Cathedral, Forge, and Waterwheel: Technology and Invention in the Middle Ages - Frances Gies, Joseph Gies (1995)

4. THE ASIAN CONNECTION

THE GIFTS TO EUROPE IN THE EARLY MIDDLE Ages of silk culture and production, padded horse collar and stirrup, and perhaps the crank were part of a long history of technology transfer among regions and continents dating back to Neolithic times. Such long-distance exchanges are indicated by similar weapons, tools, and religious practices found by archaeology among Eskimos (Inuit), North American Indians, Chinese, and Siberian peoples. Later the great Bronze Age inventions of Egypt, Mesopotamia, and the Indus Valley traveled in both directions, to Europe and to central and eastern Asia. Along with bronze founding, the actual forms of products—swords, axes, vessels—spread east and west, appearing simultaneously among archaeological finds in the Hallstatt civilization of central Europe and in Shang dynasty China (beginning c. 1600 B.C.).¹

For medieval Europe, by far the most important source of borrowed technology was China. The most isolated of the ancient civilizations, with its own characteristic cultural patterns and style of thought, China developed its science independent of Greek influence. It remained almost entirely in China. In the early Middle Ages some exchange took place with India in medicine, mathematics, astronomy, and alchemy, but very little with Europe. Joseph Needham suggests that in the medieval world science was everywhere too intimately related to the cultural environment for easy exchange of scientific ideas.

With technology, the case was different. Throughout the first thirteen centuries of the Christian era, technical innovations filtered slowly but steadily from the advanced East to the backward West. “Inventions of immediate practical value” tended to travel “rather than speculations and theories,” Needham observes.² Some Chinese innovations passed quickly to the West; some took centuries. The course of transmission of some can be tracked step by step; that of others remains speculative.

Transmission Routes of Chinese Technology

One agency of contact between China and the West that became a catalyst for the transmission of technology was silk, the luxury textile par excellence of the ancient and medieval worlds. So closely did the Romans identify the product with its producers that they called the Chinese the “Seres,” from the Chinese word for silk.³ Carried at first through Central Asia over the four-thousand-mile Silk Road and later by sea, silk provided the single permanent line of communication between East and West for many centuries.

According to legend, the mulberry silkworm native to China and the Himalayas was domesticated in the third millennium B.C. when Lei-Tsu, chief concubine of the mythical “Yellow Emperor” Huang-Ti, invented the basic techniques of preparation and weaving while watching a silkworm spin its thread. Whatever the truth of the legend, methods of dealing with the delicate cocoons were devised: soaking in boiling water to kill the chrysalis and remove the gum that holds the fibers together, then picking up the loose ends and reeling the long filaments, “throwing” them (twisting them together), and finally warping and weaving. Eventually silk technology influenced the manufacture of other textiles.

The almost magical attraction of silk was owing to more than its scarcity and cost. The special luster and feel of the fabric—its “hand”—caused by the absence of surface irregularities, gave it the unique quality of “silkiness” that made it a prime article in East-West commerce for more than a millennium.

Silk culture eventually spread to Japan, India, and Persia. The Asian monopoly on silk making was temporarily broken in the fourth century B.C., when Alexander the Great brought the process to the Mediterranean from India. Aristotle described “loosening” threads and “reeling them up” from cocoons that were probably imported rather than cultivated, since the manufacture ceased shortly after. The techniques were forgotten by the time of Pliny (first century A.D.), who believed that silk fibers grew on trees.⁴

The first caravans from China to Persia began to move in 106 B.C., proceeding through either Samarkand or Bactria to Merv, south of the Aral Sea, thence into what is now Iraq, and eventually to the eastern frontier of the Roman Empire. The difficult stage from Iraq to Antioch and Egypt was sometimes avoided by circumnavigating Arabia via the Persian Gulf and the Red Sea, a course that in the first three centuries A.D. became part of a sea route between Greece and India. Later the sea route was extended by Chinese ships that by the fifth century A.D. were sailing as far as Aden in Arabia and the mouth of the Euphrates in Iraq. The sea route gained importance in A.D. 751, when two expanding empires, Chinese and Islamic, clashed in battle at the Talas River in central Asia. Chinese defeat effectively closed the land route for four hundred years.⁵

The sequel to the battle of Talas demonstrates that other groups besides merchants were carriers of technology. A Chinese officer taken prisoner returned home eleven years later to report that Chinese artisans in silk making and other crafts, apparently also captives, had settled at Kufah, in Iraq, the capital of the Abbasid Caliphate. The officer’s story, recorded by his brother, the scholar Tu Yu, stated: “As for the weavers who make light silks [in Kufah], the goldsmiths [who work] gold and silver [there], and the painters, [the arts which they practice] were started by Chinese technicians. For example, for painting, Fan Shu and Liu Tzhu from the capital [Sian], and for silk throwing and weaving, Yueh Huan and Lu Li from Shensi.”⁶ Part of the transmission was the introduction of the horizontal treadle silk loom, probable ancestor of the loom introduced to Europe in the twelfth century for all fabrics.

