[This series is a companion to our International Year of the Periodic Table project — Timeline of Elements and Mendeleev Mosaic. Time periods from our timeline project will be featured highlighting the historical and scientific advancements resulting in the discoveries of the elements of that period. Jim Marshall researches the history of the discovery of the elements. His studies have carried him to over 20 countries where he has photographed and documented specific sites which he describes in his publications on chemical history. Explore the artwork for the Timeline of Elements for Miners with individual discovery stories of each element with acknowledgement to artist(s), teacher, school and countries on our Timeline of Elements website. ]
Modern science depends upon both theory (basic science) and technology (practical applications). Likewise, progress during the Middle Ages depended upon both theory and technology — as the alchemists were plodding along with their secret recipes and cryptic writings, the practical miners were advancing their techniques for extracting the metals from the ores for spears, plowshares and ornaments.
A marvelous volume was produced by Georgius Agricola (1494-1555) toward the end of this period. This work, entitled De Re Metallica (“About Metal”) described the complete production of metals from ores, including prospecting, mining, smelting and assaying. This 650-page book includes spectacular woodcuts which meticulously describe the methods of the time. Originally written in Latin, De Re Metallica was translated into English by Herbert Hoover (who before his Presidency had earlier been a mining engineer) and his wife Lou Henry Hoover. Different methodologies were used for different metals and different ores. Mercury, for example, was produced by merely heating the ores. Indeed, cinnabar and other mercury ores commonly show a metallic “sweat” in nature. Other metals, such as lead, required a more elaborate scheme of roasting litharge and other lead ores. Copper was the main structural metal to be smelted; it comprised the tools used by the ancient Egyptian pyramid builders. Mixed with tin, copper would form a fine alloy used in statues. Iron, the most difficult of the ancient metals to smelt, required special reducing conditions and a hotter temperature, and the use of iron lagged behind that of copper.
The mines of these times were dark and spooky places. Illumination was provided by flame and was meager. Every corner of the mine was shadowy and hid mischievous gnomes and goblins who caused havoc with the mining and smelting processes. In church the miners and their families would pray for safety and protection from these evil spirits.
The ancient miners had good cause to be confused, because nickel and cobalt ores that appeared like common copper ores did indeed give them cause to think that gnomes were busy in their mischievous ways. A notable example of how these gnomes would “play tricks” on the miners were their ability to cause “copper ores” to sometimes not behave properly in the smelting process. What the miners did not know was that niccolite, (NiAs, also known as nickeline), of a pale copper-red color, could alter with time (oxidize) to annabergite, Ni3(AsO4)2∙8H2O, of an applegreen color. This transformation from red to green color precisely mirrors the behavior of copper. The Statue of Liberty, for example, is constructed of copper but with age acquires a pretty green patina of malachite, Cu2(CO3)2(OH)2. Thus, the miners would conclude that sometimes copper ores were hexed by Satan. Likewise, the similar appearances of “cobalt blue” and azurite, Cu3(CO3)2(OH)2), were equally mystifying to the ancient miners.
The Scandinavian miners
The ingenuity of the miners unraveled the complexities of their trade, mysteries were being resolved, and more and more metals were being discovered. The problems of cobalt and nickel were resolved by Swedish chemists. Brandt in 1737 was able to isolate a metal as an impurity from Scandinavian ores and was able to show that this new substance was the cause of the difficulty in smelting copper and iron ores. He named this metal after the German “Kobold” — gnome — and thereby discovered cobalt. Cobalt had actually been known for hundreds of years as a blue compound, used in glass — known today as “cobalt blue glass.” Cronsted, a Swedish mineralogist, likewise investigated the “green ores” of the Scandinavian mines and was able to isolate another of these troublesome impurities. He named the new metal “nickel” after the German “Kupfernickel,” another one of the meddling “devils” in the smelting process (“nickel” means “Satan”).
Perhaps the most gifted chemist of all was Scheele, who discovered tungsten, a heavy metal (the name is derived from the Swedish name for “heavy-stone”). Scheele also extracted molybdenum from molybdenite (molybdenum sulfide) by the reaction of the ore with nitric acid, then charcoal. Scheele also recognized barium as an “earth” similar to but separate from calcium. Scheele also chanced upon a toxic gas emanated when pyrolusite (manganese oxide, used as a decolorizer in the preparation of glass) was treated with hydrochloric acid; this gas was chlorine, which may have contributed to Scheele’s early demise (he died at the age of 44). The chemist who actually discovered manganese as an element was another Swede, Gahn, who isolated it from pyrolusite. And another Swede, Ekeberg discovered tantalum from feldspar quarries in Sweden and Finland.
