Also unique for Chinese bronzes is the consistent use of high tin bronze (17-21% tin) which is very hard and breaks if stressed too far, whereas other cultures preferred lower tin bronze (usually 10%), which bends if stressed too far. ([email protected])
Is there a good explanation for why this distinction happened?
Not all blades were constructed in the same way and of the same materials, but the Chinese are noted for originating binary swords.
Ancient Chinese metallurgy recorded six different bronzes. In practice, the archeological record shows a much wider array of proportions, if only because much bronze was likely to have been recycled, but it seems clear that they would have known about the properties of high-tin and low-tin alloys. High-tin bronze is very hard, as you note, and very resistant to corrosion. It thus would not deform in battle (i.e. bend permanently instead of springing back into shape), and would hold its edge for a long time, at the expense of brittleness.
Early high-tin blades in particular tended to be short (50-60cm) on account of the brittleness, but by the late "Spring and Autumn Period" (~500 BC), the Chinese were quite advanced in metalworking, and were casting bimetallic swords. The core of the sword was softer and more resilient low-tin bronze, whereas the edges were formed from harder high-tin bronze.
(from http://thomaschen.freewebspace.com/photo3.html , original source not provided)
One should note also that swords in this period were a weapon of the nobility. Tin was rare in the south, and would have been expensive. This technique was also too complex and expensive for mass production. The primary weapon for foot soldiers of this era would have been the dagger-axes, and later spears and halberds, and it was improvements in ironworking and steel making (originating in the south) in the Han Dynasty that would displace the bronze sword.
I would say it has something to do with the sharpness gained with the high-tin content, according to several sources higher tin content seems to correlate with sharpness. After that it comes down to a fighting style, the Chinese refined the art of fighting (martial arts have been evidenced in China as far back as the 5th century BC while the earliest reference in europe seems to be around 1200 AD), using precise, deliberate cuts with sword, if you ever tried to use a Jian or for that case a Katana (some claim the Japanese learned blade-smithing from the chinese), it would shatter if you bash it against a tree for example (although a seasoned practitioner might be able to cut the tree without breaking the sword although it would probably be seriously damaged), an ancient middle-eastern or medieval blade would likely just warp. This precision in fighting may have the Chinese would prefer sharpnes to tensile strength
(I dunno if brittleness specifically correlates to sharpness as ceramic and obsidian are both very sharp yet very brittle)
First of all, the source given in the Wikipedia article says absolutely nothing about the tin content of bronze swords. In fact, the article does not even say anything about bronze swords at all and all of the bronze artifacts are axes or arrow heads. So the purported fact that Chinese bronze swords had high tin content is not even suggested at all by the referenced article.
As for the tin content in bronzes in general there is a lot of variability. Determining the tin content of an alloy also is not simple and it is easy for an inexperienced metallurgist to make blunders that will have incorrect results.
A third factor to be aware of is that the presence of other metals will have a large effect on the behavior of the primary alloy. For example, a bronze having even a small amount of zinc in it will behave metallurgically much different than one that does not.
Several reasons why this may have happened:
- different composition of the ore. If there were/are copper veins in China with a high amount of tin contamination, it's naturally lead to high tin bronze as a result.
- different needs. Chinese used different style and type of weapons and tools. Maybe those need to be more resistant to bending rather than breaking.
- maybe the Europeans (and others) would have liked to use more tin in their bronze but it was simply not available in the quantities required, so lower concentrations were used for economic reasons.
No doubt the actual reason historically would be a combination of factors like this. If you can only make hard, brittle, bronze, rather than soft, bendable, bronze, the design of the items you make will reflect that. Which tends to resist changing the composition of the alloy if you do get knowledge of the other kind. Why change what works after all (especially in a society as steeped in tradition as China, where anything coming from the outside was viewed with extreme suspicion).
in that time was the essential and typical weapon of the soldier, and used throughout the whole age. It features the convenient hooked blade with the directly-fixed helve and is a similar shape to today's reaphook or sickle. It is the most standard weapon the same as the modern ones.
A Twin Towers' Survivor Story
Saving Venice From the Sea
Stable Isotopes in Forensics
No material is so impressive in its versatility. This follows from nature's own design, endowing woody plants with a great range of strengths, densities, and flexibility. This, in turn, is largely due to the composite structure of the material—generally combinations of strong fibers and tough binders. The result may be dense and heavy, like oak or hornbeam, or soft and light, like balsa. It may be extremely flexible, like willow or laurel, or tough and resistant to change, like teak or mahogany.
Mastery of wood allowed humans to transform rivers and seas from barriers to highways to build fences, homes, and walls, even when little stone was available and to furnish their lives with everything from beds and chairs to buckets and barrels. In the last century or so, this mastery—and the dependency that followed—has extended to entirely new forms, including slices, laminates, particles, and chips.
In the 21st century, we tend not to think much about pots—or any of a host of things made from fired clay. But to archeologists, the existence or absence of ceramics is one of the most fundamental indicators of a society's stage of development. An "aceramic" society has few ways of storing food or water, and thus its agriculture remains limited and primitive until it learns how to fire clay.
Clay can be shaped and then hardened by drying, but only when it is baked to a sufficiently high temperature does its chemistry and structure permanently change to make it impervious to liquids and allow it to retain its shape over a range of conditions. The earliest of the great civilizations—in Mesopotamia (modern Iraq), China, and India—thrived on creating not only practical containers but also colorful tiles, statues, and jewelry. Combining clays with other minerals and then firing the mixture resulted in brilliant colors—the first glazes.
Ironically, for this most ancient of manufactured materials, some of the most advanced substances to come from 21st-century laboratories, such as high-temperature superconductors, are ceramics.
Fiber & cloth
So ubiquitous is cloth that we hardly even think of it as a material, but it is arguably the first complex manufacture that humans mastered. While a limited number of "fibers" exist in nature, there is no cloth. And the fibers that do exist—silk, cotton, or wool, for example—have to be transformed before they can be made into cloth. How humans learned to take the hair of a sheep or goat and twist hundreds or thousands of individual hairs together to make woolen thread or yarn, or how they learned to soak the straw of the flax plant to separate fibers that they could then spin into linen, is one of the great mysteries of our early history.
