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Sergey Venezky
STORIES ON METALS

LEAD

DESTROYED ROME

Watchful geese. - The sad fate of the patricians. - In the service of the Inquisition. - Secrets of the Brahmans. - Screams of horror on the Bridge of sighs. - A strong argument. - Eighty years under water. - Invalid "Amateur". - Clouds over the city rose. - In the snows of Greenland. - A pillar of ice. - To set the box office. - Heavy writing. - Under the tinkling of crystal. - "Made in Rodos". - Fire in the Athens port. - Are there miracles? - Tricks "the Peruvian artist. - Poisonous "sugar". - In offense and defense. - Mini-window. - Finding under a layer of ash. - Beetles are no "breaks". - In the gardens of Babylon. - One in ten million. - Why the secrecy? - Family ties. - A cat named cat.

Rome was saved by geese is known to all. Vigilant birds timely notice of the approach of enemy troops and immediately a sharp guttural sounds signaled danger. This time for the ancient Romans, all went well.

However, the Roman Empire was destined subsequently fall. What caused the fall of the once powerful state? What destroyed Rome?

Ancient Rome were poisoned by lead" - this is the conclusion of some American and canadian scientists, toxicologists. In their opinion, the use of lead containers (bottles, glasses, cups) and cosmetic paints containing lead compounds, lead to chronic poisoning and the extinction of the Roman nobility. It is known that many emperors who ruled Rome in the first centuries of our era, i.e. in the last period of the Empire, suffered these or other mental illness. The average life expectancy of Roman patricians did not exceed 25 years. People of lower classes to a lesser extent were exposed to lead poisoning because they didn't have expensive dishes and did not use cosmetics. But they enjoyed the famous water supply, "Srebotnik still slaves to Rome", and pipes, as is known, were made of lead.

People have died, the Empire languished. Of course, the blame was not only the lead. There were more serious reasons - political, social, economic. And still some truth in the arguments of American scientists certainly have: discovered during the excavation of the remains of the ancient Romans contain large amounts of lead.

All soluble compounds of this element are poisonous. It is established that the water that fed the Ancient Rome, was rich in carbon dioxide. Reacting with lead, it forms highly soluble in water, carbonic acid lead. Coming even in small portions in the body lead is delayed in it and gradually replaces the calcium, which is part of the bones. This leads to chronic diseases.

On the "conscience" of lead is not only ruined Rome, but other dark deeds. During the Inquisition, the Jesuits used molten lead as an instrument of torture and execution. In India in the beginning of the last century, if a man of low caste, deliberately or accidentally overheard the reading of the sacred books of the Brahmans, he poured in the ears melt lead (in order to preserve their power over the people, the priests of Babylon, Egypt, India has long kept their knowledge in secrecy).

In Venice preserved medieval prison for state criminals, connected by the Bridge of sighs with a remarkable architectural monument of the Doge's Palace. In the attic prison had a special camera under the lead roof for very guilty. In the summer the prisoners here were dying of heat in the winter - was style from the cold. And on the Bridge of sighs were heard cries of fear...

Since invented firearms and lead began to cast deadly bullets for rifles and pistols, he became one of the most compelling arguments in a dispute warring parties. Lead not just decide the outcome and grandiose military battles, and small gang fights.

It may seem that, in addition to damage from lead won't get anything, and so the nearest and the main task of humanity is to rid this evil metal, already brought so much misery and grief. But people do not strive for such a deliverance, but on the contrary, constantly expanding production of lead. Of all non-ferrous metals only aluminum, copper and zinc are produced in larger quantities than lead. What useful activities in this metal?

History knows many examples when people were just war for their freedom and independence - and in this struggle they were helped lead. To be sure in the safety of their borders, it is necessary to have not only the powder in the tank, but all the same lead. That's why the military value of this metal is very great.

When the development of technology has led to the creation of automobiles, submarines, aircraft, and the emergence of chemical and electrical industry, in the production of lead has been especially rapid growth.

Back in 1859 by French physicist Gaston Plante invented the chemical current source - lead battery. Over the past hundred years in the world made a huge number of these simple but reliable device for energy storage: about a third of total world production of lead is spent on the "needs" of the batteries. Recently English divers, who were involved in the rise of the submarine that sank in the beginning of our century, found and raised to the surface of the lead battery. What was their surprise when it turned out that, having been under water neither little nor a lot of eighty years, he still gives you the current.

The original project was developed in the United States: in Michigan you plan to build a colossal dimensions battery lead acid batteries, which will be entrusted with the important mission - to meet the needs of staff in peak power. To charge this battery, weighs almost 3 thousand tons, will be during the hours when the energy consumption is usually observed a marked decline.

