology and mass lexical comparison, I have cut the sections devoted to those topics on this page. Here they are for future reference, and so that appropriate material can be moved to those pages. --Pfold 21:58, 7 April 2006 (UTC)

Language evolution and the comparative method
Languages change over time. What were once dialects of the same language may eventually diverge enough that they are no longer mutually intelligible and can be considered separate languages. One method to illustrate the relationship between such divergent yet related languages is to construct family trees, an idea pioneered by the 19th century historical linguist August Schleicher. The basis for the trees is the comparative method: languages presumed to be related are compared with one another, and linguists look for regular sound correspondences based on what is generally known about how languages can change, and use them to reconstruct the best hypothesis about the nature of the common ancestor language from which the attested languages are descended. Use of the comparative method is validated by its application to languages whose common ancestor is known. Thus, when the method is applied to the Romance languages (which include French, Spanish, Portuguese, Italian, and Romanian), the reconstructed common ancestor language comes out rather similar to Latin — not the classical Latin of Horace and Cicero, but Vulgar Latin, the colloquial Latin spoken in various dialects in the late Roman Empire. The comparative method can be used to reconstruct languages for which no written records exist, either because none have been preserved or because the speakers were illiterate. Thus, the Germanic languages (which include German, Dutch, English, Norwegian, Swedish, Danish, Faroese, Icelandic, Yiddish, and the extinct Gothic) can be compared to reconstruct Proto-Germanic, a language that was probably contemporaneous with Latin and for which no records are preserved. Germanic and Latin (more precisely, Proto-Italic, the ancestor of Latin and a few of its neighbors) are themselves related, being both descended from Proto-Indo-European, spoken perhaps 5000 years ago. Scholars have reconstructed a Proto-Indo-European languae on the basis of data from its nine surviving daughter branches, which are: Germanic, Italic, Celtic, Greek, Baltic, Slavic, Albanian, Armenian, Indo-Iranian, and from the two dead branches Tocharian and Anatolian. The comparative method aims to distinguish so-called genetic linguistic descent — that is, the passing of a language from parents to children, down through the generations — from resemblances that are due to cultural contact between contemporary languages. For example, about 30% of the vocabulary of Persian is taken from Arabic, as a result of the Arab conquest of Iran in the 8th century and much subsequent cultural contact. Yet Persian is considered to be a member of the Indo-European language family — because of its core vocabulary, which generally has Indo-European cognates (as in mâdar = "mother"), and of many characteristically Indo-European features of its grammar (as in bûd = "was", formed from a root related to English "be" and a suffix related to the English past tense ending "-ed".) Once the various changes in the daughter branches have been worked out, and a fair amount of the core vocabulary and grammar of the protolanguage are understood, then scholars will quite generally agree that a relationship of genetic relatedness has been proven.

Non-comparative method theories
Much more controversial are hypotheses about relatedness which are not supported by application of the comparative method. Scholars who attempt to probe deeper than the comparative method supports (for example, by tabulating similarities found by mass lexical comparison without setting up sound correspondences) are often accused of scholarly wishful thinking. The problem is that any two languages have a huge number of opportunities to resemble one another just by accident, so merely pointing out isolated resemblances has little evidentiary value. A famous example is the Persian word for "bad", which is pronounced (more or less) just like English "bad". It can be shown that the resemblance between these two words is completely accidental, and has nothing to do with the (rather remote) genetic connection between English and Persian. For further examples, see False cognate. The idea is that this linguistic "noise" may be reduced by comparing large amounts of words, which is exactly the point of mass lexical comparison. However, by ignoring known historical changes in the languages, mass lexical comparison incorporates known randomness, and therefore its conclusions are inherently inaccurate to an extent that is impossible to assess. Since supporting distant genetic relationships is so difficult, and the method for finding and proving such relationships is not well established (in the way that the comparative method is), the field of locating remote relationships is riven with scholarly controversy. Nevertheless, the temptation to pursue remote relationships remains a powerful lure to many scholars-- after all, Proto-Indo-European must have seemed a rather wild hypothesis to many when it was first proposed. This uncertainty also relates to estimates of how long it would take for languages to diverge completely. One commonly cited opinion is that if a group of people were sent to a distant galaxy, after 10,000 years they would be speaking a language that would be no more similar to their native language than any other language selected at random. This figure is based on glottochronology, using a simplified assumption of a constant 14% loss rate each millennium and a chance similarity rate of 5%. However, other work by Isidore Dyen and Sergei Starostin indicates that in fact words have wildly differing expected life spans; thus, for instance, a specialized word like "goshawk" might on average last a mere millennium or two, whereas extremely common words like "I" and "you" often last so long that it is not possible to even estimate their life span without reconstructions going further back in time than those that are universally accepted. The ultimate in remote reconstruction is the recovery of a Proto-World language. Not all scholars believe that such a language even necessarily existed, since some models of human evolution may allow the independent appearance of human speech in several parts of the world, resulting in several linguistic families with no common ancestral language. Nevertheless, Joseph Greenberg suggested that Proto-World was the language of people coming out of northeast Africa around 50,000 BC. On the other hand, according to current archaeological evidence, the native languages of South America must have been isolated from those of the Old World for 10,000 years or more; and those of Australia may have split off from the putative world language tree even earlier than that. Therefore, if one accepts the estimate that no relationships would be recognizable after 10,000 years, then we stand little chance of demonstrating a common origin for all the world languages — unless, against current expectations, they all had a common ancestor within that time span. Dené-Caucasian has also been postulated to include Na-Dené (North America), Sino-Tibetan, Ket (Siberia), Burushaski (Pakistan), North-East Caucasian (Chechen and the Dagestan languages), and Basque. This language family is extremely hypothetical. The Nostratic hypothesis was proposed by a Dane named Holger Pedersen, in 1903. The hypothesis claims that the Nostratic grouping includes such widely ranging language families as Indo-European, Afro-Asiatic, Uralic, Altaic, Sumerian, Elamo-Dravidian, and Kartvelian. Others claim other sets of languages. Some have speculated that the Nostratics were refugees from a Black Sea Flood of around 5600 BC, and some think this is the origin of Noah's Flood from the Bible. However, linguists have reached no firm conclusion about the validity of the Nostratic hypothesis. Its proponents, unlike Greenberg, use the traditional comparative method; however, their comparisons are often accused of being far-fetched or involving too many semantic shifts, while some also accuse them of simply grouping together the language families most familiar to them and neglecting to compare each of them to language families further afield.