One of the qualities of cloth that has appealed so strongly through the ages is its great variety. The Chinese discovered perhaps as much as 5,000 years ago that they could use the fine exudations of the silkworm larva to make a sheer and exquisite cloth. About the same time, cloth makers in India and Egypt were spinning the fibers of the cotton plant into a remarkably versatile fabric, one that they could weave into a range of weights and textures. Throughout much of the world, our forebears found that they could work the hair from a variety of herded animals, from camels to sheep, into some of the softest fabrics known or the scratchiest materials ever to rub human skin.
The versatility and variety of cloth has not diminished with the application of modern chemistry to its improvement. While some of the earlier efforts at fashioning clothing from synthetic materials such as rayon or polyester became the butt of jokes, today it is a rare wardrobe that does not feature some cloth whose history began in a test tube rather than on a farm.
The first metal that humans were able to make serious use of was copper. But this metal, occasionally found as nuggets though more commonly reduced from ores, is fairly soft and will not hold an edge. Bronze, an alloy of copper with small amounts of tin, is a much more useful form. We do not know how craftsmen came up with this combination, but thousands of years of working with copper preceded the discovery of bronze some 5,000 to 6,000 years ago (in a number of places).
As the first intentionally produced alloy, bronze set the precedent for the widespread use of metals, notably for weapons. The first swords had bronze blades, and the material's ability to hold a sharp edge while resisting chipping or breaking was perhaps its most valued attribute.
Because the constituents of bronze, particularly tin, are not especially common, they were probably the first products of long-distance trade. Even before classical times, the Mediterranean region saw extensive trade of copper from Cyprus (whose name comes from the Greek word for the metal) and tin from sources as far away as southwest England (Cornwall).
Iron & steel
Even in the 21st century, no more important metal exists than iron, and this has been true for as much as 3,000 years. Workable ores of iron occur in almost every part of the world, and a variety of techniques can produce forms of the metal with a great range of properties. Historically, there have been three basic forms of iron: wrought iron, cast iron, and steel. Craftsmen relying entirely on experience and observation discovered each of these forms and used them for centuries. It was not until the 19th century that the constituent differences among them were understood, particularly the role of carbon.
Wrought iron is almost pure iron, a metal that can be readily worked in a forge and that is tough and yet ductile, meaning it can be hammered into shape. Cast iron, on the other hand, has a marked amount of carbon, perhaps as much as five percent, mixed in with the metal (in both chemical and physical combination). This constitutes a product that, unlike wrought iron, can be melted in charcoal furnaces and thus poured and cast in molds. It is very hard but also brittle. Historically, cast iron was the product of blast furnaces, first used by Chinese metalsmiths perhaps as early as 2,500 years ago.
For the last century and half, the most important form of iron has been steel. Steel is actually a great range of materials, whose properties depend both on the amount of carbon contained—typically between 0.5 and 2 percent—and on other alloying materials. Generally, steel combines the toughness of wrought iron with the hardness of cast iron, hence historically it has been valued for such uses as blades and springs. Before the middle of the 19th century, achieving this balance of properties required craftsmanship of a high order, but the discovery of new tools and techniques, such as open-hearth smelting and the Bessemer process (the first inexpensive industrial process for mass-producing steel from iron), made steel cheap and plentiful, displacing its rivals for almost all uses.
The first glass was probably made by accident, as sand found its way into a kiln and then fused. This resulted in a material resembling a ceramic in cold brittleness but actually very different in structure and properties. While we think of glass as normally clear, it took centuries of experience and experiment to produce a reasonably clear glass, probably not until Roman times.
Glass is made by heating sand (silicon oxide) with a "flux," which is a mineral (such as sodium carbonate) that will lower the melting point of the mixture. The color or clearness of the glass depends on the purity of the ingredients and the particular combination of sand and flux. The result is a transparent or translucent material that is quite brittle but is nonetheless physically a liquid rather than a solid. That is, glass has no crystalline structure and actually "flows," albeit typically very slowly.
The first glassmakers who could turn out truly clear glass consistently and reliably were the Venetians, whose "cristallo" set the standard for fine glass in the late Middle Ages. Glass was much too expensive for common use in windows until about the 17th century, and true widespread application had to wait until industrial-scale manufacture in the 19th century. The material's versatility has continued to flower up to our own day, when cables of glass fiber now constitute the backbone of our Information Age.
Humans set down their language in writing for thousands of years before they had paper—writing can be put onto stone, clay, wood, cloth, skin, and other surfaces. But despite the diversity of alternatives, and the emergence of electronic media, a world without paper would be very different from the one we know.
Paper is one of a number of inventions that came out of an astonishingly creative period in China about 2,000 years ago. When fibers—either directly from a plant or, more typically, from discarded cloth—are permitted to soak and partially rot, they can be reconstituted into randomly entangled sheets. By carefully pressing these sheets until dry and then, usually, "sizing" them with a starch (to seal gaps among the fibers), an exceptionally versatile material can result. The variety of forms the final paper can take ranges from the fineness and flimsiness of tissue to the toughness of kraft and other wrapping papers or the "washi" paper the Japanese use for lanterns, screens, and even walls.
Plastics & rubber
For thousands of years, our ancestors appreciated a small number of materials distinguished by their smooth and often colorful appearance: Ivory, tortoiseshell, and horn could be turned into small luxury items that bore a warmth and elegance hard to achieve in other substances. In the 1800s, the growth of markets, combined with a greatly enlarged understanding of chemistry, gave rise to a whole new class of artificial substances that made it possible to turn out such items in great quantities at low cost. The first commercial plastic was celluloid, made from nitrated cotton and camphor. When this combination was heated under pressure, it was transformed into an astonishingly versatile substance that could be made into everything from combs and collars to dolls, playing cards, and, eventually, ping pong balls.
In the 20th century, this first plastic was joined by a host of substances that were even more, well, plastic. The new plastics, by then typically made from by-products of coal or petroleum production, were sometimes fashioned into more ersatz luxury items. But their properties also lent themselves to a host of technical uses, from telephones and other electrical devices to substitute body parts and other medical devices that would be all but unthinkable made out of any other substance.
Closely related to these plastics was rubber, which started out as a natural product brought to Europe by early explorers of South America. Natives used the milky sap of Hevea brasiliensis for waterproofing and making bouncing balls. The Europeans adapted lumps of dried sap to rub out pencil marks (hence the name "rubber"). It was not until about 1840 that Charles Goodyear discovered how to make the material into a range of stable forms, good for everything from combs to inflatable rafts. The rubber pneumatic tire proved indispensable for motor transport in the 20th century, and this dependence led to the invention of synthetic rubber, much in the same fashion as the plastics.
