Cathedral, Forge, and Waterwheel Part 1

Cathedral, Forge, and Waterwheel.

Technology and Invention in the Middle Ages.

by Frances & Joseph Gies.

1.

NIMROD'S T TOWER, NOAH'S A ARK

IN THE CENTURIES FOLLOWING THE MIDDLE Ages, thinkers of the European Enlightenment looked back on the previous period as a time "quiet as the dark of the night,"1 when the world slumbered and man's history came to "a full stop." when the world slumbered and man's history came to "a full stop."2 A spirit of otherworldliness and a preoccupation with theology were perceived as underlying a vast medieval inertia. The most influential spokesman for this point of view was historian Edward Gibbon, who in his A spirit of otherworldliness and a preoccupation with theology were perceived as underlying a vast medieval inertia. The most influential spokesman for this point of view was historian Edward Gibbon, who in his Decline and Fall of the Roman Empire Decline and Fall of the Roman Empire described medieval society as "the triumph of barbarism and religion." described medieval society as "the triumph of barbarism and religion."3 Images of lethargy and stagnation were persistently applied to the Middle Ages well into the twentieth century. Even today the popular impression remains to a great extent that of a millennium of darkness, a thousand years when "nothing happened." To the average educated person, the most surprising news about medieval technology may be the fact that there was any.

Yet not all intellectuals of the past shared the negative view of the Middle Ages. In 1550 Italian physician and mathematician Jerome Cardan wrote that the magnetic compa.s.s, printing, and gunpowder were three inventions to which "the whole of antiquity has nothing equal to show."4 A generation later, the Dutch scholar Johannes Strada.n.u.s (Jan van der Straet, 15281605) in his book A generation later, the Dutch scholar Johannes Strada.n.u.s (Jan van der Straet, 15281605) in his book Nova reperta Nova reperta listed nine great discoveries, all products of the Middle Ages. listed nine great discoveries, all products of the Middle Ages.5 Gibbon's eighteenth-century contemporary Anne-Robert-Jacques Turgot, finance minister to Louis XVI, looked back on the Middle Ages as a time when "kings were without authority, n.o.bles without constraint, peoples enslaved...commerce and communication cut off," when the barbarian invasions had "put out the fire of reason," but he saw it also as a time when a number of inventions unknown to the Greeks and Romans had been somehow produced. Turgot credited the medieval achievement to a "succession of physical experiments" undertaken by unknown individual geniuses who worked in isolation, surrounded by a sea of darkness.6 Today, on the contrary, the innovative technology of the Middle Ages appears as the silent contribution of many hands and minds working together. The most momentous changes are now understood not as single, explicit inventions but as gradual, imperceptible revolutions-in agriculture, in water and wind power, in building construction, in textile manufacture, in communications, in metallurgy, in weaponry-taking place through incremental improvements, large or small, in tools, techniques, and the organization of work. This new view is part of a broader change in historical theory that has come to perceive technological innovation in all ages as primarily a social process rather than a disconnected series of individual initiatives.

In the course of recent decades, the very expression "Dark Ages" has fallen into disrepute among historians. The 1934 Webster's a.s.serted that "the term Dark Ages Dark Ages is applied to the whole, or more often to the earlier part of the [medieval] period, because of its intellectual stagnation." The 1966 Random House dictionary agreed, defining "Dark Ages" as "1. The period in European history from about is applied to the whole, or more often to the earlier part of the [medieval] period, because of its intellectual stagnation." The 1966 Random House dictionary agreed, defining "Dark Ages" as "1. The period in European history from about A.D. A.D. 476 to about 1000; 2. The whole of the Middle Ages, from about 476 to about 1000; 2. The whole of the Middle Ages, from about A.D. A.D. 476 to the Renaissance," a description repeated verbatim in its 1987 edition. The HarperCollins dictionary of 1991, however, recognized the term's decline in scholarly favor, defining "Dark Ages" as "1. The period from about the late 5th century 476 to the Renaissance," a description repeated verbatim in its 1987 edition. The HarperCollins dictionary of 1991, however, recognized the term's decline in scholarly favor, defining "Dark Ages" as "1. The period from about the late 5th century A.D. A.D. to about 1000 to about 1000 A.D. A.D., once considered an unenlightened period; 2. (occasionally) the whole medieval period."

Recently, historians have suggested the possibility of a narrower use of the old term. In a presidential address to the Medieval Academy of America in 1984, Fred C. Robinson recommended keeping "Dark Age," in the singular, and restricting its meaning to our dim perception of the period (owing to the scarcity of doc.u.mentary evidence) rather than to its alleged "intellectual stagnation."7 The problem of definition also involves the dating of the Middle Ages. The once sovereign date of A.D. A.D. 476 as starting point has been judged essentially meaningless, since it marks only the formal abdication of the last Western Roman emperor. In fact, the now general employment of the round 476 as starting point has been judged essentially meaningless, since it marks only the formal abdication of the last Western Roman emperor. In fact, the now general employment of the round A.D. A.D. 500 is an admission by historians that there is really no valid starting point, that the beginning of the Middle Ages overlaps and intermingles with the decline and fall of the Western Roman Empire. At the other end, the precise but even less meaningful 1453 (the fall of Constantinople and the end of the Hundred Years War) has been widely replaced by the round 1500, suggestive princ.i.p.ally of the opening of the Age of Exploration and the historic impingement of Europe upon America and Asia. 500 is an admission by historians that there is really no valid starting point, that the beginning of the Middle Ages overlaps and intermingles with the decline and fall of the Western Roman Empire. At the other end, the precise but even less meaningful 1453 (the fall of Constantinople and the end of the Hundred Years War) has been widely replaced by the round 1500, suggestive princ.i.p.ally of the opening of the Age of Exploration and the historic impingement of Europe upon America and Asia.

From the third decade of the present century, a recognition of medieval technological and scientific progress has been affirmed by scholars such as Marc Bloch, Lynn White, Robert S. Lopez, Bertrand Gille, Georges Duby, and Jacques Le Goff. Most modern textbooks include in their history of invention the medieval discovery or adoption of the heavy plow, animal harness, open-field agriculture, the castle, water-powered machinery, the putting-out system, Gothic architecture, Hindu-Arabic numerals, double-entry bookkeeping, the blast furnace, the compa.s.s, eyegla.s.ses, the lateen sail, clockwork, firearms, and movable type.

