De re metallica
Encyclopedia
De re metallica is a book cataloguing the state of the art of mining
, refining
, and smelting
metals, published in 1556. The author was Georg Bauer, whose pen name was the Latinized Georgius Agricola. The book remained the authoritative text on mining for 180 years after its publication.
Agricola had spent nine years in the Bohemia
n town of Joachimsthal, now in the Czech Republic
. (Joachimsthal is famous for its silver mines and the origin of the word "Thaler
" and, ultimately, "dollar
.") After Joachimsthal, he spent the rest of his life in Chemnitz
, a prominent mining town in Saxony
. Both Joachimsthal and Chemnitz are in the Erzgebirge, or Ore Mountains.
The book consists of a preface and twelve chapters, labelled books I to XII, without titles. It also has numerous woodcuts that provide annotated diagrams illustrating equipment and processes described in the text.
and his brother Augustus, who were his main patrons. He then describes the works of ancient and contemporary writers on mining and metallurgy, the chief ancient source being Pliny the Elder
. Agricola describes several books contemporary to him, the chief being a booklet by Calbus of Freiberg in German. The works of alchemists are then described. Agricola does not reject the idea of alchemy, but notes that alchemical writings are obscure and that we do not read of any of the masters who became rich. He then describes fraudulent alchemists, who deserve the death penalty. Agricola completes his introduction by explaining that, since no other author has described the art of metals completely, he has written this work, setting forth his scheme for twelve books. Finally, he again directly addresses his audience of German princes, explaining the wealth that can be gained from this art.
, medicine
, astronomy
, surveying
, arithmetic
, architecture
, drawing
and law
, though few are masters of the whole craft and most are specialists. This section is full of classical references and shows Agricola's classical education to its fullest. The arguments range from philosophical objections to gold and silver as being intrinsically worthless, to the danger of mining to its workers and its destruction of the areas in which it is carried out. He argues that without metals, no other activity such as architecture or agriculture are possible. The dangers to miners are dismissed; most deaths and injuries are caused by carelessness and other occupations are hazardous too. Clearing woods for fuel is advantageous as the land can be farmed. Mines tend to be in mountains and gloomy valleys with little economic value. The loss of food from the forests destroyed can be replaced by purchase from profits, and metals have been placed underground by God and man is right to extract and use them. Finally, Agricola argues that mining is an honorable and profitable occupation.
in silver mines. Various minerals and colours of earths can be used to give indications of the presence of metal ores. The actual mineworking varies with the hardness of the rock, the softest is worked with a pick and requires shoring with wood, the hardest is usually broken with fire. Iron wedges, hammers and crowbars are used to break other rocks. Noxious gases and the ingress of water are described. Methods for lining tunnels and shafts with timber are described. The book concludes with a long treatise on surveying, showing the instruments required and techniques for determining the course of veins and tunnels. Surveyors allow veins to be followed, but also prevent mines removing ore from other claims and stop mine workings from breaking into other workings.
, crucibles, scorifiers and muffles are described. The correct method of preparation of the cupels is covered in detail with beech ashes being preferred. Various other additives and formulae are described, but Agricola does not judge between them. Triangular crucibles and scorifiers are made of fatty clay with a temper of ground up crucibles or bricks. Agricola then describes in detail which substances should be added as fluxes as well as lead for smelting or assaying. The choice is made by which colour the ore burns out which gives an indication of the metals present. The lead should be silver-free or be assayed separately. The prepared ore is wrapped in paper, placed on a scorifier and then placed under a muffle covered in burning charcoal in the furnace. The cupel should be heated at the same time. The scorifier is removed and the metal transferred to the cupel. Alteratively the ore can be smelted in a triangular crucible, and then have lead mixed with it when it is added to the cupel. The cupel is placed in the furnace and copper is separated into the lead which forms lithage in the cupel leaving the noble metal. Gold and silver are parted using an aqua which is probably nitric acid. Agricola describes precautions for ensuring the amount of lead is correct and also describes the amalgamation of gold with mercury. Assay techniques for base metals such as tin are described as well as techniques for alloys such as silver tin. The use of a touchstone to assay gold and silver is discussed. Finally detailed arithmetical examples show the calculations needed to give the yield from the assay.
