Editing Brass (section)

==History==
{{further|Art in bronze and brass}}

Although forms of brass have been in use since [[prehistory]],<ref>Thornton, C. P. (2007) [http://www.safarmer.com/Indo-Eurasian/Brass2007.pdf "Of brass and bronze in prehistoric southwest Asia"] {{Webarchive|url=https://web.archive.org/web/20150924093433/http://www.safarmer.com/Indo-Eurasian/Brass2007.pdf |date=24 September 2015 }} in La Niece, S. Hook, D. and Craddock, P.T. (eds.) ''Metals and mines: Studies in archaeometallurgy'' London: Archetype Publications. {{ISBN|1-904982-19-0}}</ref> its true nature as a copper-zinc alloy was not understood until the post-medieval period because the zinc [[vapor]] which reacted with copper to make brass was not recognized as a [[metal]].<ref>de Ruette, M. (1995) "From Contrefei and Speauter to Zinc: The development of the understanding of the nature of zinc and brass in Post Medieval Europe" in Hook, D. R. and [[David Gaimster|Gaimster, D. R. M]] (eds). ''Trade and Discovery: The Scientific Study of Artefacts from Post Medieval Europe and Beyond''. London: British Museum Occasional Papers 109</ref> The [[King James Bible]] makes many references to "brass"<ref>Cruden's Complete Concordance p. 55</ref> to translate "nechosheth" (bronze or copper) from Hebrew to English. The earliest brasses may have been natural alloys made by [[smelting]] zinc-rich copper [[ore]]s.<ref name=Craddock>Craddock, P. T. and Eckstein, K (2003) "Production of Brass in Antiquity by Direct Reduction" in Craddock, P. T. and Lang, J. (eds.) ''Mining and Metal Production Through the Ages''. London: British Museum, pp. 226–27</ref> By the [[Ancient Rome|Roman]] period brass was being deliberately produced from metallic copper and zinc minerals using the [[Cementation process#Brass production|cementation]] process, the product of which was [[calamine brass]], and variations on this method continued until the mid-19th century.<ref>Rehren and Martinon Torres 2008, pp. 170–175</ref> It was eventually replaced by [[spelter]]ing, the direct alloying of copper and zinc metal which was introduced to [[Europe]] in the 16th century.<ref name=Craddock/>

Brass has sometimes historically been referred to as "yellow copper".<ref>{{Cite book|last=Chen|first=Hailian|url=https://books.google.com/books?id=z2d9DwAAQBAJ&q=%22yellow+copper%22+brass&pg=PA93|title=Zinc for Coin and Brass: Bureaucrats, Merchants, Artisans, and Mining Laborers in Qing China, ca. 1680s–1830s|date=2018-12-03|publisher=BRILL|isbn=978-90-04-38304-3|language=en|df=dmy-all}}</ref><ref>{{Cite book|last=Humphreys|first=Henry Noel|url=https://books.google.com/books?id=OhoLAAAAIAAJ&q=%22yellow+copper%22+brass&pg=PA374|title=The Coin Collector's Manual: Comprising an Historical and Critical Account of the Origin and Progress of Coinage, from the Earliest Period to the Fall of the Roman Empire; with Some Account of the Coinages of Modern Europe, More Especially of Great Brit|date=1897|publisher=Bell|language=en}}</ref>

===Early copper-zinc alloys===
In [[West Asia]] and the [[Eastern Mediterranean]] early copper-zinc alloys are now known in small numbers from a number of 3rd millennium BC sites in the [[Aegean Sea|Aegean]], [[Iraq]], the [[United Arab Emirates]], [[Kalmykia]], [[Turkmenistan]] and [[Georgia (country)|Georgia]] and from 2nd millennium BC sites in [[western India]], [[Uzbekistan]], [[Iran]], [[Syria]], Iraq and [[Canaan]].<ref>Thornton 2007, pp. 189–201</ref> Isolated examples of copper-zinc [[alloy]]s are known in [[China]] from the 1st century AD, long after bronze was widely used.<ref name=r5/> The hilt of [[Sirohi sword|Sirohi swords]] were made up of [[brass]] in [[India]].