Other carriers of Chinese technology included émigrés and deserters, like those from the retinue of a Chinese embassy who settled in Persia as early as 100 B.C. and taught their new neighbors “to cast weapons and utensils” of iron. Needham speculates that at about the same time a deserter from the Chinese army taught the people of Ferghana, east of Samarkand, the art of deep drilling, using a technique developed in China a century earlier and due eventually to reach the West.⁷

In the twelfth century, when the Tartars besieged the Sung capital of Khaifeng, they demanded as hostages all kinds of Chinese artisans, including metalworkers, weavers, and tailors.⁸ Still other possible agents of transmission were the Buddhist pilgrims traveling between China and India in the early Middle Ages; their interests, however, were less technological than scientific: astrology, mineralogy, and medicine.

Technology as Government Enterprise

Throughout antiquity and the Middle Ages, the direction of technology transmission remained almost entirely from East to West. Europe had little to offer Asia; Asia, and especially China, had much to offer the West. Needham attributes Chinese technological leadership to the strong bureaucratic government that ruled China beginning with the country’s first unification under the Ch’in dynasty in the third century B.C.Most of China’s engineers and master mechanics were either directly employed or closely supervised by administrative authorities. Complex machines, such as the early water mill, could be developed only under government sponsorship.⁹ The same was true of large-scale engineering projects, of which the most famous was the Great Wall, built as a defensive barrier against the nomad horsemen of the North. Extending fifteen hundred miles from the Yellow Sea to a point in Central Asia, the massive project was completed in the third century B.C. during the Ch’in dynasty by joining together walls built earlier by the feudal states.

The identities of many ancient and medieval Chinese engineers and inventors are known. Chang Heng built the first seismograph about A.D. 130 and was the first to apply motive power to the rotation of astronomical instruments. Tu Shih created a water-powered metallurgical bellows in 31 B.C. Ma Chun (fl. A.D. 260) improved the draw loom and invented the square-pallet chain pump, widely used in China and neighboring countries. Yuwen Khai (fl. A.D. 600) superintended the building of the Grand Canal. Li Kao, Prince of Tshao (fl. A.D. 784), developed the human-powered treadmill paddle-wheel warship. The “Leonardo-like figure” Yen Su (fl. A.D. 1030), among many other inventions, designed an important type of clepsydra.¹⁰

China’s large-scale hydraulic engineering projects provided irrigation, water conservation, flood protection, and tax-grain transportation. In addition, as in the Roman Empire, they became a powerful centralizing agency, physically cutting through the boundaries of private estates and asserting superior authority over local governments. The state also built bridges, monopolized iron and steel production, and maintained imperial workshops for the crafts. The Thang dynasty (A.D. 618-906) sustained eight workshops and a Bureau for Barter with Foreign Peoples—an export-sales department.¹¹

Imperial interests stimulated innovation in other areas. The practice of geomancy, the pseudoscience that studied “local currents of the cosmic breath” in order to harmonize the palaces and tombs of the imperial family with the influences of the earth, produced discoveries that led eventually to the magnetic compass.¹² Problems of dynastic succession stimulated accurate calendar making and timekeeping by the imperial bureau of astronomy. The government’s standardized texts for civil service examinations helped create the demand that presently inspired the invention of printing.

Despite the large government role, however, small-scale private enterprise flourished. Most crafts were worked by individual craftsmen and their families, with skills sometimes concentrated in particular localities—lacquer making in Fuchow, pottery in Ching-te-chen, well drilling in Tzu-liu-ching.¹³ Both patterns—family production and the local concentration of skills—were repeated in Europe.

