Wednesday, 24 July 2013

The Special Product of Gold

Gold Car
As early master goldsmiths, the Etruscans attempted another, more personal ornamental and decorative gold working skill using the metal in dentistry. Broad bands of gold were attached to the Etruscan patient's existing teeth to help set in place artificial teeth carved from bone or ivory. Teeth in gold or I simply calves' teeth were used to fill gaps. Dentists of the period also secured loose teeth with bands of gold wire.

The Greeks, for all their substantial intellectual contributions to civilization, contributed little to the technology of gold mining and gold working. The Romans, however, were more concerned with practical matters. They developed various mining techniques. Pliny the Elder (AD 23-79) was, for a short period, governor of the conquered provinces of Spain which dispatched considerable amounts of gold to Rome. He left behind a vivid account of gold mining in Asturias, Galicia and Lusitania.

The hunger for gold, particularly among the rich and powerful, never ceased to grow. Known sources of gold were, however, exhausted over comparatively brief periods. It was therefore not surprising that, in the early Middle Ages, the idea of deriving gold from "baser metals" was widely promoted. It was to produce unexpected results.

Gold HomeThere was nothing new to the idea of making gold from other substances. Old papyri tell of Egyptian foundry men who produced an alloy of copper, tin and zinc which proved to be similar to gold in color. There was also malachite, the beautiful green veined stone which, when heated to high tempera tures, produced a lump of copper. Why then should t there not be a stone which could be made into gold? The belief that gold could be made from "lesser" substances can be traced back to ancient Egypt; so can the word for the process alchemy.

The European alchemists of the middle Ages were under strong pressure from their feudal patrons to produce gold. They failed. It was their latter day colleagues the atomic physicists who would succeed, although the cost of the process they would use would far exceed the value of the metal produced. However, the dream of making gold in a laboratory produced a rich harvest of 'non golden chance results over the course of time. Those medieval alchemists, with their steaming brews and bubbling phials, achieved an insight into the relationship between materials which they might not have attained had they not been fruitlessly seeking gold. Without the efforts of t those luckless experimenters, the birth of modern chemistry might have been considerably delayed.

Gold Scorpion
An unsuccessful attempt to make gold is said to have led the fourteenth century German Franciscan monk Berthold Schwarz to the invention of gunpowder, the use of which revolutionized warfare in the late middle Ages. Johann Kunckel (1630-1703) was awarded a barony and the aristocratic name of von Lowenstern because he accidentally dropped a piece of gold wire into a chemical solution, thereby producing, not gold, but deep ruby red glass. It earned a fortune for his patron, a Saxon duke.

Johann Friedrich Bottcher was less lucky. In 1708 when his abortive effort to produce gold led instead to the first European commercial production of porcelain (it had been made in China long before), he was punished rather than rewarded. Fearing he might betray the secret of this profitable discovery to others, his patron, another Saxon duke, took the precaution of having him locked away in prison.

The long adventure and dream of the alchemists was finally brought to an end when Dmitri Ivanovich Mendeleyev (1834-1907), professor of chemistry at St. Petersburg University, formulated the periodic table of elements. For the first time, a coherent, reasonably comprehensive system was devised to classify all the known elements according to their distinctive properties. No longer could serious persons suggest that one element could be transformed into another. (Renewal of such suggestions was to await the dawning of the nuclear age.)

Geographic Ramifications of the Gold Quest

Chemistry was not the only science in which new in ground was broken in the search for gold. Geography also made spectacular advances. Christopher Columbus and his fragile flotilla set sail to find a short route to a land of gold to the cast and he discovered America by mistake. The Spanish conquistadors who followed in his wake were motivated less by a hankering for new horizons than by an insatiable hunger for gold. It was a hunger which resulted in the sacrifice, in the name of their God and their Christian rulers, of many thousands of the Indians they encountered in Mexico and in Central and South America.

It was also an epoch which saw considerable technological advances in gold mining and processing. Bartholomaus and Anton Weiser, wealthy merchants and financiers from the German town of Augsburg, received from the Spanish throne authorization to dig for gold in the colony of Venezuela. The Weiser brothers wanted to employ a new technique for the separation of gold from rock, the technique of amalgamation. Some historians suggest that this sixteenth century invention was really rediscovery and that the Romans had already used it as early as the first century AD.

Gold GunThe Weiser expedition ended in bankruptcy. No gold was found in Venezuela. The journeys the brothers made between 1528 and 1546 proved to be in vain and the mining rights reverted to the Spanish throne. Gold was, however, discovered in adjacent Colombia. Between the middle of the sixteenth century and the beginning of the nineteenth century, Colombia could be credited with about a quarter of the world's gold production.

The Welsers had been unlucky, but some of their ideas like the amalgamation process proved revolutionary. Amalgamation involves extracting gold from its ore in the form of an alloy or amalgam with the use of mercury. The lighter rock moves to the surface of the ore and can be removed without further processing. Most of the gold can be removed from the amalgam simply by pressing it out. The remaining metal alloy can be distilled away at temperatures of about 360 degrees centigrade. The mercury evaporates and gold is left. Amalgamation eventually became the most important gold processing technique in use until the end of the nineteenth century. The method, so much simpler and more effective than anything known before, made possible a substantial increase in gold production.

No comments:

Post a Comment