The compositions of these early "brass" objects are highly variable and most have zinc contents of between 5% and 15% wt which is lower than in brass produced by cementation.<ref name="Craddock and Eckstein 2003 p.217">Craddock and Eckstein 2003 p. 217</ref> These may be "natural alloys" manufactured by smelting zinc rich copper ores in [[redox]] conditions. Many have similar tin contents to contemporary bronze [[Artifact (archaeology)|artefacts]] and it is possible that some copper-zinc alloys were accidental and perhaps not even distinguished from copper.<ref name="Craddock and Eckstein 2003 p.217"/> However the large number of copper-zinc alloys now known suggests that at least some were deliberately manufactured and many have zinc contents of more than 12% wt which would have resulted in a distinctive golden colour.<ref name="Craddock and Eckstein 2003 p.217" /><ref>Thornton, C. P. and Ehlers, C. B. (2003) "Early Brass in the ancient Near East", in IAMS Newsletter 23 pp. 27–36</ref>

By the 8th–7th century BC [[Assyria]]n [[cuneiform]] tablets mention the exploitation of the "copper of the mountains" and this may refer to "natural" brass.<ref>Bayley 1990, p. 8</ref> "Oreikhalkon" (mountain copper),<ref>{{cite web|url=http://www.oxforddictionaries.com/definition/english/orichalc?q=orichalcum|archive-url=https://web.archive.org/web/20150109114154/http://www.oxforddictionaries.com/definition/english/orichalc?q=orichalcum|url-status=dead|archive-date=9 January 2015|title=orichalc – definition of orichalc in English from the Oxford dictionary|work=oxforddictionaries.com}}</ref> the [[Ancient Greek]] translation of this term, was later adapted to the [[Latin]] ''[[aurichalcum]]'' meaning "golden copper" which became the standard term for brass.<ref>Rehren and Martinon Torres 2008, p. 169</ref> In the 4th century BC [[Plato]] knew ''orichalkos'' as rare and nearly as valuable as gold<ref name=r11/> and [[Pliny the Elder|Pliny]] describes how ''aurichalcum'' had come from [[Cyprus|Cypriot]] ore deposits which had been exhausted by the 1st century AD.<ref>Pliny the Elder ''Historia Naturalis'' XXXIV 2</ref> [[X-ray fluorescence]] analysis of 39 [[orichalcum]] ingots recovered from a 2,600-year-old shipwreck off Sicily found them to be an alloy made with 75–80% copper, 15–20% zinc and small percentages of nickel, lead and iron.<ref>{{cite web|url=http://news.discovery.com/history/archaeology/atlantis-legendary-metal-found-in-shipwreck-150106.htm|title=Atlantis' Legendary Metal Found in Shipwreck|work=DNews|date=2017-05-10|df=dmy-all|access-date=9 January 2015|archive-date=17 May 2016|archive-url=https://web.archive.org/web/20160517080612/http://news.discovery.com/history/archaeology/atlantis-legendary-metal-found-in-shipwreck-150106.htm|url-status=dead}}</ref><ref>{{cite web|url=http://www.archaeology.org/news/2874-150107-sicily-orichalcum-metal|title=Unusual Metal Recovered from Ancient Greek Shipwreck – Archaeology Magazine|author=Jessica E. Saraceni|work=archaeology.org|date=7 January 2015 }}</ref>

===Roman world===
[[File:Iranian - Ewer - Walters 54457 - Profile.jpg|thumb|upright|7th-century Persian [[ewer]] in brass with copper inlay, [[Walters Art Museum]], [[Baltimore]], Maryland, US]]

