Monthly Archives: April 2015
a tunnel beneath a Mexican pyramid, a finding that could suggest the existence
of a king’s tomb or a ritual chamber far below one of the most ancient cities
of the Americas.
he had discovered “large quantities” of liquid mercury in a chamber below the
Pyramid of the Feathered Serpent, the third largest pyramid of Teotihuacan, the
ruined city in central Mexico.
(Feathered Serpent) Temple near the Pyramid of the Sun at the Teotihuacan
archaeological site, north of Mexico City. Photograph: Henry Romero/Reuters
which was unsealed in 2003 after 1,800 years. Last November, Gómez and a team
announced they had found three chambers at the tunnel’s 300ft end, almost 60ft
below the the temple. Near the entrance of the chambers, they a found trove of
strange artifacts: jade statues, jaguar remains, a box filled with carved
shells and rubber balls.
corridor beneath the pyramid, battling humidity and now obliged to wear
protective gear against the dangers of mercury poisoning, Gómez and his team
are meticulously exploring the three chambers.
through prolonged exposure; the liquid metal had no apparent practical purpose
for ancient Mesoamericans. But it has been discovered at other sites. Rosemary
Joyce, a professor of anthropology at the University of California, Berkeley,
said that archaeologists have found mercury at three other sites around Central
that his team is close to uncovering the first royal tomb ever found in Teotihuacan
after decades of excavation – and centuries of mystery surrounding the
leadership of the cryptic but well-preserved city.
Gómez postulated, an idea that resonated with Annabeth Headreck, a professor at
the University of Denver and the author of works on Teotihuacan and
have resembled “an underworld river, not that different from the river Styx,”
Headrick said, “if only in the concept that it’s the entrance to the
supernatural world and the entrance to the underworld.”
world, they were a way to divine what might happen in the future,” she said.
“It could be a sort of river, albeit a pretty spectacular one.”
fascinated the ancient people generally, and that the liquid mercury may have
held been regarded as “somewhat magical … there for ritual purposes or symbolic
fascination: “a lot of ritual objects were made reflective with mica,” a
sparkling mineral likely imported to the region.
which they dubbed “disco balls” in an un-excavated portion of the tunnel, near
pyrite mirrors. “I wish I could understand all the things these guys are
finding down there,” Headrick said, “but it’s unique and that’s why it’s hard.”
Mesoamerica, who knew of underground water systems and lakes that could be
accessed through caves. Teotihuacan once had springs as well, though they are
now dried out.
mercury by heating mercury ore, known as cinnabar, which they also used for its
blood-red pigment. The Maya used cinnabar to decorate jade objects and color
the bodies of their royalty, for instance; the people of Teotihuacan – for whom
archaeologists have not agreed on a name – have not left any obvious royal
remains for study.
Teotihuacan was ruled, and Joyce said that the concentration of artifacts
outside the tunnel chambers could be associated with a tomb – or a set of
city, which flourished between 100-700AD, was ruled by dynasties in the manner
of the Maya, though with far less obvious flair for self-glorification.
may fit with a competing idea about the city. Linda Manzanilla, a Mexican
archaeologist acclaimed by many of her peers, contends that the city was
governed by four co-rulers and notes that the city lacks a palace or apparent
depiction of kings on its many murals. The excavation by Gomez my find one of
those co-rulers, under this hypothesis.
lineages or clans traded rule but never cemented into dynasties, or in which
the rulers relied on agreements with the military to maintain power, and
authority was vested more in an office than a family. Ancient Teotihuacan was a
city with familiar factions vying for influence: the elite, the military, the
merchants, the priests and the people.
digging and deducing. Gomez says he hopes excavation of the chambers to be
complete by October, and Headrick said that archeologists are looking at the
city from new angles. Some are trying to decipher the paintings and
hieroglyphics around the city, others trying to parse what may be a writing
system without verbs or syntax.
unprecedented and bizarre, that Gomez and his fellows are disinterring from
beneath the pyramid. “It’s quite the mystery,” Headrick said. “It’s fun.”
via Blogger http://ift.tt/1Ew5VC7
árguros, Latin: argentum, both from the Indo-European root *h₂erǵ- for
“grey” or “shining”) and atomic number 47.
lustrous transition metal, it possesses the highest electrical conductivity of
any element, the highest thermal conductivity and reflectivity of any metal.
The metal occurs naturally in its pure, free form (native silver), as an alloy
with gold and other metals, and in minerals such as argentite and
chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead,
and zinc refining.
abundant than gold, silver metal has in many premodern monetary systems
functioned as coinable specie, sometimes even alongside gold. In addition,
silver has numerous applications beyond currency, such as in solar panels,
water filtration, jewelry and ornaments, high-value tableware and utensils
(hence the term silverware), and also as an investment in the forms ofcoins and
specialized mirrors, window coatings and in catalysis of chemical reactions.
Its compounds are used in photographic film and X-rays. Dilute silver nitrate
solutions and other silver compounds are used as disinfectants and
microbiocides (oligodynamic effect), added to bandages and wound-dressings,
catheters and other medical instruments.
via Blogger http://ift.tt/1D6Yz3G
|Electrolytically refined silver|
via Blogger http://ift.tt/1EzmwoW
1959 – NASA selects first US astronauts.
via Blogger http://ift.tt/1NeYPrF
Stained glass can refer to coloured glass as a material or to works created from it – most commonly seen in the stained glass windows of churches and other buildings. Coloured glass is also found in everyday life such as green wine bottles.
As a material stained glass is glass that has been coloured by adding metallic salts during its manufacture.
There are two main types of glass – soda lime glass – commonly used in beverage bottles and the like and borosilicate glass – used in laboratory glassware and also some domestic glassware such as oven proof dishes.
Coloured glass is made in a number of ways. There are three main ways.
The first involves introducing metallic or rare earth metal oxides to the glass as mentioned above.
Silver compounds for example such as silver nitrate are used as stain applied to the surface of glass and fired on. They can produce a range of colours from orange-red to yellow. The way the glass is heated and cooled can significantly affect the colours produced by these compounds.
Another way is by formation of colloidal particles. This means particles of a substance are suspended throughout the glass. The particles scatter light of particular frequencies as it passes through the glass, causing colouration.
Gold gives a ruby red colour, and selenium gives a pink to intense red.
The final main way in which colour can be introduced is through the addition of already coloured particles to the glass. Examples of this type of colouration include milk glass and smoked glass; milk glass is achieved by adding tin oxide.
The infographic below from Compound Interest shows what chemicals are involved in the colour process. Click for a larger image.
|Click to enlarge|
via Blogger http://ift.tt/1HrX9E2