But while the pioneering work in medieval technology by Marc Bloch and Lynn White was undertaken in an era (roughly 1925 to 1960) that affirmed human progress and regarded advances in technology as self-evidently positive, the climate of the last part of the twentieth century has become less favorable to technology in general and even to the idea of progress. Suddenly, instead of being credited with no technology, the Middle Ages is found by some to have had too much. Activities once universally regarded as beneficent (such as the land-clearance campaigns of the great monasteries) have been condemned: "The deforestation of Europe during the twelfth century-especially during the 1170s and 1180s-may be seen as the first great ecological disaster," wrote George Ovitt, Jr., in 1987.8 Such present-minded thinking permeated Jean Gimpel's The Medieval Machine The Medieval Machine (1976). Drawing a parallel with twentieth-century industrial society, which he envisioned in Spenglerian decline, Gimpel pictured an overindustrialized late medieval Europe suffering from overpopulation, pollution, economic instability, dwindling energy sources, and general malaise. (1976). Drawing a parallel with twentieth-century industrial society, which he envisioned in Spenglerian decline, Gimpel pictured an overindustrialized late medieval Europe suffering from overpopulation, pollution, economic instability, dwindling energy sources, and general malaise.9 But despite the many medieval contributions to technology, to speak as Gimpel does of an "industrial revolution" of the Middle Ages is hyperbole. By the same token, pollution was slight, energy sources were largely untapped, the financial crisis of the fourteenth century was temporary and local, and population was excessive only in respect to the limitations of existing agricultural technology. Advanced though it was over the cla.s.sical age, medieval technology was still in what Lewis Mumford called the "eotechnic" phase-the age of wood, stone, wind, and water-to be followed, in Mumford's terminology, by a "paleotechnic" phase in which coal and iron dominated, and finally by our present "neotechnic" phase of electricity, electronics, nuclear energy, alloys, plastics, and synthetics.10

When Gibbon indicted the Middle Ages as "the triumph of barbarism and religion," he coupled the two great bugbears of the intellectual elite of his day, both widely regarded as hostile to scientific and technical progress. The Catholic Church long stood condemned as the enemy of enlightenment, with the alleged suppressions of Copernicus and Galileo as Exhibit A. More recent historians, however, have pointed to evidence of Church att.i.tudes and policies of a quite different coloration. Lynn White a.s.serted that Christian theology actually gave the Middle Ages a fiat for technology: "Man shares in great measure G.o.d's transcendence of nature. Christianity, in absolute contrast to ancient paganism and Asia's religions...not only established a dualism of man and nature but also insisted that it is G.o.d's will that man exploit nature for his proper ends."11 Even earlier, Max Weber (18641920) drew attention to the prominent role given by the Benedictine Rule to monastic labor ("Idleness is the enemy of the soul. Therefore the brothers should have a specified period for manual labor as well as for prayerful reading.") and to the well-organized physical self-sufficiency of the monastic community.12 In the same vein, Ernest Benz pointed to medieval iconography showing G.o.d as a master mason, measuring out the universe with compa.s.ses and T square, and noted that such images, drawing a parallel between G.o.d's labors and those of men, offer an indication of the status of technology in medieval Christendom. In the same vein, Ernest Benz pointed to medieval iconography showing G.o.d as a master mason, measuring out the universe with compa.s.ses and T square, and noted that such images, drawing a parallel between G.o.d's labors and those of men, offer an indication of the status of technology in medieval Christendom.13 G.o.d as master mason measures the universe. [Osterreichische Nationalbibliothek. Codex 2.554, f. 1.]

More recently, George Ovitt, studying the att.i.tudes of medieval theologians, has found that they advocated stewardship of nature at the same time that ecological evidence shows "an ethic of appropriation" and a "social commitment to the primacy of human habitation" over competing interests.14 Their varying and contradictory att.i.tudes, he has concluded, represent a rationalization "in response to changes in the 'structures of everyday life' that were created by others," Their varying and contradictory att.i.tudes, he has concluded, represent a rationalization "in response to changes in the 'structures of everyday life' that were created by others,"15 that is, in response to what was actually going on in the real world. that is, in response to what was actually going on in the real world.

The forces that impelled medieval men to clear land for cultivation and to develop new ways of exploiting nature were complex, but they were surely social and economic rather than ethical or religious. And while the monasteries were among the great clearers of land, the chief conservationists of the Middle Ages were the kings and great lords, who stringently protected their forests, not as guardians of nature, but in the interest of the aristocratic recreation of hunting (just as latter-day hunters' organizations help to preserve wilderness).

Did Christian theologians of the Middle Ages believe, as Lynn White wrote, that "it is G.o.d's will that man exploit nature for his proper ends"? And were the theologians' att.i.tudes toward labor and the crafts as benign as Ernest Benz thought?

One of the early Church Fathers, Tertullian (c. A.D. A.D. 160240), commented eloquently on the effects of human enterprise on the earth: "Farms have replaced wastelands, cultivated land has subdued the forests, cattle have put to flight the wild beast, barren lands have become fertile, rocks have become soil, swamps have been drained, and the number of cities exceeds the number of poor huts found in former times...Everywhere there are people, communities-everywhere there is human life!" To such a point that "the world is full. The elements scarcely suffice us. Our needs press...Pestilence, famine, wars, [earthquakes] are intended, indeed, as remedies, as prunings, against the growth of the human race." 160240), commented eloquently on the effects of human enterprise on the earth: "Farms have replaced wastelands, cultivated land has subdued the forests, cattle have put to flight the wild beast, barren lands have become fertile, rocks have become soil, swamps have been drained, and the number of cities exceeds the number of poor huts found in former times...Everywhere there are people, communities-everywhere there is human life!" To such a point that "the world is full. The elements scarcely suffice us. Our needs press...Pestilence, famine, wars, [earthquakes] are intended, indeed, as remedies, as prunings, against the growth of the human race."16 Tertullian antic.i.p.ated Malthus in his gloomy view. He was echoed by St. Augustine (A.D. 354430), who cited Adam's Fall as the dividing point between man's living in harmony with nature and his exploiting it. Prelapsarian (before the Fall) Adam dwelt peacefully in a world where conception occurred "without the pa.s.sion of l.u.s.t," childbirth without "the moanings of the mother in pain," where man's "life was free from want...There were food and drink to keep away hunger and thirst and the tree of life to stave off death from senescence...Not a sickness a.s.sailed him from within, and he feared no harm from without." 354430), who cited Adam's Fall as the dividing point between man's living in harmony with nature and his exploiting it. Prelapsarian (before the Fall) Adam dwelt peacefully in a world where conception occurred "without the pa.s.sion of l.u.s.t," childbirth without "the moanings of the mother in pain," where man's "life was free from want...There were food and drink to keep away hunger and thirst and the tree of life to stave off death from senescence...Not a sickness a.s.sailed him from within, and he feared no harm from without."17 But where prelapsarian Adam lived wholesomely within nature, postlapsarian Adam lived greedily off its bounty. Only by recovering their moral and spiritual innocence could Adam's successors restore the perfection of the world before the Fall. But where prelapsarian Adam lived wholesomely within nature, postlapsarian Adam lived greedily off its bounty. Only by recovering their moral and spiritual innocence could Adam's successors restore the perfection of the world before the Fall.