For millennia, the range of metals available for making things comprised a limited set of elements. Apart from precious metals used for money and jewelry, the practical metals were exclusively forms or alloys of lead, copper, or iron. This changed in the late 19th century, most spectacularly with the introduction of aluminum. This was a metal that was not even suspected to exist until about 200 years ago, when chemists began to use new tools to explore the composition of common minerals.
One of the minerals they investigated was alum, which people had relied on since ancient times as an astringent and in making dyes more stable. This material appeared to have an unknown metallic origin, but the metal was not separated out until the 1820s and not purified until the 1850s. Even then, it was very expensive and difficult to make. The wonderful properties of aluminum—especially its remarkable light weight and its silvery luster—attracted wide attention. Precious jewelry and exotic objects such as opera glasses were fabricated from it. It was even seen fitting to make the small apex of the Washington Monument, completed in 1884, out of pure aluminum.
The status of aluminum changed dramatically in the 1880s, when two young chemists, one in France and the other in the United States, discovered how to make pure aluminum metal using strong electric currents. This "electrolytic process" made the metal readily available, depending only on the availability of cheap electricity. The coming of aviation in the early 1900s gave aluminum new strategic value, and expanded production to meet wartime demand led to the metal becoming one of the most ubiquitous of the 20th century.
As scientists began to develop a much deeper appreciation for the various properties of materials, particularly from the mid-19th century onward, one of the key behaviors they described was how readily or not an electric current passed through the material. Some substances, such as wood or glass, appeared to resist the passage of electricity, while others conducted currents easily. The former were used to insulate and the latter, such as copper and then aluminum, as conductors, typically in the form of wires. These investigations of electrical properties turned up another class of materials that resided midway between the two main classes. Such "semiconductors," including carbon, allowed electric currents to pass but only poorly and with some physical response. (Carbon, for example, tends to heat up, which is why it was the material Edison found suitable for the filaments of his light bulb.)
These 19th-century investigators could never have suspected that in the latter part of the next century, these semiconductors would be put to work in ways that would transform our world as profoundly as any other material. Early in the 20th century, inventors devised means of controlling electrical currents and waves in remarkable ways, leading to marvelous new forms of communication, such as radio and television. The means they discovered involved controlling the actions of electrons: When these movements were controlled precisely, sound, light, and other phenomena could be picked up, transmitted, replicated, amplified, and manipulated to inform, entertain, investigate, and calculate in ways never before possible.
At first this electronic control depended on vacuum tubes, but this was at a great expense in energy, speed, and efficiency. Spurred on by World War II and then the rapid expansion of demands for communications and control technologies, alternatives to vacuum tubes, such as the transistor, began to appear in the post-war years. These alternatives, at first made with very exotic and expensive semiconductor materials, were not initially easy to manufacture or use. But when chemists discovered how to create large and very pure crystals of silicon, a host of new possibilities opened up. With the development of the techniques for imprinting cheaply and reliably entire complex circuits, including the workings of digital computers, onto wafers of silicon, a revolution in information and communications became possible—a revolution that we continue to see unfolding before us today.
Traditional Chinese battleaxes had many different shapes and were mainly used on the battlefield before the Tang Dynasty (618 – 907).
During the Xia, Shang and Zhou Dynasties in the period between 2,000 BC and 250 BC, battleaxe was chiefly utilised as the symbol of state power.
- How did Shang (shahng) people make bronze a mixture of copper, tin, and often lead that produces a strong metal. vessels?
- What are some different symbols shapes or designs that are recognizable and have a meaning associated with them used to decorate the bronze vessel a container such as a cup, bowl, pot, or dish. ?
- How were these bronze vessels used?
The Shang dynasty the earliest Chinese dynasty verified by scholars, ruling from ca. 1600 to 1050 BCE. (ca. 1600–1050 BCE) marked the middle of China’s Bronze Age a period of human culture characterized by the initial use of weapons, tools, and other objects made of bronze. , which first began around 2000 BCE. Bronze a mixture of copper, tin, and often lead that produces a strong metal. played an important role in the agricultural, religious, and military life of the Shang (shahng) period. Religious rites, which included human and animal sacrifices, also included offerings of wine and food presented in decorated bronze vessels. These ritual a set pattern of behavior for a religious or other kind of ceremony. bronze vessels were frequently buried with members of the royal family of the Shang state. Many bronze vessels, weapons, tools, and even musical instruments (bells) of that period have been unearthed. These buried bronze objects demonstrate high levels of technology and casting an object made by pouring molten metal or other material into a mold. skills. Shang people used a piece-mold casting a technique used for casting bronzes. After a desired vessel was fashioned from clay, it was covered with an additional layer of clay that, when dried, was carefully cut away in matching vertical sections (usually three or four) to create the casting molds. The original clay model was then shaved down for the interior core, and the mold sections were reassembled around it to make the outer walls. The space between the core and outer molds was then filled with molten bronze. In many cases, the joins between mold sections appear as raised ribs on the exterior of finished bronzes. After the bronze cooled, the clay molds were broken and removed, and the vessel was polished to take away flaws and any metal that had seeped into gaps between the mold sections. technique to create different types of bronzes. These vessels not only functioned as a symbol a shape or design that is recognizable and has a meaning associated with it. of power, wealth, and luxury but also revealed a great degree of creativity, efficiency, and innovation.
One of the excellent examples of Shang dynasty a series of rulers from a single family. bronze casting from the Freer Gallery’s collection is a ritual ewer a jug or pitcher to hold water or wine. shaped as a small elephant standing on top of a larger elephant’s back. Liquid was stored in the larger elephant’s belly and poured from the trunk. The smaller elephant served as a knob for the vessel’s lid. The ewer is decorated with different ornaments, depicting mythical creatures, such as dragons or zoomorphic shaped like an animal. masks called taotie (t-ow-tee-eh) a stylized monster face-mask design pattern commonly found on ancient Chinese bronzes with symmetrically arranged eyes, ears, horns, snout, and jaw. . Taotie typically consists of eyes, jaw, beak or fang, snout, crest, horn, legs, and tail. The taotie face pattern is usually frontal and symmetrical a mirror image in which objects on one side of an imaginary line are exactly like objects on the other side. , but its body is shown in profile. Although animal-shaped bronze vessels were relatively rare in the Shang state’s capital, located in the northern Yellow River valley, people who lived in the southern Yangzi (yahng dz) River region showed their appreciation of animals by creating animal-shaped bronzes.
ancestor someone from whom you are descended. In Western thought, it is usually more distant than a grandparent however, in Chinese culture, deceased parents and grandparents are considered ancestors. : someone from whom you are descended. In Western thought, it is usually more distant than a grandparent however, in Chinese culture, deceased parents and grandparents are considered ancestors.
bronze a mixture of copper, tin, and often lead that produces a strong metal. : a mixture of copper a soft malleable metal of a pinkish-orange color with high thermal and electrical conductivity. , tin a silvery-white metal, the chemical element of atomic number 50. , and often lead that produces a strong metal.