These are very similar for smelting different metals, constructed of brick or soft stone with a brick front and mechanically driven bellows at the rear. At the front is a pit called the fore-hearth to receive the metal. The furnace is charged with beneficiated ore and crushed charcoal and lit. In some gold and silver smelting a lot of slag is produced because of the relative poverty of the ore and the tap hole has to be opened at various times to remove different slag materials. When the furnace is ready, the forehearth is filled with molten lead into which the furnace is tapped. In other furnaces the smelting can be continuous, and lead is placed into the furnace if there is none in the ore. The slag is skimmed off the top of the metal as it is tapped. The lead containing the gold is separated by cupellation, the metal rich slags are re-smelted. Other smelting processes are similar, but lead is not added. Agricola also describes making crucible steel and distilling mercury and bismuth in this book.
s.
In 1912, the first English translation
of De Re Metallica was privately published in London
by subscription. The translators were Herbert Hoover
, a mining engineer (and later President of the United States
), and his wife, Lou Henry Hoover
, a geologist and Latinist. The translation is notable not only for its clarity of language, but for the extensive footnotes, which detail the classical references to mining and metals, such as the Naturalis Historia
of Pliny the Elder
, the history of mining law in England, France, and the German states; safety in mines, including historical safety; and known minerals at the time that Agricola wrote De Re Metallica.
Subsequent translations into other languages, including German, owe much to the Hoover translations, as their footnotes detail their difficulties with Agricola's invention of several hundred Latin expressions to cover Mediaeval German mining and milling terms unknown to classical Latin.
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
, refining
Refining (metallurgy)
Refining consists of purifying an impure material, in this case a metal. It is to be distinguished from other processes such as smelting and calcining in that those two involve a chemical change to the raw material, whereas in refining, the final material is usually identical chemically to the...
, and smelting
Smelting
Smelting is a form of extractive metallurgy; its main use is to produce a metal from its ore. This includes iron extraction from iron ore, and copper extraction and other base metals from their ores...
metals, published in 1556. The author was Georg Bauer, whose pen name was the Latinized Georgius Agricola. The book remained the authoritative text on mining for 180 years after its publication.
Agricola had spent nine years in the Bohemia
Bohemia
Bohemia is a historical region in central Europe, occupying the western two-thirds of the traditional Czech Lands. It is located in the contemporary Czech Republic with its capital in Prague...
n town of Joachimsthal, now in the Czech Republic
Czech Republic
The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
. (Joachimsthal is famous for its silver mines and the origin of the word "Thaler
Thaler
The Thaler was a silver coin used throughout Europe for almost four hundred years. Its name lives on in various currencies as the dollar or tolar. Etymologically, "Thaler" is an abbreviation of "Joachimsthaler", a coin type from the city of Joachimsthal in Bohemia, where some of the first such...
" and, ultimately, "dollar
Dollar
The dollar is the name of the official currency of many countries, including Australia, Belize, Canada, Ecuador, El Salvador, Hong Kong, New Zealand, Singapore, Taiwan, and the United States.-Etymology:...
.") After Joachimsthal, he spent the rest of his life in Chemnitz
Chemnitz
Chemnitz is the third-largest city of the Free State of Saxony, Germany. Chemnitz is an independent city which is not part of any county and seat of the government region Direktionsbezirk Chemnitz. Located in the northern foothills of the Ore Mountains, it is a part of the Saxon triangle...
, a prominent mining town in Saxony
Saxony
The Free State of Saxony is a landlocked state of Germany, contingent with Brandenburg, Saxony Anhalt, Thuringia, Bavaria, the Czech Republic and Poland. It is the tenth-largest German state in area, with of Germany's sixteen states....
. Both Joachimsthal and Chemnitz are in the Erzgebirge, or Ore Mountains.
Summary
Preface
Agricola addresses the book to prominent German aristocrats, the most important of whom were Maurice, Elector of SaxonyMaurice, Elector of Saxony
Maurice was Duke and later Elector of Saxony. His clever manipulation of alliances and disputes gained the Albertine branch of the Wettin dynasty extensive lands and the electoral dignity....
and his brother Augustus, who were his main patrons. He then describes the works of ancient and contemporary writers on mining and metallurgy, the chief ancient source being Pliny the Elder
Pliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...
. Agricola describes several books contemporary to him, the chief being a booklet by Calbus of Freiberg in German. The works of alchemists are then described. Agricola does not reject the idea of alchemy, but notes that alchemical writings are obscure and that we do not read of any of the masters who became rich. He then describes fraudulent alchemists, who deserve the death penalty. Agricola completes his introduction by explaining that, since no other author has described the art of metals completely, he has written this work, setting forth his scheme for twelve books. Finally, he again directly addresses his audience of German princes, explaining the wealth that can be gained from this art.