In the eighth century Anglo-Saxon theologian and historian Bede expanded on Augustine, picturing Adam and Eve before the Fall as vegetarians, living on fruits and herbs and practicing agriculture as an idyllic pastime, symbolic of the cooperation between human beings and a benign nature. With the Fall, as man turned exploiter, Bede agreed, he lost his natural sovereignty.18 Five centuries after Bede, at the height of the Middle Ages, St. Thomas Aquinas echoed his and Augustine's message and further rationalized it by a.s.serting that "by the very course of nature...the less perfect fall to the use of the more perfect," and therefore man holds power over the animals and the rest of the natural world. Before the Fall, all remained obedient to man, like domestic animals, but man's reign was not exploitative. Adam governed by reason, for the common good. Only with the fall of reason was the providential order overthrown. Five centuries after Bede, at the height of the Middle Ages, St. Thomas Aquinas echoed his and Augustine's message and further rationalized it by a.s.serting that "by the very course of nature...the less perfect fall to the use of the more perfect," and therefore man holds power over the animals and the rest of the natural world. Before the Fall, all remained obedient to man, like domestic animals, but man's reign was not exploitative. Adam governed by reason, for the common good. Only with the fall of reason was the providential order overthrown.19 Thus medieval theologians' interpretation of the Creation and the Fall revealed a G.o.d-ordained world dominated by human beings, whose role in respect to nature, however, was not exploitation but stewardship and cooperation. Thus medieval theologians' interpretation of the Creation and the Fall revealed a G.o.d-ordained world dominated by human beings, whose role in respect to nature, however, was not exploitation but stewardship and cooperation.

Commentaries on Adam's Fall illuminated one aspect of the Church's fundamental posture in respect to technology. Another lay in the theologians' att.i.tudes toward labor and toward crafts and craftsmen. Ambivalence was characteristic of both.

Benign Adam names the animals. [Bodleian Library. Ashmole Bestiary, Ms. Ashmole 1511, f. 9.]

From its earliest beginnings, Christian monasticism emphasized the importance of labor in the interests of the communal life and of humility. In the religious settlements founded in Egypt by Pachomius (A.D. 290346), productive labor was treated as beneficial both materially and spiritually. Bishop and chronicler Palladius ( 290346), productive labor was treated as beneficial both materially and spiritually. Bishop and chronicler Palladius (A.D. 363431) reported that at one Pachomian settlement he saw monks working at every kind of craft, including "fifteen tailors, seven metalworkers, four carpenters, twelve camel-drivers, and fifteen fullers." 363431) reported that at one Pachomian settlement he saw monks working at every kind of craft, including "fifteen tailors, seven metalworkers, four carpenters, twelve camel-drivers, and fifteen fullers."20 St. Jerome ( St. Jerome (A.D. c. 347420) described a similar community: "Brothers of the same craft live in one house under one master. Those, for example, who weave linen are together, and those who weave mats are looked upon as being one family. Tailors, carriage makers, fullers, shoemakers-all are governed by their own masters." Labor was accompanied by spiritual exercises and discipline. c. 347420) described a similar community: "Brothers of the same craft live in one house under one master. Those, for example, who weave linen are together, and those who weave mats are looked upon as being one family. Tailors, carriage makers, fullers, shoemakers-all are governed by their own masters." Labor was accompanied by spiritual exercises and discipline.21 The Benedictine Rule, composed in the sixth century, similarly mingled labor and prayer. Labor supported the community, discouraged idleness, and taught obedience and humility; its ends were primarily spiritual. In the following centuries, monasticism struggled to keep the balance between spirituality and economic self-sufficiency. In the course of time, Benedictine monasteries became the victims of their own success, as they grew wealthy from rents, church revenues, gifts, t.i.thes, and other fees, and labor ceased to be performed by the monks but was delegated to peasants and servants.

Late in the eleventh century, the new Cistercian Order attempted to return to the letter of the Benedictine Rule. Founding communities in the wilderness, far from centers of population, the Cistercians divested themselves of many of the sources of income exploited by the Benedictines and at the same time tried to restore the model of manual labor performed by the community itself. The order's outstanding leader, Bernard of Clairvaux (10901153), believed that work and contemplation must be kept in balance. The ideal monk was one who mastered "all the skills and jobs of the peasants"-carpentry, masonry, gardening, and weaving-as a means of bringing order to the world.22 The Cistercians, however, soon attempted to solve the problem of balance by splitting St. Bernard's ideal monk in two, a.s.signing prayer and work to different categories of brothers, drawn from different social cla.s.ses. Alongside the regular monks, with aristocratic backgrounds, they established an order of lay brothers, conversi conversi, recruited from the lower cla.s.ses, to perform their communities' skilled labor, supplemented by hired unskilled laborers. Like their predecessors, the Cistercians grew rich, and as the numbers of conversi conversi declined and communities relied increasingly on hired labor, they found themselves following the very practices that they had renounced. declined and communities relied increasingly on hired labor, they found themselves following the very practices that they had renounced.

Much the same fate befell similar efforts by other monastic orders, and the exemplar of the Benedictine Rule, the monk who prayed, labored with his hands, and studied the Bible, was abandoned.23 Where the Cistercian pioneer Aelred of Rievaulx (c. 11101167) "did not spare the soft skin of his hands," according to his biographer, "but manfully wielded with his slender fingers the rough tools of his field tasks," Where the Cistercian pioneer Aelred of Rievaulx (c. 11101167) "did not spare the soft skin of his hands," according to his biographer, "but manfully wielded with his slender fingers the rough tools of his field tasks,"24 his contemporary, Premonstratensian monk Adam of Dryburgh, expressed feelings shared by many fellow monastics in complaining that "manual labor irritates me greatly" and declaring that agricultural work should be performed not by educated and ordained men but by peasants accustomed to hard labor. his contemporary, Premonstratensian monk Adam of Dryburgh, expressed feelings shared by many fellow monastics in complaining that "manual labor irritates me greatly" and declaring that agricultural work should be performed not by educated and ordained men but by peasants accustomed to hard labor.25 Work was no longer an integral part of the service of G.o.d. Work was no longer an integral part of the service of G.o.d.