During the later part of first millennium BC the use of brass spread across a wide geographical area from [[United Kingdom|Britain]]<ref>{{cite journal |last1=Craddock |first1=P. T. |last2=Cowell |first2=M. |last3=Stead |first3=I. |year=2004 |title=Britain's first brass |journal=Antiquaries Journal |doi=10.1017/S000358150004587X |volume=84 |pages=339–46|s2cid=163717910 }}</ref> and [[Spain]]<ref name=r13/> in the west to [[Iran]], and [[India]] in the east.<ref>Craddock and Eckstein 2003, pp. 216–7</ref> This seems to have been encouraged by exports and influence from the [[Middle East]] and eastern Mediterranean where deliberate production of brass from metallic copper and zinc ores had been introduced.<ref>Craddock and Eckstein 2003, p. 217</ref> The 4th century BC writer [[Theopompus]], quoted by [[Strabo]], describes how heating earth from [[Astyra (Aeolis)|Andeira]] in [[Turkey]] produced "droplets of false silver", probably metallic zinc, which could be used to turn copper into oreichalkos.<ref>Bayley 1990, p. 9</ref> In the 1st century BC the Greek [[Dioscorides]] seems to have recognized a link between zinc [[mineral]]s and brass describing how [[Cadmia]] ([[zinc oxide]]) was found on the walls of [[Metallurgical furnace|furnace]]s used to heat either zinc ore or copper and explaining that it can then be used to make brass.<ref>Craddock and Eckstein 2003, pp. 222–224. Bayley 1990, p. 10.</ref>

By the first century BC brass was available in sufficient supply to use as [[coin]]age in [[Phrygia]] and [[Bithynia]],<ref name=r14/> and after the Augustan [[currency reform]] of 23 BC it was also used to make Roman ''[[dupondius|dupondii]]'' and ''[[Sestertius|sestertii]]''.<ref name=r15/> The uniform use of brass for coinage and military equipment across the [[Roman world]] may indicate a degree of state involvement in the industry,<ref>Bayley 1990, p. 21</ref><ref name=r16/> and brass even seems to have been deliberately boycotted by [[Jewish]] communities in Palestine because of its association with Roman authority.<ref name=r17/>
 
Brass was produced by the cementation process where copper and zinc ore are heated together until zinc vapor is produced which reacts with the copper. There is good archaeological evidence for this process and [[crucible]]s used to produce brass by cementation have been found on [[Roman period]] sites including [[Xanten]]<ref name=r18/> and [[Nidda, Hesse|Nidda]]<ref name=r19/> in [[Germany]], [[Lyon]] in [[France]]<ref name="ReferenceA">Rehren and Martinon Torres 2008, pp. 170–71</ref> and at a number of sites in Britain.<ref>Bayley 1990</ref> They vary in size from tiny acorn sized to large [[amphora]]e like vessels but all have elevated levels of zinc on the interior and are lidded.<ref name="ReferenceA"/> They show no signs of [[slag]] or metal [[prills]] suggesting that zinc minerals were heated to produce zinc vapor which reacted with metallic copper in a [[solid state reaction]]. The fabric of these crucibles is porous, probably designed to prevent a buildup of pressure, and many have small holes in the lids which may be designed to release pressure<ref name="ReferenceA"/> or to add additional zinc minerals near the end of the process. Dioscorides mentioned that zinc minerals were used for both the working and finishing of brass, perhaps suggesting secondary additions.<ref name = ce2003p224>Craddock and Eckstein 2003, p. 224</ref>

Brass made during the early Roman period seems to have varied between 20% and 28% wt zinc.<ref name = ce2003p224/> The high content of zinc in coinage and brass objects declined after the first century AD and it has been suggested that this reflects zinc loss during [[recycling]] and thus an interruption in the production of new brass.<ref name = r15/> However it is now thought this was probably a deliberate change in composition<ref name=r21/> and overall the use of brass increases over this period making up around 40% of all [[copper alloys]] used in the Roman world by the 4th century AD.<ref>Craddock 1978, p. 14</ref>