Mass comparison etc.
I have rewritten the paragraph that mentions alternatives to the comparative method because the previous version treated such techniques as later developments intended to overcome limitations of the comparative method when in fact these techniques are the remnants of prescientific historical linguistics.Bill 06:49, 15 May 2006 (UTC)

Tower of Babel
Why is there no section here on the Tower of Babel?--Filll 03:17, 19 January 2007 (UTC)
 * Because it has nothing to do with the modern discipline of historical linguistics --Pfold 08:31, 19 January 2007 (UTC)

But why do you guys not get attacked by the rabid biblical literalists on here like some other articles?--Filll 15:01, 19 January 2007 (UTC)
 * Well, it doesn't seem to specifically reject a Babal-like event as far as this article is concerned, its not very detailed though. Homestarmy 15:12, 19 January 2007 (UTC)

You know though what historical linguistics teaches dont you? It completely violates the Tower of Babel account !--Filll 15:54, 19 January 2007 (UTC)
 * Reading this article, I get the sense historical linguistics is less certain about things than most other fields when things go farther back in time. Homestarmy 16:19, 19 January 2007 (UTC)

It is a bit tougher to get good data, of course. When you go back before written languages, things get even more difficult.--Filll 16:31, 19 January 2007 (UTC)
 * And there are so many languages about which there is little knowledge. My favorite are language isolates, about which there are lot of really good speculation, but no good theories.  I especially loved the one that tied Basque, Na-Dene and Caucasian (that would be the language of Caucasus region) together.  When you get this kind of information, the Tower of Babel may not be a bad metaphor for all of this.  But in 100 years, everyone will be speaking English, and then what happens?  The end of the world?  :)  Orangemarlin 16:45, 19 January 2007 (UTC)

 * I have always been fascinated with the purported link between Finnish, Hungarian (Magyar) and Ainu.--Filll 17:40, 19 January 2007 (UTC)
 * The link between Finnish and Hungarian is pretty much certain. Much less certain is any link between those languages and Ainu. Or any languages and Ainu, for that matter. --86.138.30.7 (talk) 06:22, 1 November 2008 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Historical linguistics/Archive 1


text:
Hack

Hack may refer to:

Games

 * Hack (Unix video game), a 1984 roguelike video game
 * .hack (video game series), a series of video games by the multimedia franchise .hack

Music

 * Hack (album), a 1990 album by Information Society

Film

 * Hack!, a 2007 film starring Danica McKellar
 * Hacked (film), a 2011 Bollywood thriller film
 * The Den (2013 film), a 2013 American film also known as Hacked

Other uses in arts, entertainment, and media

 * Hack (comedy), a joke that is considered obvious, frequently used, or stolen
 * Hack (comics), a Marvel Comics Universe mutant character
 * Hack (radio program), an Australian current affairs program
 * Hack (TV series), an American television series
 * .hack, a Japanese multimedia franchise
 * Lifehacker, a weblog about life hacks and software

Computing

 * Hack (computer science), an inelegant but effective solution to a computing problem
 * Hack (computer security), to break into computers and computer networks
 * Hack (programming language), a programming language developed by Meta
 * HACK (tag), a possible tag in a comment in programming
 * Hack (typeface), an open source typeface designed for source code editing
 * Domain hack, a domain name that suggests a word, phrase, or name

Animals

 * Hack (falconry), training method for young falcons
 * Hack (horse), an animal used for pleasure riding, as well as the verb form (hacking, to hack) for the activity

Sports

 * Hack, a piece of equipment used for traction in the sport of curling
 * Hack, a goal in a game of hacky sack, or the footbag circle kicking game
 * Hack squat, a variant of the squat exercise

Transport

 * Hack, a motorcycle with a sidecar attached
 * Hack, an illegal taxicab operation
 * Hackney carriage, a London cab also known as a hack

Other uses

 * Hack (masonry), a row of stacked unfired bricks protected from the rain
 * Hack (name), a surname, given name and nickname
 * Hack Circle, an amphitheatre in Christchurch, New Zealand, also known as Hack
 * Hack writer or hack, a writer or journalist who produces low-quality articles or books
 * Eduard Hackel (standard author abbreviation: Hack.) (1850–1926), Austrian botanist
 * Life hack, productivity techniques used by programmers to solve everyday problems
 * MIT hack, a clever, benign, and ethical prank or practical joke at the Massachusetts Institute of Technology
 * Political hack, a person who devotes him/herself to party-political machinations
 * Backslash, also known as hack

title: Hack


text:
Huey, Dewey, and Louie

Huey, Dewey, and Louie are triplet cartoon characters created by storyboard artist (screenwriter) Carl Barks for The Walt Disney Company from an idea proposed by cartoonist Al Taliaferro. They are the nephews of Donald Duck and the grand-nephews of Scrooge McDuck. Like their maternal uncles, the brothers are anthropomorphic white ducks with yellow-orange bills and feet. The boys are sometimes distinguished by the color of their shirts and baseball caps (with Huey wearing red, Dewey wearing blue, and Louie wearing green). They appeared in many Donald Duck animated shorts, as well as in the television show DuckTales and its reboot, but the comics remain their primary medium.

While the boys were originally created as troublemakers to provoke Donald's famous easily-triggered temper, in later appearances, beginning especially in the comic books stories by Carl Barks, they are shown growing to be heroes in their own right and valuable assets to him and Uncle Scrooge on their adventures. All three of the triplets are members of a fictional scouting organization called the Junior Woodchucks.

Origins

Al Taliaferro, the artist for the Silly Symphony comic strip, proposed the idea for the film Donald's Nephews, so that the studio would have duck counterparts to Morty and Ferdie Fieldmouse, the nephews of Mickey Mouse. The Walt Disney Productions Story Dept. on February 5, 1937, sent Taliaferro a memo recognizing him as the source of the idea for the planned short.

The memo indicated, “we have decided to actually put a story crew to work on Donald’s Nephews.” With the short already in production more than eight months before the boys' Silly Symphonies comic strip debut (on October 17, 1937), the animation studio's model sheet and storyline would have been Taliaferro and writer Ted Osborne's frame of reference for the comic strip. Because the strip was an adaptation of the animated shorts, it could utilize ideas from films still in production (DuckTales reversed this, being a TV adaptation of the comics). Similarly, Barks' Junior Woodchuck prototype, Good Scouts, was released three months after identical scouting uniforms were introduced by Taliaferro and Bob Karp in the comic strip.

