The development over time of systematic techniques for making and doing things. The term technology, a combination of the Greek techne, "art, craft," with logos, "word, speech," meant in Greece a discourse on the arts, both fine and applied. When it first appeared in English in the 17th century, it was used to mean a discussion of the applied arts only, and gradually these "arts" themselves came to be the object of the designation. By the early 20th century, the term embraced a growing range of means, processes, and ideas in addition to tools and machines. By mid-century, technology was defined by such phrases as "the means or activity by which man seeks to change or manipulate his environment." Even such broad definitions have been criticized by observers who point out the increasing difficulty of distinguishing between scientific inquiry and technological activity.
A highly compressed account of the history of technology such as this one must adopt a rigorous methodological pattern if it is to do justice to the subject without grossly distorting it one way or another. The plan followed in the present article is primarily chronological, tracing the development of technology through phases that succeed each other in time. Obviously, the division between phases is to a large extent arbitrary. One factor in the weighting has been the enormous acceleration of Western technological development in recent centuries; Eastern technology is considered in this article in the main only as it relates to the development of modern technology.
Within each chronological phase a standard method has been adopted for surveying the technological experience and innovations. This begins with a brief review of the general social conditions of the period under discussion, and then goes on to consider the dominant materials and sources of power of the period, and their application to food production, manufacturing industry, building construction, transport and communications, military technology, and medical technology. In a final section the sociocultural consequences of technological change in the period are examined. This framework is modified according to the particular requirements of every period-- discussions of new materials, for instance, occupy a substantial place in the accounts of earlier phases when new metals were being introduced but are comparatively unimportant in descriptions of some of the later phases--but the general pattern is retained throughout. One key factor that does not fit easily into this pattern is that of the development of tools. It has seemed most convenient to relate these to the study of materials, rather than to any particular application, but it has not been possible to be completely consistent in this treatment. For
Essentially, techniques are methods of creating new tools and products of tools, and the capacity for constructing such artifacts is a determining characteristic of manlike species. Other species make artifacts: bees build elaborate hives to deposit their honey, birds make nests, and beavers build dams. But these attributes are the result of patterns of instinctive behaviour and cannot be varied to suit rapidly changing circumstances. Man, in contrast with other species, does not possess highly developed instinctive reactions but does have the capacity to think systematically and creatively about techniques. He can thus innovate and consciously modify his environment in a way no other species has achieved. An ape may on occasion use a stick to beat bananas from a tree: a man can fashion the stick into a cutting tool and remove a whole bunch of bananas. Somewhere in the transition between the two, the hominid, or the first manlike species, emerges. By virtue of his nature as a toolmaker, man is therefore a technologist from the beginning, and the history of technology encompasses the whole evolution of man.
In using his rational faculties to devise techniques and modify his environment, man has attacked problems other than those of survival and the production of wealth with which the term technology is usually associated today. The technique of language, for example, involves the manipulation of sounds and symbols in a meaningful way, and similarly the techniques of artistic and ritual creativity represent other aspects of the technological incentive. This article does not deal with these cultural and religious techniques, but it is valuable to establish their relationship at the outset because the history of technology reveals a profound interaction between the incentives and opportunities of technological innovation on the one hand and the sociocultural conditions of the human group within which they occur on the other.
Social involvement in technological advances An awareness of this interaction is important in surveying the development of technology through successive
civilizations. To simplify the relationship as much as possible, there are three points at which there must be some social involvement
in technological innovation: social need, social resources, and a sympathetic social ethos. In default of any of these factors it is
unlikely that a technological innovation will be widely adopted or be successful. The sense of social need must be strongly felt, or people will not be prepared to devote resources to a
technological innovation. The thing needed may be a more efficient cutting tool, a more powerful lifting device, a laboursaving machine,
or a means of utilizing new fuels or a new source of energy. Or, because military needs have always provided a stimulus to technological
innovation, it may take the form of a requirement for better weapons. In modern societies, needs have been generated by advertising.