An element in the failure to incorporate labor successfully into the monastic life on a permanent basis was the fact that, as Europe's new intellectual cla.s.s, the churchmen were the inheritors of a long tradition of disdain for what Aristotle called the "banausic," or utilitarian arts, "the industries that earn wages," that "degrade the mind" and were unworthy of the free man.26 These arts might have practical value, Aristotle conceded, but "to dwell long upon them would be in poor taste." These arts might have practical value, Aristotle conceded, but "to dwell long upon them would be in poor taste."27 Aristotle's prejudice was sustained by most of the Greek and Roman philosophers and thinkers. Even Cicero, who extolled man's ability to change his environment through technology, thought that "no workshop can have anything liberal about it." Aristotle's prejudice was sustained by most of the Greek and Roman philosophers and thinkers. Even Cicero, who extolled man's ability to change his environment through technology, thought that "no workshop can have anything liberal about it."28 The Church Fathers retained some of the cla.s.sical att.i.tude but showed a new interest in and enthusiasm for what St. Augustine called "our human nature" and its "power of inventing, learning, and applying all such arts" as minister to life's necessities and "to human enjoyment." Augustine pointed to "the progress and perfection which human skill has reached in the astonishing achievement of clothmaking, architecture, agriculture, and navigation...in ceramics...drugs and appliances...condiments and sauces." These accomplishments were the products of "human genius," but, he added, this genius was often used for purposes that were "superfluous, perilous, and pernicious." What was most needed, in Augustine's eyes, was a capacity for "living in virtue" in the grace of G.o.d.29 Boethius, the last great Roman intellectual (c. 480524), followed the cla.s.sical tradition in devising an educational curriculum composed of the seven liberal arts, organized into the trivium trivium (grammar, rhetoric, and logic) and the (grammar, rhetoric, and logic) and the quadrivium quadrivium (arithmetic, geometry, astronomy, and music), with no room for the vulgar "banausic" arts frowned on by Aristotle. Boethius's elitist cla.s.sification became the basis of the medieval educational system, but other contemporary writers included the crafts at least as secondary adjuncts. The Greek historian Ca.s.siodorus (c. 490c. 585) wrote enthusiastically about inventions used in the monastery that he had founded: the "cleverly built lamps," the sundials and water clocks, the water-powered mills and the irrigation system, the Egyptian-invented papyrus-"the snowy entrails of a green herb, which keeps the sweet harvest of the mind, and restores it to the reader whenever he chooses to consult it." Mechanics, he judged, was a wonderful art, "almost Nature's comrade, opening her secrets, changing her manifestations, sporting with miracles." (arithmetic, geometry, astronomy, and music), with no room for the vulgar "banausic" arts frowned on by Aristotle. Boethius's elitist cla.s.sification became the basis of the medieval educational system, but other contemporary writers included the crafts at least as secondary adjuncts. The Greek historian Ca.s.siodorus (c. 490c. 585) wrote enthusiastically about inventions used in the monastery that he had founded: the "cleverly built lamps," the sundials and water clocks, the water-powered mills and the irrigation system, the Egyptian-invented papyrus-"the snowy entrails of a green herb, which keeps the sweet harvest of the mind, and restores it to the reader whenever he chooses to consult it." Mechanics, he judged, was a wonderful art, "almost Nature's comrade, opening her secrets, changing her manifestations, sporting with miracles."30 A century later encyclopedist Isidore of Seville showed a lively interest in technology, devoting six of the twenty books of his Etymologies Etymologies to the vocabulary of crafts-the types and elements of ships, buildings, clothing, weapons, harnesses, and household utensils-and cla.s.sifying mechanics, astrology, and medicine as elements of physics and philosophy. to the vocabulary of crafts-the types and elements of ships, buildings, clothing, weapons, harnesses, and household utensils-and cla.s.sifying mechanics, astrology, and medicine as elements of physics and philosophy.31 A major innovation in semantics followed in the era of Charlemagne when philosopher John Scotus Erigena invented the term A major innovation in semantics followed in the era of Charlemagne when philosopher John Scotus Erigena invented the term artes mechanicae artes mechanicae (mechanical arts), describing these as supplements of the liberal arts. (mechanical arts), describing these as supplements of the liberal arts.32 Following his lead a tardy three centuries later, scholar Honorius of Autun described ten liberal arts: the usual seven, plus Following his lead a tardy three centuries later, scholar Honorius of Autun described ten liberal arts: the usual seven, plus physica physica (medicine), economics, and (medicine), economics, and mechanica: mechanica: "Concerning mechanics...it teaches...every work in metals, wood, or marble, in addition to painting, sculpture, and all arts which are done with the hands. By this art Nimrod erected his tower, Solomon constructed his temple. By it Noah fashioned his ark, and all the fortifications in the entire world were built, and it taught the various weavings of garments." "Concerning mechanics...it teaches...every work in metals, wood, or marble, in addition to painting, sculpture, and all arts which are done with the hands. By this art Nimrod erected his tower, Solomon constructed his temple. By it Noah fashioned his ark, and all the fortifications in the entire world were built, and it taught the various weavings of garments."33 Finally, the economic revival of the high Middle Ages, accompanied as it was by a flood of technical advances, stimulated the exploration of new ways of integrating technology into the circle of human knowledge, usually as a physical and material side of theoretical science. The most comprehensive of these systems was that of Hugh of St. Victor (10961141), a German theologian who taught in Paris and who compiled an encyclopedic work called the Didascalicon Didascalicon. Hugh advocated a life of contemplation that, however, included secular learning. In correspondence with the seven liberal arts of Boethius, he envisioned seven categories of mechanical arts: textile manufacture, armament, navigation, agriculture, hunting, medicine, and theatrics, describing each in detail, for example: Textile manufacture includes all types of weaving, sewing, and spinning which are done by hand, needle, spindle, awl, reel, comb, loom, crisper, iron, or any other instrument out of any material of flax or wool, or any sort of skin, whether sc.r.a.ped or hairy, also out of hemp, or cork, or rushes, hair, tufts, or anything of the kind which can be used for making clothes, coverings, drapery, blankets, saddles, carpets, curtains, napkins, felts, strings, nets, ropes; out of straw, too, from which men usually make their hats and baskets. All these studies pertain to textile manufacture.34 In Hugh's cla.s.sification, the mechanical art of navigatio navigatio (navigation) included not only the techniques of sailing but commerce itself-"every sort of dealing in the purchase, sale, and exchange of domestic or foreign goods." Hugh extolled all those who courageously penetrated "the secret places of the world," approaching "sh.o.r.es unseen" and exploring "fearful wildernesses," bringing peace and reconciliation to all nations and commuting "the private good of individuals into the common benefit of all." His "armament" was a similarly broad category, including architecture, carpentry, and metallurgy; "hunting" included food gathering, cooking, and selling and serving food and drink; "theatrics" all kinds of games and amus.e.m.e.nts. (navigation) included not only the techniques of sailing but commerce itself-"every sort of dealing in the purchase, sale, and exchange of domestic or foreign goods." Hugh extolled all those who courageously penetrated "the secret places of the world," approaching "sh.o.r.es unseen" and exploring "fearful wildernesses," bringing peace and reconciliation to all nations and commuting "the private good of individuals into the common benefit of all." His "armament" was a similarly broad category, including architecture, carpentry, and metallurgy; "hunting" included food gathering, cooking, and selling and serving food and drink; "theatrics" all kinds of games and amus.e.m.e.nts.35 Although ranking technology lowest among the arts, Hugh accorded it a moral value, conferred by G.o.d as a partial remedy for man's fallen condition. Other creatures were born clothed: "Bark encircles the tree, feathers cover the bird, scales encase the fish, fleece clothes the sheep, hair garbs cattle and wild beasts, a sh.e.l.l protects the tortoise, and ivory makes the elephant unafraid of spears." Only man "is brought forth naked and unarmed" therefore man was equipped with reason, to invent the things naturally given to the other animals. "Want is what has devised all that you see most excellent in the occupations of men. From this the infinite varieties of painting, weaving, carving, and founding have arisen, so that we look with wonder not at nature alone but at the artificer as well."36 Other twelfth-century thinkers adopted Hugh's cla.s.sification, accepting technology as a part of human life, inferior to intellectual and spiritual elements but necessary and natural. Technology made life easier, freeing the mind from material concerns and supplementing man's innate powers. Hugh's influence extended to such thirteenth-century luminaries as Albertus Magnus, St. Bonaventure, Vincent of Beauvais, and Robert Kilwardby. In his De ortu scientiarum De ortu scientiarum (On the origin of sciences) Kilwardby (d. 1279) dignified the mechanical arts by explaining them as practical divisions of the speculative sciences. Every speculative science had a practical aspect. Science explained the (On the origin of sciences) Kilwardby (d. 1279) dignified the mechanical arts by explaining them as practical divisions of the speculative sciences. Every speculative science had a practical aspect. Science explained the propter quid propter quid, the reason for being, the cause; the mechanical arts the quia sunt quia sunt, the way things are. The two lent each other mutual support. Geometry was necessary to carpenters and masons, astronomy to navigation and agriculture. Wool manufacture was subject to mathematics, since it "examines the number and texture of threads and the measurement and form of the warp, stating in each of these matters that it is this way or that way, while mathematics examines the causes. Similarly all other mechanical arts are found to be under some speculative science or sciences."37 Kilwardby, in a word, replaced Hugh's concept of the moral value of technology with that of an intellectual value, a more modern view but one that subordinated technology to the theoretical sciences. The English Franciscan Roger Bacon (c. 12201292) carried the relationship a daring step further, awarding precedence to technology; in Bacon's eyes the practical arts gave man a power over the natural world that theoretical science could never provide. Practical science, he speculated, had almost unlimited application and, like all other knowledge, was given to man "by one G.o.d, to one world, for one purpose," as an aid to faith and remedy for the ills of the world.38 Thus the Church's att.i.tude toward technology, evolving from diverse sources over time-Adam's Fall, the monastic experience, the cla.s.sifications of knowledge-may be described as ambivalent, but on balance positive.

