Legacy of the Ancient World

Steven Dutch, Professor Emeritus, Natural and Applied Sciences, Universityof Wisconsin - Green Bay

Pre-Greek Accomplishments

The key to technology and civilization is enough food to eat. Roughly 8,000 years ago,agriculture, irrigation, and animal domestication had appeared in the Middle East and wereindependently discovered in many other times and places. Ceramics (pottery) likewiseappeared in many places. The discovery of metals was not so widespread, although smeltingseems to have been independently discovered in the Middle East, China, and southeast Asia.Seven metals are mentioned in the Bible: gold, silver, copper, iron, lead, mercury(quicksilver) and tin. The chemical symbols for these elements (Au, Ag, Cu, Fe, Pb, Hg,and Sn, respectively) are unrelated to their modern names. The symbols come from theirLatin names, a testament to their antiquity. Probably the first metals discovered weregold and silver, and perhaps copper. These metals occur in nature in the metallic form,although copper does so rarely. These metals can be beaten into shape without smelting;the Copper Culture Indians of the American Midwest used metallic copper from Michigan injust that way about 4000 B.C. But sophisticated metal use requires smelting: removal ofmetal from its ores.

How did Metallurgy Begin?

There are many riddles connected with ancient metallurgy, starting with how smeltingwas discovered at all. The campfire theory holds that ores were accidentally usedto build stone enclosures around cooking fires, and that people noticed new metalsappearing from the ashes. This process may have worked for lead and mercury, which areeasily smelted from their ores at low temperatures. However, temperatures are not highenough in campfires to smelt copper, and certainly not iron. Another possibility is thatpeople experimenting with mineral pigments discovered accidentally that theycontained metals. This theory is attractive because iron and copper minerals are alsobrightly-colored natural pigments and it furnishes a likely setting for people to tinkerwith various methods and observe the results. But the most likely setting to discoversmelting is one where high temperatures are routinely applied, preferably under oxygenpoor conditions, where ore minerals were likely to be placed, and where the process wouldbe repeated often enough for people to observe cause and effect clearly. Such a place wasknown in ancient times: pottery kilns. Mineral pigments used in coloring andglazing pottery would occasionally have been chemically reduced to pure metal (and oftenare in primitive kilns today). Ancient smelting was laborious at best: to keep the firehot enough, assistants (most likely slaves) would have to pump bellows for long periods.Even then, the final result was likely to be a mass of metal mixed with slag that wouldhave to be crushed and the metal picked out by hand.

The Mystery of Bronze

Copper was the first metal to be smelted and used in abundance, but the realmetallurgical innovation was the discovery of copper alloys. Brass is an alloy of copperand zinc. Even though zinc was not known as a metal in ancient times, zinc and copperminerals often occur together. Zinc could be a contaminant in copper ores often enough forthe discovery of brass to be reasonably simple. Not so for bronze, an alloy of copper andtin. Copper and tin minerals rarely occur together and there is no abundant source of tinin the Middle East. The nearest source known is in Afghanistan, a plausible place becausea precious blue stone, lapis lazuli, comes from the same region and was widely traded inancient times. Nevertheless, it is a deep mystery how bronze came to be discovered. But itwas the first industrial metal; much harder than copper and able to maintain a sharp edge.The fact that the earliest metalworking period is called the Bronze Age is testimony tothe importance of bronze.

Iron

Iron requires a much higher temperature to smelt than copper and seems to have beendiscovered by the Hittites of present-day central Turkey. The myth is that the Hittitesoverwhelmed their neighbors because of their superior iron weapons. The reality is thatancient iron was far too variable in quality to be clearly superior to bronze. Pure ironis very soft; most ancient iron was impure and often brittle. The real reason iron sweptthe world is that it was cheap; far more abundant than copper and tin. A thousand peasantsarmed with cheap iron swords can overwhelm a hundred trained soldiers with fine bronzeswords. Through most of history iron was extracted by smelting ore to get"bloom", a mixture of iron and slag; the iron was broken free and laboriouslypounded into larger masses. To shape it, the iron was heated red hot and pounded intoshape. Melting iron and pouring it into molds, as we do, would have been the wildestfantasy to ancient metalsmiths; they would regard our cheap iron and steel as the mostfabulous luxury. Streets paved in solid gold would be scarcely more amazing to someonefrom ancient times than railroads with iron rails.