Lead contaminates the environmentLargest consumer of lead - fuel industry. In gasoline engines fuel mixture before burn, compress, and the stronger it is the compression, the more efficient the engine is running. But with a significant degree of compression of the fuel mixture explodes, not waiting when it will fire. Naturally, such "Amateur" is invalid. Came to the aid of tetraethyl lead. Small additives to the gasoline (less than 1 gram per liter) prevent explosions, causing the fuel to burn evenly, and most importantly - at the very moment when it is needed.

As tetraethyl lead is very poisonous, leaded gasoline, paint in pink, green, orange-red, and others (depending on the brand) color to distinguish it from the ordinary.

Unfortunately, significant amounts of toxic substances emitted by motor engines with exhaust gases. Scientists at California Institute of technology (USA) has estimated that over large cities are worn clouds of lead (as you can see, the literary epithet "leaden clouds" may have a literal meaning): for the year only over the oceans and seas of the Northern hemisphere there is about 50 thousand tons of metal, formed mainly of additives to gasoline. Here you have 1 gram per liter! The lead car of origin was detected even in the snows of the Arctic. Assistants needed 'a replacement for tetraethyl lead and has already achieved some successes.

Interesting data obtained from the analysis of the Greenland firn (snow). The firn samples were taken from different horizons corresponding to a particular historical period. In samples dated to the eighth century BC, for every kilogram of firn found no more 0,0000004 milligram of lead (this figure is taken as the level of natural contamination, the main source of which is a volcanic eruption). Examples relating to the mid-eighteenth century (the beginning of the industrial revolution), contained lead at the age of twenty five times. In the future, it began a real "invasion" of this element in Greenland: its content in the firn samples taken in the upper horizons, i.e. relevant to our times in five hundred times the natural level.

Richer lead the eternal snow of the European mountain ranges. So, its content in the firn of one of the glaciers of the High Tatras in the last hundred years has increased approximately fifteen times. If we start from the level of natural concentrations, it appears that in the High Tatras, near industrial areas, this level was exceeded by nearly two hundred thousand times!

Recently the object of study by Swedish scientists began centuries-old oaks growing in a Park in Central Stockholm. It was found that the lead content in the trees, numbering four hundred years, have recently dramatically increased along with the growth of vehicle traffic. So, if in the last century in the wood of these oak trees contained only 0,000001 % of lead by the middle of the XX century lead "supply" has doubled, and by the end of 70-ies has increased about ten times. Especially rich in lead that side of the tree that faces the road and therefore more exposed to the exhaust gases.

At the world exhibition "Expo-75", held in Japan on the island of Okinawa, the attention of visitors was attracted by the unusual exhibit - thirty-meter column of ice, cut from the iceberg, the age of which is approximately three thousand years. Research conducted by scientists from Japan, the USA and the USSR, have shown that in recent decades the iceberg had to "adopt" a considerable amount of lead is the result of rapid development of road transport.

In the modern technology have lead a lot of other activities. In the electrical industry, for example, the metal serves as a reliable and sufficiently elastic sheath cables. A significant number go on manufacturing solders. Chemical plants and nonferrous metallurgy enterprises to protect equipment from corrosion produce Svencioniu (coating a thin layer of lead) of the inner surface of the chambers and towers for the production of sulfuric acid, pipes, etching and electrolytic baths. In many machines and mechanisms can be found bearing alloys of lead with other elements.

One of the lead alloys worth discussing in detail. Together with antimony and tin lead for several centuries is part of the HART - typographic alloy, which makes the fonts and other elements for books, Newspapers and magazines. Very figuratively appreciated the role of the lead German educator of the eighteenth century, Georg Christoph Lichtenberg: "More than gold, " he wrote, " the world was changed by the lead while the lead is not from the barrels of guns and lead-out gang of cash".

The truth note that the lead had a rather direct relation to writing long before the great German inventor Johannes Gutenberg used the metal for casting printing type. Not so long ago the Soviet archeologists found on the island of Berezan, located in the Black sea at the entrance to the Dnieper estuary, Greek letter on a thin lead plate, rolled into a tube. Equally weighty message was found during excavations of the ruins of the ancient city of Olbia, on the banks of the bug. This type of correspondence was widespread in Ancient Greece, but before modern scientists "came" only five lead letters. Why are these metal scrolls - a rarity? Because, completely ignoring the interests of their curious children, the recipient had read the letter, used it then for the manufacture of weights and sinkers, for roof repairs and other utilitarian purposes.

Letter found on Berezan, dates from the sixth century B.C. In it some of Achallader tells the Anaxagoras about the quarrel over slaves. In another letter relating to the IV century BC, one of Batikan shares with his friend Diplom feelings about the failed trial. So after two and a half millennia lead told historians about some touches of life and social relations of the Greek colonists, then developing the black sea.