Bronze Age a period of human culture characterized by the initial use of weapons, tools, and other objects made of bronze. : a period of human culture characterized by the initial use of weapons, tools, and other objects made of bronze. Changes in material culture engendered profound alterations in social, political, and economic systems. The Chinese Bronze Age is dated between about 1800 and about 300 BCE.
casting an object made by pouring molten metal or other material into a mold. : an object made by pouring molten metal or other material into a mold an outer housing used to shape an object. .
coiling method one of the oldest techniques for making pottery. Coils of clay are layered on top of each other and then pressed together. : one of the oldest techniques for making pottery vessels. Coils of clay are layered on top of each other and then pressed together.
ewer a jug or pitcher to hold water or wine. : a pouring vessel a container such as a cup, bowl, pot, or dish. like a jug or pitcher used to hold water or wine.
mold: an outer housing used to shape an object.
motif a repeating design, pattern, or image. : a repeating design, pattern, or image.
ornament an object or motif used for decorative purposes. : an object or motif used for decorative purposes.
piece-mold casting a technique used for casting bronzes. After a desired vessel was fashioned from clay, it was covered with an additional layer of clay that, when dried, was carefully cut away in matching vertical sections (usually three or four) to create the casting molds. The original clay model was then shaved down for the interior core, and the mold sections were reassembled around it to make the outer walls. The space between the core and outer molds was then filled with molten bronze. In many cases, the joins between mold sections appear as raised ribs on the exterior of finished bronzes. After the bronze cooled, the clay molds were broken and removed, and the vessel was polished to take away flaws and any metal that had seeped into gaps between the mold sections. : a technique used for casting bronzes. After a desired vessel was fashioned from clay, it was covered with an additional layer of clay that, when dried, was carefully cut away in matching vertical sections (usually three or four) to create the casting molds. The original clay model was then shaved down for the interior core, and the mold sections were reassembled around it to make the outer walls. The space between the core and outer molds was then filled with molten bronze. In many cases, the joins between mold sections appear as raised ribs on the exterior of finished bronzes. After the bronze cooled, the clay molds were broken and removed, and the vessel was polished to take away flaws and any metal that had seeped into gaps between the mold sections.
pinch-pot method one of the oldest techniques for making pottery. The shape of a vessel is created by pinching the walls with one’s fingers. : one of the oldest techniques for making pottery. The shape of a vessel is created by pinching the walls with one’s fingers.
relief three-dimensional forms that protrude from a flat surface. : three-dimensional forms that protrude from a flat surface.
ritual a set pattern of behavior for a religious or other kind of ceremony. : a set pattern of behavior for a religious or other kind of ceremony.
symbol a shape or design that is recognizable and has a meaning associated with it. : a sign, drawing, word, or design that represents an idea or an act.
symmetrical a mirror image in which objects on one side of an imaginary line are exactly like objects on the other side. : a mirror image in which objects on one side of an imaginary middle line are exactly like objects on the other side.
taotie (t-ow-tee-eh) a stylized monster face-mask design pattern commonly found on ancient Chinese bronzes with symmetrically arranged eyes, ears, horns, snout, and jaw. : a stylized animal face-mask pattern commonly found on ancient Chinese bronzes with symmetrically arranged eyes, ears, horns, snout, and jaw.
vessel: a container such as a cup, bowl, pot, or dish.
zoomorphic shaped like an animal. : shaped like an animal.
Iron and Empire: The Rise of Assyria
Iron was first utilized as a technology of war around 1300 bce by the Hittites. By the beginning of the first millennium bce, the secret of iron metallurgy and cold forging had spread to Palestine and Egypt by way of the nomadic invasions, and perhaps to Mesopotamia as well. Iron weapons were superior to bronze weapons because they were heated and hammered into shape rather than cast, making them stronger, less brittle and more reliable than their bronze counterparts. Within a few centuries the secret of tempering was discovered and diffused, and iron became the basic weapon material for all the armies of the period.
The invention and diffusion of iron smelting, cold forging and tempering created no less than a military revolution in the classical world. The importance of iron in the development of classical warfare lay not only in its strength and ability to hold an edge, but also in the widespread availability of iron ore. No longer were civilizations dependent on copper and tin deposits to make their bronze weapons. Five hundred times more prevalent in the earth’s surface than copper, iron was commonly and widely available almost everywhere. The plentiful supply of this strategic material allowed states to produce enormous quantities of reliable weapons cheaply. In fact, a democratization of warfare took place, with most members of an army now being issued iron weapons. Now almost any state could equip large armies with reliable weapons, with the result being a dramatic increase in both the size of battles and the frequency of war. The first people to take full advantage of the potential of the Iron Age were the Assyrians.
Assyrian monarchs had long understood the precarious strategic position of their state. Centred on the three major cities of Nimrud, Nineveh and Ashur on the upper Tigris River, in what is now north-western Iraq, Assyria was cursed with a dearth of natural resources and few natural barriers to keep out enemy invasions. Assyria lacked wood for constructing forts, temples and dams, stone for building walls and castles, and iron ore deposits to forge weapons. Assyria also lacked the large steppes necessary to support large horse herds, essential for chariotry and cavalry. If Assyria was to survive, it needed to expand at the expense of its more advantaged neighbours. Beginning in the fourteenth century bce, the Assyrians successfully resisted Mitannian, Hittite and Babylonian expansion and subjugation to finally emerge as a regional power under Tiglath-pileser I (c.1115–1077 bce). The empire created by Tiglath-pileser did not long survive his passing, and a new phase of expansion began in the ninth century under the reign of Shalmaneser III (858–824 bce). By Tiglath-pileser III’s reign (744–727 bce), the Assyrians had expanded into Syria and Babylonia, securing their western and eastern frontiers.