Masonry

The ancient world worked materials other than metals. With bronze and later iron tools,stone cutting, dressing, and sculpting were possible. In many places (for example, by theIncas of South America) these operations were done to high sophistication even with stonetools. To build large structures, it is necessary to have some means of spanning openings:an arch. Post- and-lintel arches, uprights with a beam across the top, are intuitivelyobvious. Stonehenge is a famous prehistoric example in stone. Larger openings can bespanned by stepping stones out over each other in an inverted-staircase arrangement untilthe stones meet. This is called a corbelled arch; it was widely used in the Old World andthe Americas. The circular arch, a fan of tapered stones where increased weight acts topress the stones tighter, was known only in the Old World (except for one intriguingexception: the Inuit igloo). Large rooms were spanned with large timbers and later withmasonry domes or arches, but the truss, the use of a triangle of timbers to createrigidity, was unknown until the Middle Ages.

Simple Machines

Muscle power is augmented by machines, and the three fundamental simple machines wereknown in ancient times. The lever consists of three elements: the place where forceis applied, the load to be moved, and the pivot point or fulcrum. These can be arranged invarious orders. The familiar situation of pushing down on a beam to lift a load has theelements in the order force- fulcrum-load. A wheelbarrow is a lever with its elements inthe order force-load-fulcrum (the wheel is the fulcrum). The lever was still amazingenough that in the third century B.C., the Greek scientist Archimedes could awe listenersby saying "give me a place to stand and a lever long enough, and I will move theEarth". The second simple machine is the wedge. The general idea behind awedge is that a small force applied over a long distance along the length of the wedgetranslates into a large force acting over a short distance at right angles to the wedge. Ahammer blow drives a wedge easily into a crack, while the wedge pries the crack apart withenormous force. A variation on the wedge principle is the inclined plane; it's a loteasier to push a load up a gentle slope than lift it vertically.

The third and most profound simple machine is the wheel. The wheel is a goodexercise in understanding why technology develops. For starters, why is the wheelvirtually unknown in biology? The answer is that wheels do not work well on unevensurfaces. This insight helps us understand why some societies never developed the wheel.The Incas had superb roads, but many of these roads consist of steep flights of stepshacked into mountains and rope bridges crossing gorges. Amazing as this engineering is,wheels would not be very effective on Inca roads. To invent the wheel in a roadless world,the necessary prerequisites seem to be: large expanses of flat open land, a large amountof goods to move, and a need to move regularly. Mountains and jungle do not favor thedevelopment of the wheel. Nomads with minimal possessions can carry everything on packanimals. Sedentary farmers may have a lot to move, but not over long distances; packanimals will suffice for them as well. The wheel seems to have been invented not in theagrarian lands of the Middle East, but in the steppes to the north, where the land is flatand the civilized nomadic peoples had a more complex lifestyle and numerous possessions tomove.

There are numerous simple compounds of the three simple machines. Wrap an inclinedplane around a cylinder and you get a screw. The screw was known in ancient times and usedin two settings: to convert rotary motion into linear motion along the screw, and inconjunction with the lever, to apply force. Threaded fasteners were rare until the late19th century; to make a screw in ancient times, you cut the threads manually with a file.Nuts were made by drilling a hole in a metal block and forcing the nut onto the bolt usinga primitive wrench, yet another kind of lever (this is an inefficient version of themodern process of cutting threads with a tap). Once made, nuts and bolts were commonlyjoined by a cord until use because every single one was unique. We can also combine thewheel and lever in several ways, using the axle of the wheel as the fulcrum. One suchcompound is the crank, which was curiously unknown in the West in ancient times, althoughit was known in China. The pulley uses the radius of a wheel as the lever; the real powerof the pulley is that several pulleys can be connected to allow huge loads to be liftedwith small forces.

