Editing Brass (section)

===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>