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A Brief History of Engineering
The history of engineering is longer than the history of the human race. Our species, homo sapiens, has existed for about 35,000 years. Our ancestors began using stone tools almost a million years ago. Our knowledge of these early technologies is fragmentary; we know about stone tools and pots; if there were wooden tools or woven baskets, they have long since rotted to dust. One thing that does strike us about ancient technology is how slow it was to progress. Hundreds of thousands of years separate the bottom of this chart from the top. Why so slow?
One suggestion, made by the historian Lewis Mumford, is that humanity was not idle during this interval, but was developing a set of tools more powerful than stone axes -- patterns of culture, and, most importantly, language. These developments, Mumford says, were and remain more important than any physical devices, but are unacknowledged by conventional historians because of the impossibility of reconstructing them from the archaeological record.
There are other reasons for slow development: Subsistence-level communities tend to be conservative, for several reasons. One reason is size -- there are only a few people, so there will only be a few ideas. Communication between groups is poor, so there is no cross-fertilization of ideas. Experimenting with new ways requires surplus resources: one or more individuals must have leisure to do the experiment, and the group must find the materials to be used in the experiment. Perhaps more important, conservatism is safe -- if the group has survived thus far, it must be doing things right. Any change involves risk, and most changes will be deleterious.
What can force the group to innovate? Change imposed from the outside: a change in climate, for example. The most powerful impetus to change comes when a uniquely deadly threat appears from the outside: another group of humans, with unfamiliar weapons. A society armed with sticks and stones cannot fight invaders in bronze swords and armour; bronze armour can be sliced like cardboard by an iron sword. Here is a powerful incentive to innovate: the group that does not innovate will be at the mercy of the group that does.
Over the next two lectures, we will be searching for laws of historical development, just as we have been looking for laws of engineering. Historians such as Toynbee and Spengler have proposed such laws, and the science fiction writer Isaac Asimov has imagined a science of `psychohistory' which would allow the evolution of a society to be predicted mathematically. But Asimov's ideas remain science fiction, and every attempt to identify laws of historical development has ended in failure. The most spectacular failure of recent memory may be Marx's dialectical materialism, according to which all societies evolve via feudalism, capitalism and socialism to the ideal state of communism. The belief that such laws of historical development exist is called `historicism', and Sir Karl Popper has argued [in ``The Poverty of Historicism"] that the quest for such laws is doomed to futility; that the future development of society is unknowable.
On the other hand, we often talk as though the laws of development were not just knowable, but obvious. For example, we speak of the `developed world' -- the U.S., Canada, Japan -- and the `developing world' -- India, Indonesia, Nigeria -- and we think of it as both natural and desirable that every society should move towards greater development. The only debate concerns the most efficient way to develop.
Engineering in prehistoric times was limited because prehistoric societies did not have surplus food to support professional inventors or designers. This first changed with the invention of agriculture, about 10,000 years ago. People began to raise crops and domesticate animals, making it possible for humanity to remain in one place in large groups, rather than wandering in small bands from one area to another, hunting and gathering until they exhausted the local food supplies.
The first engineers whose names we know lived in ancient Egypt. Imhotep was a builder of tombs. Khufu-onekh built the Great Pyramid. The new science of agriculture in the fertile Nile valley could support a population far larger than that needed to grow the crops, and Khufu-onekh used tens, or perhaps hundreds, of thousands of men from this population, over a period of twenty years, to cut and move the more than five million tons of stone the pyramid required.
The pyramids are an impressive achievement; we can wonder how much of our own technology will exist in five thousand years. But how well does Khufu-onekh's work fit thew common notion of engineering as the application of science to the improvement of the human condition? The work that he supervised condemned many thousands to slave labour, for the supposed benefit of one man, the Pharaoh. And even the benefit the Pharaoh expected -- eternal life in the Western Lands -- may have been illusory.
In 400 BC, the Mediterranean city of Syracuse was ruled by a shrewd, ambitious king, Dionysios the Elder. Like many more modern dictators, Dionysios protected himself against assassination by wearing a steel vest. His ambitions included the conquest of the island of Sicily. Diodorus Siculus, a Roman historian, describes how, to further this aim, Dionysius founded the first engineering research laboratory: ``He gathered skilled workmen, commandeering them from the cities under his control and attracting them by high wages from Italy and Greece. . . he divided them into groups in accordance with their skills and appointed over them the most conspicuous citizens, offering great bounties to any who created a supply of arms."
The Syracusan tradition of military engineering reached its greatest height a few centuries later, with the greatest engineer of the ancient world, Archimedes. Archimedes was a relative and friend of Hieron the second, ruler of Syracuse. The Mediterranean was at this time involved in a naval arms race between the various heirs to the empire of Alexander the Great. The engineering skills of Archimedes helped Syracuse pull ahead in this race: among other things, he designed a ship, the Syrakosia, larger than any existing at the time -- so large, in fact, that nothing bigger was built in the next two thousand years. The launching of the ship was remarkable, in that Archimedes did it single-handed, turning a windlass that pulled through a series of compound pulleys.