A modern carpenter would recognize many basic hand tools in even the most ancient toolkits. Hammers, saws, squares, plumb lines, pliers, chisels and files were all in use.Ancient shovels, hoes, rakes and pitchforks looked pretty much like their modernequivalents. Conspicuously missing, of course, were tools for working with threadedfasteners, like screwdrivers and wrenches.

Heavy engineering in ancient times, apart from large buildings, included theconstruction of catapults and other kinds of seige machinery, and shipbuilding. By 3000B.C. boats capable of crossing the open Mediterranean were in use.

Glass

Glass-making was known to the ancient Egyptians. Glass results from heating quartz sandwith lye or potash, and can be regarded as the first truly synthetic material. Glass wasinitially placed on a par with gem stones, but as the technology spread, the priceplummeted. The Greeks made lovely small bottles by winding threads of molten colored glassonto a core of clay mixed with manure, then scoring the still-soft glass with a knife tosmear the colors, much the way one might with cake frosting. There is a truly amazingvideo of the technique on view at the Corning Glass Museum in Corning, New York. By Romantimes, clear glass was available in sufficient quantity and cheaply enough that evencommon people could afford it. At about the same time, glass- blowing was also invented,further driving down the cost of glass vessels.

A famous ancient quotation tells us a lot about ancient glass technology. Nowadays wewould say something is clear as glass, or that a still lake looked like a mirror. It was alot different 2000 years ago. Writing about our spirtual ignorance, Saint Paul that now wesee "through a glass darkly". In other translations, the quotation is translated"now we see indistinctly, as in a mirror". Either way, the quote is revealing;ancient glass was clear enough to transmit light but not to see through sharply. Ancientmirrors were polished metal with uneven surfaces and imperfect finish.

One of the first areas of "pure science", as well as one of the first casesof pure science being applied, was astronomy. The Egyptians and many other peoples hadaccurate calendars.

Greek Technology and Science

Among the Greeks, we can distinguish several major traditions:

The Ionian tradition, mercantile and experimental, grew up on the islands of theAegean. This was the closest approach in ancient times to what we would call a technicaland scientific society. Ionian colonists settled islands west of Greece, accounting forthe confusing fact that the "Ionian Sea" on present maps is on the opposite sideof Greece from where the Ionian culture originated. Important Ionians include Aristarchusof Samos, the first known thinker to reason that the Earth goes around the Sun, andDemocritus, the first scientist to describe atoms.

The Pythagorean tradition was mathematical but mystical. Pythagoreans werefascinated by the so-called perfect solids, whose faces were regular polygons, and also bywhole numbers. They were so shocked to discover that the square root of two could not beexpressed as a ratio of whole numbers that according to legend, they decreed death for anymember of the cult who divulged the secret to outsiders. To this day,"irrational" has a sinister non-mathematical meaning, although it originallymeant only that a number could not be expressed as a fraction.

The many Athenian schools of philosophy, stressing logic, deduction, andidealization are epitomized by Plato, Aristotle, and Socrates. Plato, a Pythagorean,stressed the existence of an "ideal" world of which our sense picture is only animperfect approximation. Aristotle is best known for his emphasis on the use of purereason in understanding the world. Athens enjoyed a famous and glorious, but brief"Golden Age" under the leadership of Pericles about 450 B.C.