Whatever the source of social need, it is essential that enough people be conscious of it to provide a market for an artifact or
commodity that can meet the need. Social
resources are similarly an indispensable prerequisite to a successful innovation. Many
inventions have foundered because the social resources vital for their
realization--the capital, materials, and skilled personnel--were not available. The notebooks of Leonardo da Vinci are full of ideas for
helicopters, submarines, and airplanes, but few of these reached even the model stage because resources of one sort or another were
lacking. The resource of capital involves the existence of surplus productivity and an organization capable of directing the available
wealth into channels in which the inventor can use it. The resource of materials involves the availability of appropriate metallurgical,
ceramic, plastic, or textile substances that can perform whatever functions a new invention requires of them. The resource of skilled
personnel implies the presence of technicians capable of constructing new artifacts and devising novel processes. A society, in short,
has to be well primed with suitable resources in order to sustain technological innovation. A sympathetic
social ethos implies an environment receptive to new ideas, one in which the
dominant social groups are prepared to consider innovation seriously. Such receptivity may be limited to specific fields of
innovation--for example, improvements in weapons or in navigational techniques--or it may take the form of a more generalized attitude
of inquiry, as was the case among the industrial middle classes in Britain during the 18th century, who were willing to cultivate new
ideas and inventors, the breeders of such ideas. Whatever the psychological basis of inventive genius, there can be no doubt that the
existence of socially important groups willing to encourage inventors and to use their ideas has been a crucial factor in the history of
technology. Social
conditions are thus of the utmost importance in the development of new
techniques, some of which will be considered below in more detail. It is worthwhile, however, to register another explanatory note. This
concerns the rationality of technology. It has already been observed that technology involves the application of reason to techniques,
and in the 20th century it has come to be regarded as almost axiomatic that technology is a rational activity stemming from the
traditions of modern science. Nevertheless, it should be observed that technology, in the sense in which the term is being used here, is
much older than science, and also that techniques have tended to ossify over centuries of practice or to become diverted into such
para-rational exercises as alchemy. Some techniques became so complex, often depending upon processes of chemical change that were not
understood even when they were widely practiced, that technology sometimes became itself a "mystery" or cult into which an apprentice
had to be initiated like a priest into holy orders, and in which it was more important to copy an ancient formula than to innovate. The
modern philosophy of progress cannot be read back into the history of technology; for most of its long existence technology has been
virtually stagnant, mysterious, and even irrational. It is not fanciful to see some lingering fragments of this powerful technological
tradition in the modern world, and there is more than an element of irrationality in the contemporary dilemma of a highly technological
society contemplating the likelihood that it will use its sophisticated techniques in order to accomplish its own destruction. It is
thus necessary to beware of overfacile identification of technology with the "progressive" forces in contemporary
civilization. On the other hand it is impossible
to deny that there is a progressive element in technology, as it is clear from the most elementary survey that the acquisition of
techniques is a cumulative matter, in which each generation inherits a stock of techniques on which it can build if it chooses and if
social conditions permit. Over a long period of time the history of technology inevitably highlights the moments of innovation that show
this cumulative quality as some societies advance, stage by stage, from comparatively primitive to more sophisticated techniques. But
although this development has occurred and is still going on, it is not intrinsic to the nature of technology that such a process of
accumulation should occur, and it has certainly not been an inevitable development. The fact that many societies have remained stagnant
for long periods of time, even at quite developed stages of technological evolution, and that some have actually regressed and lost the
accumulated techniques passed on to them, demonstrates the ambiguous nature of technology and the critical importance of its
relationship with other social factors.
