The use of tools

It is a commonplace that humans are distinguished from other creatures by a technological ability, and man has often been described as a tool-using animal. The distinction is not entirely valid. Some animals do use tools. Chimpanzees are the most often quoted example, stripping a twig to plunge it into an anthill and then eating the tasty termites which cling to the end of it. A more modern example of tool-using is that of crows living in a walnut avenue in the Japanese town of Sendai. The walnuts are too hard to crack. So the crows have taken to dropping them on a pedestrian crossing where they are crushed by the passing traffic. When it is the pedestrians' turn, the crows fly in to bear off the fragments.
But there is a difference between using a tool which comes to hand, however improbably, and fashioning one for a purpose. Shaping a tool for cutting or scraping (two basic and useful functions) is a difficult task. Such a tool must be made of a hard material, and the hardest material easily available on the surface of the earth is stone. But how does one shape a stone without tools? The history of human technology begins with the discovery of how to give stone a cutting edge. The type of stone found most suitable for the purpose is flint.
Stone tools: from 2.5 million years ago
The human discovery that round nodules of flint can be split and chipped to form a sharp edge is extremely ancient. Tools made in this way have been found in Africa from about 2.5 million years ago (the earliest known examples have been discovered at Gona, in the Awash Valley in Ethiopia). Gradually, over the millennia, in an extremely slow version of an industrial revolution, new and improved techniques are developed for striking off slivers of stone. Variations in the flints found with fossil remains (differing both in the method by which flakes are chipped from the core, and in the range of shapes created) are used by anthropologists as one way of assigning human skeletal remains to specific groups or Divisions of the Stone Age.
In the earliest periods a sgle tool is usually made from the core of the flint, resulting in an instrument that can be used in a fairly rough manner for either cutting or scraping. Hundreds of thousands of years later, craftsmen have become skilled at forming the flakes themselves into implements of various kinds, producing specialist tools for cutting, scraping, gouging or boring, as well as sharp points for arrow and spear heads. These sophisticated stone tools, in their turn, make it possible to carve materials such as antler or bone to create even sharper points, or more complex shapes (such as hooks or needles).
Fire: from 500,000 years ago
An event of crucial importance in the development of technology is man's taming of fire. This probably happens some 500,000 years ago in China, where the caves occupied by Peking man contain what appear to be hearths. Some experts believe there is evidence of the use of fire much earlier in south Africa. It will be many millennia before fire is adapted to any purpose other than for warmth and for roasting meat and root vegetables. But more than 250,000 years ago hunters realize that the sharpened point of a wooden spear can be hardened by charring it in embers.
Neolithic technology: from 8000 BC
The technological potential of fire is not discovered until well into the neolithic period. Pottery, fired in a primitive kiln, is known from about 6500 BC. The smelting and casting of metal require considerably higher temperatures and are not attempted until much later, from about 4000 BC. The introduction of copper, and then bronze, brings to an end the neolithic period. Other basic technologies, not requiring fire, are well established in neolithic times. Textiles feature almost as early as Pottery. Weights designed for spinning are common in neolithic sites, and fragments of fine woven cloth survive in graves at Catal Huyuk from as early as 5800 BC.
Bricks: from 8000 BC
An innovation in the neolithic period is the use of bricks. In their simplest form (still familiar today in many hot regions), bricks are shaped by pressing mud or clay into a mould. The damp blocks are then left to bake hard in the sun. Bricks of this kind are known in Jericho from about 8000 BC. The more durable type of brick, baked in a kiln, is an offshoot of the potter's technology. Kiln bricks are widely used in the two earliest civilizations, in Mesopotamia and Egypt, often to provide the outer surface of walls on an inner core of sun-dried brick.
Spinning: from 8000 BC
The spindle develops naturally from the process of twisting fibres into a thread by hand. The spun thread must be stored, and the easiest way is to wind it onto a stick. This means that the stick is also attached to the unfinished thread (the fibres which are still being twisted). The stick must therefore twist with the fibres. Instead of being an encumbrance, this can be turned to advantage. If the stick is given greater weight, by attaching to it a lump of clay or a stone, its momentum will help in spinning the thread.
The thread can be turned into fabric in either of two ways. One of them links a continuous length of thread in rows of interconnected loops. This is knitting, which can create garments of any shape. The other method, going back to at least 5800 BC, uses the thread in a rectangular criss-cross pattern to produce flat cloth. The vertical threads are stretched taut to form a grille; the horizontal threads are then interwoven between them. This is the process for all textiles of cotton, linen, silk or wool. It also produces tapestry. It makes the cloth which is decorated in embroidery. When loops are inserted, it gives the soft pile of rugs and carpets. All these involve the basic craft of weaving.
So the spindle acquires its two characteristics. It is a bobbin, on to which the spun thread is wound; and it is a flywheel, prolonging the spinning motion which creates the thread. The spinner uses one hand to draw out the fibres from the bundle of wool, cotton or flax, thus extending the half-spun thread to which the spindle is attached. The other hand gives a rotating flick to the spindle whenever it begins to lose impetus. Hand-spinning of this sort becomes a basic cottage industry throughout the world.
Loom: from 6000 BC
Weaving of cloth requires a loom - a structure which will hold taut the vertical threads (the warp), while the weaver snakes each horizontal thread in and out to form the weft. When the threads of the weft are pressed down tight, to form a solid mesh with the warp, a section of the cloth at the bottom of the loom is complete. A pattern is achieved by varying the colour of the threads in warp and weft. The earliest known evidence of a loom comes from Egypt in about 4400 BC, but some method of supporting the warp exists from the beginning of weaving. The threads must either be suspended (and held taut by a weight at the bottom) or else must be stretched in the rigid frame of a conventional loom.