The Assyrians quickly mastered iron metallurgy and applied this new technology to military equipment and tactics. By the eighth century bce, the Assyrians had used their large, iron-equipped armies to conquer much of the Fertile Crescent, and, for a short time in the seventh century, Egypt as well. The general size, logistical capabilities, and strategic and tactical mobility of the Assyrian army were indeed impressive, even by modern standards, with the lessons learned by the Assyrians being passed on to the Persians.
As early as 854 bce at the battle of Karkara (modern Tel Qarqur), Shalmaneser III was able to field a multinational army of over 70,000 men, made up of 65,000 infantrymen, 1,200 cavalrymen and 4,000 chariots. By the eighth century bce, the entire Assyrian armed forces consisted of at least 150,000 to 200,000 men and were the largest standing military force the Near East had ever witnessed. An Assyrian field army numbered approximately 50,000 men and was a combined-arms force consisting of various mixes of infantry, cavalry and chariots which, when arrayed for battle, had a frontage of 2,500 yards and a depth of 100 yards. Still, the Assyrian army, as large as it was, seemed small when compared to armies that appeared some three centuries later. For instance, by 500 bce, a Persian Great King could raise an army of around 300,000 men from his vast territories, and Alexander may have faced a Persian army at the battle of Gaugamela of perhaps 250,000 men, including 20,000 cavalrymen, 250 chariots and 50 elephants.
The Assyrians also recognized the need for increased specialization in weapon systems. With the exception of an elite royal bodyguard and foreign mercenaries, Assyrian kings relied on a farmer-militia raised by a levée en masse. But as these mobilizations increased in frequency, the Assyrians began to supplement their militia muster with an ever-growing cadre of specialized troops. By Sargon II’s time (r. 721–705 bce), the Assyrian army was a combined-arms fighting force of heavy and light infantry, cavalry, chariots and siege machinery supported by specialized units of scouts, engineers, spies and sappers.
Assyrian heavy infantry were armed with a long, double-bladed spear and a straight sword for shock combat, and were protected by a conical iron helmet, knee-length coat of lamellar armour (a shirt of laminated layers of leather sown or glued together, then fitted with iron plates) and a small iron shield. There is some evidence that can be gathered from the panoply depicted on stone bas-reliefs that the Assyrian royal guard was a professional corps of articulated heavy infantry who fought in a phalanx. In battle, these Assyrian heavy infantrymen were organized in a battle square with a ten-man front and files twenty men deep. But even if these troops were capable of offensive articulation, the financial resources, drill, discipline and esprit de corps necessary to field large numbers of these specialized troops was not a dominant part of the Near Eastern art of war, so if present, it was not the decisive tactical system that it would become under the Greeks. Instead, light infantry archers were probably the main offensive arm of the Assyrian army.
Assyrian archers wore a slightly shorter coat of mail armour and the same conical helm as their heavy infantry counterparts, and are often depicted with a shield-bearer carrying a large, rectangular shield made of densely matted reeds covered with oiled skins or metal, similar to a pavise of the medieval period. The shield was curved backward along its top edge to provide extra cover from long-distance arrow or stone attacks and against missiles fired from enemy walls. Archers came from many regions within the empire, so bow types differed, with the simpler self-bow in use as much as the composite bow. The Assyrians invented a quiver that could hold as many as fifty arrows, with some arrows fitted with special heads capable of launching combustible materials. Referred to as ‘the messengers of death’, these flame arrows were targeted at enemy homes or crops. Slingers constitute another type of light infantry employed by the Assyrians. They are often depicted on stone bas-reliefs standing behind archers.
Changes in technology also enabled Assyrian ironsmiths to design a stronger chariot, with builders emulating earlier Egyptian designs by moving the wheel axis from the centre to the rear of the carriage. The result was a highly manoeuvrable vehicle that reduced traction effort. Still, the chariot suffered from terrain restrictions, unable to exploit its impressive shock capabilities on anything but level ground. Perhaps the chariot remained the dominant weapon system into the early Iron Age because of the sociology and psychology of the forces the chariot led and faced. In the Bronze Age the chariot was the weapon of the aristocracy, ridden into parade and battle by a social class culturally ordained as superior to the common soldiers who gazed upon these often excessively decorated weapons. It is possible that the utility of cavalry was not fully tested by the Assyrians because of a carry-over preoccupation with the Bronze Age domination of the battlefield by chariots. For over 2,000 years chariots were free to scatter formations of poorly equipped and weakly motivated infantry. This preoccupation with a battlefield anachronism would continue with the Persians as well, until their final defeat in 331 bce at Gaugamela by a Macedonian army unburdened by chariots.
Most significantly, Assyria was the first civilization in the west to exploit the potential of the horse as a mount. The introduction of larger, sturdier horses from the Eurasian steppes gave the Assyrians a new weapon system, the cavalryman. The first Assyrian cavalry were probably nomadic cavalry, perhaps Median mercenaries from tributary states across the Zagros Mountains on the Eurasian steppes. But not wanting to rely on foreign horsemen, the Assyrians began to develop their own cavalry corps, specializing in both light and heavy tactical systems. Assyrian light infantry emulated their nomadic neighbours, riding smaller, faster steeds and firing arrows from composite bows on the fly. It is notable that writers of the Old Testament called these Assyrian cavalrymen ‘hurricanes on horseback’. Assyrian light cavalry faced all kinds of opponents, including camels used as platforms for Arab missiles, with mounted archers sitting behind the beasts’ jockeys back-to-back and firing at pursuing Assyrian infantry and cavalry.
Assyrian heavy cavalry was in a state of continuous evolution. The original mounted lancer modified the equipment of foot soldiers to meet the needs of shock combat. The armoured coat was reduced to waist length and the shield was made smaller. Heavy cavalry were armed with both sword and lance, but the absence of a stabilizing stirrup meant Assyrian lancers, like their other classical-age counterparts, thrust out and loosened their spear at their enemy as they passed instead of riding through their target using the synergy of horse and rider.
Over time, the Assyrians developed their own cavalry corps and their own horse recruitment, acquiring specialized ‘yoke’ horses for chariots and riding horses for cavalry from as far away as Nubia and Iran. It remains a mystery why this weapon system, far superior to the chariot in both strategic and tactical mobility, was never fully exploited by the Assyrians. Possibly the lack of the horseshoe made the use of cavalry in rough terrain too expensive in animals, or the Assyrians’ preoccupation with chariots precluded them from sustaining large forces of both chariots and cavalry.