Technology in the ancient world The beginnings--Stone Age technology (to c. 3000 BC) The
identification of the history of technology with the history of manlike species does not help in fixing a precise point for its origin,
because the estimates of prehistorians and anthropologists concerning the emergence of human species vary so widely. Animals
occasionally use natural tools such as sticks or stones, and the creature that became man doubtless did the same for hundreds of
millennia before the first giant step of fashioning his own tools. Even then it was an interminable time before he put such toolmaking
on a regular basis, and still more aeons passed as he arrived at the successive stages of standardizing his simple stone choppers and
pounders and of manufacturing them--that is, providing sites and assigning specialists to the work. A degree of specialization in
toolmaking was achieved by the time of Neanderthal man (70,000 BC); more advanced tools, requiring assemblage of head and haft, were
produced by Cro-Magnon Homo sapiens (perhaps as early as 35,000 BC), while the application of mechanical principles was achieved
by pottery-making Neolithic man (6000 BC) and by Metal Age man (about 3000 BC). Earliest communities For all except approximately the last 10,000 years, man has lived almost entirely in small nomadic communities,
dependent for survival on his skill in gathering food by hunting and fishing and in avoiding predators. It is reasonable to suppose that
most of these communities developed in tropical latitudes, especially in Africa, where climatic conditions are most favourable to a
creature with such poor bodily protection as man. It is also reasonable to suppose that tribes of men moved out thence into the
subtropical regions and eventually into the landmass of Eurasia, although their colonization of this region must have been severely
limited by the successive periods of glaciation, which rendered large parts of it inhospitable and even uninhabitable, even though man
has shown remarkable versatility in adapting to such unfavourable conditions. The Neolithic Revolution Toward the end of the last ice age, some 15,000 to 20,000
years ago, a few of the human communities that were most favoured by geography and climate began to make the transition from the long
period of Paleolithic, or Old Stone Age, savagery to a more settled way of life depending on animal husbandry and agriculture. This
period of transition, the Neolithic Period, or New Stone Age, led eventually to a marked rise in population, to a growth in the size of
communities, and to the beginnings of town life. It is sometimes referred to as the Neolithic Revolution because the speed of
technological innovation increased so greatly and the social and political organization of human groups underwent a corresponding
increase in complexity. To understand the beginnings of technology it is thus necessary to survey developments from the Old Stone Age
through the New Stone Age down to the emergence of the first urban civilizations about 3000 BC. Stone The
material that gives its name and a technological unity to these periods of
prehistory is stone. Though it may be assumed that primitive man used other materials such as wood, bone, fur, leaves, and grasses
before he mastered the use of stone, apart from bone antlers, presumably used as picks in flint mines and elsewhere, and other fragments
of bone implements, none of these has survived. The stone tools of early man, on the other hand, have survived in surprising abundance,
and over the many millennia of prehistory important advances in technique were made in the use of stone. Stones became tools only when
they were shaped deliberately for specific purposes, and, for this to be done efficiently, suitable hard and fine-grained stones had to
be found and means devised for shaping them and particularly for putting a cutting edge on them.
Flint became a very popular stone for this purpose, although fine sandstones
and certain volcanic rocks were also widely used. There is much Paleolithic evidence of skill in flaking and polishing stones to make
scraping and cutting tools. These early tools were held in the hand, but gradually ways of protecting the hand from sharp edges on the
stone, at first by wrapping one end in fur or grass or setting it in a wooden handle, were devised. Much later, the technique of fixing
the stone head to a haft converted these hand tools into more versatile tools and weapons. With the widening mastery of the material world in the Neolithic
Period, other substances were brought into the service of man, such as clay for pottery and brick; and increasing competence in handling
textile raw materials led to the creation of the first woven fabrics to take the place of animal skins. About the same time, curiosity
about the behaviour of metallic oxides in the presence of fire promoted one of the most significant technological innovations of all
time and marked the succession from the Stone Age to the Metal Age. Power The use of
fire was another basic technique mastered at some unknown time in the Old
Stone Age. The discovery that fire could be tamed and controlled and the further discovery that a fire could be generated by persistent
friction between two dry wooden surfaces were momentous. Fire was the most important contribution of prehistory to power technology,
although little power was obtained directly from fire except as defense against wild animals. For the most part, prehistoric communities