===Medieval period===
[[File:Renier de Huy JPG0.jpg|thumb|''[[Baptism of Jesus|Baptism of Christ]]'' on the 12th-century [[baptismal font at St Bartholomew's Church, Liège]]]]
Little is known about the production of brass during the centuries immediately after the collapse of the [[Roman Empire]]. Disruption in the trade of tin for bronze from [[Western Europe]] may have contributed to the increasing popularity of brass in the east and by the 6th–7th centuries AD over 90% of [[copper alloy]] artefacts from [[Egypt]] were made of brass.<ref>Craddock, P. T., La Niece, S. C., and Hook, D. (1990). "Brass in the Medieval Islamic World". In Craddock, P. T. (ed.), ''2000 Years of Zinc and Brass''. London: British Museum, p. 73</ref> However other alloys such as low tin bronze were also used and they vary depending on local cultural attitudes, the purpose of the metal and access to zinc, especially between the [[Islamic]] and [[Byzantine]] world.<ref name=r4/> Conversely the use of true brass seems to have declined in Western Europe during this period in favor of [[gunmetal]]s and other mixed alloys<ref>Bayley 1990, p. 22</ref> but by about 1000 brass artefacts are found in [[Scandinavia]]n graves in [[Scotland]],<ref name=r24/> brass was being used in the manufacture of coins in [[Northumbria]]<ref>Gilmore, G. R. and Metcalf, D. M. (1980). "The alloy of the Northumbrian coinage in the mid-ninth century". In Metcalf, D. and Oddy, W. ''Metallurgy in Numismatics'' 1 pp. 83–98</ref> and there is archaeological and historical evidence for the production of [[calamine brass]] in Germany<ref name="r18" /> and [[the Low Countries]],<ref>Day 1990, pp. 123–150</ref> areas rich in [[Calamine (mineral)|calamine]] ore.

These places would remain important centres of brass making throughout the [[Middle Ages]] period,<ref>Day 1990, pp. 124–133</ref> especially [[Dinant]]. Brass objects are still collectively known as ''dinanderie'' in French. The [[baptismal font at St Bartholomew's Church, Liège]] in modern [[Belgium]] (before 1117) is an outstanding masterpiece of [[Romanesque art|Romanesque]] brass casting, though also often described as bronze. The metal of the early 12th-century [[Gloucester Candlestick]] is unusual even by medieval standards in being a mixture of copper, zinc, tin, lead, [[nickel]], iron, [[antimony]] and [[arsenic]] with an unusually large amount of [[silver]], ranging from 22.5% in the base to 5.76% in the pan below the candle. The proportions of this mixture may suggest that the candlestick was made from a hoard of old coins, probably Late Roman.<ref>Noel Stratford, pp. 232, 245, in Zarnecki, George and others; ''English Romanesque Art, 1066–1200'', 1984, Arts Council of Great Britain, {{ISBN|0728703866}}</ref> [[Latten]] is a term for medieval alloys of uncertain and often variable composition often covering decorative borders and similar objects cut from sheet metal, whether of brass or bronze. Especially in [[Tibetan art]], analysis of some objects shows very different compositions from different ends of a large piece. [[Aquamanile]]s were typically made in brass in both the European and Islamic worlds.

[[File:Lion Aquamanile, 1200-1250 AD, German, Lower Saxony, Hildesheim, bronze - Cleveland Museum of Art - DSC08638.JPG|thumb|left|upright|Brass [[aquamanile]] from [[Lower Saxony]], Germany, c. 1250]]
The cementation process continued to be used but literary sources from both Europe and the [[Islamic world]] seem to describe variants of a higher temperature liquid process which took place in open-topped crucibles.<ref>Craddock and Eckstein 2003, pp. 224–25</ref> Islamic cementation seems to have used zinc oxide known as ''tutiya'' or [[tutty]] rather than zinc ores for brass-making, resulting in a metal with lower [[iron]] impurities.<ref>Craddock et al. 1990, 78</ref> A number of Islamic writers and the 13th century [[Italians|Italian]] [[Marco Polo]] describe how this was obtained by [[sublimation (phase transition)|sublimation]] from zinc ores and [[Condensation|condensed]] onto [[clay]] or iron bars, archaeological examples of which have been identified at [[Hindu Kush|Kush]] in Iran.<ref>Craddock et al. 1990, pp. 73–76</ref> It could then be used for brass making or medicinal purposes. In 10th century [[Yemen]] [[Abū Muhammad al-Hasan al-Hamdānī|al-Hamdani]] described how spreading [[al-iglimiya]], probably zinc oxide, onto the surface of molten copper produced tutiya vapor which then reacted with the metal.<ref>Craddock et al. 1990, p. 75</ref> The 13th century Iranian writer [[al-Kashani]] describes a more complex process whereby ''tutiya'' was mixed with [[raisin]]s and gently roasted before being added to the surface of the molten metal. A temporary lid was added at this point presumably to minimize the escape of zinc vapor.<ref>Craddock et al. 1990, p. 76</ref>

