Prehistory


The dawn of discovery

A long slow sequence of invention and discovery has made possible the familiar details of our everyday lives. Mankind's programme of improvements has been erratic and unpredictable. But good ideas are rarely forgotten. They are borrowed and copied and spread more widely, in an accelerating process which makes the luxuries of one age the necessities of the next.

The story is a disjointed one, since inventions and discoveries occur in a random fashion. They are described here in an approximately chronological sequence.

Two million years of Stone technology represent the first long era of discovery at the start of human history. The use of Fire, more than 500,000 years ago, is also a discovery. And some Stone Age artefacts (such as winged arrow-heads to stick in the flesh of the prey, or hooks carved in bone) have almost the quality of inventions. But these are developments of such an extended nature that they seem different in kind from the discoveries and inventions of more recent history.

Perhaps the first two ideas worthy of the name of 'invention', even though invented many times in many different places, are the eye of a needle and the string of a bow.

Needle and thread: from 15000 years ago

In districts where warm clothing is necessary, Stone Age people stitch skins together with threads of tendon or leather thongs. For each stitch they bore a hole and then hook the thread through it.

The development of a bone or ivory needle, with an eye, speeds up the process immeasurably. The hole is now created by the same implement which then pulls the thread through, in an almost continuous movement. Needles of this kind have been found in caves in Europe from the late palaeolithic period, about 15,000 years ago. Several are so thin as to imply the use of materials such as horsehair for the thread.

The bow and arrow: from 15000 years ago

The sudden release of stored energy, when a forcibly bent strip of wood is allowed to snap back into its natural shape, is more rapid and therefore more powerful than any impulse of which human muscles are capable - yet human muscles, at a slower rate, have the strength to bend the strip of wood.

The principle of the bow is discovered about 15,000 years ago. Bows and arrows feature from that time, no doubt both in hunting and warfare, in the regions of north Africa and southern Europe. The wood is usually ewe or elm. Stone age technology is capable of producing sharp flint points for the arrows, often with barbs to secure them in the victim's flesh.

Making fire: more than 10000 years ago

At some unknown time, before the beginning of settled life in the Neolithic revolution, humans learn how to make fire. No doubt the discovery happens at many different times in many different places over a very long period. The knowledge of how to create a spark, and to nurture it until it develops into a flame, is an intrinsic skill of human society.

Almost without exception Stone age tribes, surviving into modern times, have evolved in isolation their own methods of making fire. It is likely that the same was true when all humanity lived in the Stone age.

The most common way of making fire is by friction, using a fire drill. This consists of a stick of hard wood, pointed at one end, and a slab of softer wood with a hole in it. If the point is placed in the cavity and rapidly twirled (by rubbing between the palms, or by means of a bow string looped round and pulled back and forth), the softer wood begins to smoulder. Shreds of dry tinder, placed in the smouldering cavity, can be carefully blown into a flame.

Another more sophisticated technique involves flint and pyrite. Evidence of both methods is found in neolithic tombs.

The useful quality of the naturally occurring mineral pyrite, or iron pyrites, is that it makes a spark if struck with a flint. If the spark is aimed into dry tinder, blowing can achieve a flame.

With the introduction of iron, it is discovered that the same principle applies between flint and steel. This eventually becomes the standard method of making fire. The European tinderbox of the 16th century is a portable fire-making kit, consisting of flint, steel, tinder to catch the spark and a match (like the wick of a lamp) to hold the fire in a steady and lasting glow. Not until the 19th century is this equipment replaced by matches in the modern sense.

However ingenious such methods of creating spark and flame, the process is laborious and in certain weather conditions impossible. Conserving fire, rather than making it, remains until modern times the practical approach to this most useful and dangerous of mankind's allies.

This important priority of domestic life is reflected in Rome's Vestal Virgins, priestesses of great prestige and sanctity whose only ritual task is tending a flame.

