Editing Natural History (Pliny) (section)

===Metallurgy===

Pliny extensively discusses metals starting with gold and silver (Book XXXIII), and then the base metals copper, [[mercury (element)|mercury]], lead, [[tin]] and iron, as well as their many alloys such as [[electrum]], [[bronze]], [[pewter]], and steel (Book XXXIV).

He is critical of greed for gold, such as the absurdity of using the metal for coins in the early Republic. He gives examples of the way rulers proclaimed their prowess by exhibiting gold looted from their campaigns, such as that by Claudius after conquering Britain, and tells the stories of [[Midas]] and [[Croesus]]. He discusses why gold is unique in its [[malleability]] and [[ductility]], far greater than any other metal. The examples given are its ability to be beaten into fine [[foil (metal)|foil]] with just one ounce producing 750 leaves four inches square. Fine gold [[wire]] can be woven into cloth, although imperial clothes usually combined it with natural fibres like wool. He once saw [[Agrippina the Younger]], wife of Claudius, at a public show on the [[Fucine Lake]] involving a naval battle, wearing a military cloak made of gold. He rejects Herodotus's claims of [[Gold-digging ant|Indian gold obtained by ants]] or dug up by [[griffin]]s in [[Scythia]].

[[Silver]], he writes, does not occur in native form and has to be mined, usually occurring with lead ores. Spain produced the most silver in his time, many of the mines having been started by [[Hannibal]]. One of the largest had galleries running up to two miles into the mountain, while men worked day and night draining the mine in shifts. Pliny is probably referring to the [[reverse overshot water-wheel]]s operated by treadmill and found in Roman mines. Britain, he says, is very rich in lead, which is found on the surface at many places, and thus very easy to extract; production was so high that a law was passed attempting to restrict mining.

[[File:Rmcoinmolds.jpg|thumb|left|upright=1.25<!--size very low image to roughly normal area-->|Roman coins were struck, not cast, so these coin moulds were created for forgery.]]

Fraud and forgery are described in detail; in particular [[coin counterfeiting]] by mixing copper with silver, or even admixture with iron. Tests had been developed for counterfeit coins and proved very popular with the victims, mostly ordinary people. He deals with the liquid metal mercury, also found in [[silver mine]]s. He records that it is toxic, and [[Amalgam (chemistry)|amalgamates]] with gold, so is used for refining and extracting that metal. He says mercury is used for [[gilding]] copper, while [[antimony]] is found in silver mines and is used as an [[eyebrow]] [[Cosmetics|cosmetic]].

The main ore of mercury is [[cinnabar]], long used as a pigment by painters. He says that the colour is similar to ''scolecium'', probably the [[Kermes (dye)|kermes insect]].{{efn|[[John Gerard]]'s influential ''Herball'' (1597) called ''scolecium'' "Maggot berrie" and supposed "Cutchonele" ([[Cochineal]]) to be a form of this. Many later authors have copied Gerard in this error.<ref>{{cite book|last1=Greenfield|first1=Amy Butler|title=A Perfect Red: Empire, Espionage and the Quest for the Colour of Desire|date=2011|publisher=Random House|page=351}}</ref>}} The dust is very toxic, so workers handling the material wear face masks of bladder skin. Copper and bronze are, says Pliny, most famous for their use in statues including colossi, gigantic statues as tall as towers, the most famous being the [[Colossus of Rhodes]]. He personally saw the massive statue of [[Nero]] in Rome, which was removed after the emperor's death. The face of the statue was modified shortly after Nero's death during Vespasian's reign, to make it a statue of [[Sol (Roman mythology)|Sol]]. [[Hadrian]] moved it, with the help of the architect Decrianus and 24 elephants, to a position next to the [[Flavian Amphitheatre]] (now called the [[Colosseum]]).

Pliny gives a special place to iron, distinguishing the hardness of steel from what is now called [[wrought iron]], a softer grade. He is scathing about the use of iron in warfare.