The nephews being triplets who finished each others' sentences was developed by Carl Barks, the screenwriter of Donald's Nephews, for whom Happy Hooligan, a comic strip that featured such triplets, was a childhood influence. This characteristic appeared for the first time at the end of the film, as the boys parted with Donald. In the comic strip, it was first implemented a week after the film's release.

The nephews' names were devised by Disney gag man Dana Coty, who took them from Huey Long, Thomas Dewey, and Louis Schmitt, a Disney Studio animator. In translation, the nephews' names often follow the repetition (parachesis) of their names in English, for example, Tupu, Hupu and Lupu (Finnish) and Hyzio, Dyzio and Zyzio (Polish).

Character background
Huey, Dewey, and Louie are the sons of Donald's sister Della Duck; in Donald's Nephews, their mother is instead named Dumbella. In the original theatrical shorts, they were originally sent to visit Donald for only one day; in the comics, the three were sent to stay with Donald on a temporary basis, until their father came back from the hospital (the boys ended up sending him there after a practical joke of putting firecrackers under his chair). In both the comics and animated shorts, the boys' parents were never heard from or mentioned again after these instances, with the boys ending up permanently living with Donald. All four of them live in the fictional city of Duckburg, in the fictional state of Calisota.

In the theatrical shorts, Huey, Dewey, and Louie often behave in a rambunctious and mischievous manner, and they sometimes commit retaliation or revenge on Donald. In the early Barks comics, the ducklings were still wild and unruly, but their character improved considerably due to their membership in the Junior Woodchucks and the good influence of Grandma Duck. As the boys mature, they prefer to assist Donald and Scrooge in the adventure at hand.

Colors of Huey, Dewey, and Louie's outfits

In early comic books and shorts, the caps of Huey, Dewey, and Louie were colored randomly, depending on the whim of the colorist. On a few occasions until 1945 and most cartoons shortly afterward, all three nephews wore identical outfits (most commonly red).

It was not until the 1980s when it became established that Huey is dressed in pink then in 1982 changed to red, Dewey in black then in 1982 changed to blue, and Louie in brown then in 1982 changed to green. Disney's archivist Dave Smith, in "Disney A to Z", said, "Note that the brightest hue of the three is red (Huey), the color of water, dew, is blue (Dewey), and that leaves Louie, and leaves are green (Louie)."

A few random combinations appear in early Disney merchandise and books, such as orange and yellow. Another combination that shows up from time to time is Huey in blue, Dewey in green, and Louie in red. In-story, this inconsistency is explained away as a result of the ducklings borrowing each other's clothes. The trio have often been depicted wearing indistinguishable black shirts (or the same dark color).

The Don Rosa story An Eye for Detail was based around Donald spending so much time trying to tell his three nephews apart that he developed a heightened sense of sight.

Voices
Clarence Nash, Donald's voice actor, voiced the nephews in the cartoon shorts, making their voices just as duck-like (and thereby difficult to understand) as Donald's. Huey, Dewey, and Louie were all voiced by Russi Taylor in DuckTales. In Quack Pack, they were voiced by Jeannie Elias, Pamela Segall, and Elizabeth Daily, respectively. Tony Anselmo voiced the characters in Down and Out with Donald Duck (1987), Mickey Mouse Works, House of Mouse, and the Have a Laugh! shorts, while Taylor continued voicing the trio in other projects, such as the video games, Donald Duck: Goin' Quackers and Mickey's Speedway USA, and the direct-to-video films Mickey's Once and Twice Upon a Christmas. Taylor also reprised her role as the nephews in the DuckTales: Remastered video game and the post-2013 Mickey Mouse shorts until her death in 2019. Danny Pudi, Ben Schwartz, and Bobby Moynihan voiced the trio in the 2017 DuckTales reboot.

Phooey Duck
On a few occasions, an artist by error drew four nephews and the error was published. This fourth nephew has been named Phooey Duck by Disney comic editor Bob Foster.

The six-page Danish Egmont-licensed Disney comic Much Ado About Phooey (1999), plotted by Lars Jensen, written by Jack Sutter and drawn by Tino Santanach Hernandez, used Phooey as a character and explained Phooey's sporadic appearances as a freak incident of nature. (The text in the two speech balloons says "It is a fourth nephew! An exact copy of the others! / Yes, it's probably best that I explain".) Phooey also made a cameo appearance in the 2017 DuckTales animated series episode, "A Nightmare on Killmotor Hill!", during a dream sequence.

Comics
In the comics, Huey, Dewey, and Louie often play a major role in most stories involving either their "Unca Donald" or great-uncle Scrooge McDuck, accompanying them on most of their adventures. Originating in the comics is the boys' membership in the Boy Scouts of America-like organization, the Junior Woodchucks, including their use of the Junior Woodchucks Guidebook, a fantastically exhaustive field guide containing information on science, history and survival skills. This youth organization, which has twin goals of preserving knowledge and protecting the environment, was instrumental in transforming the three brothers from "little hellions" to upstanding young ducks.

In Disney comic writer Don Rosa's continuity, Huey, Dewey, and Louie Duck were born around 1940 in Duckburg. In his award-winning epic series, Life and Times of Scrooge McDuck, Rosa reveals the domestic pain felt by the boys' loss of their parents. When Scrooge first meets Donald and his nephews, he says: "I'm not used to relatives, either! The few I had seem to have... disappeared!" Huey, Dewey, and Louie respond: "We know how that feels, Unca Scrooge!"

In Some Heir Over the Rainbow by Carl Barks, Huey, Dewey, and Louie, along with Donald Duck and Gladstone Gander, are tested by Scrooge McDuck, who wants to pick an heir to his fortune. Using the legend of a pot of gold at the end of a rainbow, Scrooge secretly gives the nephews, Donald and their cousin each $1,000 to invest. Donald uses his money for a down payment of a new car, now being $1,000 in debt. Gladstone, considering himself too lucky to need the money this soon, hides the money for when and if he needs it, causing Scrooge to consider him a better option than Donald. Huey, Dewey, and Louie lend their money to a man who claims to need the money to search for a treasure. Initially thinking they were tricked out of the money, Scrooge actually considers leaving his fortune to Gladstone, even though he sees that as "an awful injustice to the world", but the man actually finds the treasure and pays the kids back. Scrooge makes Huey, Dewey, and Louie his heirs. It seems to be the most solidly canon indication of Scrooge's plans.