Why did Chinese use high tin bronze for swords? - History
In 1933, a bone needle was found in the ruins of Dragon Bone Hill at Zhoukoudian, Fangshan, Beijing. Apart from one crack, the 18,000-year-old needle's body was intact. To make bone needles, a piece of bone has to be split into strips, polished, ground to fine point and perforated at one end. This earliest sewing device ever discovered in China is proof that during the late years of the Old Stone Age women were already stitching animal skins to make clothes using bone needles.
China began to make jade objects during the New Stone Age, 7,000 years ago. A jade dragon made after carving and grinding from a single piece of dark green jade unearthed in Chifeng, in the Inner Mongolia Autonomous Region, in 1971 is a shiny object in the shape of a dragon's body, curved like a C. On the back of the dragon is a small hole through which a string can pass so that the piece can be hung up. The highly expressive dragon was shaped using the methods of sculpture-in-the-round and relief.
Among the funerary objects belonging to the Liangzhu Culture of the New Stone Age, some 6,000 years ago, is a square cylinder made of jade. This superbly processed item is marked off into nineteen sections. Studies suggest that that it was either a ritual object for sacrificial ceremonies or a burial object. A recent deduction was offered by Nobel laureate C. N. Yang, who believes that jade objects like this were used by the ancient Chinese as tools to observe the sky.
In 1976, the excavation of a tomb in Anyang, Henan Province, belonging to a noblewoman who lived more than 3,000 years ago caused a sensation in archaeological circles. According to written records, Fu Hao, the owner of the tomb, was a woman general and wife of Wu Ding, king of Shang. The tomb yielded a large amount of arms made of bronze, which proves that during the Shang Dynasty (16 th -11 th centuries BC), soldiers were already armed with bronze weapons.
The Chinese began to smelt bronze in the Xia Dynasty (21st-16th centuries BC). About 5,000 years ago, people began to extract brass from ore to make small objects with the cold-forging technique. Then they added a certain percentage of tin to lower the melting point and increase solidity. Tin gave brass a bluish tinge, and the alloy became known as bronze, which in Chinese simply means bluish copper. In the Shang Dynasty, bronze smelting became the most important branch of the handicraft industries. Shang bronzes come in many varieties, chiefly ritual objects, wine vessels, weapons, musical instruments and food containers. Many ritual bronzes were engraved with records of the military exploits of rulers, which are extremely valuable for historical research. Bronze working reached its prime in the Spring and Autumn Period, which covered the period from 770 to 476 BC, with the creation of the lost-wax method. This method used easy-melting wax sprinkled with fine mud and refractory materials. When the wax solidified, it was made into molds. After baking, the wax melted and flowed away, creating a vacuum which was filled with bronze liquid to eventually produce a bronze ware item. The tripod which Wang Ziwu, son of the prince of Chu, offered when he prayed for longevity is regarded as one of the first bronze wares made with the lost-wax method.
During the Shang Dynasty, Chinese people began to learn to use iron. The iron-edged bronze sword unearthed at Liujiahe Village in Pinggu, Beijing, is one of the earliest iron-containing objects discovered in China. The iron blade was cast from smelted meteorite iron, and then inlaid into the bronze handle. The sword is testimony to the fact that people had mastered the fairly advanced technique of iron smelting and casting iron with bronze.
Iron smelting technology made breakthroughs during the Warring States Period (475-221 BC). Technologies for cast-iron forging, and carburized bronze from "block iron" showed a marked improvement. Malleable cast iron products show greater hardness and better ductility. An iron mold from the Warring States Period excavated in Xinglong, Hebei Province, was a standard white-iron casting instrument.
Qin, a ducal state of the Warring States Period, experienced speedy development of productivity. Bronze pliers unearthed in Fengxiang, Shaanxi Province, previously part of the State of Qin, are very similar to the same type of tools used today.
Handicrafts such as lacquer, textiles, leather processing, jade carving and the making of gold and silver wares all achieved great progress during the Warring States Period. In the late years of this period, the art of adding a metal edge to the mouth, middle part and lower end of lacquer wares not only increased the durability of the objects but also had a highly decorative effect, making lacquer wares more valuable.
Iron smelting in the Han Dynasty (206 BC-AD 220) made further progress, as indicated by the appearance of various kinds of furnaces, the use of refractory materials and bellows which were made of leather and powered by human strength. Bellows drastically increased the temperature of the furnace, and further promoted metallurgy.
The Han Dynasty yielded another highly valuable cultural relic-bronze calipers carved with the year when they were made. In order to measure things, one simply pulled a ring on the movable part to change the gauge. Very similar to the modern vernier calipers, it is the earliest such measuring instrument found in the world to date and valuable material for the study of the science of measurement and the ancient history of mathematics.
Carts and boats were the two major types of transportation in ancient times. Horse-drawn carriages of the Han Dynasty showed great improvements in both appearance and construction techniques. Carriages in the Shang and Zhou dynasties had two wheels but one shaft while those of the Warring States Period acquired two shafts. By the Eastern Han Dynasty, double-shaft horse-drawn carriages had become very common. The pottery carriage excavated at Yangzi Hill in Chengdu, Sichuan, in 1954 is rectangular in shape, and has a canopy which, in the real thing, could be rolled up. The two shafts are straight but the ends are S-shaped.
Depictions of horse-drawn carriages with a great variety of shapes and appearances have been found on Han Dynasty brick and stone carvings. A stone carving with vivid images of carriage wheels has been excavated at Jiaxiang, Shandong Province.
The fact that Han Dynasty carriages could carry heavy loads, as they often could accommodate four to five people each, was largely due to the advanced harness used. Studies of the history of the harness have shown that in 1,000 BC, Europeans used the throat-and-girth harness, which did not allow beasts of burden to pull a weight of more than 500 kg. The reason was that the animal's neck could only withstand so much pressure.
In the early Han Dynasty, around 200 BC, China already had the breast-harness, which allowed the animal to breathe easily while pulling heavier loads. In the 11th century, the yoke was introduced to Europe from China, which enabled horses to pull plows instead of physically weaker cattle, greatly facilitating agricultural production in Europe.
The single-wheel barrow invented in the early days of the Eastern Han had a simple structure, was easy to handle and could be used on flat surfaces, hilly areas or narrow paths. It could carry both people and cargo, making it an economical and practical means of transportation at the time. The barrow marked an important invention in the history of transportation in China. This type of barrow is still in use in some areas of China.
