Engineering and Technology

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Engineering and Technology


Technological Innovations. As in the imposition of political order, the Roman genius was especially evident in engineering and technological innovations. Under their rule the life spans of peoples within the Empire increased, and their health improved as well. In part these changes were because of good nutrition, but perhaps to a greater degree they were attributable to improvements in hygiene and, above all, clean water supplies.

Attitudes Toward Engineering. To a degree the Romans adopted the Greeks’ attitude toward work. Simply stated, a virtuous person, one with intelligence, does not work with his hands. Indeed, success is indicated by the absence of work. Plutarch (died circa 120 c.e.)

summed up the aristocratic attitude toward work when he connected Plato’s notion of the aspiring soul longing for abstract truth to Archimedes’ aversion to being associated with engineering. Plato reviled the engineer who took abstract geometry and applied it to practical things. For posterity Archimedes wanted only to be known for his contributions to abstract geometry and mathematics. He was reluctant to acknowledge his invention of several amazing mechanical devices, such as the water-screw for lifting water in mines, compound pulleys for lifting heavy objects, and ingenious military machines for the defense of his native city of Syracuse.

Suspicion of Technology. Two reasons advanced for the fall of the Roman Empire are: first, the Romans afforded little social prestige for the engineer; and second, concerns about the employment of the urban proletariat and their labor-intensive system in reliance on slave labor blocked necessary innovative technological solutions for their economy. The attitude is reflected in an incident during Vespasian’s rule (69-79 c.e.) when some enterprising inventor designed a machine that could haul huge columns up to the Capitol at a minimum expense. Vespasian offered the inventor a reward and asked the perplexed man to destroy the machine, because “I must always ensure that the working classes earn enough money to buy themselves food” (Suetonius, Vespasian 18). The very fact that Roman historians did not record details of the machine is one indication that such inventions were unwelcome. For all of the physical remains of Roman construction and engineering, we have surprisingly little of the actual works from these engineers. There are two notable exceptions: Vitruvius Pollio (died circa 25 b.c.e.), who wrote on architecture, and Sextus Julius Frontinus (flourishing 100 c.e.), who wrote on aqueducts.

The Ideal Architect. With these aristocratic, paternalistic attitudes notwithstanding, the Romans were proud of their material achievements—roads, public buildings, aqueducts, gigantic bathhouses, and centrally heated homes, for example—and they did afford some prestige to the engineer. Vitruvius said that an ideal engineer or architect ought to “be a man of letters, a skillful draftsman, a mathematician, familiar with historical studies, a diligent student of philosophy, acquainted with music; not ignorant of medicine, learned in the responses of jurisconsults, familiar with astronomy and astrological calculations” (Vitruvius 1.1.3). All the same, Vitruvius lamented that architects could practice without training or experience, there being no licensing procedures—such as would be established in the modern world—or guild control in the Middle Ages. Even so, his ideal architect (virtually the same as an engineer), who directs the laying of bricks, should be familiar with how matter was expected to change, as enunciated by the Presocratic philosophers. Vitruvius’s ideal was unlikely to have been realized in only a few of those individuals who engaged in the professional activity during the Roman Republic or Empire.

Construction Technology. Wherever the Roman legions went, there followed durable roads, bridges, aqueducts, centrally heated houses and public buildings, and scrupulous attention to hygiene. When tourists visit

Europe, Asia, and Africa, where once was Rome’s empire, they see the visible remains of Roman construction-engineering. Ancient Roman bridges not only majestically traverse rivers and streams but now carry the burden of automobile and truck traffic as well.

Concrete Mortar. Perhaps the greatest Roman innovation was the invention of concrete mortar. Early Roman buildings were constructed of wood, stone, clay, and brick, both mud and baked. In the third century b.c.e. Roman builders found deposits of ash near the volcano Vesuvius. To the natural ash they added lime mortar and water. When the mixed substance dried it was hard and durable. Slowly they perfected the formula. The result was cement that they called pulvis puteolanus (Puteolian powder), Puteolia being a city near where the ash was found. Employing the mortar between baked brick, they constructed well-designed buildings, some of which still stand. Many a Roman basilica, standing in the center of a city, was converted into a mosque or Christian church and still functions today. Without mortar the Romans could not have built the aqueduct systems that supplied clean water to public buildings and houses. For most public and some private buildings, marble slabs were placed on the cemented brick as a veneer, thereby giving the appearance of pure marble. The pockmarks that one sees, for instance, on the Roman Colosseum are the holds for marble slabs. Many of the marble slabs are now in the medieval churches of Rome, to which they were recycled from pagan buildings. Augustus boasted that he found Rome a city of mud bricks but he left her clothed in marble. Pliny the Elder marveled at Roman ingenuity but was apprehensive about their manipulation of nature.

Roads and Bridges. Beginning in 312 b.c.e., when the first stretch of the famous road called the Appian Way was constructed, the Romans developed a system of roads designed to get the military forces to far-flung places as rapidly as possible. Digging deeply for foundation and drainage, the roads were constructed to be durable with smooth hard surfaces of stone. Most roads consisted of four to five layers and varied from four to six feet beneath the surface. With picks and shovels the legionaries traversed plains, rivers, deserts, and mountain ranges. Bridges on brick and concrete piles spanned rivers. Although built for the military by the military, roads were also used by civilian and commercial vehicles. Moving straight up inclines, grades could be as much as 20 percent. Heavy wagons would have to find zigzagged, parallel roads near the paved surface in order to negotiate uphill climbs and to brake for descents. Cities were connected to one another, and all major Italian roads to Rome, in whose center was the golden milestone. Along the roads were milestones placed at intervals called “miles” (from milk passuum, a “thousand paces”), based on a standard number of steps. Typically the inscriptions told of the distances to Rome, the provincial capital, the nearest city for administration of the district, the name of the legion constructing the site, and the emperor at the time of construction.