Book I: Arguments for and against this art
This book consists of the arguments used against the art and Agricola's counter arguments. He explains that mining and prospecting are not just a matter of luck and hard work; there is specialized knowledge that must be learned. A miner should have knowledge of philosophyPhilosophy
Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...
, medicine
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
, surveying
Surveying
See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...
, arithmetic
Arithmetic
Arithmetic or arithmetics is the oldest and most elementary branch of mathematics, used by almost everyone, for tasks ranging from simple day-to-day counting to advanced science and business calculations. It involves the study of quantity, especially as the result of combining numbers...
, architecture
Architecture
Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...
, drawing
Drawing
Drawing is a form of visual art that makes use of any number of drawing instruments to mark a two-dimensional medium. Common instruments include graphite pencils, pen and ink, inked brushes, wax color pencils, crayons, charcoal, chalk, pastels, markers, styluses, and various metals .An artist who...
and law
Law
Law is a system of rules and guidelines which are enforced through social institutions to govern behavior, wherever possible. It shapes politics, economics and society in numerous ways and serves as a social mediator of relations between people. Contract law regulates everything from buying a bus...
, though few are masters of the whole craft and most are specialists. This section is full of classical references and shows Agricola's classical education to its fullest. The arguments range from philosophical objections to gold and silver as being intrinsically worthless, to the danger of mining to its workers and its destruction of the areas in which it is carried out. He argues that without metals, no other activity such as architecture or agriculture are possible. The dangers to miners are dismissed; most deaths and injuries are caused by carelessness and other occupations are hazardous too. Clearing woods for fuel is advantageous as the land can be farmed. Mines tend to be in mountains and gloomy valleys with little economic value. The loss of food from the forests destroyed can be replaced by purchase from profits, and metals have been placed underground by God and man is right to extract and use them. Finally, Agricola argues that mining is an honorable and profitable occupation.
Book II: The miner and a discourse on the finding of veins
This book describes the miner and the finding of veins. Agricola assumes that his audience is the mine owner, or an investor in mines. He advises owners to live at the mine and to appoint good deputies. It is recommended to buy shares in mines that have not started to produce as well as existing mines to balance the risks. The next section of this book recommends areas where miners should search. These are generally mountains with wood available for fuel and a good supply of water. A navigable river can be used to bring fuel, but only gold or gemstones can be mined if no fuel is available. The roads must be good and the area healthy. Agricola describes searching streams for metals and gems that have been washed from the veins. He also suggests looking for exposed veins and also describes the effects of metals on the overlying vegetation. He recommends trenching to investigate veins beneath the surface. He then describes dowsing with a forked twig although he rejects the method himself. Finally he comments on the practice of naming veins or shafts.Book III: Veins and stringers and seams in the rocks
This book is a description of the various types of veins that can be found. There are 30 illustrations of different forms of these veins, forming the majority of Book III. Agricola also describes a compass to determine the direction of veins and mentions that some writers claim that veins lying in certain directions are richer, although he provides counter-examples. He also mentions the theory that the sun draws the metals in veins to the surface, although he himself doubts this. Finally he explains that gold is not generated in the beds of streams and rivers and east-west streams are not more productive than others inherently. Gold occurs in streams because it is torn from veins by the water.Book IV: Delimiting veins and the functions of mining officials
This book describes how an official, the Bergmeister, is in charge of mining. He marks out the land into areas called meers when a vein is discovered. The rest of the book covers the laws of mining. There is a section on how the mine can be divided into shares. The roles of various other officials in regulating mines and taxing the production are stated. The shifts of the miners are fixed. The chief trades in the mine are listed and are regulated by both the Bergmeister and their foremen.Book V: The digging of ore and the surveyor's art
This book covers underground mining and surveying. When a vein below ground is to be exploited a shaft is begun and a wooden shed with a windlass is placed above it. The tunnel dug at the bottom follows the vein and is just big enough for a man. The entire vein should be removed. Sometimes the tunnel eventually connects with a tunnel mouth in a hill side. Stringers and cross veins should be explored with cross tunnels or shafts when they occur. Agricola next describes that gold, silver, copper and mercury can be found as native metals, the others very rarely. Gold and silver ores are described in detail. Agricola then states that it is rarely worthwhile digging for other metals unless the ores are rich. Gems are found in some mines, but rarely have their own veins, lodestone is found in iron mines and emeryEmery
Emery may refer to:* Emery ** Emery paper** Emery board, nail filers* Emery , a post-hardcore band from Rock Hill, South Carolina* Emery Theatre, a historic multi-purpose theatre in Cincinnati, Ohio* Emery Worldwide, a cargo airline...