Exporting Chinese Technology

Beginning with cast iron in the fourth century B.C., one major innovation after another appears in the Chinese record, to emerge later, usually only after a long lapse, in the Near East and Europe. In some cases transmission of a device or process from China to the West can be demonstrated; in others, it can only be conjectured, raising the unresolved issue of independent invention, or the possibility of what Needham calls “stimulus diffusion”—the transmission of a general idea, to be developed in different detail. Perhaps the best-known example of such a question is the invention of movable metal type, which took place in China and Korea only slightly earlier than in Europe, and in which transmission is difficult to establish.¹⁴

An important technology in which China anticipated the rest of the world by at least a thousand years was the production of cast iron. Although China’s discovery of iron (513 B.C.) came long after the West’s, China leapfrogged ahead in producing cast iron. Chinese ore had a high phosphorus content, which gave it a lower melting point, but the application of waterpower and efficient bellows was probably the decisive factor. By the fourth century B.C., the technique of melting iron and casting it in molds was in regular use for tools and weapons.¹⁵ An ironworks of the Early Han period (second and first centuries B.C.) excavated in Honan contained seventeen smelting furnaces, eight of them blast furnaces, not developed in Europe until a millennium and a half later. The Chinese iron process may have been introduced to the West through the intermediary of Persia in the thirteenth century, though no hard evidence exists.¹⁶

Waterpower was applied to the iron-casting process by A.D. 31, when a text records that the engineer Tu Shih “invented a water-powered reciprocator for the casting of [iron] agricultural implements.” Smelters and casters were “instructed to use the rushing of the water to operate” their bellows.¹⁷ Waterpower was also applied at an early date to the grinding of grain. The large rotary mill appeared in China at about the same time as in Europe (second century B.C.), but while in Europe the slave- or donkey-powered “Pompeian” mill emerged first, in China the waterwheel took precedence, and when animal-powered mills appeared in about A.D. 175, they were called “dry water mills.”¹⁸ As in Europe, mills were highly profitable, both to the great monasteries and to entrepreneurs. Early in the Thang dynasty, the water mill spread to Korea, Japan, and Tibet.

Metallurgical bellows, powered by horizontal waterwheel, from a Chinese work of 1313. [From Joseph Needham, Science and Civilization in China, Cambridge University Press.]

Chinese waterwheels, like those on the periphery of Europe and everywhere east of Persia, were typically horizontal. The vertical wheel was known, however, and used to operate trip-hammers, a single large wheel often turning several shafts; widespread in China by the third and fourth centuries A.D., it was used not only in forges but in hulling rice and crushing ore. The vertical fall of water was also used in other devices. The spoon tilt hammer consisted of a lever with a hammer at one end and a trough at the other; as the trough filled, the hammer was raised; the trough then automatically emptied, dropping the hammer.¹⁹ The edge-runner mill was another crushing device, in which materials were pulverized by a disk on edge running around a lower millstone. The edge runner appeared in China in the fifth century A.D.²⁰Both trip-hammer and edge runner arrived in Europe in the twelfth century.

Floating mills like those of Belisarius were known in China at least by the eighth century A.D. and perhaps much earlier. They may have inspired another invention: the paddle-wheel boat. Instead of water turning a wheel on an anchored boat, the wheel, turned by a man-powered treadmill, propelled the boat. It was probably such boats that astonished the enemy in a naval action in A.D. 418: they “saw the ships advancing up the Wei [River] but could not see anyone on board making them move” because “the men propelling the boats were all [hidden] inside the vessels.” Chinese treadmill-paddle-wheel ships reached their apogee in the early twelfth century when a Sung-dynasty marine engineer built a ship carrying a crew of two or three hundred men, with eleven paddle wheels on either side and a stern wheel. The idea eventually reached the West, but much later.²¹

An even more remarkable Chinese application of the waterwheel was its employment in driving mechanized astronomical instruments and finally timekeepers. A succession of planetary models, armillary spheres, and mechanically rotated star maps culminated in A.D. 1090 in a forty-foot-high tower clock built in Khaifeng, capital of the Northern Sung dynasty, antedating the European mechanical clock by more than two centuries. Among the intermediate devices, one instrument, the “Water-Driven Spherical Bird’s-Eye-View Map of the Heavens,” built in the Thang capital of Chhang-an in A.D. 725, incorporated what seems to have been the world’s first escapement, a combination, in the words of a contemporary, of “hooks, pins, and interlocking rods, coupling devices, and locks checking mutually.”

Su Sung’s astronomical clock-tower, built in 1090 at Khaifeng, was driven by a waterwheel with a complex escapement. Drawing by John Christiansen from Su Sung’s description. [From Joseph Needham, Science and Civilization in China, Cambridge University Press.]