Felt rugs and rush matting: 25000 to 6000 years ago

Whether living in caves or temporary shelters, hunter-gatherers of the distant past make the ground more pleasant by strewing it with rushes or similar material. The first rugs, of a kind which can be lifted and used elsewhere, are probably of Felt, made from the bark of trees. Felt rugs of this kind may have been used in the late Palaeolithic period, about 25,000 years ago.

The development of Weaving, in the form of basketry, allows for the plaiting of rushes as a floor covering. This too may well begin in Palaeolithic times. But the first archaeological traces of plaited rushes on the floor date from no earlier than about 4000 BC, in Mesopotamia.

From 8000 BC


Felt garments: from 8000 BC

It is arguable that the invention of textiles is the single most liberating step in human history. Previously people have had a choice only of going naked in warm regions or wearing rough and clumsy furs in colder climates. The most elementary of fabrics - felt - is probably the first to be developed for garments.

Felt is a fabric in which fibres of any kind are made to intermesh not by spinning and weaving, but by processes of heat, damp and pressure. Wool, hair and fur are the conventional ingredients of felt. It can also be made from strips of bark, to produce floor coverings of the kind which Palaeolithic man may have used.

Woollen felt is probably in use for garments at least 10,000 years ago, well before the first Weaving of textiles. But felt has little lasting strength. Its fibres pull gradually apart.

For a fabric with greater resilience, a woven material is required. The yarn for this can be acquired from the wool of sheep or goat, from the fluff surrounding the seeds of cotton, from the fibre in the stems of flax, or from the thin threads excreted by the silk worm. Any of these substances can be twisted by hand to form a strong thread. But greater efficiency requires the Spindle.

The crafts of settled life: from 8000 BC

With the beginning of the Neolithic revolution, about 10,000 years ago, several of mankind's basic crafts emerge over a relatively short span of time.

Sun-dried bricks make possible the beginning of architecture. In textiles, the spindle evolves to transform the spinning of thread. Weaving is perhaps first practised in the making of baskets, but soon the loom is developed for weaving cloth. Pottery provides greatly improved facilities for the storing and cooking of food.

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.

Basketry: from 7000 BC

The development of basketry can be seen also as the first step towards weaving. The interweaving of strands of reed or osier, to make a simple container, is an elementary process which rapidly provides an extremely useful object.

The impermanence of the materials means that the earliest surviving fragments of baskets (from a cave in Utah) date only from about 7000 BC, but the craft is almost certainly practised considerably earlier. From around 5800 BC we have scraps of woven textiles, preserved because carbonized in the fire which destroys one of the levels of Catal Huyuk.

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.

Pottery: from 6500 BC

One of the most useful of all human discoveries is Pottery. Indeed a standard distinction made by archaeologists, when describing successive cultures in an area, is between groups which are 'aceramic' (without Pottery) and others which have mastered the technology of clay and kiln.

In western Asia, where the Neolithic revolution is most advanced, the first Pottery at sites such as Catal Huyuk dates from about 6500 BC.

The earliest wares at Catal Huyuk are made by one of the standard methods of primitive potters. Rings or coils of clay are built up from a circular base. The walls of the pot are then smoothed and thinned (by simultaneous pressure on the inner and outer surfaces) before being fired in a bread oven or in the most elementary of kilns - a hole in the ground, above which a bonfire is lit.

Early neolithic Pottery is usually undecorated. Where there is decoration, it takes the form of patterns cut or pressed into the damp clay.

Alcohol: from the 4th millennium BC

Humans must frequently have discovered, in a series of happy accidents, the pleasant side-effects of drinking the fermented juice of grape or grain. The earliest evidence of the systematic production of alcohol comes from Mesopotamia, where by the 4th millennium BC beer is brewed on a regular basis. Barley is indigenous in the region.