Hieron appointed Archimedes general of ordnance for the city. After Hieron's death, the city allied itself with Carthage in the second Punic War, and was promptly attacked by the Romans. The invaders met with the most advanced military defences in the ancient world: cranes that reached over the city walls and lifted Roman galleys out of the water, raised them high, then let them fall back to destruction; great catapults and crossbows, operated by teams of soldiers. It was once believed that his weaponry included a heat ray; the Roman historian Diodorus says ``He devised a hexagonal mirror, and at an appropriate distance from it set small quadrangular mirrors of the same type, which could be adjusted by metal plates and small hinges. ...by the reflection of the sun's rays in this, a fearsome fiery heat was kindled in the barges, and from the distance of an arrow's flight he reduced them to ashes."
(Most later sources I've read say that this would not be possible in practice. However, in 1973 AD the Greek scientist Ioannis Sakas organised sixty soldiers, holding large mirrors, to aim reflected light at a boat 50 metres away, and set the boat afire within three minutes.)
Despite Archimedes's devices, the Romans eventually conquered the city, attacking a weakly defended tower while the defenders were celebrating a religious festival. The Roman general gave orders that Archimedes was to be captured alive, but he was slain by a Roman soldier.
These creations must have been the most visible of Archimedes's work at the time, though his prodigiously inventive mind also did many other things, such as the invention of hydrostatics and many discoveries in mathematics. Despite his engineering achievements, the historian Plutarch says of him,
``He possessed so high a spirit, so profound a soul, and such treasures of scientific knowledge, that though these inventions had now obtained him the renown of more-than-human sagacity, he yet would not deign to leave behind him any commentary or writing on such subjects; but, repudiating as sordid and ignoble the whole trade of engineering, and every sort of art that lends itself to mere use and profit, he placed his whole affection and ambition in those purer speculations where there can be no reference to the vulgar needs of life; studies, the superiority of which to all others is unquestioned and which the only doubt can be whether the beauty and grandeur of the subjects examined, or the precision and cogency of the methods and means of proof, most deserve our admiration"
(Note: he means maths). This reminds us of Duhem; yet, remember, this is Plutarch, a Roman aristocrat, speaking, not Archimedes. An aristocrat in a hierarchical, slave-owning society will naturally have contempt for occupations which get the hands dirty, and we may wonder, if Archimedes himself had this attitude to engineering, why he did so much of it and was so good at it.
The Romans continued to develop catapults for military use. The Latin word for these devices was ingenium; which is where we get the root of the word `engineer'.
I am now going to skip one and a half thousand years, into thirteenth century Europe. Looking around, we have to ask, what happened? We left a Europe in early Roman times; the continent was becoming united under a strong central government, networks of roads were being developed, Heron of Alexandria was experimenting with a prototype steam engine. We think of progress as natural; the 386 is replaced by the 486, which in turn is replaced by the Pentium. Why didn't this happen in Rome? Why didn't the Industrial Revolution start then? One reason may have been a plentiful supply of slaves, but the true causes are largely a mystery; it is also a mystery why engineering began to grow again in the Middle Ages. One cause that has been suggested is the Black Death:
Between 1350 and 1400, almost a third of the population of Europe died of plague. The population only regained its 1350 level two centuries later. So there was a sudden need for an external input of power to keep the depopulated society working. This power came first from windmills and water wheels. Another source of energy was coal, though it would still be several centuries before anyone discovered how to turn the thermal energy of combustion into mechanical work. Coal provided a concentrated source of heat, useful for burning lime to produce mortar -- it was so widely used for this purpose that in 1307, the lime-burners of London were forbidden to fire their kilns with coal, because the city was suffocating. Concentrated heat energy was also useful for smelting iron, and watermills provided power to pump the bellows and hammer the finished iron into shape.
Coal can be found on the surface of the earth, or floating in the sea, and the Romans had relied on these sources. The medieval engineers quickly exhausted these supplies, and turned to mining. And as the use of coal continued, the mines grew deeper. But in a damp climate, deep mines quickly fill with water. The miners first attempted to deal with this by bucket brigades -- hundreds of men passing buckets from hand to hand. Then the first horse-powered and water-powered pumps were developed.
How accurately did engineering at this time fit its popular description as `the application of the sciences to practical ends''? It didn't fit this description in any way. Experimental science did not yet exist. Theoretical science, or natural philosophy, was practiced almost exclusively within the church, and took the form of expanding or commenting on the work of Aristotle.
The next great advance in engineering -- the invention of the steam engine and its use to pump out the mines -- took place with no help from science. And as steam engines were developed over the next century, the steam engineers created their own theory of design. That theory -- the theory of thermodynamics -- is now one of the cornerstones of science. Yet it was one of the two major scientific theories to be developed by practicing engineers, not scientists. (We will be examining the nature and significance of thermodynamics in a few weeks.)
Nevertheless, there was a sense in which enginering, even now, was moving closer to science. The devices of the early industrial revolution were seen by their designers as entirely separate from one another: a water-powered mill was one kind of thing, a water-powered pump was another kind of thing. There was no notion of a water-wheel as a distinct mechanism common to both devices. One of the first engineers to grasp this idea of a general mechanism, common to several devices, was Leonardo da Vinci.
It was at about this time that engineering began to divide itself into specialities. To see how people thought of engineering at the time, we need only look at the name the first specialist engineers gave themselves, to distinguish them from ordinary engineers. They called themselves `civil engineers'; that is, civilian engineers, engineers who were doing something other than the original and natural kind of engineering, military engineering.
Next: A Brief History 2