In the Jin Dynasty (265-420) a kind of odometer was used on carriages. It was a wooden figure connected to the wheels by a series of gears, and which beat a drum to indicate the distance covered. The wheels had a circumference of five meters, and so with every 100 revolutions the carriage had covered 500 meters, and the figure would strike its drum.
China led the world in shipbuilding in ancient times. Canoes first appeared during the period of primitive society, and large warships were made during the Spring and Autumn and Warring States periods. Shipbuilding technology made breakthroughs during the Han Dynasty, as evidenced by the invention and application of helms and anchors. An Eastern Han pottery boat unearthed at Xianlie Road, Guangzhou, 1954, shows that the helm was installed in the stern. Underneath the bow of the ship hangs a Y-shaped anchor, which would have been made of stone for a real ship. These technological improvements raised the navigational accuracy and safety levels when the ship was sailing and stability when it anchored.
The first mechanical crossbow appeared during the Spring and Autumn period, and this type of weapon grew in popularity during the Han and Jin periods. Some of the mechanical devices on crossbows of the Han Dynasty bear marks which allowed the archer to take aim by following the appropriate mark. This helped raise accuracy. In 1979, such a mechanical device was excavated in Zibo, Shandong. The gilded parts on the device, which was a burial object in the tomb of Duke Liu Xiang, indicate that the original owner of the crossbow was a man of unusually high social status.
The tradition of having jade burial objects goes back a long way in ancient China, and jade objects had been found in tombs of the New Stone Age. The tradition became more fashionable during the Han Dynasty. Apart from traditional concepts at work, perhaps another reason for this custom was the habit of elaborate burials and superstitious practices. People at the time believed that jade could prevent the corpse decaying and hence ensure the chance for rebirth. As a result, jade burial suits made by linking up jade pieces with metal or silk thread were prepared for emperors and his empresses as well as some of the nobility in the Han Dynasty. According to the volume on rituals in the History of the Later Han Dynasty, the burial suits for dead emperors were sown with gold thread, those for the princes, first-generation dukes and marquises, nobles and princesses were woven with silver thread, while those of the sons of the first-generation nobles and daughters of princes, with copper thread. Silk thread was used for the grave clothes of people of subordinate ranks. Ordinary officials and the common people were forbidden to have jade burial clothes.
The jade burial suit belonging to Prince Huai of the Western Han Dynasty, unearthed in Dingxian, Hebei, in 1973, was made with a total of 1,203 pieces of jade and 2,580 grams of gold thread. The suit consists of parts for the head, body, arms, legs and feet. The jade pieces are in trapezoid, rectangular, square and triangular shapes. All of them were well ground and polished, reflecting advanced jade carving techniques.
Zhang Heng was the leading scientist of the Eastern Han period (25-220). In 132, he built the world's first seismograph. The original of the device has long been lost, but based on the volume on Zhang Heng in the History of the Later Han Dynasty and archaeological research findings, Mr. Wang Zhenduo reconstructed Zhang Heng's seismograph in 1951.
The seismograph looked like a huge wine jar with a diameter of 1.9 meters. Eight dragon figures representing the eight directions (east, west, north, south, northeast, northwest, southeast and southwest) were arranged on the outside of the jar. In the mouth of each dragon was a small bronze ball, and underneath each dragon's head was a toad with its mouth gaping upwards. In the center of the seismograph was a sort of pendulum, surrounding which were eight groups of lever mechanisms distributed in the eight directions and connected to the mouths of the dragons. If a tremor occurred in any direction and seismic waves were transmitted to the seismograph, the pendulum would incline to one direction and trigger a lever in the dragon's head. The dragon would then open its mouth, and release its bronze ball, which would fall into the mouth of the toad underneath. Thus, the direction in which the earthquake had occurred was known. Making clever use of the mechanical theory of inertia, the seismograph had a high degree of sensitivity. According to the History of the Later Han Dynasty, one day in 138 the dragon in the west direction spit out its bronze ball, but people did not feel any tremor. Several days later, however, a horseman galloped to the capital, bringing the news that an earthquake had struck Longxi, in western Gansu Province, some 500 kilometers from the capital city of Luoyang. This anecdote is evidence that the seismograph was not only very sensitive, but also accurate.
Zhang Heng's seismograph was 1,700 years earlier than similar devices built in Europe, demonstrating ancient China's advanced level in earthquake studies.
From the 1 st to the 3 rd centuries, ethnic minorities in China's north and northwest gradually migrated southward to areas south of the Great Wall and along the Yellow River. Among them were the Xiongnu, Xianbei, Jie, Di and Qiang tribes. North China's tribal people were good at riding and shooting from horseback. Under their influence, the Han people saw increasing sophistication of their horse gear, particularly with the appearance of double stirrups. Two gilded bronze stirrups which were unearthed in Beipiao, Liaoning, in 1965 are in the shape of round triangles with long perforated handles. The stirrups were made of mulberry wood in a triangular shape, with triangular wood pegs to facilitate steadying the feet while riding. The surface of the stirrups is covered in gilded bronze. With improved horse gear, cavalrymen found it easier to control and tame horses, gaining greater flexibility for fighting on horseback.
People have commented that a handful of inventions, such as stirrups, which were so simple exerted an enormously catalytic impact on the history of mankind. Joseph Needham, once a professor at Cambridge University and a specialist in China's history of science, believed that stirrups allowed the rider and the horse to form an entity, greatly facilitating the cavalry charge. Once stirrups were introduced to Europe, they soon helped the class of knights to stabilize the feudal system.
From the 3 rd to the 6 th centuries, iron smelting made further progress, as it became possible to mix cast and wrought iron together. Copper-iron so smelted could be used to produce swords, but more often than not, it was used to make production tools and daily life utensils, greatly facilitating people's production activities and daily life.
The Zhaozhou Bridge, which was built during the Sui Dynasty (581-618) and is still in use today, is one of the architectural wonders that artisans of ancient times have left us. The single-arch bridge, 50.82 m long and 9.8 m wide, stretches from north to south over a span of 37.37 meters. Its low arch and gentle surface made it easy for both vehicles and pedestrians to cross. On each side of the arch are two small spandrel holes, which reduce the weight of the bridge, but also divert floodwaters and save building materials. They also add to the elegant appearance of the bridge.