remained completely dependent upon manpower, but, in making the transition to a more settled pattern of life in the New Stone Age, man
began to derive some power from animals that had been domesticated. It also seems likely that by the end of prehistoric times the sail
had emerged as a means of harnessing the wind for small boats, beginning a long sequence of developments in marine
transport. Tools and weapons The basic
tools of prehistoric peoples were determined by the materials at their
disposal. But once they had acquired the techniques of working stone, they were resourceful in devising tools and weapons with points
and barbs. Thus the stone-headed spear, the harpoon, and the arrow all came into widespread use. The
spear was given increased impetus by the spear-thrower, a notched pole that
gave a sling effect. The bow and arrow were an even more effective
combination, the use of which is clearly demonstrated in the earliest "documentary" evidence in the history of technology, the cave
paintings of southern France and northern Spain, which depict the bow being used in hunting. The ingenuity of these primitive hunters is
shown also in their slings, throwing-sticks (the boomerang of the Australian Aborigines is a remarkable surviving example), blowguns,
bird snares, fish and animal traps, and nets. These tools did not evolve uniformly, as each primitive community developed only those
instruments that were most suitable for its own specialized purposes, but all were in use by the end of the Stone Age. In addition, the
Neolithic Revolution had contributed some important new tools that were not primarily concerned with hunting. These were the first
mechanical applications of rotary action in the shape of the potter's wheel, the bow drill, the pole lathe, and the wheel itself. It is
not possible to be sure when these significant devices were invented, but their presence in the early urban civilizations suggests some
continuity with the Late Neolithic Period. The potter's wheel, driven by kicks from the operator, and the wheels of early vehicles both
gave continuous rotary movement in one direction. The drill and the lathe, on the other hand, were derived from the bow and had the
effect of spinning the drill piece or the workpiece first in one direction and then in the other. Developments in
food production brought further refinements in tools. The processes of food
production in Paleolithic times were simple, consisting of gathering, hunting, and fishing. If these methods proved inadequate to
sustain a community, it moved to better hunting grounds or perished. With the onset of the Neolithic Revolution, new food-producing
skills were devised to serve the needs of agriculture and animal husbandry. Digging sticks and the first crude plows, stone sickles,
querns that ground grain by friction between two stones and, most complicated of all, irrigation techniques for keeping the ground
watered and fertile--all these became well established in the great subtropical river valleys of Egypt and Mesopotamia in the millennia
before 3000 BC. Building techniques Prehistoric building techniques also underwent
significant developments in the Neolithic Revolution. Nothing is known of the building ability of Paleolithic peoples beyond what can be
inferred from a few fragments of stone shelters, but in the New Stone Age some impressive structures were erected, primarily tombs and
burial mounds and other religious edifices, but also, toward the end of the period, domestic housing in which sun-dried brick was first
used. In northern Europe, where the Neolithic transformation began later than around the eastern Mediterranean and lasted longer, huge
stone monuments, of which Stonehenge in England is the outstanding
example, still bear eloquent testimony to the technical skill, not to mention the imagination and mathematical competence, of the later
Stone Age societies. Manufacturing Manufacturing industry had its origin in the New Stone
Age, with the application of techniques for grinding corn, baking clay, spinning and weaving textiles, and also, it seems likely, for
dyeing, fermenting, and distilling. Some evidence for all these processes can be derived from archaeological findings, and some of them
at least were developing into specialized crafts by the time the first urban civilizations appeared. In the same way, the early
metalworkers were beginning to acquire the techniques of extracting and working the softer metals, gold, silver, copper, and tin, that
were to make their successors a select class of craftsmen. All these incipient fields of specialization, moreover, implied developing
trade between different communities and regions, and again the archaeological evidence of the transfer of manufactured products in the
later Stone Age is impressive. Flint arrowheads of particular types, for example, can be found widely dispersed over Europe, and the
implication of a common locus of manufacture for each is strong. Such transmission suggests improving facilities for transport and communication. Paleolithic man presumably depended
entirely on his own feet, and this remained the normal mode of transport throughout the Stone Age. Domestication of the ox, the donkey,
and the camel undoubtedly brought some help, although difficulties in harnessing the horse long delayed its effective use. The dugout
canoe and the birch-bark canoe had demonstrated the potential of water transport, and, again, there is some evidence that the sail had
