Thursday, September 11, 2008

Ancient Technology Preserved

by Dick Teresi

The narrative of humankind's seed civilizations is already an old story: replete with technological and social advances, imperialism, conquest; then the wars, the social and technological disintegration, and the sack. Each succeeding empire, while destroying much of the previous society, retained and advanced some of its technologies. The Greeks and Romans took some. The North Africans carried away some to Egypt and its great city, Alexandria. But much of the science and technology packages put together by the peoples of the ancient Middle East remained, tended to and enhanced, first by the Persians, and later the Muslims.

In the arid ecology of the Middle East, water was a constant preoccupation. Given an annual rainfall in Iran that averages six to eight inches, for example, it is unsurprising that the supreme large-scale technology of the ancient Middle East was hydrology. Although the pyramids of Egypt were among the biggest construction projects ever undertaken (c. 2000 B.C.), as much labor and ingenuity went into constructing Mesopotamian embankments and canals, built at about the same time for flood control and irrigation.9 Water management remained the most important technology from the ancient civilizations through the brilliant centuries of medieval Islam. Providing people with water, Muhammad is said to have observed, is the act of greatest value.10 (See Frank Herbert's planet Dune and its Fremen culture.)

One of the first irrigation systems in recorded history was in Jericho, where water tanks have been dated to around 6000 B.c.11 One of the first canals on record, the Al-Gharrif waterway from the Tigris, was cut by the governor of the Sumerian city of Lagash before 2500 B.c. (The work of the Sumerians wasn't all positive. Alfred Crosby points out that they ruined much of the farmland of the Middle East by irrigating their fields with water from their rivers. The water evaporated, leaving salt behind, the "same process," says Crosby, "going on in our southwest, where, as in Sumeria, there are fields white with salt." Still, says Crosby, the difference between the Sumerians and the Stone Age people who preceded them is greater than the contrast between the Sumerians and ourselves.)12 The Egyptians had a department of irrigation as early as 2800 B.C. The dam Sadd-al-Kafra, twenty miles south of Cairo, was built in 2500 B.C. The remains survive. In 690 B.C. the Assyrian king Sennacherib constructed a masonry dam on the Atrush River and a thirty-six-mile long canal to Ninevah.13 Around 100 B.C. the Nabateans of south Jordan and the Negev Desert of Israel built seventeen thousand dams.

The Persians inherited this mastery of dam, canal, and underground waterworks. In one instance, the Persians captured an entire Roman army and put them to work building a dam.14 In a huge engineering feat between A.D. 530 and 580, the Persians constructed two dams that diverted water from the Tigris River into the Nahrwan Canal. After their conquest of the Middle East in the seventh century A.D., the Muslims adapted the inherited techniques, and enormously extended the application of mechanical and hydraulic technology. Near the city of Basra, founded in the seventh century A.D., Muslims built up a vast network of dams and dam-fed canals. A dam built over the Kor River in Iran between Shiraz and Persepolis in A.D. 960 irrigated three hundred villages with more than ten water-raising wheels and ten water mills. It still exists.15 South of Qum in Iran, thirteenth century Muslims built the first known example of a true arch dam. Unlike most dams, it did not depend on gravity for its resistance. Instead it was constructed as an arch laid on its side, its convexity pointing upstream, the sides anchored into the rocky banks of a gorge, where the forces of water pressure against it transferred to abutments.

During the Islamic expansion, Muslims built many dams on the Iberian peninsula, including a dam at Cordova that was fourteen hundred feet long and a series of eight dams on the Turia River in Valencia, with associated canals. These canals had a total capacity that was slightly less than that of the river, suggesting that the engineers were able to gauge a river and then design dams and canals to match it.16

Water mills were a variation on the theme to exploit water for power. Their origin is unclear, but some were present in the pre-Islamic Middle East. By the Islamic medieval period, three types of water mills were in use: undershot, vertical and horizontal overshot. They were used for flour production, papermaking, cloth making, and the crushing of sugarcane and metallic ores.

There was a remarkable diversity of machines for milling in Iran and Iraq. In Baghdad, with a population approaching one million inhabitants, conventional milling wheels could not keep up with demand, so Baghdadis carried out corn milling using a series of floating water mills on the Tigris that operated continuously on twenty-four-hour shifts, using undershot wheels that drove the millstones through wooden gears. By A.D. 1000 smaller horizontal, turbine-like wheels with the millstone mounted on the same shaft, directly above, were used throughout Eurasia, from western Europe to China. Near Basra, ten mills operated by the ebb and flow of tides about a century before the first mention of tidal mills in Europe.17

Windmills were also invented in the Middle East, where water for power was scarce. Records from eastern Iran date windmills in that area from around A.D. 950. Some of those are still operating today. According to legend, the inventor of the windmill lived in Iran during the time it was conquered by the Muslims in the mid-seventh century. The second caliph, Omat, levied heavy taxes on windmills, and, according to the story, the inventor was so irate that he murdered Omat. Nonetheless, windmills spread throughout the Islamic world, then to India and perhaps China. The technology reached England in the mid—twelfth century. 18

