Witchcraft and the Occult, 1400-1700
Georgius Agricola (1494-1555)
Index
I have omitted all those things which I have not myself seen, or have not read or heard of from persons upon whom I can rely. That which I have neither seen, nor carefully considered after reading or hearing of, I have not written about. The same rule must be understood with regard to all my instruction, whether I enjoin things which ought to be done, or describe things which are usual, or condemn things which are done.                        Agricola, Preface to De Re Metallica, 1556

Although he was not strictly an occult philosopher, the work of Georgius Agricola exemplifies the practical utility of alchemical and natural historical studies, and the propagation of one technology, that of mining, through the medium of another, the printed book illustrated with woodcuts.  Like his contemporary, the great anatomist Andreas Vesalius, Agricola was a humanist physician who observed and experimented for himself, and then used printing to disseminate his findings.  In the context of this class, however, it should also be mentioned that Agricola gave considerable credence to the stories of miners about the little spirits to be met with underground [see Maxwell-Stuart source book, p.40].

Georg Bauer was born in Glauchau, in Saxony.  He matriculated at Leipzig University in 1514, received his BA in 1515, and then taught Latin and Greek for a few years.  In 1517, he was chosen as ludi moderator and in 1519 as rector extraordinarius at the school at Zwickau.  In 1523, he returned to Leipzig to study medicine under Heinrich Stromer von Auerbach.  To support him during his second period of study he was endowed with a prebend of the St. Erasmus altar for three years by the council of Zwickau. He studied in Bologna, Venice, and probably Padua, and is said to have returned to Germany with an MD.  During his time at Bologna and Venice, he served as a member of the editorial staff for the Aldine Press editions of Galen and Hippocrates.

In 1527-30, he was elected town physician and apothecary of St. Joachimstal in Bohemia, an important silver mining centre.  In 1533, he moved to Chemnitz, another important mining centre, as town physician. His knowledge of mining allowed him to speculate in mining shares, which he did with great success. By 1542, he is said to have been one of the twelve richest inhabitants of Chemnitz.


water power          horse power
Agricola enjoyed the patronage of the Dukes of Brunswick and Saxony, who consulted him especially for his vast knowledge of mining techniques.  Agricola's greatest patron was the Protestant Duke Moritz of Saxony, to whom he dedicated his book De Natura Fossilium (1546) and for whose father, Duke Georg, he had worked as official historiographer. Most of his books are dedicated to Moritz or his successor Augustus. In 1543, Moritz presented him with a house and plot in Chemnitz, and granted him special exemptions from municipal laws. Agricola was called to special diplomatic and advisory service in 1546, after the war of Schmalkalden had broken out. Thereafter, he was heavily involved in the Duke's diplomacy, a rare example of a prominent Catholic at a Protestant court. He attended the Diet of Freiburg (1546), the Council of Dresden (1546), the Diets of Leipzig (1547, 1549, & 1553), the Diets of Torgau (1550 & 1555), the Diet of Leipzig (1553), and the Diet of Dresden (1553). He was also sent on diplomatic missions to the Emperor Charles and King Ferdinand of Austria. In addition, Moritz appointed him mayor of Chemnitz four times (1546, 1548, 1551, & 1553).  It is noted that Agricola worked day and night during the plague of 1551- 1552, an experience that led to the writing of De peste (1554).  He died in 1555, one year before the posthumous publication of De Re Metallica, his greatest work.  However, seeking to avoid religious controversy, Moritz ordered that he should not be buried in the parish plot at Chemnitz, an honour traditionally conferred on mayors.  Agricola's friend, Julius von Pflug, bishop of Zeitz-Naumberg, arranged for him to be buried at Zeitz cathedral.