In our days multifaceted application find lead compounds. For several centuries the world famous crystal glass, clear as the morning dew, pleasing cheerful play of light and pure melodic sound. And his appearance crystal must... the occasion and lead. In the early seventeenth century English glassmakers moved with wood heating for coal. All would be well, if not soot, which has become much more: getting into the glass mass, the particles of soot did the glass is dark and muddy. To avoid this, the glass began to boil in covered pot, but it is often not cooked, and then, specifically in 1635, the master glass cases decided to add in the weight of the lead, Ponizovsky the temperature of its melting point. And a miracle happened: the glass from the new glass sparkled like a diamond, and gave birth to a charming bells. By similarity with beautiful natural rock crystal lead glass also became known as crystal. So, thanks to lead people found a wonderful material from which made a truly amazing product.

But one of the "lovers" of lead crystal, in contrast, brought a big disappointment. Once the relevant authorities investigated the case of fire. The house burned to the ground, but fortunately for the owner, and all property was fully insured and he was a respectable sum, because, according to him, among other things, the house was kept a valuable collection of crystal - fire turned it into a shapeless pieces of glass-like mass. However, workers who conducted the investigation of the fire, doubted that it was "the remains of the crystal and sent them for examination. And that's fluorescence analysis showed that the lead content in the investigated substance is extremely small, while in the crystal it must be present in significant amounts. As a result, the crystal was ordinary glass, and the case of fire - a case of arson. As it turned out, the owner of the house had previously removed all valuables, replaced the crystal glass, and then set fire to his house and began to patiently wait for a large insurance claim. But prevented the lead.

Long known and paints containing this element. White lead, for example, were able to produce more than three thousand years ago. The largest supplier white was considered in those days the island of Rhodes. The way here was made the paint was not perfect, but fairly reliable. In the barrel poured the vinegar solution from the top to the put Bush branches, and on these pieces of lead, after which the barrel tightly corked. When after some time they were opened, the lead was covered with white bloom. They were white. They scraped with metal, Packed in containers and exported to various countries.

Once in the Athenian port of Piraeus, where there was a ship with a cargo of white lead, a fire broke out. Nearby at this time was a painter nicias. Knowing that the burning ship paints, he took it, hoping to save at least one barrel paint then were expensive, and to get them sometimes was not easy. To the surprise of her life in charred barrels he saw not white, and some thick mass of bright red color. Choose one of the barrels, the artist left the ship and hurried into his workshop. The contents of the barrel proved to be an excellent paint. She was subsequently called minium and began to get without burning through white lead.

Minium was opened by fire in the Athenian port

It is known that the paintings and icons painted with lead paint, eventually darken: under the action of traces of hydrogen sulfide, is always present in the air, formed a dark lead sulphide. But it is necessary to wipe the image of a weak solution of hydrogen peroxide or vinegar as paints again become bright. Sailors, floating near the Pacific coast of Latin America (in particular, off the coast of Peru, where some of the layers of water rich in hydrogen sulphide), familiar with the works of "the Peruvian artist. So, as a joke, they call the phenomenon causing to be surprised and dismayed uninitiated passengers: liner, a former yesterday evening white in the morning was completely black. And the blame for this, as you already know, was the lead.

In medicine lead compounds used as astringent, analgesic and anti-inflammatory agents. Acetate of lead, for example, known as "lead lotion". For the sweet taste it is sometimes called lead sugar. But in any case we must not forget that this "sugar" can cause severe poisoning of the body.

Not by chance in the shops and laboratories, where one is dealing with lead or its compounds, take special precautions. Hygienists and engineers in occupational safety is constantly monitored to ensure that the content of lead in air did not exceed permissible limits - within 0.00001 of a milligram per liter. If in the past lead poisoning were occupational disease workers syncopating factories and printing presses, and in our time because of improvement of technologies of production, measures ventilation and dedusting about these diseases almost forgot.

Interestingly, people are not only protected from lead, but protected... lead.

Metallic lead has proven to be one of the most opaque materials for all types of radioactive and x-rays. If you take up the apron of the doctor-radiologist or his gloves, then you will be amazed by their severity: the rubber from which they are made, put the lead - it delays the x-rays, thereby protecting the organism from their destructive actions. In cobalt guns used for the treatment of malignant tumors, speck of radioactive cobalt securely hidden in a lead sheath-pear.

Lead shields are used in nuclear power engineering, nuclear engineering. From radioactive radiation and protects the glass, which consists of the oxides of lead. This glass allows you to monitor the handling of radioactive materials by mechanical arms - manipulator. In the nuclear centre in Bucharest there is a window of leaded glass with a thickness of 1 meter . It weighs more than six tons.