Hellenistic Tradition

Socrates taught Plato. Plato taught Aristotle. Aristotle taught Alexander the Great.Something apparently got lost in translation. Alexander, from Macedonia in northernGreece, conquered all of Greece, then turned the tables on the Persian Empire, which hadinvaded Greece several times. He overran Persia, and by his death in 323 B.C. had carvedout an empire (map above) that reached from Greece to India and Egypt to central Asia. Theempire fragmented after Alexander's death, but a transplanted Greek culture, termedHellenistic, took root around the eastern Mediterranean. (Most of the rest of the empiresoon reverted to its old ways. Interestingly enough, some of the longest surviving Greeksuccessor kingdoms were in remote central Asia.) It is thanks to this transplanted Greekculture that the New Testament was written in Greek. The great Library at Alexandria wasonce the greatest repository of learning in the ancient world. Hellenistic Greek colonistssettled in Sicily, southern Italy, and even around the Black Sea in modern Russia.Important Hellenstic scientists included Euclid, who codified geometry, Eratosthenes, whocalculated the size of the Earth, and Ptolemy, whose model of the solar system woulddominate European thinking for 1500 years. Heron of Alexandria was one of the first knownpeople to experiment with steam power. Among the colonists, the most famous was theinventor Archimedes, who lived at Syracuse in Sicily.

The major Greek traditions represent ways of thinking that have been independentlydiscovered many times. All are appropriate in certain situations; it is wrong tostereotype any as "helpful" or "harmful" to science and technology.The pragmatic approach of the Ionians speaks to us most clearly today, but scientistsconstantly speak of ideal concepts: for example, objects would fall at the same rate ifnot for air resistance. Plato would agree. Scientists have a faith in whole numbers thatPythagoras would find familiar. Early experiments to determine chemical formulas almostnever gave exact whole numbers for the proportions of atoms, just very close. But thenumbers were so close that scientists were convinced they reflect the existence ofdiscrete, countable atoms. Finally, it is impossible to overstate the importance of logicand deduction in science. It is hardly Aristotle's fault that people later put him on apedestal.

Why didn't the Greeks develop modern science?

First and foremost, they weren't trying to be us! They were more interested infundamental questions like the nature of cause and effect. When they observed a rock beingthrown, they weren't interested in its exact path, but the question why does it keepmoving without anything pushing it?. They didn't have our agenda and they weren'tinterested in the questions that intrigue us. Also, it was not at all clear that closeinvestigation of nature would reveal anything of use or interest. We have inherited theresults of work by thousands of people over centuries, but would you invest your life instudying nature in a world where very little was known about science? Those that didtended to focus on small problems with foreseeable solutions. It's one thing to spend yourlife carrying bricks to build a cathedral; it's another matter to spend your life makingand accumulating bricks on the off chance that somebody might someday build a greatbuilding with them. We can sum up the riddle of the Greeks by noting that they had all theelements of modern science: observation, experiment, mathematics, deduction. But nobodyever achieved a synthesis of all these elements.

The Etruscans

The Etruscans spoke a non-Indo-European language and occupied the northern half ofItaly in Pre-Roman times. Because their language is extinct and unrelated to Europeanlanguages, there was once little hope of deciphering their history. Thanks to moderntechniques of linguistic analysis, much of their language can now be read. The Etruscanswere a fairly sophisticated people, with expertise in iron working and extensive tradecontacts. Their principal historical importance is as a link between the Greeks and theRomans. The Etruscans used the Greek alphabet to write their own language, and passed iton to the Romans, along with many other Greek ideas. A couple of tidbits from theEtruscans: the letter F and the "Roman" numerals V, L and D. The early Greekshad a letter like F called "digamma" - it looked like two letter gammas joinedtogether and represented a "kh" sound. The letter fell into disuse among theGreeks because they had another letter with nearly the same sound, so the Etruscansadopted it for the "f" sound, which the Greeks did not have (the "ph"of the letter phi was pronounced "p-h", not "f"). For severalcenturies Rome was ruled by the Etruscans, but the Romans overthrew the Etruscans andeventually absorbed them. Etruscan was apparently widely spoken for a long time, butnobody in Rome bothered to leave an account of the language. The map below shows some ofthe principal peoples of western Europe about 300 B.C.

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Created 13 January 1998, Last Update 21 September 1999