mining shafts
Agricola's geological writings reflect an immense amount of study and first-hand observation, not
just of rocks and minerals, but of every aspect of mining technology and practice of the time.  Agricola wrote the first book on physical geology, De Ortu et Causis Subterraneorum (1546), notable for its descriptions of wind and water as powerful geological forces, and for its explanation of earthquakes and volcanic eruptions as produced by subterranean vapors and gases heated by the Earth's internal heat. However, his greatest contribution to palaeontology was his book De Natura Fossilium, also published in 1546. This book is not restricted to what would be called fossils today.  The Latin word fossilis meant anything dug out of the ground, and Agricola's book included descriptions of all kinds of minerals, gemstones, and even gallstones. As a good humanist [see the article by Owen Hannaway], he summed up what the ancient authors had written about minerals, and included a list of a hundred authors whose he had consulted, but he took his own experimental and observational experience as the touchstone of truth.  His work on rocks and minerals in that it classified them, not alphabetically or by their supposed powers, but by simple physical properties: "Thus minerals have differences which we observe by color, taste, odour, place of origin, natural strength and weakness, shape, form, and size." His work is thus comparable to the work of other natural historians, of the Aristotelian rather than the Plinian tendency.  Agricola gave standardized names to various minerals, and not only recorded their appearance but the localities where they could be found. He also noted how the same fossils might have different colours and appearances in different places. Although Agricola's early works included no pictures, his descriptions of fossils are clearly recognizable:

"Lapis judaicus. . . usually occurs in the form of symmetrical acorns. Prominent lines run from the blunt to the pointed end and these are so regular they appear to have been made in a lathe and resemble the striae on a shell. The people who call this mineral pyren liken these lines to the bones of a fish that extend from the back down to the belly. . . When split open it is light inside and glistens like marble and in some cases the outside also has a high lustre."

"Certain rocks, when split open, are found to contain shells; for example, the conchites beds of Megara and the rocks of France. . . Ostracites is a stone that takes its name from ostreum [oyster] which it resembles. There are two species, the larger found in the moat on the north side of Hildesheim. . . The smaller species is found not far from Hanover on a cliff near the village of Linda in an unctuous light green earth. . .  It forms in strata that are conspicuous. When tapped with the finger it has the sound of a jug."

Agricola noted the resemblance of many of his "fossils" to living organisms, but rarely stated that any of
his fossils actually did represent once-living organisms.  He rejected many popular beliefs but listed the magical and medicinal uses to which rocks, minerals and fossils were put: powdered lapis judaicus (the blastoid echinoderm Pentremites) was prescribed for kidney stones, while ostreites (fossil oyster shell), moistened with water, "reduces inflammation of the breasts, heals ulcers and is poisonous to crawling insects."

His magnum opus, the posthumous De Re Metallica (On the Nature of Minerals, rather than "metals" in the modern sense) reviewed everything then known about mining, including equipment and machinery, means of finding ores, methods of surveying and digging, assaying ores, smelting, mine administration, and the occupational diseases of miners. In this last respect, he was a pioneer, as little was written about occupation-specific ailments other than those of princes and scholars until the work of Ramazzini, 150 years later.  The book also contains descriptions of ores and of strata. His book was profusely illustrated with woodcuts [see below]. Agricola noted that rocks were laid down in definite layers, or strata, and that these layers occurred in a consistent order and could be traced over a wide area.

Selected images of mining machinery from De Re Metallica, in PDF files; click on icons for explanation

Ore hoist          To remove ore from the mine; simple windlass with
                        handcranks lowers and raises ore buckets on a rope in a
                        vertical mining shaft.                                                            Agricola, 161

Water hoist      To remove water from the mine; endless chain of water
                       dippers in a vertical shaft, manually powered by a treadmill.     Agricola, 174

Sump pump     To remove water from the mine; hand-operated sump
                       pump for a vertical shaft                                                        Agricola, 177

Ventilating fan  To ventilate mine shafts; three hand and wind operated fans     Agricola, 205

Ventilating bellows   To ventilate mine shafts; hand operated                           Agricola, 209

Assay furnace   To smelt small samples of metal ore for purposes of
                        assaying, (determining the amount of metal in the ore)            Agricola, 223

Bellows for assay furnace      To provide a blast of air to raise the
                                            temperature of the assay furnace                       Agricola, 227