In Europe a similar liquid process in open-topped crucibles took place which was probably less efficient than the Roman process and the use of the term tutty by [[Albertus Magnus]] in the 13th century suggests influence from Islamic technology.<ref>Rehren, T (1999) "The same... but different: A juxtaposition of Roman and Medieval brass making in Europe" in Young, S. M. M. (ed.) ''Metals in antiquity'' Oxford: Archaeopress pp. 252–257</ref> The 12th century [[Germans|German]] monk [[Theophilus Presbyter|Theophilus]] described how preheated crucibles were one sixth filled with powdered calamine and [[charcoal]] then topped up with copper and charcoal before being melted, stirred then filled again. The final product was [[casting|cast]], then again melted with calamine. It has been suggested that this second melting may have taken place at a lower temperature to allow more zinc to be [[Absorption (chemistry)|absorbed]].<ref>Craddock and Eckstein 2003, 226</ref> Albertus Magnus noted that the "power" of both calamine and tutty could [[evaporate]] and described how the addition of powdered [[glass]] could create a film to bind it to the metal.<ref>Rehren and Martinon Torres 2008, pp. 176–178</ref> 
German brass making crucibles are known from [[Dortmund]] dating to the 10th century AD and from [[Soest, Germany|Soest]] and [[Schwerte]] in [[Westphalia]] dating to around the 13th century confirm Theophilus' account, as they are open-topped, although [[ceramic]] discs from Soest may have served as loose lids which may have been used to reduce zinc [[evaporation]], and have slag on the interior resulting from a liquid process.<ref>Rehren and Martinon Torres 2008, pp. 173–175</ref>

===Africa===
[[File:Arte yoruba, nigeria, testa da ife, 12-15mo secolo.JPG|thumb|upright|12th century "[[Bronze Head from Ife]]", actually of "heavily leaded zinc-brass"]]
Some of the most famous objects in [[African art]] are the [[lost wax]] castings of West Africa, mostly from what is now [[Nigeria]], produced first by the [[Kingdom of Ife]] and then the [[Benin Empire]]. Though normally described as "bronzes", the [[Benin Bronzes]], now mostly in the [[British Museum]] and other Western collections, and the large portrait heads such as the [[Bronze Head from Ife]] of "heavily leaded zinc-brass" and the [[Bronze Head of Queen Idia]], both also British Museum, are better described as brass, though of variable compositions.<ref>[https://www.britishmuseum.org/research/collection_online/collection_object_details.aspx?objectId=618380 "The Ife Head"] {{Webarchive|url=https://web.archive.org/web/20160920155753/https://www.britishmuseum.org/research/collection_online/collection_object_details.aspx?objectId=618380 |date=20 September 2016 }} on the British Museum collection database. Accessed 26 May 2014</ref>  Work in brass or bronze continued to be important in [[Benin art]] and other West African traditions such as [[Akan goldweights]], where the metal was regarded as a more valuable material than in Europe.

===Renaissance and post-medieval Europe===
The [[Renaissance]] saw important changes to both the theory and practice of brassmaking in Europe. By the 15th century there is evidence for the renewed use of lidded cementation crucibles at [[Zwickau]] in Germany.<ref>Martinon Torres and Rehren 2002, pp. 95–111</ref> These large crucibles were capable of producing c.20&nbsp;kg of brass.<ref>Martinon Torres and Rehren 2002, pp. 105–06</ref> There are traces of slag and pieces of metal on the interior. Their irregular composition suggests that this was a lower temperature, not entirely liquid, process.<ref>Martinon Torres and Rehren 2002, p. 103</ref> The crucible lids had small holes which were blocked with clay plugs near the end of the process presumably to maximize zinc [[absorption (chemistry)|absorption]] in the final stages.<ref>Martinon Torres and Rehren 2002, p. 104</ref> Triangular crucibles were then used to melt the brass for [[casting]].<ref>Martinon Torres and Rehren 2002, p. 100</ref>