After the collapse of the Roman Empire, the burning of the library at Alexandria (the Birdcage of the Muses) in A.D. 640 and the European Dark Ages, the Islamic Middle East preserved engineering technologies as well as pure science. Such fields included building construction, mirrors, weights (gravity physics), surveying, hydraulics, military technology, navigation, and the designing of ingenious machines. Often technology and engineering were given as much merit as pure science. The word handasa in Arabic, for example, means architecture and engineering as well as geometry. The distinction was not rigidly made between scientists and technicians. Many men were both.19

The obvious Islamic paragons of this type were the three Banu Musa brothers of ninth-century Baghdad. They were astronomers and mathematicians as well as engineers. Around 850 they wrote a compendium, Kitab al-Hiyal (The Book of Ingenious Devices, or On Mechanical Devices).20

The Banu Musa brothers designed increasingly complex waterwheels and other sophisticated water-drawing systems. Although they were influenced by the clever Alexandrine inventors of Hellenistic Egypt, whose work was translated into Arabic during their lifetimes, the Banu Musa made many advances. They designed a device for providing hot and cold water, dredging machines for harvesting jewels from sea and river bottoms,21 and an oil lamp that raised its own wick and fed itself more oil. The brothers built elaborate fountains. They are credited with the earliest use of a crank as part of a machine (the crank wasn't employed in Europe until the fifteenth century) and the first use of suction pipes.22

Fun was an important element. The Arabic word hiyal can denote almost any mechanical object, from a small toy to a siege engine. The leisure class took its toys seriously, and Islamic courtly circles funded engineers. Consequently, many of the most advanced Arab designs were both toy-like and useful. The Banu Musa brothers designed eighty-three "trick vessels." There are pitchers from which pouring cannot be resumed after it has been interrupted; vessels that replenish themselves if a small amount of water is removed; vessels into which a mixture of liquids can be poured together, yet discharged separately. The components usually included variations on conical valves, siphons, airholes, balances, pulleys, gears, miniature waterwheels, floats, and cranks.23

Automata, or self-operating mechanisms, were very popular. A prominent designer of automata was Badi al-Zaman al-Jazari, a twelfth and thirteenth-century engineer who may have been in the employ of the southeastern Turkish Artuqid dynasty. Al-Jazari devised most of his large-scale automata to collect and transport water, and was known for his gear systems, one of which showed up two centuries later in Europe in Giovanni de' Dondi's mechanical clock. One of al-Jazari's automata toys was a mechanical boat with drinking men, designed to amuse guests at a drinking party. When activated, the hiyal came alive in a counterpoint of sailors rowing and musicians playing.24

The caliphs of Baghdad exploited this richness of invention and engineering to build private playgrounds. Perhaps memories of Babylon inspired Islam's monumental gardens, models of paradise on earth. A report from the early tenth century describes a pond-filled garden. In the middle of one pond stood a tree with a silver and gold mechanical whistling bird. Another of the garden's ponds was filled with mercury, upon which floated gold boats. Around the ponds were automata of singing birds, roaring lions, and other moving animals.25 A thousand years ago the Arabs were experimenting with animatronics.

Many of the basic building blocks of European technology originated in the ancient Middle Eastern river-valley civilizations. Medieval Islam's central location in Eurasia allowed it to acquire inventions from India and China as well as make crucial advances on technology inherited from ancient Greece and Hellenistic Egypt. In time, the technological knowledge of the Middle East was transferred to Europe via Spain, and to Asia and Africa. Muslim engineers contributed enormously to the technology of medieval Europe, and Europeans may have feared the dominance of Middle Eastern technology and learning. Dante reveals European animosity toward Islamic culture in the Commedia. In Canto VIII of The Inferno, the Florentine poet places the mosques in the city of Dis, and in Canto XXVIII he puts Muhammad in the eighth circle.

9. Arnold Pacey, "Technology," in Encyclopaedia of the History of Science, Technology,

and Medicine in Non-Western Cultures, ed. Helaine Selin (Dordrecht/

Boston/London: Kluwer Academic Publishers, 1997),p. 937.

10. Howard R. Turner, Science in Medieval Islam:An Illustrated Introduction (Austin:

University of Texas Press, 1995), p. 165.

11. Pacey, in Encyclopaedia, p. 937.

12. Alfred Crosby, professor of history at the University of Texas, in a letter to the

author, December 29,2000.

13. James and Thorpe, Ancient Inventions, p. 384.

14. Arnold Pacey, Technology in World Civilization: A Thousand Year History, Cambridge,

Mass.: MIT Press, 1990), p. 8.

15. Donald R. Hill, "Technology in the Islamic World," in Encyclopaedia, p. 948.

16. Ibid.,p.949.

17. Pacey, Technology in World Civilization, pp. 10—11.

18. James and Thorpe, Ancient Inventions, p. 393.

19. Ahmad Y. Al-Hassan and Donald R. Hill, Islamic Technology:An Illustrated History

(Cambridge: Cambridge University Press, 1987), p. 264.

20. Pacey, Technology in World Civilization, p. 34.

21. James and Thorpe, Ancient Inventions, p. 139.

22. al-Hassan and Hill, Islamic Technology, p. 45.

23. Ibid.,pp.59,90,61.

24. Turner, Science in Medieval Islam, p. 188.

25. James and Thorpe, Ancient Inventions, p. 140.

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