Crushing gold and silver ore    Cottage setting for manual hammering
                                             to break up gold and silver ore for smelting        Agricola, 270

Crushing roasted ore     In Westphalia, Germany, miners roast ore, then
                                   break up the ore with hammers on a stone pavement    Agricola, 272

Roasting ore     Variety of methods for roasting ore to remove sulphur and
                       other impurities                                                                      Agricola, 277

Stamping mill   Stamping mill for crushing ore into smaller pieces, powered
                       by a water wheel                                                                    Agricola, 284

Making Stamps   Workers make parts of stamps before assembly                      Agricola, 285

Sieves            Workers use different sieves to separate ore into different
                      crushing sizes                                                                           Agricola, 289

Grinding mill   A mill, powered by a water wheel, constructed to grind
                      copper or tin ore into a power, similar to a grain grinding mill        Agricola, 294

Power for grinding mill      Four kinds of power are depicted: wind, water,
                                       animal, human.                                                        Agricola, 296

Gold separation tubs          Powered, mechanical wash tubs to separate gold
                                       from its ore with quicksilver (mercury)                       Agricola, 299

Roasting tin      In preparation for smelting (at high temperatures), tin-stone
                        is "roasted" at lower temperature. This burns off impurities.        Agricola, 349

Roasting copper "cakes"    Copper ore heated can produce a cake-like mass of
                                       copper and substances like alum and saltpetre. These
                                       must be removed before smelting. To remove them,
                                       the cakes are roasted in open pits.                               Agricola, 350

Smelters, front view         Front view of smelting furnaces                                   Agricola, 357

Smelters, cut-away view   Smelters, with water trough exposed, forehearths,
                                      and doors and tap-holes indicated                                 Agricola, 358

Smelters, bellows for blast          View of back side of smelter furnace building,
                                                 with water-powered bellows shown                   Agricola, 359

Making furnace liner, "lute", for smelters    Furnace liner, "lute", for the smelter
                                                               is made from ash and earth                 Agricola, 377

Smelter and alloy              The smelter pours alloy out of the smelting furnace,
                                       while another worker pours the allow into a mould.       Agricola, 383

Making steel out of iron    At a forge or a furnace, with bellows for blast,
                                      the smith makes steel out of iron.                                  Agricola, 425

Separating gold from impurities    In a gold shop, gold is separated from
                                                 impurities by heating the ore with reagents.         Agricola, 442

Separating silver from lead   Lead and mercury and other "fluxes" used to separate
                                         silver and/or gold from ore were poisonous. Smelters
                                         had to take precautions to avoid fumes from crucibles
                                         and furnaces. Here, lead is being used to separate silver.
                                         The foreman eats butter to protect against fumes.        Agricola, 474

Plan for gold smelting house  The building is over 264 feet long and 70 feet wide.   Agricola, 493

Agricola, De Re Metallica, trans. Herbert Clark Hoover and Lou Henry Hoover, 1912 (Pbk. reprint, New York, 1950)

Agricola, De Natura Fossilium, trans. Mark Chance Bandy and Jean A. Bandy, Geological Society of America, Special Paper 63 (1955)

Marco Beretta, "Humanism and chemistry : the spread of Georgius Agricola's metallurgical writings", Nuncius 12/1 (1997) 17-47

Owen Hannaway, "Reading the pictures : the context of Georgius Agricola's woodcuts", Nuncius 12/1 (1997) 49-66

Marco Beretta, The Enlightenment of Matter: The Definition of Chemistry from Agricola to Lavoisier (Nantucket, Mass., 1993)

Owen Hannaway, "Georgius Agricola as humanist", Journal of the History of Ideas 53 (1992) 553-560

Owen Hannaway, "Herbert Hoover and Georgius Agricola: The distorting mirrors of history", Bulletin for the History of Chemistry 12 (1992) 3-10  [ND library holdings of this journal start in 1994]

Alan J. Rocke, "Agricola, Paracelsus, and 'chymia' ", Ambix 32 (1985) 38-45
 

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