In a 1994 interview, Erik Svane asked Barks who would inherit Scrooge's money. Barks' response was "Probably Donald's nephews." Svane further queried, "Why would Huey, Dewey and Louie receive it?" Barks: "Oh, well, because they are so much more practical than Donald. In the later stories, as I developed those duck people and the whole community of Duckburg and all of its problems, I began giving those kids much more intelligence than anybody else in Duckburg. And so, I guess that when Uncle Scrooge passes on, he will leave all of his money to his three nephews. And I'm sure they will do a lot of good in the world, their Junior Woodchucks organization. They will save all the birds and all the whales."

Television
Huey, Dewey, and Louie starred in the 1987 animated television series DuckTales, in which they went on adventures with their great-uncle, Scrooge McDuck, after their "Unca Donald" left them with him to enlist in the U.S. Navy. The boys' personalities in this series were mainly based on their comic book appearances versus the theatrical shorts. In the 1996 series Quack Pack, the three were portrayed as teenagers and given distinct personalities, with Huey serving as the group's leader, Dewey as a computer whiz, and Louie as a sports enthusiast. After Quack Pack, the boys were reverted to their original ages for most appearances, including the 1999 series Mickey Mouse Works. An exception was the 2001 series House of Mouse, in which they served as the house band in a variety of different styles (most commonly as "The Quackstreet Boys").

In the 2017 DuckTales series, the brothers are once again given distinct designs, voices, and personalities: Huey is intelligent and logical, Dewey is adventurous and excitable, and Louie is laid-back and cunning. The boys move to Scrooge's mansion with Donald after Dewey accidentally destroys their houseboat and travel the world on adventures with their uncles. They also have different roles: Huey is a Junior Woodchuck, Dewey likes to go on adventures, and Louie wants to be wealthy like Scrooge, except that he likes to do everything the easy way. This iteration also changed Dewey's real name to Dewford, while making Dingus his middle name, and Louie's real name to Llewellyn. In the second season, the boys are reunited with their long-lost mother Della, who reveals she intended to name them "Jet (Huey), Turbo (Dewey), and Rebel (Louie)" before she disappeared, after which Donald named them instead.

Video games
Huey, Dewey and Louie have been given many appearances in video games over the years, starting with DuckTales (1989), a popular NES game based on the show, wherein they aid their Uncle Scrooge in finding treasure. The game also got a remaster in 2013.

In The Lucky Dime Caper (1991) for Sega's Game Gear and Master System, the nephews are kidnapped by Magica De Spell. Donald must find Scrooge's lucky dime and barter for their safety. The trio also appear in the Sega Genesis and Sega Saturn game, Quackshot (1991), piloting Donald's plane as he travels the world in search of a lost treasure. The object of Disney's Magical Quest 3 Starring Mickey & Donald (1995), for Super Famicom (Japan) and Game Boy Advance, is to rescue the nephews from the clutches of the villainous King Pete.

Donald Duck: Goin' Quackers (2000) was released for many gaming systems. The boys aid Donald to bat Gladstone in rescuing Daisy Duck, while he also rescues their hexed play toys. The nephews appear as unlockable playable characters in Mickey's Speedway USA (2000) for Nintendo 64. In Dance Dance Revolution: Disney Mix (2000), that premiered as an arcade game in Japan and afterward on PlayStation and as a Plug-and-Play handheld TV game, they appear as DJ's for certain music tracks. They are playable characters in Disney Magic Kingdoms (2016), a Disney Parks themed game for iOS, Android and Windows.

Kingdom Hearts
Huey, Dewey, and Louie have recurring roles as shopkeepers in the Kingdom Hearts video game series. In the first entry (2002), the trio work in the item shop in the First District of Traverse Town. In Kingdom Hearts II (2005), they individually run an item shop (Huey), an accessory shop (Dewey), and a weapon shop (Louie) in Hollow Bastion/Radiant Garden. In both games' endings, they are seen returning to Disney Castle.

Kingdom Hearts: Birth By Sleep (2010) features the nephews in Disney Town, recreating Ice Cream flavors, this time with a speaking role. Kingdom Hearts Coded (2008) also has Huey, Dewey, and Louie in Traverse Town, much like the first game. The three nephews were investigating the strange block phenomena occurring in their world which also resided inside Jiminy's journal. In Kingdom Hearts χ (2013), they are displayed on special Support medals that grant the player's other medals a set number of experience points based on the medal's star value. They appear in the Tram Common area of Twilight Town in Kingdom Hearts III (2019), where they each take turns running the gummi shop. In all of their Kingdom Hearts appearances, the nephews look similar to their appearance in the original DuckTales.

Parks and attractions
Huey, Dewey and Louie have made numerous appearances at Disney theme parks.

Tokyo Disney
The nephews appeared in seasonal parades during Easter, Halloween and Christmas 2011 after a long absence. They also appeared in the Countdown Party Parade 2011.

Disneyland Paris
Huey, Dewey and Louie appear regularly in Paris. They appeared during the Christmas season 2010 in their daytime and nighttime Parades at "Disneyland Paris's Magic Kingdom", Disney's Once Upon a Dream Parade and in the Disney's Fantillusion Parade in glittery outfits. They made another appearance at Disneyland Paris for meet-and-greet at the Disneyland Hotel on April 2, 2011, the day of the Press Event for the launch of the Magical Moments Festival. They also appeared at Disney's Once Upon a Dream Parade at the Disneyland Park in special outfits for the parade and at the Disney's Stars 'n' Cars Parade at the Walt Disney Studios Park in directors outfits.

The nephews appeared at Disneyland Paris's Halloween season 2011. They have their own show during Mickey's Not-So-Scary Halloween Parties at the Disneyland Park in Disneyland Paris, titled Huey, Dewey and Louie's Trick or Treat Party. They also made an appearance for meet-and-greet at Disneyland Paris's "Disney's Halloween Party" on October 31, 2011. They were also part of the Christmas Eve and New Year's Eve 2011–2012 celebrations at the Disneyland Hotel.