in silver mines. Various minerals and colours of earths can be used to give indications of the presence of metal ores. The actual mineworking varies with the hardness of the rock, the softest is worked with a pick and requires shoring with wood, the hardest is usually broken with fire. Iron wedges, hammers and crowbars are used to break other rocks. Noxious gases and the ingress of water are described. Methods for lining tunnels and shafts with timber are described. The book concludes with a long treatise on surveying, showing the instruments required and techniques for determining the course of veins and tunnels. Surveyors allow veins to be followed, but also prevent mines removing ore from other claims and stop mine workings from breaking into other workings.
Book VI: The miners' tools and machines
This book is extensively illustrated and describes the tools and machinery associated with mining. Handtools and different sorts of buckets, wheelbarrows and trucks on wooded plankways are described. Packs for horses and sledges are used to carry loads above ground. Agricola then provides details of various kinds of machines for lifting weights. Some of these are man-powered and some powered by up to four horses or by waterwheels. Horizontal drive shafts along tunnels allow lifting in shafts not directly connected to the surface. If this is not possible treadmills will be installed underground. Instead of lifting weights similar machines use chains of buckets to lift water. Agricola also describes several designs of piston force pumps which are either man or animal powered or powered by waterwheels. Because these pumps can only lift water about 24 feet batteries of pumps are required for the deepest mines. Water pipe designs are also covered in this section. Designs of wind scoop for ventilating shafts or forced air using fans or bellows are also described. Finally ladders and lifts using wicker cages are used to get miners up and down shafts.Book VII: On the assaying of ore
This book deals with assaying techniques. Various designs of furnaces are detailed. Then cupellationCupellation
Cupellation is a metallurgical process in which ores or alloyed metals are treated under high temperatures and carefully controlled operations in order to separate noble metals, like gold and silver, from base metals like lead, copper, zinc, arsenic, antimony or bismuth, that might be present in...
, crucibles, scorifiers and muffles are described. The correct method of preparation of the cupels is covered in detail with beech ashes being preferred. Various other additives and formulae are described, but Agricola does not judge between them. Triangular crucibles and scorifiers are made of fatty clay with a temper of ground up crucibles or bricks. Agricola then describes in detail which substances should be added as fluxes as well as lead for smelting or assaying. The choice is made by which colour the ore burns out which gives an indication of the metals present. The lead should be silver-free or be assayed separately. The prepared ore is wrapped in paper, placed on a scorifier and then placed under a muffle covered in burning charcoal in the furnace. The cupel should be heated at the same time. The scorifier is removed and the metal transferred to the cupel. Alteratively the ore can be smelted in a triangular crucible, and then have lead mixed with it when it is added to the cupel. The cupel is placed in the furnace and copper is separated into the lead which forms lithage in the cupel leaving the noble metal. Gold and silver are parted using an aqua which is probably nitric acid. Agricola describes precautions for ensuring the amount of lead is correct and also describes the amalgamation of gold with mercury. Assay techniques for base metals such as tin are described as well as techniques for alloys such as silver tin. The use of a touchstone to assay gold and silver is discussed. Finally detailed arithmetical examples show the calculations needed to give the yield from the assay.
Book VIII: Roasting, crushing and washing ore
In this book Agricola provides a detailed account of beneficiation of different ores. He describes the processes involved in ore sorting, roasting and crushing. The use of water for washing ores is discussed in great detail, e.g. the use of launders and washing tables. Several different types of machinery for crushing ore and washing it are illustrated and different techniques for different metals and different regions are described.Book IX: Methods of smelting ores
This book describes smelting, which Agricola describes as perfecting the metal by fire. The design of furnaces is first explained.These are very similar for smelting different metals, constructed of brick or soft stone with a brick front and mechanically driven bellows at the rear. At the front is a pit called the fore-hearth to receive the metal. The furnace is charged with beneficiated ore and crushed charcoal and lit. In some gold and silver smelting a lot of slag is produced because of the relative poverty of the ore and the tap hole has to be opened at various times to remove different slag materials. When the furnace is ready, the forehearth is filled with molten lead into which the furnace is tapped. In other furnaces the smelting can be continuous, and lead is placed into the furnace if there is none in the ore. The slag is skimmed off the top of the metal as it is tapped. The lead containing the gold is separated by cupellation, the metal rich slags are re-smelted. Other smelting processes are similar, but lead is not added. Agricola also describes making crucible steel and distilling mercury and bismuth in this book.