The Khaifeng clock of 1090 was the creation of Su Sung, who first built a wooden pilot model, then cast his working parts in bronze. The water that supplied power was contained in a reservoir, refilled periodically by manually operated norias. Water passed by siphon from the reservoir to a constant-level tank and thence to the scoops of the waterwheel. An endless-chain drive slowly turned a celestial globe and an armillary sphere one revolution per day. The same waterwheel turned a series of shafts, gears, and wheels working the bells and drums that announced the time (like all early mechanical clocks, Su Sung’s had no face). The escapement that was the “soul of the timekeeping machine” and that kept its movement at an even pace was a complex arrangement of balances, counterweights, and locks that divided the flow of the water into equal parts by repeated weighing, automatically dividing the revolution of the wheel into equal intervals.

In 1126, when the Chin Tartars captured Khaifeng, they destroyed Su Sung’s clock tower and carried off the clock, along with several families of craftsmen, who set it up in Peking, the Chin capital. The armillary sphere was struck by lightning in 1195 but was repaired. Early in the thirteenth century when the Chin court fled from the Mongols, the emperor’s aides proposed that the armillary sphere be melted down, but the emperor could not bring himself to destroy it, and it was left behind. By the time the Mongols made Peking their capital in 1264, the clock was no longer in working condition.

Meanwhile, in the area beyond the Yangtze to which they had withdrawn, Sung engineers tried to build another clock, but the secret of the escapement had been lost. A contemporary reported, “Now it is said that the design is no longer known, even to the descendants of Su Sung himself.” Clock makers returned to the clepsydra, and Chinese clock making reached a dead end, receiving its final blow in the fourteenth century when the Ming dynasty captured Peking and destroyed the remains of Su Sung’s famous mechanism.²²

Perhaps because China never gave a name to its timekeeping devices, they were completely forgotten when, in the seventeenth century, Jesuit missionaries brought to China the European mechanical clock, which the Chinese admired as “a new European invention of dazzling ingenuity” (Needham). Yet Chinese escapements, Needham believes, may have provided at least a stimulus diffusion to the European mechanical clock—perhaps no more than the suggestion that a timekeeper had been invented in the East with a device that divided its movement into equal parts, a problem which Western clock makers solved in an entirely different way.²³

The wheelbarrow, described in Chinese army specifications in A.D. 230, surfaced in Europe in the twelfth or early thirteenth century. The Chinese “single-[wheel] push-barrow” usually had its wheel in the middle of a boxlike structure, bearing the entire load, so that the pusher moved it but did not support it.²⁴

The suspension bridge was first given durable form in the sixth century when Chinese engineers employed iron chains to suspend roadways, a technique copied in Tibet but one that appeared in Europe only at the end of the eighteenth century. The segmental arch bridge, built in China shortly after A.D. 600, was imitated in the West in the fourteenth century.²⁵ Lock gates built under the Sung dynasty (960-1279) followed in Europe in the late fourteenth century.²⁶

A Chinese art that the West tried vainly to copy in the Middle Ages was the production of porcelain, the vitrified (glasslike), fine-grained, and usually translucent pottery in latter days associated with the word “china.” In the seventh century A.D., Chinese potters discovered that the mineral feldspar could be incorporated into stoneware, resulting in a primitive type of porcelain. The process was perfected in the thirteenth century under the Mongols by mixing china stone, a rock containing feldspar, with kaolin, white china clay, and firing it at extremely high temperatures (up to 1,450°C). During the late Middle Ages, European potters attempted to imitate Chinese porcelain, their efforts eventually culminating in the sixteenth century in an inferior product, soft-paste or artificial porcelain, a mixture of clay and ground glass fired at a lower temperature. True hard-paste porcelain was not produced in Europe until the eighteenth century.²⁷

One pattern that was repeated through antiquity and the Middle Ages was the appearance of a device in Greece and Rome, paralleled or closely followed in China, then forgotten in the West but continuing to develop in the East, and finally revived in Europe. One such device was the odometer, known to Vitruvius and Heron of Alexandria, then disappearing until the end of the fifteenth century, when it was depicted by Leonardo da Vinci. In China the mechanism seems to have originated sometime in the first century B.C. as a mechanical toy, a vehicle in imperial processions whose turning wheels activated drums and gongs. The device’s value for surveying and mapmaking was soon recognized, and the wheels and gears were arranged to measure distance. An eleventh-century historian described an elaborate model: “It is painted red, with pictures of flowers and birds on the four sides, and constructed in two stories, handsomely adorned with carvings. At the completion of every li, the wooden figure of a man in the lower story strikes a drum; at the completion of every ten li, the wooden figure in the upper story strikes a bell.”²⁸