Feature films

 * Mickey's Christmas Carol (1983) (cameo)
 * Who Framed Roger Rabbit (1988) (cameo)
 * DuckTales the Movie: Treasure of the Lost Lamp (1990)
 * Mickey's Once Upon a Christmas (1999)
 * Mickey's Magical Christmas: Snowed in at the House of Mouse (2001)
 * Mickey's House of Villains (2002)
 * Mickey's Twice Upon a Christmas (2004)
 * Chip 'n Dale: Rescue Rangers (2022) (cameo)

Television shows and specials

 * Donald Duck Presents (1983)
 * DuckTales (1987)
 * Sport Goofy in Soccermania (1987)
 * Cartoon All-Stars to the Rescue (1990)
 * Quack Pack (1996)
 * Mickey Mouse Works (1999)
 * House of Mouse (2001)
 * Mickey Mouse (2013)
 * DuckTales (2017)
 * The Wonderful World of Mickey Mouse (2020)

Video games

 * DuckTales (1989)
 * The Lucky Dime Caper (1991)
 * Quackshot (1991)
 * Disney's Magical Quest 3 Starring Mickey & Donald (1995)
 * Donald Duck: Goin' Quackers (2000)
 * Mickey's Speedway USA (2000)
 * Dance Dance Revolution: Disney Mix (2000)
 * Kingdom Hearts (2002)
 * Kingdom Hearts II (2005)
 * Kingdom Hearts: Birth By Sleep (2010)
 * DuckTales: Remastered (2013)
 * Kingdom Hearts Unchained (2013)
 * Disney Magic Kingdoms (2016)
 * Kingdom Hearts III (2019)

title: Huey, Dewey, and Louie


text:
Hammurabi

Hammurabi (c. 1810), also spelled Hammurapi, was the sixth Amorite king of the Old Babylonian Empire, reigning from c. 1792 to c. 1750 BC. He was preceded by his father, Sin-Muballit, who abdicated due to failing health. During his reign, he conquered the city-states of Larsa, Eshnunna, and Mari. He ousted Ishme-Dagan I, the king of Assyria, and forced his son Mut-Ashkur to pay tribute, bringing almost all of Mesopotamia under Babylonian rule.

Hammurabi is best known for having issued the Code of Hammurabi, which he claimed to have received from Shamash, the Babylonian god of justice. Unlike earlier Sumerian law codes, such as the Code of Ur-Nammu, which had focused on compensating the victim of the crime, the Law of Hammurabi was one of the first law codes to place greater emphasis on the physical punishment of the perpetrator. It prescribed specific penalties for each crime and is among the first codes to establish the presumption of innocence. They were intended to limit what a wronged person was permitted to do in retribution. The Code of Hammurabi and the Law of Moses in the Torah contain numerous similarities.

Hammurabi was seen by many as a god within his own lifetime. After his death, Hammurabi was revered as a great conqueror who spread civilization and forced all peoples to pay obeisance to Marduk, the national god of the Babylonians. Later, his military accomplishments became de-emphasized and his role as the ideal lawgiver became the primary aspect of his legacy. For later Mesopotamians, Hammurabi's reign became the frame of reference for all events occurring in the distant past. Even after the empire he built collapsed, he was still revered as a model ruler, and many kings across the Near East claimed him as an ancestor. Hammurabi was rediscovered by archaeologists in the late nineteenth century and has since been seen as an important figure in the history of law.

Background and ascension
Hammurabi ascended to the throne as the king of a minor kingdom in the midst of a complex geopolitical situation. Hammurabi was an Amorite First Dynasty king of the city-state of Babylon, and inherited the power from his father, Sin-Muballit, in c. 1792 BC. Babylon was one of the many largely Amorite-ruled city-states that dotted the central and southern Mesopotamian plains and waged war on each other for control of fertile agricultural land. Though many cultures co-existed in Mesopotamia, Babylonian culture gained a degree of prominence among the literate classes throughout the Middle East under Hammurabi. The kings who came before Hammurabi had founded a relatively minor city-state in 1894 BC, which controlled little territory outside of the city itself. Babylon was overshadowed by older, larger, and more powerful kingdoms, such as Elam, Assyria, Isin, Eshnunna, and Larsa for a century or so after its founding. However, his father Sin-Muballit had begun to consolidate rule of a small area of south central Mesopotamia under Babylonian rule and, by the time of his reign, had conquered the minor city-states of Borsippa, Kish, and Sippar.

The powerful kingdom of Eshnunna controlled the upper Tigris River, while Larsa controlled the river delta. To the east of Mesopotamia lay the powerful kingdom of Elam, which regularly invaded and forced tribute upon the small states of southern Mesopotamia. In northern Mesopotamia, the Assyrian king Shamshi-Adad I, who had already inherited centuries-old Assyrian colonies in Asia Minor, had expanded his territory into the Levant and central Mesopotamia, although his untimely death would somewhat fragment his empire.

Reign and conquests
The first few years of Hammurabi's reign were quite peaceful. Hammurabi used his power to undertake a series of public works, including heightening the city walls for defensive purposes, and expanding the temples. The powerful kingdom of Elam, which straddled important trade routes across the Zagros Mountains, invaded the Mesopotamian plain. With allies among the plain states, Elam attacked and destroyed the kingdom of Eshnunna, destroying a number of cities and imposing its rule on portions of the plain for the first time.

In order to consolidate its position, Elam tried to start a war between Hammurabi's Babylonian kingdom and the kingdom of Larsa. Hammurabi and the king of Larsa made an alliance when they discovered this duplicity and were able to crush the Elamites, although Larsa did not contribute greatly to the military effort. Angered by Larsa's failure to come to his aid, Hammurabi turned on that southern power, thus gaining control of the entirety of the lower Mesopotamian plain by c. 1763 BC.

As Hammurabi was assisted during the war in the south by his allies from the north such as Yamhad and Mari, the absence of soldiers in the north led to unrest. Continuing his expansion, Hammurabi turned his attention northward, quelling the unrest. Soon after, he destroyed Eshnunna. Next the Babylonian armies conquered the remaining northern states, including Babylon's former ally Mari, although it is possible that the conquest of Mari was a surrender without any actual conflict.

Hammurabi entered into a protracted war with Ishme-Dagan I of Assyria for control of Mesopotamia, with both kings making alliances with minor states in order to gain the upper hand. Eventually Hammurabi prevailed, ousting Ishme-Dagan I just before his own death. Mut-Ashkur, the new king of Assyria, was forced to pay tribute to Hammurabi.

In just a few years, Hammurabi succeeded in uniting all of Mesopotamia under his rule. The Assyrian kingdom survived but was forced to pay tribute during his reign, and of the major city-states in the region, only Aleppo and Qatna to the west in the Levant maintained their independence. However, one stele (stone monument) of Hammurabi has been found as far north as Diyarbekir, where he claims the title "King of the Amorites".

Vast numbers of contract tablets, dated to the reigns of Hammurabi and his successors, have been discovered, as well as 55 of his own letters. These letters give a glimpse into the daily trials of ruling an empire, from dealing with floods and mandating changes to a flawed calendar, to taking care of Babylon's massive herds of livestock. Hammurabi died and passed the reins of the empire on to his son Samsu-iluna in c. 1750 BC, under whose rule the Babylonian empire quickly began to unravel.