16th-century technical writers such as [[Vannoccio Biringuccio|Biringuccio]], [[Lazarus Ercker|Ercker]] and [[Georgius Agricola|Agricola]] described a variety of cementation brass making techniques and came closer to understanding the true nature of the process noting that copper became heavier as it changed to brass and that it became more golden as additional calamine was added.<ref>Martinon Torres and Rehren 2008, 181–82, de Ruette 1995</ref> Zinc metal was also becoming more commonplace. By 1513 metallic zinc [[ingot]]s from India and China were arriving in [[London]] and pellets of zinc condensed in [[Metallurgical furnace|furnace]] flues at the [[Rammelsberg]] in Germany were exploited for cementation brass making from around 1550.<ref>de Ruette 1995, 198</ref>

Eventually it was discovered that metallic zinc could be [[alloy]]ed with copper to make brass, a process known as speltering,<ref name="Craddock and Eckstein 2003, 228">Craddock and Eckstein 2003, 228</ref> and by 1657 the German chemist [[Johann Glauber]] had recognized that calamine was "nothing else but unmeltable zinc" and that zinc was a "half ripe metal".<ref>de Ruette 1995, 198–9</ref> However some earlier high zinc, low iron brasses such as the 1530 Wightman brass memorial [[Commemorative plaque|plaque]] from England may have been made by alloying copper with ''zinc'' and include traces of [[cadmium]] similar to those found in some zinc ingots from China.<ref name="Craddock and Eckstein 2003, 228"/>
 
However, the cementation process was not abandoned, and as late as the early 19th century there are descriptions of [[Solid-state chemistry|solid-state]] cementation in a domed furnace at around 900–950&nbsp;°C and lasting up to 10 hours.<ref>Craddock and Eckstein 2003, 226–27.</ref> The European brass industry continued to flourish into the post medieval period buoyed by innovations such as the 16th century introduction of water powered hammers for the production of wares such as pots.<ref name="Day 1990, 131">Day 1990, p. 131</ref> By 1559 the Germany city of [[Aachen]] alone was capable of producing 300,000 [[centum weight|cwt]] of brass per year.<ref name="Day 1990, 131"/> After several false starts during the 16th and 17th centuries the brass industry was also established in England taking advantage of abundant supplies of cheap copper [[smelted]] in the new [[coal]] fired [[reverberatory furnace]].<ref>Day 1991, pp. 135–144</ref> In 1723 [[Bristol]] brass maker Nehemiah Champion patented the use of [[granulated]] copper, produced by pouring molten metal into cold water.<ref>Day 1990, p. 138</ref> This increased the [[surface area]] of the copper helping it react and zinc contents of up to 33% wt were reported using this new technique.<ref>Craddock and Eckstein 2003, p. 227</ref>

In 1738 Nehemiah's son [[William Champion (metallurgist)|William Champion]] patented a technique for the first industrial scale [[distillation]] of metallic zinc known as ''distillation per descencum'' or "the English process".<ref>Day 1991, pp. 179–181</ref><ref name=r3/> This local zinc was used in speltering and allowed greater control over the zinc content of brass and the production of high-zinc copper alloys which would have been difficult or impossible to produce using cementation, for use in expensive objects such as [[scientific instruments]], [[clock]]s, brass [[buttons]] and [[costume jewelry]].<ref name="Day 1991, 183">Day 1991, p. 183</ref> However Champion continued to use the cheaper calamine cementation method to produce lower-zinc brass<ref name="Day 1991, 183"/> and the archaeological remains of bee-hive shaped cementation furnaces have been identified at his works at [[Warmley]].<ref name=r2/> By the mid-to-late 18th century developments in cheaper zinc distillation such as John-Jaques Dony's horizontal furnaces in Belgium and the reduction of tariffs on zinc<ref>Day 1991, pp. 186–189</ref> as well as demand for [[corrosion]]-resistant high zinc alloys increased the popularity of speltering and as a result cementation was largely abandoned by the mid-19th century.<ref>Day 1991, pp. 192–93, Craddock and Eckstein 2003, p. 228</ref>