How large was technology's role in the social changes that took place during the thousand years of the Middle Ages? Pioneer historian of technology Richard Lefebvre des Noettes, writing in the 1930s, saw the adoption of a new harness that transformed the horse into an important draft animal as the chief factor in the decline and near disappearance of slavery.39 In 1940 and subsequently Lynn White broadened Lefebvre's thesis with the bold a.s.sertion that the dominant social and political systems of the Middle Ages owed their origins to technological innovations: feudalism to the stirrup, the manorial system to the heavy wheeled plow. In 1940 and subsequently Lynn White broadened Lefebvre's thesis with the bold a.s.sertion that the dominant social and political systems of the Middle Ages owed their origins to technological innovations: feudalism to the stirrup, the manorial system to the heavy wheeled plow.40 Such radical determinism could not fail to provoke a flood of research and a.n.a.lysis by other scholars, and we now acknowledge that, as usual, the truth is far from simple. Technology is only one of the forces, along with new social and economic patterns, that formed medieval society, but for a long time, until Lefebvre and White, it was the most neglected. Such radical determinism could not fail to provoke a flood of research and a.n.a.lysis by other scholars, and we now acknowledge that, as usual, the truth is far from simple. Technology is only one of the forces, along with new social and economic patterns, that formed medieval society, but for a long time, until Lefebvre and White, it was the most neglected.

Human history records a number of technological "revolutions," the first to be pointed out and labeled being the Industrial Revolution of the eighteenth century. The first to take place, however, was the invention of tools, in effect, the discovery of technology itself, a determining factor in the distinction between man and the other animals. The second, what anthropologist Gordon Childe called the "Neolithic Revolution," was the shift from hunting and gathering to cultivation. A third was the creation of the great irrigation civilizations of Mesopotamia, Egypt, the Indus Valley, and China, which generated cities, governments, and most of our inst.i.tutions.41 Today we recognize that one of the great technological revolutions took place during the medieval millennium with the disappearance of ma.s.s slavery, the shift to water- and wind-power, the introduction of the open-field system of agriculture, and the importation, adaptation, or invention of an array of devices, from the wheelbarrow to double-entry bookkeeping, climaxed by those two avatars of modern Western civilization, firearms and printing.

A historical surprise uncovered by recent scholarship, especially through the work of Joseph Needham and his colleagues at Cambridge University, is the size and scope of technology transmission from East to West. Scores of major and minor inventions were introduced from China and India, often through the medium of Islamic North Africa and the Near East. The channels of transmission to Europe are sometimes easy to trace, or to postulate, sometimes more mysterious. Technology traveled with merchants on their trade routes, both overland and by sea; it moved with nomads, armies, and migrating populations; it was carried by amba.s.sadors and visiting scholars, and by craftsmen imported from one country to another. Sometimes the transmission was direct and total. Sometimes, as Needham proposes, "a simple hint, a faint suggestion of an idea, might be sufficient to set off a train of development which would lead to roughly similar phenomena in later ages, apparently wholly independent in origin...Or the news that some technical process had successfully been accomplished in some far-away part of the world might encourage certain people to solve the problem anew entirely in their own way."42 Armed with innovative technology, both borrowed and homegrown, the European civilization that Edward Gibbon believed had been brought to a long standstill by "the triumph of barbarism and religion" had in reality taken an immense stride forward. The Romans so congenial to Gibbon would have marveled at what the millennium following their own era had wrought. More perceptive than Gibbon was English scientist Joseph Glanvill, who wrote in 1661: "These last Ages have shewn us what Antiquity never saw; no, not in a dream."43

Technology-Aristotle's "banausic arts"-embraces the whole range of human activities involving tools, machines, instrumentation, power, and organization of work. What follows in this book cannot attempt to be, even in a compact or shorthand sense, a complete history of Western technology from A.D. A.D. 500 to 500 to A.D. A.D. 1500. Its intention is limited to the identification of the main technological elements that entered significantly into medieval European history, their known or probable sources, and their princ.i.p.al impacts. 1500. Its intention is limited to the identification of the main technological elements that entered significantly into medieval European history, their known or probable sources, and their princ.i.p.al impacts.

2.

THE T TRIUMPHS AND F FAILURES OF A ANCIENT T TECHNOLOGY.

NEARLY EVERYTHING THAT SIXTH-CENTURY Europe knew about technology came to it from Rome. Rome, however, invented few of the tools and processes it bequeathed to the Middle Ages. Roman civilization achieved a high level of culture and sophistication and left many monuments, but most of its technology was inherited from the Stone, Bronze, and early Iron Ages.