The “south-pointing carriage,” a celebrated vehicle peculiar to China dating from the third century A.D., was once erroneously believed to represent a step in the development of the magnetic compass. A two-wheeled horse-drawn chariot on which a figure was mounted with its arm preset to point due south, the vehicle had gears so arranged that whichever way it turned, the figure pivoted to hold its south-pointing posture. Although it was an invention without further application, whose secret was later forgotten in China, the carriage was not without significance in cybernetics, as a pioneer self-regulating mechanism employing negative feedback.²⁹

The magnetic compass, however, did originate in China in the early Middle Ages. Both European and Chinese antiquity were aware of the ability of the lodestone (a variety of magnetite) to attract and repel iron, and of its inductive property—the power to magnetize iron, to impart the same attraction and repulsion to it. Discovery of the directive possibilities of the magnet, however, belonged to China, as did the invention of the magnetic needle, to make readings more accurate.

The earliest certain reference to the magnetic compass goes back to A.D. 83, in the Han dynasty, when a scholar described the “south-controlling spoon” which when thrown on the geomancer’s divining board came to rest pointing south (the arrow on a compass may be, and often was, made to point south rather than north). The board used by geomancers to detect the “winds and waters of the earth” consisted of two plates, the lower square, symbolizing the earth, the upper round, symbolizing the heavens. The upper plate, engraved with the compass points, revolved on a central pivot and bore in the middle a representation of the Great Bear. This plate was turned on its axis to follow the annual path of the bear’s tail. The spoon, cut from lodestone, also represented the bear. Aside from its role in divination, some form of “south-pointer” was used by Chinese travelers; a reference from the Han dynasty states that “when the people of Cheng go out to collect jade, they carry a south-pointer with them so as not to lose their way.”³⁰

The compass matured with the development of more accurate instruments, including the magnetized needle, introduced in China in the eighth century A.D. Created by rubbing an iron needle with a magnet, the device was floated on water on a bit of wood or suspended by a silken thread.³¹ By at least the ninth century, the Chinese were aware of the principle of magnetic declination—the fact that the compass needle does not point true north (or south), the inclination varying with the meridian where the reading is taken.³²

Probably because most of China’s water travel took place on its network of canals and rivers or along the coast, the compass was slow to be adopted for navigation. Sometime between 850 and 1050, it began to appear aboard ships, the first certain mention in a Chinese text occurring early in the twelfth century, in a reference to events of the late eleventh: “The [seagoing] ship’s pilots are acquainted with the configuration of the coasts; at night they steer by the stars, and in the day-time by the sun. In dark weather they look at the south-pointing needle.”³³

Incidental to the final development of the mariner’s compass was a device with a number of applications, an eventual one of which was to provide mounting to keep the compass in horizontal equilibrium, independent of the ship’s motion. Called in the West the “Cardan suspension” because it was described, much later, by Italian scientist Jerome Cardan, it was known in China from the second century, when an account described an incense burner with “a contrivance of rings which could revolve…so that the body of the burner remained constantly level and could [safely] be placed among bedclothes and cushions.” Similar portable stoves were known to the Arabs, who probably transmitted the invention to Europe.³⁴

Gunpowder appeared in China as early as the ninth century, when the first reference to the mixing of saltpeter, sulfur, and carbonaceous material occurred in a Taoist alchemy book. The first reaction of the inventors was to warn others against it, lest they singe their beards and burn down their laboratories.³⁵ Contrary to popular belief, however, the Chinese did not limit early use of the invention to fireworks but very quickly incorporated it into military weapons, evolving from about A.D. 950 into sophisticated rockets and guns.³⁶ It seems almost certain that the secret was transmitted westward, though the route of diffusion has baffled discovery.

One Chinese invention whose passage to Europe can be traced step by step is paper. A felted sheet of fibers formed from a water-suspension process using a sievelike screen as a mold, paper was first manufactured in China sometime before the Christian era and was widely used in the third century A.D., by which time it had already spread beyond Chinese borders.³⁷

Paper may have been first produced accidentally during the process of felting—making nonwoven fabric by applying heat, water, and pounding to plant or animal fibers, or shrinking and matting woven rags by the same process. In the Chinese paper industry, rags were soon replaced in high-grade papers by the bark of the paper mulberry. Gradually the product was improved with sizing and dyes, and by the use of molds made of bamboo strips to replace the earlier screens of coarse cloth.³⁸

Cheap and light, paper was first used in China not for writing or printing but for applications such as wrapping. Only in the third century A.D. did it completely replace silk, bamboo, and wood as a writing medium. The two writing materials of the ancient West, animal hides (parchment and vellum) and plant leaves (papyrus), were never used for writing in China, where paper came to have a unique importance. Among its hundreds of uses besides writing were cut-out designs, fans, and umbrellas from the third century; clothing, household furnishings, visiting cards, kites, lanterns, napkins, and toilet paper by the fifth or sixth century, playing cards and money by the ninth.