already appeared by the end of the New Stone Age. It is notable that the developments so far described in human prehistory took place over a long period of time,
compared with the 5,000 years of recorded history, and that they took place first in very small areas of the Earth's surface and
involved populations minute by modern criteria. The Neolithic Revolution occurred first in those parts of the world with an unusual
combination of qualities: a warm climate, encouraging rapid crop growth, and an annual cycle of flooding that naturally regenerated the
fertility of the land. On the Eurasian-African landmass such conditions occur only in Egypt, Mesopotamia, northern India, and some of
the great river valleys of China. It was there, then, that men and women of the New Stone Age were stimulated to develop and apply new
techniques of agriculture, animal husbandry, irrigation, and manufacture; and it was there that their enterprise was rewarded by
increasing productivity, which encouraged the growth of population and triggered a succession of sociopolitical changes that converted
the settled Neolithic communities into the first civilizations. Elsewhere, the stimulus to technological innovation was lacking or was
unrewarded, so that these areas had to await the transmission of technical expertise from the more highly favoured areas. Herein is
rooted the separation of the great world civilizations, for while the Egyptian and Mesopotamian civilizations spread their influence
westward through the Mediterranean and Europe, those of India and China were limited by geographical barriers to their own hinterlands,
which, although vast, were largely isolated from the mainstream of Western technological progress. The Urban Revolution (c. 3000-500 BC) The technological change so far described took
place very slowly over a long period of time, in response to only the most basic social needs, the search for food and shelter, and with
few social resources available for any activity other than the fulfillment of these needs. About 5,000 years ago, however, a momentous
cultural transition began to take place in a few well-favoured geographical situations. It generated new needs and resources and was
accompanied by a significant increase in technological innovation. It was the beginning of the invention of the city. Craftsmen and
scientists The accumulated agricultural skill
of the New Stone Age had made possible a growth in population, and the larger population in turn created a need for the products of
specialized craftsmen in a wide range of commodities. These craftsmen included a number of
metalworkers, first those treating metals that could be easily obtained in
metallic form and particularly the soft metals, such as gold and copper, which could be fashioned by beating. Then came the discovery of
the possibility of extracting certain metals from the ores in which they generally occur. Probably the first such material to be used
was the carbonate of copper known as malachite, then already in use as a
cosmetic and easily reduced to copper in a strong fire. It is impossible to be precise about the time and place of this discovery, but
its consequences were tremendous. It led to the search for other metallic ores, to the development of metallurgy, to the encouragement
of trade in order to secure specific metals, and to the further development of specialist skills. It contributed substantially to the
emergence of urban societies, as it relied heavily upon trade and manufacturing industries, and thus to the rise of the first
civilizations. The Stone Age gave way to the early Metal Age, and a new
epoch in the story of mankind had begun. By
fairly general consent, civilization consists of a large society with a common culture, settled communities, and sophisticated
institutions, all of which presuppose a mastery of elementary literacy and numeration. Mastery of the civilized arts was a minority
pursuit in the early civilizations, in all probability the carefully guarded possession of a priestly caste. The very existence of these
skills, however, even in the hands of a small minority of the population, is significant because they made available a facility for
recording and transmitting information that greatly enlarged the scope for innovation and speculative thought. Hitherto, technology had existed without the benefit of science,
but, by the time of the first Sumerian astronomers, who plotted the motion of the heavenly bodies with remarkable accuracy and based
calculations about the calendar and irrigation systems upon their observations, the possibility of a creative relationship between
science and technology had appeared. The first fruits of this relationship appeared in greatly improved abilities to measure land,
weigh, and keep time, all practical techniques, essential to any complex society, and inconceivable without literacy and the beginnings
of scientific observation. With the emergence of these skills in the 3rd millennium BC, the first civilizations arose in the valleys of
the Nile and of the Tigris-Euphrates. Copper and bronze The fact that the era of the early civilizations
coincides with the technological classification of the Copper and Bronze
ages is a clue to the technological basis of these societies. The softness of copper, gold, and silver made it inevitable that they
should be the first to be worked, but archaeologists now seem to agree that there was no true "Copper Age," except perhaps for a short