Code of laws
The Code of Hammurabi was a collection of 282 laws dealing with a wide range of issues. It is not the earliest surviving law code but was proved more influential in world politics and international relations as instead of focusing on compensating the victim of crime, as in earlier Sumerian law codes, the Code of Hammurabi instead focused on physically punishing the perpetrator. It was also one of the first law codes to place restrictions on what a wronged person was allowed to do in retribution and one of the earliest examples of the idea of presumption of innocence, suggesting that the accused and accuser have the opportunity to provide evidence. The structure of the code is very specific, with each offense receiving a specified punishment. Many offenses resulted in death, disfigurement, or the use of the Lex Talionis philosophy ("Eye for eye, tooth for tooth").

The Code of Hammurabi was inscribed on a stele and placed in a public place so that all could see it, although it is thought that few were literate. The stele was later plundered by the Elamites and removed to their capital, Susa; it was rediscovered there in 1901 in Iran and is now in the Louvre Museum in Paris. The code of Hammurabi contains 282 laws, written by scribes on 12 tablets. Unlike earlier laws, it was written in Akkadian, the daily language of Babylon, and could therefore be read by any literate person in the city. At this time, Akkadian replaced Sumerian, and Hammurabi began language reforms that would make Akkadian the most common language at this time. A carving at the top of the stele portrays Hammurabi receiving the laws from Shamash, the Babylonian god of justice, and the preface states that Hammurabi was chosen by Shamash to bring the laws to the people.

Because of Hammurabi's reputation as a lawgiver, his depiction can be found in law buildings throughout the world. Hammurabi is one of the 23 lawgivers depicted in marble bas-reliefs in the chamber of the U.S. House of Representatives in the United States Capitol. A frieze by Adolph Weinman depicting the "great lawgivers of history", including Hammurabi, is on the south wall of the U.S. Supreme Court building.

Posthumous commemoration

Hammurabi was honored above all other kings of the second millennium BC and he received the unique honor of being declared to be a god within his own lifetime. The personal name "Hammurabi-ili" meaning "Hammurabi is my god" became common during and after his reign. In writings from shortly after his death, Hammurabi is commemorated mainly for three achievements: bringing victory in war, bringing peace, and bringing justice. Hammurabi's conquests came to be regarded as part of a sacred mission to spread civilization to all nations. A stele from Ur glorifies him in his own voice as a mighty ruler who forces evil into submission and compels all peoples to worship Marduk. The stele declares: "The people of Elam, Gutium, Subartu, and Tukrish, whose mountains are distant and whose languages are obscure, I placed into [Marduk's] hand. I myself continued to put straight their confused minds." A later hymn also written in Hammurabi's own voice extols him as a powerful, supernatural force for Marduk:

I am the king, the brace that grasps wrongdoers, that makes people of one mind, I am the great dragon among kings, who throws their counsel in disarray, I am the net that is stretched over the enemy, I am the fear-inspiring, who, when lifting his fierce eyes, gives the disobedient the death sentence, I am the great net that covers evil intent, I am the young lion, who breaks nets and scepters, I am the battle net that catches him who offends me.

After extolling Hammurabi's military accomplishments, the hymn finally declares: "I am Hammurabi, the king of justice." In later commemorations, Hammurabi's role as a great lawgiver came to be emphasized above all his other accomplishments and his military achievements became de-emphasized. Hammurabi's reign became the point of reference for all events in the distant past. A hymn to the goddess Ishtar, whose language suggests it was written during the reign of Ammisaduqa, Hammurabi's fourth successor, declares: "The king who first heard this song as a song of your heroism is Hammurabi. This song for you was composed in his reign. May he be given life forever!" For centuries after his death, Hammurabi's laws continued to be copied by scribes as part of their writing exercises and they were even partially translated into Sumerian.

Political legacy

During the reign of Hammurabi, Babylon usurped the position of "most holy city" in southern Mesopotamia from its predecessor, Nippur. Under the rule of Hammurabi's successor Samsu-iluna, the short-lived Babylonian Empire began to collapse. In northern Mesopotamia, both the Amorites and Babylonians were driven from Assyria by Puzur-Sin a native Akkadian-speaking ruler, c. 1740 BC. Around the same time, native Akkadian speakers threw off Amorite Babylonian rule in the far south of Mesopotamia, creating the Sealand Dynasty, in more or less the region of ancient Sumer. Hammurabi's ineffectual successors met with further defeats and loss of territory at the hands of Assyrian kings such as Adasi and Bel-ibni, as well as to the Sealand Dynasty to the south, Elam to the east, and to the Kassites from the northeast. Thus was Babylon quickly reduced to the small and minor state it had once been upon its founding.

The coup de grace for the Hammurabi's Amorite Dynasty occurred in 1595 BC, when Babylon was sacked and conquered by the powerful Hittite Empire, thereby ending all Amorite political presence in Mesopotamia. However, the Indo-European-speaking Hittites did not remain, turning over Babylon to their Kassite allies, a people speaking a language isolate, from the Zagros mountains region. This Kassite Dynasty ruled Babylon for over 400 years and adopted many aspects of the Babylonian culture, including Hammurabi's code of laws. Even after the fall of the Amorite Dynasty, however, Hammurabi was still remembered and revered. When the Elamite king Shutruk-Nahhunte I raided Babylon in 1158 BC and carried off many stone monuments, he had most of the inscriptions on these monuments erased and new inscriptions carved into them. On the stele containing Hammurabi's laws, however, only four or five columns were wiped out and no new inscription was ever added. Over a thousand years after Hammurabi's death, the kings of Suhu, a land along the Euphrates river, just northwest of Babylon, claimed him as their ancestor.

A Neo-Babylonian royal inscription, which was intended for display on a stele, commemorates a royal grant of tax exemptions to nine Babylonian cities and presents the royal protagonist as a second Hammurabi.