The use of toilet paper was recorded by a sixth-century Chinese scholar who wrote, “Paper on which there are quotations or commentaries from the Five Classics or the names of sages, I dare not use for toilet purposes.” In 851 an Arab traveler commented unfavorably on the cleanliness of the Chinese, who did not “wash themselves with water when they have done their necessities; but they only wipe themselves with paper.” Toilet paper was made from rice straw, cheap and soft. In 1393 the Bureau of Imperial Supplies recorded the manufacture of 720,000 large sheets for the use of the court and 15,000 sheets, three inches square, light yellow, thick but soft, and perfumed, for the use of the imperial family.³⁹

Paper money seems to have originated in the early ninth century when increased business and government transactions encouraged the institution of “flying money,” a credit medium rather than a true money, as a way to avoid carrying the weight of metal coins. Originally a private arrangement of merchants, the system was taken over by the government in A.D. 812 and gradually evolved into a true paper currency.⁴⁰

Two centuries before Cassiodorus sang the praises of papyrus, a Chinese scholar wrote a panegyric to paper in rhymed prose:

Lovely and precious is this material,

Luxury but at a small price;

Matter immaculate and pure in its nature

Embodied in beauty with elegance incarnate,

Truly it pleases men of letters.

It makes new substance out of rags,

Open it stretches,

Closed it rolls up,

Contracting, expanding,

Secreting, expounding.

To kinship and friendship scattered afar,

When you are lonely and no one is by,

You take brush to write on paper…⁴¹

Transmission of paper westward occurred in two stages, the paper and paper products arriving first, followed a century or two later by the manufacturing technique. Neighboring Korea, Japan, and Indo-China learned papermaking as soon as they began to have contact with China (c. second century A.D.). Moving westward over the Old Silk Road, paper arrived in eastern Turkestan, on the shores of the Caspian Sea, in the third century. Chinese paper craftsmen captured at the battle of Talas River in 751 were brought to Samarkand to found an industry that made “paper of Samarkand” an important article of commerce, leading to the establishment of a mill at Baghdad in about 794.⁴² Arab manuscripts written on paper survive from the following century.⁴³ Paper products finally entered Europe in the tenth century through Muslim Spain, which also became the first European country to develop a paper industry, followed a little later by Muslim Sicily and southern Italy. Waterpower was first applied to the pounding process in Baghdad about 950.⁴⁴

In China paper had many advantages over its alternatives, clumsy bamboo and wood and expensive silk. In Europe it had only the advantage of cheapness over papyrus and parchment, and it was more fragile and perishable. Not until the advent of printing in Europe did paper fulfill its potential, replacing parchment for all but the most permanent records.

The course of transmission of printing is much less easily discerned than that of paper. After a long history of preprinting techniques—seals for stamping, stencils to duplicate designs, inked impressions from stone inscriptions—the Chinese began to use woodblock printing in the seventh century. More practical than movable type for written Chinese, with its thousands of ideograms rather than an alphabet, the woodblock dominated Chinese printing for several centuries. A Persian historian described the reproduction and distribution of woodblock-printed Chinese books: a skilled calligrapher copied the author’s text onto wooden tablets; these were corrected by proofreaders before being carved on the tablet surface by expert engravers. The tablets (pages-to-be) were then consecutively numbered and placed in sealed bags. When a copy of the book was wanted, the customer paid a charge fixed by the government, and the tablets were taken out, inked, and imposed on sheets of paper.⁴⁵

Since under the Chinese ideograph system the amount of movable type required a large capital investment and elaborate organization of labor, it was profitable only for large-scale production. In about 1045 an artisan named Pi Sheng formed clay characters “as thin as the edge of a coin,” fired them; assembled the type on an iron plate coated with pine resin, wax, and ashes; warmed and cooled the plate to solidify the type; then inked it and made the impression. A contemporary, describing the process, explained, “If one were to print only two or three copies, this method would be neither simple nor easy. But for printing hundreds or thousands of copies, it was marvelously quick.” Pi Sheng usually worked with two forms, taking the impression from one while type was being set on the other, enabling the printing to be done “with great rapidity.” The type was arranged in wooden cases with paper labels, “one label for words of each rhyme-group.”⁴⁶

The first practical wooden movable type appeared late in the thirteenth century, when a magistrate named Wang Chen used characters cut out of wood blocks with a small, fine-toothed saw, then finished with a knife for exact uniformity and arranged for easier handling in compartmental wooden cases on revolving tables.⁴⁷ Metal movable type was developed early in the fifteenth century in Korea, where three cast-bronze fonts were made before the appearance of metal type in Europe or China.