The Tang Dynasty (618-907) has left us a treasure trove of splendid gold and silver wares. At the time, simple lathes were used for cutting and polishing. Many complicated industrial processing arts, including metal shaping, were employed. The patterns on the wares were meticulously executed and covered a wide range of subjects with strong influence from foreign cultures. Brass mirrors of the Tang Dynasty are highly representative in their shapes and decoration methods. Increasing amounts of silver and tin were used in the brass alloy. The surface of the mirrors is shiny and smooth. On the basis of highly developed mirror making technology, artisans in the Tang Dynasty used optical theory to successfully produce mirror-like implements used to generate fire from the sun, which was an unusual invention 1,300 years ago.
E. Other Common Bronze Implements
LÚ 炉 爐 , 鑪) Incense censer, regardless of shape.
Long after the end of the Bronze Age (even up to the present) reproductions of many different bronze vessels were used as antiquarian incense burners.
XŪN 熏 薰 To perfume, hence a term used for any implement which may be used to perfume, including incense burners.
GǓ 鼓 Any sort of drum. The most important bronze ones come in a range of sizes and usually date from the Hàn 汉 dynasty (period 6, roughly 200 BC to 200 AD). They are often quite large, like the one shown here from Chicago's Field Museum, where it has been an object of eager pounding for generations of school-age visitors (including me as a kid). Similar drums were produced especially in south China and southeast Asia.
(Most museums don't let kids whack at their drums, and they are probably right. But the Chicago drum seems to be surviving just fine. It is cast metal after all, and it was originally made to be pounded!)
ZHŌNG 钟 鐘 A “bell,” sometimes suspended with the open end downward and sometimes positioned with the open end at the top. Chinese bells were played by striking from the outside with a wooden hammer.
(Language note: The same word is used for a kind of bottle.)
BIĀN ZHŌNG 编钟 編鐘 Chime set of tuned bells suspended in rows to be struck by hammers. Sets of various sizes have been found containing up to sixteen bells. Each of the bells shown here can play two notes, depending upon where it is struck, so the set of seven is potentially a set of fourteen notes.
CHÚN 錞 錞 A “small mouthed” bell, played with the opening toward the bottom and suspended by a toggle or sculpture on the slightly bulbous top.
BIĀN QÌNG 编磬 編磬 Chime of sixteen musical stones suspended in two rows.
NÁO 铙 鐃 Percussion instrument, probably a carriage bell
JIÀN 鉴 鑑 Mirror.
In no part of the ancient world were there mirrors that anybody would want to use today, and bronze mirrors were by no means the best of them, at least if modern attempts at reproducing them are to be trusted.
They were, however, shiny, which made them interesting enough to give them cosmic associations. They may have been used in exorcism, but a large number of them also have clearly religious (Daoist) symbols on the "back" (non-flat) side. The handle was apparently a cord passed through a hole across the lump in the center.
(Language note: the same word is used for a kind of “punch bowl.”)
DĒNG 灯 燈 Oil lamp, regardless of shape.
GǍO 镐 鎬 A kind of hoe
GŌU 钩 鉤 Generic term for a hook
HÉ 盒 Generic term for a box. Although the box theoretically can be made of bronze, the term normally includes small ceramic or lacquer boxes designed to hold cosmetics, pins, small desk objects, and the like.
Bronze WeaponsDUÌ 镦 鐓 Butt and ferrule for spear handle.
FŪ 鈇 鈇 Ax or hatchet. Contrasts with yuè, a large ax.
GĒ 戈 Dagger-axe or halberd
JIÀN 箭 Arrow
JIÀN 剑 劍 , 劎 Double-edged sword
MÁO 茅 Spear, spear head
YUÈ 钺 鉞 Large ax. Contrasts with fū, a small ax. Although bronze actions can be functional, they competed poorly with stone and eventually iron, so even when undecorated, like the one on the right, it seems likely that they were ceremonial. the heavily decorated one here was clearly intended as a prestigious work of art, not intended for actual use except perhaps in a rare and purely ritual context.
Because shell has small and exquisite appearance, bright color, solid texture, and the feature of easy to carry and count, shell is used as a kind of primitive money circulated at the end of the Neolithic Age. Shell money is a kind of commodity money lasting the longest time. The unit of shell money is ‘peng’ (朋 in Chinese, means friend), which originally means two clusters of shells. Generally speaking, one peng is made up by two clusters of 10 shells. At the end of the Shang Dynasty (1675 BC–1029 BC), due to the lack of shells in Northeast China, there were other forms of shell money which can be made of pottery, stone, bone, jade, copper and gold. However, the most common one is made from natural shells.
The invention of shell money which made of copper at the end of the Shang Dynasty (1675 BC–1029 AD) marks the beginning of the use of metal coins in China.
The Sword of Goujian – still untarnished after 2700 years
The Sword of Goujian is an archaeological artefact belonging to the Spring and Autumn period (771 to 403 BCE) found in 1965 in China.
The Spring and Autumn Period was a feudal era renowned for military expeditions these conflicts led to the perfectioning of weapons to the point that they were incredibly resistant and deadly, taking years to forge and lasting for centuries, or even more. Such is the case with the Goujian Sword, which was recovered 7 kilometers (4.3 mi) from the ruins of Jinan, an ancient capital of Chu.
The sword has two columns of text on the sides an analysis of the text on one side revealed that the sword belonged to the King of Yue, and the other one wrote ‘made this sword for [his] personal use’.
The historical identity of the king, however, sparkled some archaeological controversy after years of discussion and scholarly debate, the general consensus was that it belonged to Goujian, the King of Yue made famous by his perseverance in times of hardship.
Aside from the absolutely remarkable fact that the sword has no tarnish whatsoever, its blade is still sharp! Researchers have used modern hi-tech equipment to figure out how this was possible. They found out that the body of the sword is made of copper, which makes it far less likely to shatter, the edges have a higher quantity of tin, which makes them more likely to remain sharp, and the sword also contains traces of sulfur, decreasing the chance of tarnish apparition. These conditions, as well as the air-tight scabbard, made it possible for the sword to still be useful as a fighting weapon today.
Andrei's background is in geophysics, and he's been fascinated by it ever since he was a child. Feeling that there is a gap between scientists and the general audience, he started ZME Science -- and the results are what you see today.
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© 2007-2019 ZME Science - Not exactly rocket science. All Rights Reserved.