From the long Paleolithic (Old Stone) Age came the tools and techniques that separated humankind forever from the animal world: language, fire making, hunting weapons and methods, domestication of animals. From the short Neolithic (New Stone) Age, beginning about 8000 B.C. B.C. in Mesopotamia, came agriculture and its tools-plow, sickle, ax, and mortar and pestle or stone grain crusher. The wheel and axle appeared in Mesopotamia between 3000 and 4000 in Mesopotamia, came agriculture and its tools-plow, sickle, ax, and mortar and pestle or stone grain crusher. The wheel and axle appeared in Mesopotamia between 3000 and 4000 B.C. B.C. The arts of cloth making were invented: felting, matting fibers together by boiling and beating to produce a nonwoven fabric; spinning, drawing out fibers of flax or wool and twisting them into a continuous strand, usually by means of a spindle; weaving, interlacing threads with the aid of a loom; fulling, soaking and beating cloth to remove grease; and dyeing. Raw hides were converted into leather by sc.r.a.ping and soaking with tannin, derived from oak bark. The important art of pottery making first modeled clay with fingers and thumb, then coiled strands of clay, and finally shaped its work with the potter's wheel, invented about 3000 The arts of cloth making were invented: felting, matting fibers together by boiling and beating to produce a nonwoven fabric; spinning, drawing out fibers of flax or wool and twisting them into a continuous strand, usually by means of a spindle; weaving, interlacing threads with the aid of a loom; fulling, soaking and beating cloth to remove grease; and dyeing. Raw hides were converted into leather by sc.r.a.ping and soaking with tannin, derived from oak bark. The important art of pottery making first modeled clay with fingers and thumb, then coiled strands of clay, and finally shaped its work with the potter's wheel, invented about 3000 B.C. B.C.

Copper, sometimes found in a free metallic state, was used by Neolithic man as a subst.i.tute for stone, wood, and bone long before the addition of a small amount of tin, probably by accident (c. 3500 B.C. B.C.), created the superior alloy bronze. The brief Bronze Age that followed overlapped the Neolithic Age at one end and the longer (still going on) Iron Age at the other. The two metal ages const.i.tute not so much historical periods as stages in technological evolution that took place over different times in different places. The Bronze Age never occurred in pre-Columbian America, where accessible tin was lacking. In the Near East copper continued to be widely used, but the harder yet malleable bronze made better tools and especially better weapons, including the arms and armor of Homer's heroes. Besides its hardness, bronze had a low melting point that permitted casting in molds.

As the Bronze Age introduced "the first great technical civilizations" (Bertrand Gille),1 the long, unrecorded life of the Stone Ages gave way to written history (including much written in the archaeological record). Civilized communities grew up in widely separated places, with little contact, or no contact at all, with each other. To the Roman and early medieval European worlds, societies in Africa, southeast Asia, Oceania, and America remained totally invisible. Even China and India, whose civilizations rivaled or surpa.s.sed those of the West, were scarcely glimpsed across the barrier of geographical distance. Only the civilizations that grew up on the banks of the Tigris-Euphrates and the Nile connected closely with their successor Greco-Roman societies and so contributed significantly to the Roman legacy to medieval Europe. the long, unrecorded life of the Stone Ages gave way to written history (including much written in the archaeological record). Civilized communities grew up in widely separated places, with little contact, or no contact at all, with each other. To the Roman and early medieval European worlds, societies in Africa, southeast Asia, Oceania, and America remained totally invisible. Even China and India, whose civilizations rivaled or surpa.s.sed those of the West, were scarcely glimpsed across the barrier of geographical distance. Only the civilizations that grew up on the banks of the Tigris-Euphrates and the Nile connected closely with their successor Greco-Roman societies and so contributed significantly to the Roman legacy to medieval Europe.

Besides inventing writing (in the form of the ideograph), the peoples of Mesopotamia (Sumerians, Babylonians, a.s.syrians) and the Egyptians of the Nile pioneered astronomy, mathematics, and engineering. Their river-dependent agriculture inspired the first dams and ca.n.a.ls, and the first water-lifting device, the shaduf shaduf or swape (c. 3000 or swape (c. 3000 B.C. B.C.), a counterweighted lever with a bucket on one end. Cultivation of grape and olive stimulated the invention about 1500 B.C. B.C. of the beam press, worked by a lever. Fermentation, discovered by the Egyptians, converted grape juice into wine and cereal into bread or beer; the rotary quern, invented about 1000 of the beam press, worked by a lever. Fermentation, discovered by the Egyptians, converted grape juice into wine and cereal into bread or beer; the rotary quern, invented about 1000 B.C. B.C., speeded the universal daily labor of milling. Techniques of food preservation-drying, salting, smoking-were invented (or more likely discovered). Cloth makers invented the vertical loom described by Homer, the "great loom standing in the hall" with "the fine warp of some vast fabric on it," in Penelope's artfully unfinished task.2 Cities built the first water-supply and drainage systems; street paving was pioneered in Babylon and road paving in Crete. Cities built the first water-supply and drainage systems; street paving was pioneered in Babylon and road paving in Crete.3 Egypt and Babylon produced the first clock to supplement the ancient sundial: the clepsydra, or water clock, a vessel out of which water ran slowly, with graduated marks to indicate the pa.s.sage of hours as it emptied. It operated at first with mediocre accuracy, since as the water diminished the flow slackened. Egypt and Babylon produced the first clock to supplement the ancient sundial: the clepsydra, or water clock, a vessel out of which water ran slowly, with graduated marks to indicate the pa.s.sage of hours as it emptied. It operated at first with mediocre accuracy, since as the water diminished the flow slackened.4 Like bronze, iron came on the scene by accident. Because iron has a higher melting point than copper, it could not easily be separated from its ore but had to be hammered loose. Even then it found little use for a thousand years after its first discovery (c. 2500 B.C. B.C.), until smiths in the Armenian mountains near the Black Sea found that repeated heatings and hammerings in a charcoal fire hardened it.5 In the In the Iliad Iliad, weapons are made of bronze, tools of iron, "the democratic metal."6 The irrigation civilizations of the Nile and Tigris-Euphrates built temples, palaces, obelisks, and tombs, the Egyptians of the early dynasties (third millennium B.C. B.C.) employing copper tools, ramps, levers, and guy ropes, but neither pulley nor wheel. The ma.s.sive blocks of stone that formed the Pyramids were hauled on boards greased with animal fat and raised to the upper courses by means of earthen ramps, afterward removed. While the Mesopotamians made some use of the arch to support their roofs, Egypt and Greece relied on the post and lintel (two vertical columns joined at the top by a horizontal member). Pericles' Athens borrowed Egyptian stonemasonry techniques, such as the a.s.sembling of columns out of stacks of drums, while strengthening their structures with metal strips, pins, and clamps. The beams that held up the ceiling of the Propylaea on the Acropolis (440430 B.C. B.C.) were reinforced with iron bars, the first use of metal structural members in building construction. Mesopotamia, poor in wood and stone, invented brick making, first with sun-dried brick in Sumer (before 3000 B.C. B.C.), later with kiln-dried brick in Babylon.7 The horse was tamed by at least the eleventh century B.C. B.C.,8 but the absence of saddle and stirrups limited its military value, while the problem of harness reduced its role as a draft animal. The throat-and-girth harness that suited the configuration of the ox choked the horse, which could consequently pull only light loads, such as the two-wheeled war chariot of the but the absence of saddle and stirrups limited its military value, while the problem of harness reduced its role as a draft animal. The throat-and-girth harness that suited the configuration of the ox choked the horse, which could consequently pull only light loads, such as the two-wheeled war chariot of the Iliad Iliad. At the same time, lack of a firm saddle handicapped pack animals.