Houses. Roman houses were sturdy, usually of brick and mortar, and well designed for the comfort afforded by

Mediterranean climates. Many, if not most, had central heating from ducts in the floors. A furnace was constructed on the side of the house where a fire, usually burning wood, was fed by a draft taking in outside air, which was heated in the ductlike furnace and flowed through passageways under the floors (called hypocausta). On the other side or through walls an upper duct led out to the open air, thereby providing well-circulated conductive heat. Similar arrangements were made for public buildings. Much-larger and more-elaborate furnaces furnished heated water in great volumes for the bathhouses, as well as radiated heat through the floors. Construction-engineering evolved with innovative use of arches to span distances for roofs, bridges, and aqueducts. Many houses were attached to the municipal water system that had main lines down the streets. The water was clean and used for drinking, cooking, bathing, decorating (fountains in courtyards), and for toilets, which were constantly flushed with running water beneath the seats. Even those people unable or unwilling to live in individual houses had good apartment houses called insulae (islands). With increased population densities, there was a tendency toward higher, multistoried dwellings, but a series of disastrous collapses resulted in building codes and height limitations. Similar provisions were made in housing codes for protection against fires with firewalls required between units. Public sanitation was the consequence of deliberate, rational town planning. Awareness of sanitation, especially clean water and location of sewage disposal, is notably seen not only in town planning but also in the way that the Roman army constructed their camps, even for one-night stays.

Water Consumption. Contributing immeasurably to public health was the availability of an abundance of clean water. With ingenuity and pride the Romans furnished towns with clean water transported from springs and mountain streams many miles away; some towns consumed more gallons of water per citizen than modern cities. Sextus Julius Frontinus, appointed commissioner of the City of Rome’s water supply in 97 c.e., did not restrain his pride when he wrote, “With such an array of indispensable structures carrying so many waters, compare, if you will, the idle Pyramids or the useless, though famous, works of the Greeks!” (Frontinus, Aqueducts of Rome 1. 16).

Aqueducts. The Anio vetus, Rome’s earliest aqueduct system, was begun in 272 b.c.e. and, when it was completed, moved water 63.6 kilometers (almost entirely below ground). In the course of three centuries, Rome added six more systems that totaled 386.2 kilometers, of which 49.6 kilometers were above ground and 336.6 kilometers below ground. The Aqua Claudia, completed in 52 c.e., ran some 68.7 kilometers (42 miles). Stone bridges with sturdy arcades transported water in pipes that were laid in a trough atop the aqueducts. Not confined to Rome, aqueducts supplied clean water to cities throughout the empire. Almost always transported using a gravity flow, water was gradually led downhill from mountains or higher altitudes to neighboring cities. It is said that one could roll a bowling ball from beginning to end on the aqueduct that ran from the Eifel mountains to the Roman city of Colonia Agrippina (modern-day Cologne). Rarely was water conveyed in open channels; normally, the channel was covered to reduce evaporation and contamination. Waterproof cement was used to form the troughs. Frequently, pipes carried the water and were placed in the troughs. Made of lead, wood, stone, and, most often, terra-cotta (earthenware), the pipes were required for siphons in order for water to move uphill. In areas where the softness of the water caused absorption of lead, Roman engineers avoided lead pipes because they were aware of its toxicity. Pipes would negate minor bumps in level, whereas the uneven bumps would be a problem for open channels. The troughs normally had three or more small pipes, rather than one large one. At the delivery point in the city, the aqueduct would have to enter the highest point to ensure distribution throughout the city. Water was employed to flush the public and private toilets, for public and private baths, for city fountains, for the irrigation of gardens in and around the city, and even in a few instances to turn water wheels for mills. A large municipal basin with distribution pipes exiting at different levels, the lowest being the highest priority, solved the problem for droughts when the water was low at its source. Politically, city councils could determine whether, for example, private houses had priority over public baths. At least, priorities may have been the intent; however, on the basis of some archaeological finds it appears that, in some cities, the pipes may have been arranged to ensure equal distribution to private houses, public fountains, baths, and theaters.

Water Bill. Private homes were supposed to pay dues for tapping into the municipal supply by purchasing a pipe with a city seal on it. In archaeological finds, however, it was discovered that some homeowners secretly tapped into the city main without paying. The construction and operation of aqueducts were maintained by both public taxation and private philanthropy.

Sanitation Engineering. The water systems did not operate with valves; rather, the water flowed continuously. For example, the public toilets had water running beneath the seats themselves; in front of the seats, a foot or so from the wall (allowing a person’s foot to rest), ran a small stream of water. When the act was completed, one would cup one’s hand and splash water to clean oneself. Deliberate care was exercised in ensuring that waste would be discharged sufficiently downstream so as not to contaminate access waters. No system of sewerage processing was developed, but the relatively small population sizes did not present such problems as would compromise comparable modern systems.


L. Sprague DeCamp, The Ancient Engineers (Garden City, N.Y.: Doubleday, 1963).

Donald Hill, A History of Engineering in Classical and Medieval Times (London: Croom Helm, 1984).

A. Trevor Hodge, Roman Aqueducts & Water Supply (London: Duck-worth, 1992).

Henry Hodges, Technology in the Ancient World (London: John Lane, 1970; New York: Knopf, 1970).

K. D. White, Greek and Roman Technology (Ithaca, N.Y.: Cornell University Press, 1984).

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