Book X: Separating silver from gold and lead from gold or silver
Agricola describes parting silver from gold in this book by using acids. He also describes heating with antimony sulphide (stibium), which would give silver sulphide and a mixture of gold and antimony. The gold and silver can then be recovered with cupellation. Gold can also be parted using salts or using mercury. Large scale cupellation using a cupellation hearth is also covered in this bookBook XI: Separating silver from copper
This book describes separating silver from copper or iron. This is achieved by adding large amounts of lead at a temperature just above the melting point of lead. The lead will liquate out with the silver. This process will need to be repeated several times. The lead and silver can be separated by cupellation.Book XII: Manufacturing salt, soda, alum, vitriol, sulphur, bitumen, and glass
This describes the preparation of what Agricola calls "juices": salt, soda, nitre, alum, vitriol, saltpetre, sulphur and bitumen. Finally glass making is covered. Agricola seems less secure about this process. He is not clear about making glass from the raw ingredients but clearer about remelting glass to make objects.Publication history
Although Agricola died in 1555, the publication was delayed until the completion of the extensive and detailed woodcutWoodcut
Woodcut—occasionally known as xylography—is a relief printing artistic technique in printmaking in which an image is carved into the surface of a block of wood, with the printing parts remaining level with the surface while the non-printing parts are removed, typically with gouges...
s.
In 1912, the first English translation
Translation
Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. Whereas interpreting undoubtedly antedates writing, translation began only after the appearance of written literature; there exist partial translations of the Sumerian Epic of...
of De Re Metallica was privately published in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
by subscription. The translators were Herbert Hoover
Herbert Hoover
Herbert Clark Hoover was the 31st President of the United States . Hoover was originally a professional mining engineer and author. As the United States Secretary of Commerce in the 1920s under Presidents Warren Harding and Calvin Coolidge, he promoted partnerships between government and business...
, a mining engineer (and later President of the United States
President of the United States
The President of the United States of America is the head of state and head of government of the United States. The president leads the executive branch of the federal government and is the commander-in-chief of the United States Armed Forces....
), and his wife, Lou Henry Hoover
Lou Henry Hoover
Lou Henry Hoover was the wife of President of the United States Herbert Hoover and First Lady of the United States, 1929-1933. Mrs. Hoover was president of the Girl Scouts of the USA for two terms, 1922-1925 and 1935-1937....
, a geologist and Latinist. The translation is notable not only for its clarity of language, but for the extensive footnotes, which detail the classical references to mining and metals, such as the Naturalis Historia
Naturalis Historia
The Natural History is an encyclopedia published circa AD 77–79 by Pliny the Elder. It is one of the largest single works to have survived from the Roman Empire to the modern day and purports to cover the entire field of ancient knowledge, based on the best authorities available to Pliny...
of Pliny the Elder
Pliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...
, the history of mining law in England, France, and the German states; safety in mines, including historical safety; and known minerals at the time that Agricola wrote De Re Metallica.
Subsequent translations into other languages, including German, owe much to the Hoover translations, as their footnotes detail their difficulties with Agricola's invention of several hundred Latin expressions to cover Mediaeval German mining and milling terms unknown to classical Latin.
See also
- De la pirotechniaDe la pirotechniaDe la Pirotechnia is considered to be the first printed book on metallurgy to have been published in Europe. It was written in Italian and published in Venice in 1540...
- Naturalis HistoriaNaturalis HistoriaThe Natural History is an encyclopedia published circa AD 77–79 by Pliny the Elder. It is one of the largest single works to have survived from the Roman Empire to the modern day and purports to cover the entire field of ancient knowledge, based on the best authorities available to Pliny...
- Pliny the ElderPliny the ElderGaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...
- Scientific literatureScientific literatureScientific literature comprises scientific publications that report original empirical and theoretical work in the natural and social sciences, and within a scientific field is often abbreviated as the literature. Academic publishing is the process of placing the results of one's research into the...
- TheophrastusTheophrastusTheophrastus , a Greek native of Eresos in Lesbos, was the successor to Aristotle in the Peripatetic school. He came to Athens at a young age, and initially studied in Plato's school. After Plato's death he attached himself to Aristotle. Aristotle bequeathed to Theophrastus his writings, and...