While land transportation hardly progressed between Neolithic and Roman times, water transportation made a great leap forward. By 1000 B.C. B.C. the Phoenicians, the master mariners of the ancient world, were building ships with stempost, sternpost, and skeleton of ribs that reinforced hull planking fitted edge to edge and joined by mortise and tenon-in a word, modern construction. the Phoenicians, the master mariners of the ancient world, were building ships with stempost, sternpost, and skeleton of ribs that reinforced hull planking fitted edge to edge and joined by mortise and tenon-in a word, modern construction.9 Homer, writing in the seventh or eighth century Homer, writing in the seventh or eighth century B.C. B.C., depicted Odysseus single-handedly building the boat that carried him from Calypso's isle, boring his timbers with an auger and fastening them together with wooden dowels.10 Ships used both sail and oar. The early Egyptians paddled facing forward; the oar, a less obvious device than the paddle, turned the crew around and faced them backward. The sail may also have been born on the Nile, where prevailing winds conveniently blow in the direction opposite to the current; Egyptians sailed up and floated down their great river. The single sail (cotton, linen, or Egyptian papyrus) was square, rigged at right angles to the hull. Steering was done with a large oar mounted on one side near the stern. Navigation was by sun and stars and the unaided eye, and by dead reckoning: a rough calculation of the ship's speed, course, and drift. With such ships and techniques, the Phoenicians ("greedy knaves," according to the Odyssey Odyssey)11 not only sailed and rowed from their homeland (roughly modern Lebanon) the length and breadth of the Mediterranean but ventured into the Atlantic after British tin. not only sailed and rowed from their homeland (roughly modern Lebanon) the length and breadth of the Mediterranean but ventured into the Atlantic after British tin.

Needing written records and communications, Phoenician mariner-merchants invented one of the alphabets (as opposed to ideographs) of the ancient world, the one that pa.s.sed, with variations, to the Greeks, thence to the Romans, and so to medieval Europe. Its spread was a.s.sisted by the advent of the second of the world's three great writing materials, parchment, the dried, stretched, and shaved hide of sheep, goats, and calves, smoother and more durable than Egypt's reed-derived papyrus. Parchment received its final improvement in the second century B.C. B.C. in Greek Pergamum (whence the name "parchment"), in the form of slaking in lime for several days. Both sides of the resulting material could be written on and the leaves bound into a book (codex), more convenient than the ancient scroll. in Greek Pergamum (whence the name "parchment"), in the form of slaking in lime for several days. Both sides of the resulting material could be written on and the leaves bound into a book (codex), more convenient than the ancient scroll.

Most of the military history of the ancient world is irrelevant to the record of humanity's progress, but the conquests of Alexander the Great in the late fourth century B.C. B.C. had the significant effect of promoting the "h.e.l.lenization" (h.e.l.las: Greece) of the whole Near East and eastern Mediterranean. The succeeding age is famous for its philosophers, mathematicians, and natural scientists, headed by Alexander's own tutor, Aristotle (384322 had the significant effect of promoting the "h.e.l.lenization" (h.e.l.las: Greece) of the whole Near East and eastern Mediterranean. The succeeding age is famous for its philosophers, mathematicians, and natural scientists, headed by Alexander's own tutor, Aristotle (384322 B.C. B.C.). Although Aristotle shared the prejudice of his master Plato against the arts and crafts, among the works attributed to him or (more recently) to his pupil Strato is Mechanics Mechanics, the world's first engineering text. Mechanics Mechanics contains the earliest mention of multiple pulleys and gear wheels, along with all the simple mechanical-advantage devices except the screw. contains the earliest mention of multiple pulleys and gear wheels, along with all the simple mechanical-advantage devices except the screw.

Alexander's eponymous city on the sh.o.r.e of Egypt, Alexandria, came to house the greatest library of learning in the Mediterranean world and to shelter some of the greatest scientists. These included the mathematician Euclid (fl. c. 300), Eratosthenes (c. 276194 B.C. B.C.), who made the first calculation of the earth's circ.u.mference, and the astronomer-geographer Ptolemy (fl. A.D. A.D. 127145). The aim of the dilettante scientists of h.e.l.lenistic Greece was "to know, not to do, to understand nature, not to tame her" (M. I. Finley). 127145). The aim of the dilettante scientists of h.e.l.lenistic Greece was "to know, not to do, to understand nature, not to tame her" (M. I. Finley).12 Nevertheless, they made serious contributions to technology as well as to science. Archimedes (c. 287212 Nevertheless, they made serious contributions to technology as well as to science. Archimedes (c. 287212 B.C. B.C.) discovered the principle of buoyancy and stated that of the lever. Another of the basic machine components, the screw, has been attributed to him but may have existed earlier: in its original form a water-lifting device, a spiral tube inside an inclined cylinder turned by slaves or animals walking a treadmill. Archimedes may also have invented the toothed wheel and gear train, first described in Western writings by him.13 Two other Alexandrians who left evidence of inventive minds and outlooks were Ctesibius (fl. 270 B.C. B.C.) and Heron (fl. first century A.D. A.D.). Ctesibius discovered the compressibility of air and probably invented the force pump, a pair of cylinders whose pistons were driven by a horizontal bar on a fulcrum between them, alternately forcing the water out of one and drawing it into the other. He also solved the problem of the water clock's irregularity by providing an overflow outlet that kept the water in the operative vessel at constant depth.14 Heron invented a number of mechanical toys, including a miniature steam engine, creations whose principles would eventually be applied to practical uses but only after the world had pa.s.sed through several preparatory revolutions. Heron invented a number of mechanical toys, including a miniature steam engine, creations whose principles would eventually be applied to practical uses but only after the world had pa.s.sed through several preparatory revolutions.