A reasonable conjecture is that printing followed the path of paper to Turkestan, whence it reached Persia during the thirteenth-century Mongol domination of central Asia, to appear in Europe, first in block form and then as movable type.⁴⁸

One outstanding Chinese invention that did not migrate westward was the junk, one of the best sailing ships ever designed. Powered by square sails composed of linen panels that were raised and lowered like venetian blinds, the junk had a high stern and massive stern rudder (an idea that did eventually reach the West) that on the junk doubled as a keel. Another notable feature was the watertight compartment.

The Technology of India and Persia

The technological contributions of India and Persia, many of them fundamental inventions, belong mostly to prehistory and antiquity. Indian metallurgy was far ahead of European; the Romans imported Indian steel. Medieval India produced landmark scientific advances, notably in mathematics—algebra and the so-called Hindu-Arabic numerals, embodying the principle of place value and the zero. Of its technical innovations, one, the churka (cotton gin) had an enormous impact on the West. India may also have produced the original ancestor of the spinning wheel, for use with cotton.

Persia’s chief medieval invention was the Eastern version of the windmill, mentioned for the first time in the seventh century. Like the Eastern waterwheel, it was horizontal, with enclosing walls admitting the wind on one side. Windmills of the Persian type spread to Turkestan and thence to China, where they took on a nautical form, with fore-and-aft sails mounted on masts around a drum. If a connection exists between these horizontal windmills and the vertically mounted windmill that began to appear in Europe in the twelfth century, it is probably that of stimulus diffusion.

The Arabs, Transmitters and Inventors

In the immense transfer of science and technology that marked the Middle Ages in Europe, Africa, and Asia, the Arabs played a unique role. Along with the spices and silks they carried from China and India, they brought many of Asia’s discoveries and inventions, and they provided the means by which Europe at last recovered its own lost heritage of Greek knowledge. The protracted conflict between Islam and Christian Europe has obscured the remarkable service performed by the former to the benefit of the latter, but the process occurred naturally enough. “Between the eighth and the twelfth centuries, the sophistication and culture of the Islamic world made it the suitable heir of classical civilization” (Joel Mokyr),⁴⁹ and as such it readily absorbed the science and philosophy of Greece.

The Arab Age of Translation began during the reign of Harun-al-Rashid (A.D. 786-809), when scholar-physicians at a Nestorian Christian academy in Jundi-Shapur, in southwest Persia, were brought to Baghdad to translate Greek manuscripts gathered by the caliph’s agents, acting, in the words of a modern writer, as “buyers of culture.”⁵⁰ A young scholar from Jundi-Shapur, Hunayn ibn-Ishaq, became court physician to Harun’s son, Caliph al-Mamun, and in 830 was named head of the “House of Wisdom,” a library founded by the caliph to store and translate Greek manuscripts. Hunayn and his colleagues translated Plato’s Republic, many of Aristotle’s works, and the medical writings of Hippocrates, Dioscorides, and Galen (some of whose works were later lost in the original Greek and preserved to the world solely in Hunayn’s Arabic).⁵¹

Most of the Greek works translated belonged to the Hellenistic period, and the culture they represented was not that of literary Athens but that of scientific Alexandria. Homer was never rendered into Arabic, nor were the works of Greek historians or dramatists. Aristotle’s comments about Greek drama in the Poetics puzzled Arab readers; they had no theater of their own and were totally unacquainted with Sophocles and Euripides. Their interests were essentially those of Aristotle himself: the natural sciences, medicine, chemistry, astronomy, mathematics, geography, and the philosophy underlying them. They did not stop with preservation and translation; Arab scholars expounded and interpreted the Greek material, to the great benefit of later European intellectuals. The most famous of the Arab commentators were Avicenna (Ibn-Sina, 980-1037) and Averroës (Ibn-Rushd, 1126-1198). The distinguished astronomer and mathematician al-Khwarizmi (c. 780-c. 850) revised the geography of Ptolemy and wrote an original treatise expounding the Hindu numerals which, in Latin translation, introduced them to the Christian West.