period at the beginning of Egyptian civilization, because the very softness of that metal limited its utility for everything except
decoration or coinage. Attention was thus given early to means of hardening copper to make satisfactory tools and weapons. The reduction
of mixed metallic ores probably led to the discovery of alloying,
whereby copper was fused with other metals to make bronze. Several bronzes
were made, including some containing lead, antimony, and arsenic, but by far the most popular and widespread was that of copper and tin
in proportions of about 10 to one. This was a hard yellowish metal that could be melted and cast into the shape required. The
bronzesmiths took over from the coppersmiths and goldsmiths the technique of heating the metal in a crucible over a strong fire and
casting it into simple clay or stone molds to make axheads or spearheads or other solid shapes. For the crafting of hollow vessels or
sculpture, they devised the so-called cire perdue technique, in which the
shape to be molded is formed in wax and set in clay, the wax then being melted and drained out to leave a cavity into which the molten
metal is poured. Bronze became the most
important material of the early civilizations, and elaborate arrangements were made to ensure a continuous supply of it. Metals were
scarce in the alluvial river valleys where civilization developed and therefore had to be imported. This need led to complicated trading
relationships and mining operations at great distances from the homeland. Tin presented a particularly severe problem, as it was in
short supply throughout the Middle East. The Bronze Age civilizations were compelled to search far beyond their own frontiers for
sources of the metal, and in the process knowledge of the civilized arts was gradually transmitted westward along the developing
Mediterranean trade routes. In most aspects
other than the use of metals, the transition from the technology of the New Stone Age to that of early civilizations was fairly gradual,
although there was a general increase in competence as specialized skills became more clearly defined, and in techniques of building
there were enormous increases in the scale of enterprises. There were no great innovations in power technology, but important
improvements were made in the construction of furnaces and kilns in response to the requirements of the metalworkers and potters and of
new artisans such as glassworkers. Also, the sailing ship assumed a
definitive shape, progressing from a vessel with a small sail rigged in its bows and suitable only for sailing before the prevailing
wind up the Nile River, into the substantial oceangoing ship of the later Egyptian dynasties, with a large rectangular sail rigged
amidships. Egyptian and Phoenician ships of this type could sail before the wind and across the wind, but for making headway into the
wind they had to resort to manpower (see photograph).
Nevertheless, they accomplished remarkable feats of navigation, sailing the length of the Mediterranean and even passing through the
Pillars of Hercules into the Atlantic. Irrigation Techniques of food production also showed many
improvements over Neolithic methods, including one outstanding innovation in the shape of systematic irrigation. The civilizations of
Egypt and
Mesopotamia depended heavily upon the two great river systems, the Nile and
the Tigris-Euphrates, which both watered the ground with their annual floods and rejuvenated it with the rich alluvium they deposited.
The Nile flooded with regularity each summer, and the civilizations building in its valley early learned the technique of
basin irrigation, ponding back the floodwater for as long as possible after
the river had receded, so that enriched soil could bring forth a harvest before the floods of the following season. In the
Tigris-Euphrates valley the irrigation problem was more complex, because the floods were less predictable, more fierce, and came earlier
than those of the northward-flowing Nile. They also carried more alluvium, which tended to choke irrigation channels. The task of the
Sumerian irrigation engineers was that of channeling water from the rivers
during the summer months, impounding it, and distributing it to the fields in small installments. The Sumerian system eventually broke
down because it led to an accumulation of salt in the soil, with a consequent loss of fertility. Both systems, however, depended on a
high degree of social control, requiring skill in measuring and marking out the land and an intricate legal code to ensure justice in
the distribution of precious water. Both systems, moreover, depended on intricate engineering in building dikes and embankments, canals
and aqueducts (with lengthy stretches underground to prevent loss by evaporation), and the use of water-raising devices such as the
shadoof, a balanced beam with a counterweight on one end and a bucket to lift
the water on the other. Urban manufacturing Manufacturing industry in the early civilizations concentrated on such products as pottery, wines, oils, and cosmetics,
which had begun to circulate along the incipient trade routes before the introduction of metals; these became the commodities traded for
the metals. In pottery, the potter's wheel became widely used for spinning
the clay into the desired shape, but the older technique of building pots by hand from rolls of clay remained in use for some purposes.