The h.e.l.lenistic Greeks did not invent but gave impetus to the two great "false sciences" of alchemy and astrology, speculative parents of chemistry and astronomy. Both originated in Mesopotamia at a very early date, and both were actively pursued in the h.e.l.lenistic age. A late addition to astrological theory, the casting of the individual's horoscope, had valuable consequences for science, since it demanded an accurate knowledge of the motions of the planets to determine their position at the hour of birth.

h.e.l.lenistic astrological interest resulted in the anonymous invention at Alexandria of the astrolabe, "the world's first scientific instrument."15 In its original form, the astrolabe ("astro"-"labe," star-plate) was a wooden disk bearing a map of the heavens, its outer edge marked off in 360 degrees. A pointer pivoted on a central pin could be aimed at the sun or other celestial body to give the alt.i.tude above the equator, providing a reasonably accurate indication of the time of day for a given lat.i.tude. Conversely, the astrolabe could determine lat.i.tude, but no one thought of this possibility for a long time. In its original form, the astrolabe ("astro"-"labe," star-plate) was a wooden disk bearing a map of the heavens, its outer edge marked off in 360 degrees. A pointer pivoted on a central pin could be aimed at the sun or other celestial body to give the alt.i.tude above the equator, providing a reasonably accurate indication of the time of day for a given lat.i.tude. Conversely, the astrolabe could determine lat.i.tude, but no one thought of this possibility for a long time.

Astrology pa.s.sed from the Greeks to the Romans and thence to medieval Europe, while alchemy, disdained by the Romans, reached medieval Europe only at a later date, via the Arabs. But as Roman conquest absorbed the h.e.l.lenistic world, an enormous transfer of technology took place, from the Phoenician-Greek alphabet to Archimedes' screw to masonry construction. Roman technology was strongest where Rome's predecessors were strongest, weakest in areas which they had neglected or where they had failed.

The Romans inherited most of their agricultural tools and techniques, improving and adding to them. The aratrum aratrum, the light plow that worked satisfactorily in the sandy soils of the Mediterranean region, was made more effective by two additions-first, an iron coulter, a vertical blade fixed in front of the plowshare, and, second, a wooden moldboard behind it to turn the soil. The Romans' engineering approach to agriculture improved irrigation systems and pioneered the systematic application of fertilizer. Although they did little scientific breeding of plants or animals, they increased the numbers of horses and sheep and found a better method of harvesting wool, applying shears in place of the traditional method of plucking during the molting season.16 The grinding of grain received a worthwhile Roman improvement in the transformation of the rotary hand quern into the large donkey- or slave-powered hourgla.s.s mill, examples of which are preserved in Pompeii, Herculaneum, and Ostia. The processing of grape and olive was likewise improved by the adoption of the screw press, a useful new application of Archimedes' screw with significance for the distant future.17 Roman grain mills in Herculaneum. Grain was poured into an opening in the center of the upper millstone, the flour falling into a trough around the base of the lower stone. A beam inserted through the square holes in the upper millstone served as a handle for turning the stone, either by slaves or donkeys. The mill on the right has lost its upper stone.*

From the Greeks, the Romans received a well-developed mining technology along with the system of operating mines as a government monopoly, relying on slave labor and iron tools: hammer, pick, chisel, wedge. Pillars were left to support headings; niches were cut in the walls to hold oil lamps. Ventilation remained an unsolved problem, conditions of labor miserable.18 To the iron metallurgy they inherited from the Greeks, the Romans added tempering (reheating and cooling), which hardened the metal without making it brittle. To their inherited tool chest they added the carpenter's plane, which first appears in Roman representations and may have been a Roman invention. To the iron metallurgy they inherited from the Greeks, the Romans added tempering (reheating and cooling), which hardened the metal without making it brittle. To their inherited tool chest they added the carpenter's plane, which first appears in Roman representations and may have been a Roman invention.19 Handicraft production flourished in the Roman Empire, fostered by larger markets and the growth of an affluent cla.s.s of city dwellers. The chief industry was the manufacture of wool and linen cloth (Chinese silk and Egyptian cotton were imported luxury fabrics). Women did the spinning and weaving at home or on the great estates, their instruments the ageless spindle and the vertical loom. Finishing-fulling and dyeing-required a capital outlay and therefore pa.s.sed into the hands of male specialists working in shops.20 Roman potters followed the Greek tradition that had carried the craft to artistic heights, but without improvements in processes or materials. Gla.s.s manufacture, however, whose techniques lay somewhere between ceramics and metallurgy, achieved a major innovation: gla.s.sblowing, invented in the Roman province of Syria in the first century A.D. A.D.21 Fuller's shop in Pompeii, trough for soaking textiles. Although in antiquity spinning and weaving were domestic industries performed by women, finishing was done by male specialists.

Like Egypt and Greece, the Roman Empire left its most conspicuous achievements in its building construction. Employing engineering technology on a scale never before seen in the Western world, it strewed the Mediterranean littoral and western Europe with bridges, roads, walls, public baths, sewage systems, arenas, forums, markets, triumphal arches, and theaters. Among the most characteristic of Roman ruins are the aqueducts that served the water-supply system of the capital and other cities. Generally they ran in low, open or covered masonry channels or in conduits tunneled through hillsides, but at times they strode across valleys in long, picturesque lines of stone arches. One of the most impressive of Roman relics is the triple-tiered Pont du Gard in southern France, whose two main tiers have stood for two thousand years without the aid of mortar. The Romans possessed an excellent lime mortar but used it only for construction with smaller stones, such as those in the top tier of the Pont du Gard. By mixing their mortar with a sandy volcanic ash, Roman builders produced a hydraulic cement, one that dried to rock hardness underwater. Mixed with sand and gravel, it became waterproof concrete.22 The basic design component of Roman construction was the semicircular arch, converted by extension into the barrel vault, capable of carrying a greater load and spanning a greater breadth than a simple beam. With this strong, enduring, and versatile device the Romans built aqueducts, bridges, baths, and basilicas that stood for centuries. Yet there was a blind spot in the Roman dependence on the semicircular form. As a vault, it placed tremendous weight on the supporting walls, which had to be made thick and nearly windowless. As an arch in a bridge, it required ma.s.sive piers in the stream, mounted on the always uncertain base of sapling poles driven in the river bottom to "refusal," that is, as deep as men standing in the water and mud could drive them. Cofferdams (temporary watertight enclosures built in the stream) permitted deeper-driven piles, but the resulting piers remained vulnerable to scour, the abrasive action of the current swirling sand around the pier footings. Scour was itself heightened by the constriction imposed on the current by the many thick piers. Though a number of Roman bridges endured, many fell victim to scour.23 The Pont du Gard, Roman aqueduct spanning the Gard River.

Roman engineering, which learned surveying from the Egyptians, stressed exact measurements and imposed on the Western world the system of weights and measures (inch, foot, mile, pound, amphora) that the Greeks had adapted from the Egyptians, Phoenicians, and Babylonians. Besides their monumental public works, the