Muslim philosopher Averroës (Ibn-Rushd). Detail of fresco The Triumph of St. Thomas Aquinas, by Andrea da Firenze, in Santa Maria Novella, Florence. [Alinari.]

In other fields the Arabs made original contributions. Commerce was a respectable, even prestigious profession in the world of Islam. “The honest Muslim merchant will rank with the martyrs of the faith,” said Muhammad, and “Merchants are the couriers of the world and the trusted servants of God upon earth.”⁵² Islamic business techniques in banking, bookkeeping, and coinage were so far in advance of those of Europe that when the Normans conquered Sicily (1071-1091), their pragmatic Christian kings employed Muslims to handle their finances.⁵³

To the science of distillation, already centuries old, Muslim alchemists made many practical contributions. Muslim musicians introduced the first bowed instruments, the lute and rebec, ancestors of the violin. Following the First Crusade, European military engineers learned much of the art of castle building from their Muslim foes. The secrets of Syrian glassmaking were sold to Venice (in 1277) and its techniques taught by Muslim artisans, founding a monopoly of the manufacture of fine glass long maintained by that city.⁵⁴

Undergirding the transformation of the Muslim half of the Mediterranean world lay Islam’s own revolution in agriculture. Like so much else, the crops and processes of the new system were borrowed from Asia, in this case mostly from India. Muslim enterprise, public as well as state-encouraged private, combined them into a fresh synthesis. A wide array of food and fiber plants was introduced, new patterns of cultivation were adopted, and extensive irrigation systems were built. The new crops included rice, sorghum, hard wheat, sugarcane, cotton, watermelons, eggplants, spinach, artichokes, sour oranges, lemons, limes, bananas, plantains, mangoes, and coconut palms. Most required intensive cultivation with application of fertilizer, heavy watering, and a flexible system of crop rotation that employed all the seasons of the year. New irrigation devices, also borrowed rather than invented by the Arabs, included dams, drainage tunnels, canals, and water-lifting machines. The system with its wider variety of crops, more land under cultivation, and more intensive cropping, helped stabilize Islamic agriculture, stimulating denser rural settlement and the growth of cities.

Like other elements of Islamic civilization, the new agriculture migrated from Baghdad westward, by way of Egypt, Tunisia, and Morocco, to reach Europe via Muslim Spain. Some of the techniques, notably irrigation works, were quickly imitated in Christian Europe, whose southern regions also adopted the cultivation of cotton, rice, sugarcane, and citrus fruits. At the end of the Middle Ages, many of these were successfully transplanted to the Americas.⁵⁵

In stock farming, Spanish Muslims bred the famous merino sheep, which made Spanish wool preeminent in the world. But it was in wool’s great rival, cotton, that Islam made its most important textile contribution, transmitting to Europe the secrets of its cultivation and conversion into cloth. The Arabs were the first people in the Near East and Europe to adopt cotton for ordinary clothing. Muhammad himself set the style by wearing a white cotton shirt and trousers under a woolen cloak, a costume adopted by the first caliphs. In later times, rulers and the very wealthy wore silk and embroidered cloth, but everyone else, in both town and country, wore cotton, either white or black—cotton undergarments, cotton caftans and robes, cotton mantles for women, cotton veils and turbans. Cotton was used for shrouds and funeral clothes, and for bedclothes, tablecloths, curtains, towels, and rugs.

Housed in a network of textile workshops known as tiraz factories, royal textile manufacturing was closely regulated and workmanship and production were strictly controlled. Alongside the tirazestablishments in the great cities, a flourishing private industry was carried on in surrounding smaller towns. The most prized cotton fabrics produced for international commerce came from the tiraz cities of Iraq, Persia, and Syria, while the lesser towns produced under private management textiles for local and regional markets. Arab conquest brought cotton manufacture and cultivation to North Africa, Spain, Sicily, and southern Italy. In Spain the Arab cotton industry disseminated technical knowledge via regions reconquered by the Christians. In Sicily and Italy, Europeans inherited the Arab textile systems intact.⁵⁶

Well into the Middle Ages, Europe remained a poor relation of Asia, accepting hand-me-down technology from China and India, carried westward either in artifact or in idea by intermediaries of whom the most important were the Arabs. Up to the thirteenth century, there was scarcely any direct contact between the two regions; an English cleric, French knight, or Italian merchant knew hardly more of China than had Julius Caesar. Yet through these centuries, Asian technology was steadily infiltrating Europe, unheralded and unrecognized, but with growing impact on the European way of life and patterns of work.