Perhaps our ancestors first became acquainted with lead in the form of nuggetsIn the earth's crust contains relatively little lead is thousands of times less than aluminum or iron. But despite this, he became known to man even in ancient times - about six to seven thousand years B.C. unlike many other metals, lead has a low melting point (327°C) and is in the nature of a rather unstable chemical compounds. This led to the unexpected opportunity of obtaining it. Known, for example, the case when the rich lead the field was discovered in America in the... forest fire: the burnt forest under a layer of ash were found large ingots of lead. The fire melted it from ore, which was under the roots of trees. Probably, in this way the first lead and fell into the hands of the prehistoric inhabitants of our planet.

The most ancient extant product of lead considered Egyptian figure, kept in the British Museum: its age is more than six thousand years. In Spain preserved ancient dumps lead slag: here in the third Millennium BC, the Phoenicians developed a lead-silver mine of Rio Tinto. During the excavation of the Assyrian city of Ashur was found a leaden lump weighing about 400 pounds . Archaeologists believe that it dates back to around 1300 BC

Lead is the softest of all common metals: it is easily scratched even with a fingernail. The famous German zoologist Alfred Edmund Brehm in his popular book "the Life of animals" brings an interesting fact: wasps, seeking to be free, managed to gnaw through the wall in a lead box with a thickness of 43 mm . And some beetles managed to make holes in massive leaden pipes of the city water supply. Scientists interested in this ability beetles, conducted an experiment by placing them in a glass test tube, covered with a thin lead foil. Glass beetles were clearly not on the teeth and the metal seemed insurmountable obstacle: slowly but surely they began to pave the way to freedom, Otkrytaya and throwing tiny particles of lead, visible to the naked eye. Zoologists surprised "brigade" method works insects: all prisoners alternately "drilled" one hole, as if realizing that one pass in the fence will be selected at will. To achieve the goal beetles took only six hours - part-time, but without the "smoke breaks".

The softness of the lead would not allow him to compete with copper, bronze or iron as a material for tools. But manufacturing pipes and other details of the water from this plastic metal was very convenient. We have already mentioned the Roman aqueduct. Recognized as one of the seven wonders of the world, the hanging gardens of Babylon were irrigated with water through a complex system of wells, pipes and other hydraulic structures, also made of lead. In the first half of the XVII century in Sviblova tower of the Moscow Kremlin was built the water tank, lined with lead sheets. Here the water is pumped from the Moscow river, and thence by lead pipes she had entered the Imperial mansion, gardens and other important objects. Since this tower is called the Water.

In ancient times the lead was completed and other work related to water. The ancient Greeks noticed that a poisonous oxides of lead is clearly not to the taste of the shellfish, crustaceans and other inhabitants of the underwater Kingdom, who love to stick to the bottoms of marine and river vessels. This is why the ancient shipbuilders willingly used lead as a ship's plating: "Remora" bypassed it for a mile. In addition, the lead firmly defended the iron plate and ship nails from rusting.

XX century was entrusted to lead a lot of interesting and important things, but also brought him a number of high requirements, in particular in respect of the purity of the metal. In our country developed the method of the so-called amalgam refining, which allowed for the first time in world practice to obtain ultra-pure lead: the fraction of impurities in it have only 0,00001%. This means that a ton of this lead barely manage to scrape together" a tenth of a gram of all extraneous elements, combined!

This could and finish the story about the lead, but we have not yet said anything about the name of this element. The word "lead" is, apparently, from the word "pig" - formerly known as the ingots of the metal (and still referred to as ingots). But before becoming a lead, the metal had to live under other names.

You remember the wonderful tale, SJ Marshak about how a cat called first the sun, then clouds, wind, mouse, and eventually called a cat? Something similar happened with lead.

Look in the dictionary Dahl and you know that saying "the word " tin" refers not to the tin, and lead - metal heavier, more powerful. And she is saying and is used when talking about the word good, faithful, reliable. But why this secrecy? It was easier to say directly: "the word " lead". It turns out that in old Russia the lead was called the tin. The present tin appeared later, and at first he mistook for lead (properties of those metals, indeed, in some degree similar). When, finally, they learned to distinguish, the old name has been secured for the new metal, and its predecessor was called the lead. These metals were confused and Romans. Lead they called "plumbum nigrum" (lead dark), and tin - "plumbum album" (lead white).

"Family" ties between the lead with another metal is molybdenum. In Greek "mo" means "lead". It turns out that in ancient times, many confused the minerals of these metals, Galena and molybdenite, calling both "molibdenos". When after many centuries of molybdenum was obtained a new element, he took the lead of its ancient Greek name.

So a cat called cat - lead became a lead.

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