Weaving: from 6000 BC
Until recently the earliest known scraps of cloth are woven from wool; dating from about 5800 BC, they come from Catal Huyuk in Anatolia. Similarly the first known example of linen has been from about 5000 BC in Egypt, where flax (an indigenous wild plant in the Mediterranean region) is cultivated. But a small woven fragment discovered in 1993 near the upper reaches of the Tigris probably pushes back the available evidence. It appears to be linen and has been dated to about 7000 BC. Cotton is grown in both Eurasia and America; woven cotton survives from about 2500 BC in the Indus valley and slightly later in Peru. The most precisely localized source of any major fabric is China, where pieces of woven silk are known from about 2850 BC.
The first miners: from 4000 BC
By 4000 BC deep shafts are cut into the hillside at Rudna Glava, in the Balkans, to excavate copper ore. This robbing of the earth's treasures is carried out with due solemnity. Fine pots, bearing produce from the daylight world, are placed in the mines as a form of recompense to propitiate the spirits of the dark interior of the earth. By about 3800 BC copper mines are also worked in the Sinai peninsula. Crucibles found at the site reveal that smelting is carried out as part of the mining process.
Yoke and harness: from 4000 BC
The harnessing of draught animals is a major technological advance in agriculture as well as transport. The first to be harnessed is the ox, conveniently provided by nature with a fleshy hump above the shoulders. A yoke laid in front of this will remain in place even when a heavy burden is pulled. Sometimes a lighter yoke is attached to the horns. Oxen are dragging heavy objects or loaded sledges by about 4000 BC. The camel has an even more convenient hump. Its height makes it less suitable for draught purposes than the ox, but from perhaps 1000 BC it is used in Asia and north Africa for drawing wagons and for ploughing. By contrast, harnessing the horse proves problematical.
A traditional yoke can only be kept in place on a horse by passing thongs in front of its chest. However carefully they are placed, these must pass in front of the animal's windpipe. The heavier the weight it attempts to pull, the less air it will breathe. For many centuries this means that horses are not very effectively used as draught animals. The solution, discovered in China by the 5th century AD, is to provide a firm collar, fitting round the neck and shoulders of the animal to distribute the weight. Collars of this kind reach Europe by the 9th century AD, enabling the horse to become the main draught animal of the region for both ploughing and haulage.
The plough and draught animals: from 3000 BC
The plough is almost certainly the first implement for which humans use a source of power other than their own muscles. When planting seeds, it is essential to break up the ground. In the early stages of agriculture this is achieved by hacking and scraping with a suitably pointed implement - the antler of a deer, or a hooked branch of a tree. But a useful furrow can more easily be achieved by dragging a point along the surface of the ground. The first ploughs consist of a sharp point of timber, sometimes hardened in a flame or tipped with flint, projecting downwards at the end of a long handle.
In the light soil of Egypt and Mesopotamia, where ploughing is first undertaken, a simple pointed implement of this kind is sufficient to break up the earth and form a shallow trench. Such a plough can be dragged by a couple of men. But the use of draught animals such as oxen, from at least 3000 BC, greatly speeds up the process. In northern Europe, with heavier soil, this type of plough is ineffective. A more elaborate machine is developed, probably by the Celts in the 1st century BC, in which a sharb blade cuts into the earth and an angled board turns it over to form a furrow.
The potter's wheel: 3000 BC
When a pot is built up from the base by hand, it is impossible that it should be perfectly round. The solution to this problem ia the potter's wheel, which has been a crucial factor in the history of ceramics. It is not known when or where the potter's wheel is introduced. Indeed it is likely that it develops very gradually, from a platform on which the potter turns the pot before shaping another side (thus avoiding having to walk around it). By about 3000 BC a simple revolving wheel is a part of the potter's equipment in Mesopotamia, the cradle of so many innovations.
The wheel: 3000 BC
The wheel is often quoted as the single most important advance in early technology. It is sometimes said to have evolved from the potter's wheel. Both are first known at approximately the same period, around 3000 BC. But they share no geographical origin and it is intrinsically unlikely that either form would suggest the other. Each is a natural solution to a very different problem. In early technology a wagon wheel can only be made from wood. Several of the earliest known wheels have been found in the heavily forested regions of Europe.

Mechanical gearing: from 350 BC
An important adaptation of the wheel in technology is the pulley - a wheel round which a rope is run to exert force on an object at the other end. Such a machine is first mentioned in a Greek text of the 4th century BC, but it is likely to have been known much earlier. In the simplest pulley a single wheel is used (as in hauling a flag up a flagpole). But major mechanical advantages can be achieved with two or more wheels - making it possible to lift a heavier object, albeit more slowly. The effect of two pulleys is that a force capable of pulling the rope two yards at one end will exert twice that force over a distance of only one yard at the other. The effect increases dramatically the more pulleys there are.
A closely related mechanical principle for lifting is the lever, where a non-central fulcrum means that a weak force exerted at one end of a rigid bar becomes a stronger force over a shorter distance at the other end. This discovery is often linked with Greek science, because of the legendary remark attributed to Archimedes in the 3rd century BC: 'Give me a fulcrum and I will move the earth.' In fact the lever has much earlier origins. It is probably the first mechanical device used in technology. From about 3000 BC the principle is put to practical use in both Egypt and Mesopotamia.
Another important mechanical principle, that of the screw, is also commonly associated with Archimedes. The concept may have been discovered much earlier in Egypt, or by Greeks before the time of Archimedes. But as a system of raising water, the screw has long been linked with his name. A different application, the screw press, is developed in Mediterranean regions at some time before the 1st century AD. Considerable pressure is needed to extract oil from olives. In earlier presses this is achieved by a heavy beam, on a lever principle. But a screw is more relentlessly effective, increasing the pressure to a new level with each turn.