Relationship to Biblical figures and Mosaic law
In the late nineteenth century, the Code of Hammurabi became a major center of debate in the heated Babel und Bibel ("Babylon and Bible") controversy in Germany over the relationship between the Bible and ancient Babylonian texts. In January 1902, the German Assyriologist Friedrich Delitzsch gave a lecture at the Sing-Akademie zu Berlin in front of the Kaiser and his wife, in which he argued that the Mosaic Laws of the Old Testament were directly copied off the Code of Hammurabi. Delitzsch's lecture was so controversial that, by September 1903, he had managed to collect 1,350 short articles from newspapers and journals, over 300 longer ones, and twenty-eight pamphlets, all written in response to this lecture, as well as the preceding one about the Flood story in the Epic of Gilgamesh. These articles were overwhelmingly critical of Delitzsch, though a few were sympathetic. The Kaiser distanced himself from Delitzsch and his radical views and, in fall of 1904, Delitzsch was forced to give his third lecture in Cologne and Frankfurt am Main rather than in Berlin. The putative relationship between the Mosaic Law and the Code of Hammurabi later became a major part of Delitzsch's argument in his 1920–21 book Die große Täuschung (The Great Deception) that the Hebrew Bible was irredeemably contaminated by Babylonian influence and that only by eliminating the human Old Testament entirely could Christians finally believe in the true, Aryan message of the New Testament. In the early twentieth century, many scholars believed that Hammurabi was Amraphel, the King of Shinar in the Book of Genesis 14:1. This view has now been largely rejected, and Amraphel's existence is not attested in any writings from outside the Bible.

Parallels between this narrative and the giving of the Covenant Code to Moses by Yahweh atop Mount Sinai in the Biblical Book of Exodus and similarities between the two legal codes suggest a common ancestor in the Semitic background of the two. Nonetheless, fragments of previous law codes have been found and it is unlikely that the Mosaic laws were directly inspired by the Code of Hammurabi. Some scholars have disputed this; David P. Wright argues that the Jewish Covenant Code is "directly, primarily, and throughout" based upon the Laws of Hammurabi. In 2010, a team of archaeologists from Hebrew University discovered a cuneiform tablet dating to the eighteenth or seventeenth century BC at Hazor in Israel containing laws clearly derived from the Code of Hammurabi.

title: Hammurabi


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Huygens–Fresnel principle

The Huygens–Fresnel principle (named after Dutch physicist Christiaan Huygens and French physicist Augustin-Jean Fresnel) states that every point on a wavefront is itself the source of spherical wavelets, and the secondary wavelets emanating from different points mutually interfere. The sum of these spherical wavelets forms a new wavefront. As such, the Huygens-Fresnel principle is a method of analysis applied to problems of luminous wave propagation both in the far-field limit and in near-field diffraction as well as reflection.

History
In 1678, Huygens proposed that every point reached by a luminous disturbance becomes a source of a spherical wave; the sum of these secondary waves determines the form of the wave at any subsequent time. He assumed that the secondary waves travelled only in the "forward" direction, and it is not explained in the theory why this is the case. He was able to provide a qualitative explanation of linear and spherical wave propagation, and to derive the laws of reflection and refraction using this principle, but could not explain the deviations from rectilinear propagation that occur when light encounters edges, apertures and screens, commonly known as diffraction effects. The resolution of this error was finally explained by David A. B. Miller in 1991. The resolution is that the source is a dipole (not the monopole assumed by Huygens), which cancels in the reflected direction.

In 1818, Fresnel showed that Huygens's principle, together with his own principle of interference, could explain both the rectilinear propagation of light and also diffraction effects. To obtain agreement with experimental results, he had to include additional arbitrary assumptions about the phase and amplitude of the secondary waves, and also an obliquity factor. These assumptions have no obvious physical foundation, but led to predictions that agreed with many experimental observations, including the Poisson spot.

Poisson was a member of the French Academy, which reviewed Fresnel's work. He used Fresnel's theory to predict that a bright spot ought to appear in the center of the shadow of a small disc, and deduced from this that the theory was incorrect. However, Arago, another member of the committee, performed the experiment and showed that the prediction was correct. (Lisle had observed this fifty years earlier. ) This was one of the investigations that led to the victory of the wave theory of light over then predominant corpuscular theory.

In antenna theory and engineering, the reformulation of the Huygens–Fresnel principle for radiating current sources is known as surface equivalence principle.

Huygens' principle as a microscopic model
The Huygens–Fresnel principle provides a reasonable basis for understanding and predicting the classical wave propagation of light. However, there are limitations to the principle, namely the same approximations done for deriving the Kirchhoff's diffraction formula and the approximations of near field due to Fresnel. These can be summarized in the fact that the wavelength of light is much smaller than the dimensions of any optical components encountered.

Kirchhoff's diffraction formula provides a rigorous mathematical foundation for diffraction, based on the wave equation. The arbitrary assumptions made by Fresnel to arrive at the Huygens–Fresnel equation emerge automatically from the mathematics in this derivation.

A simple example of the operation of the principle can be seen when an open doorway connects two rooms and a sound is produced in a remote corner of one of them. A person in the other room will hear the sound as if it originated at the doorway. As far as the second room is concerned, the vibrating air in the doorway is the source of the sound.

Modern physics interpretations
Not all experts agree that the Huygens' principle is an accurate microscopic representation of reality. For instance, Melvin Schwartz argued that "Huygens' principle actually does give the right answer but for the wrong reasons".

This can be reflected in the following facts:
 * The microscopic mechanics of photon creation and emission is, in general, essentially acceleration of electrons.
 * The original analysis by Huygens considered only wavefronts of uniform frequency, phase, and propagation speed, and therefore cannot properly account for effects such as interference or dispersion.
 * Huygens' original principle also does not consider the polarization of light, which would require a vector potential, in contrast to the scalar potential of a simple ocean wave or sound wave, and therefore cannot account for effects such as birefringence.
 * In the Huygens description, there is no explanation of why we choose only the forward-going (retarded wave or forward envelope of wave fronts) versus the backward-propagating advanced wave (backward envelope).
 * In the Fresnel approximation there is a concept of non-local behavior due to the sum of spherical waves with different phases that comes from the different points of the wave front, and non local theories are subject of many debates (e.g., not being Lorentz covariant) and of active research.
 * The Fresnel approximation can be interpreted in a quantum probabilistic manner but is unclear how much this sum of states (i.e., wavelets on the wavefront) is a complete list of states that are meaningful physically or represents more of an approximation on a generic basis like in the linear combination of atomic orbitals (LCAO) method.

The Huygens' principle is essentially compatible with quantum field theory in the far field approximation, considering effective fields in the center of scattering, considering small perturbations, and in the same sense that quantum optics is compatible with classical optics, other interpretations are subject of debates and active research.

The Feynman model where every point in an imaginary wave front as large as the room is generating a wavelet, shall also be interpreted in these approximations and in a probabilistic context, in this context remote points can only contribute minimally to the overall probability amplitude.

