Silver history

Properties Cobalt History Sources Properties Uses. Copper History Properties Sources Uses Silver History Sources Properties Uses Gold History Sources Properties Uses Zinc History Sources Properties Uses Mercury History Uses Boron History Sources Properties Uses... 

Metal compounds, particularly compounds of the heavy metals, have a history of importance as antimicrobial agents. Because of regulations regarding economic poisons in the environment they are no longer widely used in this appHcation. Mercury, lead, cadmium, uranium, and other metals have been imphcated in cases of poisoning that resulted in government response. The metals whose compounds have been of primary interest as antimicrobials are mercury, silver, and copper. 

Lead, because of its history as an air emission, has been fairly mobile and is particularly soluble in acid environments. Silver is used widely in the electronics industry. Intake of silver compounds can result in permanent discoloration of the skin and may result in damage to kidneys, lungs, mucous membranes, and other organs. 

The elements are obtainable in a state of very high purity but some of their physical properties are nonetheless variable because of their dependence on mechanical history. Their colours (Cu reddish, Ag white and Au yellow) and sheen are so characteristic that the names of the metals are used to describe them. Gold can also be obtained in red, blue and violet colloidal forms by the addition of vtirious reducing agents to very dilute aqueous solutions of gold(III) chloride. A remarkably stable example is the Purple of Cassius , obtained by using SnCla as reductant, which not only provides a sensitive test for Au but is also used to colour glass and ceramics. Colloidal silver and copper are also obtainable but are less stable. 

The use of mercury for extracting precious metals by amalgamation has a long history and was extensively used by Spain in the sixteenth century when her fleet carried mercury from Almaden to Mexico and returned with silver. However, environmental concerns have resulted in falling demand and excess production capacity. It is still used in the extraction of gold and in the Castner-Kellner process for manufacturing chlorine and NaOH (p. 72), and a further major use is in the manufacture of batteries. It is also used in street lamps and AC rectifiers, while its small-scale use in thermometers, barometers and gauges of different kinds, are familiar in many laboratories. 

Bushness, James William. Precious metals trade guide gold, silver, platinum. Woodstock (IL) Trident Publications, 1993. 248p. ISBN 0-9632771-00-3 Includes some historical material on the history of gold, including alchemy... 

Silver Stocks and Losses in Ancient and Medieval Times. Economic History... 

Oddy, W. A. (1991), Gilding An outline of the technological history of the plating of gold on to silver or copper in the Old World, Endeavour 15, 29-33. 

The most definitive diagnosis of AD is a postmortem examination of the brain for the presence of two characteristic lesions the neuritic plaque (NP) and the neurofibrillary tangle. Both structures were originally described in 1906 by Alois Alzheimer using silver-based histological stains. The discovery of NPs was hailed as a watershed moment in the history of neurological disease as it helped shift society s perception of age-related dementia from social stigma to physical disease [2]. 

Silver and mercury salts have a long history of use as antibacterial agents.241-243 The use of mercurochrome ((40), Figure 18) as a topical disinfectant is now discouraged. Silver sulfadiazene (38) finds use for treatment of severe burns the polymeric material slowly releases the antibacterial Ag+ ion. Silver nitrate is still used in many countries to prevent ophthalmic disease in newborn children.244 The mechanism of action of Ag and Hg is through slow release of the active metal ion—inhibition of thiol function in bacterial cell walls gives a rationale for the specificity of bacteriocidal action. 

Metals have characteristics that make them desirable for construction, implements, and ornamental uses such as in jewelry. Metals have been so important that the names Chalcolithic, Bronze, and Iron Age have been applied to epochs of history. Metals have an enduring quality. They are solid, durable, and attractive. The first draft of this passage is being written with a pen made of sterling silver (an alloy consisting of 92.5% silver and 7.5% copper). The lure of metals has drawn adventurers to remote places, and they have been the spoils of war. Their intrinsic value is exemplified by the ornaments we wear and the role of metals in monetary systems. 

Invented by Bartolome de Medina, a Spanish trader, in Mexico in 1554, and used there until the end of the 19th century. The invention changed the course of economic history in all Hispanic America 40 percent of all the silver recorded to have been produced in the world before 1900 was extracted by this process. See also Cazo, Washoe. 

Unfortunately, most early alchemists are unknown, considering that they were very secretive about their methods and left little in the way of written history. Their goals were mystical, economic, secret, unpublished, and unshared. Alchemic practices were also related to medicine as well as rehgion during some periods of time and in some countries. The alchemists main search was for the philosopher s stone that could unlock the secrets of transmutation—that is, the secrets of how to transform base metals and chemicals into different, more useful and valuable products, such as gold and silver. This also led to the futile search over many centuries for the elixir vitae that would be both the universal cure for all illnesses and the way to achieve immortality. 

Copper, being easy to mine and refine, has become a very versatile metal over the course of civilization. Early in human history, it was discovered that soft copper could be made harder and stronger when alloyed with other metals. Copper was and still is important to technology and the development of civilizations. Over the past several thousand years, brass has found multiple uses, such as in coins, cooking utensils, and many types of instruments and hardware that are resistant to corrosion. Even today, brass is used to make musical instruments and bathroom, kitchen, and marine hardware. The U.S. one-cent penny was originally made of copper, but today the penny is made of zinc with a coating of copper. Copper is also an alloy metal used as a substitute for some of the silver in several other U.S. coins. 

There is a long and mixed history for the claims of discovery for ruthenium. In 1748 Antonio de UUoa (1716—1795), a Spanish scientist and explorer, reported finding a special metal in South America. It was silvery-gray and denser than gold, but it did not have the attractive luster of gold or silver. He did know that he had located a new element along with the platinum metal. 

Regulatory facts ATSDR - minimal risk level (MRL) - inhalation 0.2 ig/m3 General facts long history of use, liquid silver evaporates at room temperature, bacteria convert to organic methyl mercury Environmental global environmental contaminant Recommendations avoid, recycle mercury-containing devices... 

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