In the production of wines and oils various forms of press were developed, while the development of cooking, brewing, and preservatives
justified the assertion that the science of chemistry began in the kitchen. Cosmetics too were an offshoot of culinary
art. Pack animals were still the primary means
of land transport, the wheeled vehicle developing slowly to meet the divergent needs of agriculture, trade, and war. In the latter
category, the chariot appeared as a weapon, even though its use was limited by the continuing difficulty of harnessing a horse. Military
technology brought the development of metal plates for armour. Building In building
technology the major developments concerned the scale of operations rather than any particular innovation. The late Stone Age
communities of Mesopotamia had already built extensively in sun-dried brick. Their successors continued the technique but extended its
scale to construct the massive square temples called ziggurats. These had
a core and facing of bricks, the facing walls sloping slightly inward and broken by regular pilasters built into the brickwork, the
whole structure ascending in two or three stages to a temple on the summit. Sumerians were also the first to build columns with brick
made from local clay, which also provided the writing material for the scribes. In Egypt, clay was scarce but good building stone was plentiful, and builders used it in constructing
the pyramids and temples that remain today as outstanding monuments of Egyptian civilization. Stones were pulled on rollers and raised
up the successive stages of the structure by ramps and by balanced levers adapted from the water-raising shadoof. The stones were shaped
by skilled masons, and they were placed in position under the careful supervision of priest-architects who were clearly competent
mathematicians and astronomers, as is evident from the precise astronomical alignments. It seems certain that the heavy labour of
construction fell upon armies of slaves, which helps to explain both the achievements and limitations of early civilizations. Slaves
were usually one of the fruits of military conquest, which presupposes a period of successful territorial expansion, although their
status as a subject race could be perpetuated indefinitely. Slave populations provided a competent and cheap labour force for the major
constructional works that have been described. On the other hand, the availability of slave labour discouraged technological innovation,
a social fact that goes far toward explaining the comparative stagnation of mechanical invention in the ancient
world. Transmitting knowledge In the ancient world, technological knowledge was transmitted by traders, who went out in search of tin and other
commodities, and by craftsmen in metal, stone, leather, and the other mediums, who passed their skills to others by direct instruction
or by providing models that challenged other craftsmen to copy them. This transmission through intermediary contact was occurring
between the ancient civilizations and their neighbours to the north and west during the 2nd millennium BC. The pace quickened in the
subsequent millennium, distinct new civilizations arising in Crete and Mycenae, in Troy and Carthage. Finally, the introduction of the
technique of working iron profoundly changed the capabilities and resources of human societies and ushered in the classical
civilizations of Greece and Rome. Technological achievements of Greece and Rome (500 BC-AD 500) The contributions of
Greece and
Rome in philosophy and religion, political and legal institutions, poetry
and drama, and in the realm of scientific speculation stand in spectacular contrast with their relatively limited contributions in
technology. Their mechanical innovation was not distinguished, and, even in the realms of military and construction engineering, in
which they showed great ingenuity and aesthetic sensibility, their work represented more a consummation of earlier lines of development
than a dramatic innovation. This apparent paradox of the classical period of the ancient world requires explanation, and the history of
technology can provide some clues to the solution of the problem. The mastery of iron The outstanding technological factor of the
Greco-Roman world was the smelting of iron, a technique--derived from unknown metallurgists, probably in Asia Minor, about 1000 BC--that
spread far beyond the provincial frontiers of the Roman Empire. The use of the metal had become general in Greece and the Aegean Islands
by the dawn of the classical period about 500 BC, and it appears to have spread quickly westward thereafter. Iron ore, long a familiar
material, had defied reduction into metallic form because of the great heat required in the furnace to perform the chemical
transformation (about 1,535º C [2,795º F] compared with the 1,083º C [1,981º F] necessary for the reduction of copper ores). To reach
this temperature, furnace construction had to be improved and ways devised
to maintain the heat for several hours. Throughout the classical period these conditions were achieved only on a small scale, in
furnaces burning charcoal and using foot bellows to intensify the heat, and even in these furnaces the heat was not sufficient to reduce
the ore completely to molten metal. Instead, a small spongy ball of iron--called a
bloom--was produced in the bottom of the furnace. This was extracted by
breaking open the furnace, and then it was hammered into bars of wrought iron, which could be shaped as required by further heating and
hammering. Apart from its greater abundance, iron for most purposes provided a harder and stronger material than the earlier metals,
although the impossibility of casting it into molds like bronze was an inconvenience. At an early date some smiths devised the
cementation process for reheating bars of iron between layers of charcoal to carburize the surface of the iron and thus to produce a
coat of steel. Such case-hardened iron could be further heated, hammered, and tempered to make knife and sword blades of high quality.
The very best steel in Roman times was Seric steel, brought into the Western world from India, where it was produced in blocks a few
inches in diameter by a crucible process; i.e., melting the ingredients in an enclosed vessel to achieve purity and consistency
in the chemical combination.