Berzelius of Stockholm, Sweden discovered selenium isolated from the dregs of sulfuric acid vats, cerium from minerals in an iron mine, zirconium from India semi-precious gemstones (zircons), and silicon from quartz found in Sweden. Yttrium was isolated by Gadolin in Finland from a strange black ore (gadolinite, a rare earth calcium silicate) from a mine in Ytterby, Sweden which furnished feldspar and quartz for the porcelain trade in Great Britain and Poland. Gadolin, also, was a Swede, working in southwest Finland, at that time a territory of Sweden.
Mainland European discoveries
Charles Hatchett, an English chemist, discovered niobium from a sample of columbite (calcium niobate) originally found in New England of the United States. This sample of columbite had been collected by Native Americans and finally found its way into the collections of the British Museum in London. This metal, originally named “columbite”, was confused with chemically similar tantalum discovered by Ekeberg; later the German chemist Heinrich Rose distinguished the two and named “columbite”, was confused with chemically similar tantalum discovered by Ekeberg; later the German chemist Heinrich Rose distinguished the two and named the New England element “niobium” (for many years this element was called “columbium” by the New World).
Vauquelin, a French mineralogist, discovered chromium in “red lead from Siberia” (crocoite, lead chromate), an unusual mineral found in the gold mines of the Ural Mountains. Vauquelin also discovered beryllium in emeralds from Peru.
Stromeyer, a German pharmacist, was curious about a yellow impurity in a medical zinc (calamine) preparation and found cadmium, whose chemical properties were similar to those of zinc. Uranium was discovered by the German Klaproth as a constituent of “Pechblende” (“worthless ore”) mined at the German-Bohemia border, which interfered with the silver production process.
Tellurium was discovered by von Reichenstein in the gold mines of Romania, from a strange black mineral that “bled” gold when heated – the mineral was nagyagite, a lead-gold-telluride/sulfide.
Strontium from a lead mine in Scotland was recognized by Hope of Edinburgh as an earth separate from barium and calcium, even though it was very similar. Also in Edinburgh, Black distinguished magnesium, found in salts from Epsom, England (Epsom salts are magnesium sulfate), as being similar to, but different from calcium. Titanium was discovered in “magnetic black sand” in Cornwall, England by Reverend Gregor, known as the “Scientific Parson”.
North American discoveries
Andrés del Río, a professor of mineralogy at the School of Mines in Mexico, isolated a new metal he named “erythronium” in “brown lead from Zimapán, Mexico” (vanadinite, lead vanadate chloride). Owing to Old World arrogance, del Río was refused recognition of this metal in Europe. The element was “rediscovered” by Sefström in Sweden, who named the metal “vanadium,” but he recognized his material was identical to del Río’s erythronium.
The platinum metals
Platinum was originally discovered in 1735 in the river sands of South America; upon closer inspection crude samples of platinum also
yielded four new similar elements in lesser concentration. These careful separations and characterizations were made by two British chemists in 1803-1804 – Wollaston (palladium and rhodium) and Tennant (iridium and osmium). These additional metals became more plentiful with the major Russian discoveries of platinum and associated metals in the Urals; the first commissioned mine in Russia was in 1824, twenty years after the work of Wollaston and Tennant.
Slowly the list of metals was growing, and each was recognized as unique — but the similarity of many of them with one another, leading to “chemical families”, was noted but not understood. Somebody had to make sense out of this hodgepodge of metals! Technology had far outstripped theory. Obviously the alchemist’s doctrine of a mingling of mercury and sulfur was woefully inadequate to explain the riches spewing from the mines and hillsides of Sweden, England, Transylvania, Mexico and the U.S. Meanwhile, the universities were questioning the basic tenets of Aristotle — how could fire, earth, water and air account for such a diversity of metals? The time was ripe for a profound change in philosophy and a recantation of two thousand years of pedagogical dogma. The next chapter tells this story — but you will have to wait until the April issue.
Photos taken from J. L. Marshall, Discovery of the Elements, Peterson Custom Publishing, 2002.