Quantum field theory does not include any microscopic model for photon creation and the concept of single photon is also put under scrutiny on a theoretical level.

Mathematical expression of the principle
Consider the case of a point source located at a point P0, vibrating at a frequency f. The disturbance may be described by a complex variable U0 known as the complex amplitude. It produces a spherical wave with wavelength λ, wavenumber $k = 2π/λ$. Within a constant of proportionality, the complex amplitude of the primary wave at the point Q located at a distance r0 from P0 is:

 * $$U(r_0) \propto \frac {U_0 e^{ikr_0}}{r_0}. $$

Note that magnitude decreases in inverse proportion to the distance traveled, and the phase changes as k times the distance traveled.

Using Huygens's theory and the principle of superposition of waves, the complex amplitude at a further point P is found by summing the contribution from each point on the sphere of radius r0. In order to get an agreement with experimental results, Fresnel found that the individual contributions from the secondary waves on the sphere had to be multiplied by a constant, −i/λ, and by an additional inclination factor, K(χ). The first assumption means that the secondary waves oscillate at a quarter of a cycle out of phase with respect to the primary wave and that the magnitude of the secondary waves are in a ratio of 1:λ to the primary wave. He also assumed that K(χ) had a maximum value when χ = 0, and was equal to zero when χ = π/2, where χ is the angle between the normal of the primary wavefront and the normal of the secondary wavefront. The complex amplitude at P, due to the contribution of secondary waves, is then given by:

 * $$ U(P) = -\frac{i}{\lambda} U(r_0) \int_{S} \frac {e^{iks}}{s} K(\chi)\,dS $$

where S describes the surface of the sphere, and s is the distance between Q and P.

Fresnel used a zone construction method to find approximate values of K for the different zones, which enabled him to make predictions that were in agreement with experimental results. The integral theorem of Kirchhoff includes the basic idea of Huygens–Fresnel principle. Kirchhoff showed that in many cases, the theorem can be approximated to a simpler form that is equivalent to the formation of Fresnel's formulation.

For an aperture illumination consisting of a single expanding spherical wave, if the radius of the curvature of the wave is sufficiently large, Kirchhoff gave the following expression for K(χ):
 * $$~K(\chi )= \frac{1}{2}(1+\cos \chi)$$

K has a maximum value at χ = 0 as in the Huygens–Fresnel principle; however, K is not equal to zero at χ = π/2, but at χ = π.

Above derivation of K(χ) assumed that the diffracting aperture is illuminated by a single spherical wave with a sufficiently large radius of curvature. However, the principle holds for more general illuminations. An arbitrary illumination can be decomposed into a collection of point sources, and the linearity of the wave equation can be invoked to apply the principle to each point source individually. K(χ) can be generally expressed as:

 * $$~K(\chi )= \cos \chi$$

In this case, K satisfies the conditions stated above (maximum value at χ = 0 and zero at χ = π/2).

Generalized Huygens' principle
Many books and references e.g. and refer to the Generalized Huygens' Principle as the one referred by Feynman in this publication.

Feynman defines the generalized principle in the following way:

This clarifies the fact that in this context the generalized principle reflects the linearity of quantum mechanics and the fact that the quantum mechanics equations are first order in time. Finally only in this case the superposition principle fully apply, i.e. the wave function in a point P can be expanded as a superposition of waves on a border surface enclosing P. Wave functions can be interpreted in the usual quantum mechanical sense as probability densities where the formalism of Green's functions and propagators apply. What is note-worthy is that this generalized principle is applicable for "matter waves" and not for light waves any more. The phase factor is now clarified as given by the action and there is no more confusion why the phases of the wavelets are different from the one of the original wave and modified by the additional Fresnel parameters.

As per Greiner the generalized principle can be expressed for $$t'>t $$ in the form:
 * $$\psi'(\mathbf{x}',t') = i \int d^3x \, G(\mathbf{x}',t';\mathbf{x},t)\psi(\mathbf{x},t)$$

where G is the usual Green function that propagates in time the wave function $$\psi$$. This description resembles and generalize the initial Fresnel's formula of the classical model.

Huygens' theory, Feynman's path integral and the modern photon wave function
Huygens' theory served as a fundamental explanation of the wave nature of light interference and was further developed by Fresnel and Young but did not fully resolve all observations such as the low-intensity double-slit experiment first performed by G. I. Taylor in 1909. It was not until the early and mid-1900s that quantum theory discussions, particularly the early discussions at the 1927 Brussels Solvay Conference, where Louis de Broglie proposed his de Broglie hypothesis that the photon is guided by a wave function.

The wave function presents a much different explanation of the observed light and dark bands in a double slit experiment. In this conception, the photon follows a path which is a probabilistic choice of one of many possible paths in the electromagnetic field. These probable paths form the pattern: in dark areas, no photons are landing, and in bright areas, many photons are landing. The set of possible photon paths is consistent with Richard Feynman's path integral theory, the paths determined by the surroundings: the photon's originating point (atom), the slit, and the screen and by tracking and summing phases. The wave function is a solution to this geometry. The wave function approach was further supported by additional double-slit experiments in Italy and Japan in the 1970s and 1980s with electrons.

Huygens' principle and quantum field theory
Huygens' principle can be seen as a consequence of the homogeneity of space—space is uniform in all locations. Any disturbance created in a sufficiently small region of homogeneous space (or in a homogeneous medium) propagates from that region in all geodesic directions. The waves produced by this disturbance, in turn, create disturbances in other regions, and so on. The superposition of all the waves results in the observed pattern of wave propagation.

Homogeneity of space is fundamental to quantum field theory (QFT) where the wave function of any object propagates along all available unobstructed paths. When integrated along all possible paths, with a phase factor proportional to the action, the interference of the wave-functions correctly predicts observable phenomena. Every point on the wavefront acts as the source of secondary wavelets that spread out in the light cone with the same speed as the wave. The new wavefront is found by constructing the surface tangent to the secondary wavelets.

In other spatial dimensions
In 1900, Jacques Hadamard observed that Huygens' principle was broken when the number of spatial dimensions is even. From this, he developed a set of conjectures that remain an active topic of research. In particular, it has been discovered that Huygens' principle holds on a large class of homogeneous spaces derived from the Coxeter group (so, for example, the Weyl groups of simple Lie algebras).

The traditional statement of Huygens' principle for the D'Alembertian gives rise to the KdV hierarchy; analogously, the Dirac operator gives rise to the AKNS hierarchy.

title: Huygens–Fresnel principle