Beer subsequently becomes the national drink of ancient Egypt. From there the secrets of brewing spread round the Mediterranean. A standard way of achieving the necessary mix of barley and yeast is to allow mashed barley bread to ferment. So brewing becomes, in these early times, part of the baker's trade.

From 3000 BC


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.

The Egyptian papyrus: 3000 BC

The discovery of an easily portable substance to write on is almost as old as writing itself. Around 3000 BC, in Egypt, people begin making a flexible smooth surface, which will accept and retain ink without blur or smudge.

It is known by the name of the aquatic plant which provides the structure - papyrus. It will remain in regular use longer than any other material in the history of written documents.

The papyrus is a form of rush which grows by the Nile. To make a scroll, strips are cut down the length of the plant. The broader ones are laid side by side to form a rectangle, and others are then laid across at right angles.

By a process of wetting and pressure, sometimes with added adhesive, the two layers bind. They are then hammered flat and dried in the sun, after which the upper side (with the broader strips) is polished smooth with a piece of ivory or a shell.

Up to twenty of the rectangles can be pasted together at their short ends, to be rolled up and sold in the form of a scroll. Almost every 'book' in the ancient civilizations of Egypt, Greece and Rome (spanning a period of more than 3500 years) is a papyrus scroll of this type. The material has been one of the most important elements in the history of Writing. (See Alexandria - a papyrus library)

The plough and draught animals: from 3000 BC

The plough is almost certainly the first implement for which humans use a source of power 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 and pointed 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, 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.

Silk: c.2850 BC

People in China find a use for the cocoons spun by the caterpillars of certain moths. If moistened, the thread of a cocoon can be carefully unwound. Twisted with the thread of other cocoons, it will make a filament strong enough for Weaving. The result is silk.

The earliest known silk consists of some threads and woven fragments assigned by carbon-dating to about 2850 BC. The thread of the earliest examples is from wild silk moths, indigenous to China. But soon one species of the moth, bombyx mori, is domesticated. The manufacture of silk becomes one of the most jealously guarded secrets of early Chinese civilization.

Glass: c.1500 BC

In Phoenicia, in about 1500 BC, the making of glass becomes a practical craft. Glass beads are known in Egypt 1000 years earlier, but they are probably shaped from glass which has been formed accidentally where the necessary materials and heat coincide.

The Phoenicians discover how to make glass on a predictable basis (from sand, limestone and sodium carbonate) and they invent ways of shaping this difficult but magically appealing substance into small vessels. The basic method, known as core-forming, consists of applying the molten glass to the outside of a solid core of soft clay. When the glass has cooled and hardened, the core can be scraped out.

These Phoenician skills are carried south to Egypt during the 15th century BC, after the shores of the eastern Mediterranean are conquered by the Egyptian pharaoh Thutmose. Small bottles, to hold precious oils for cosmetic purposes, become treasured items in rich Egyptian households. The body of the vessel is usually a transparent blue, sometimes decorated with thread-like rings of white, yellow or green applied to the surface.

Glass is an expensive rarity, and remains so in Egypt and elsewhere (Mesopotamia, Greece, Persia) until Roman times. The change to a more widely available household material results from another breakthrough in Glass technology - again in Phoenicia, now transformed into Roman syria.

Sundial and water clock: from the 2nd millennium BC

The movement of the sun through the sky makes possible a simple estimate of time, from the length and position of a shadow cast by a vertical stick. (It also makes possible more elaborate calculations, as in the attempt of Erathosthenes to measure the world - see Erathosthenes and the camels). If marks are made where the sun's shadow falls, the time of day can be recorded in a consistent manner.

The result is the sundial. An Egyptian example survives from about 800 BC, but the principle is certainly familiar to astronomers very much earlier. However it is difficult to measure time precisely on a sundial, because the sun's path throug the sky changes with the seasons. Early attempts at precision in time-keeping rely on a different principle.

The water clock, known from a Greek word as the clepsydra, attempts to measure time by the amount of water which drips from a tank. This would be a reliable form of clock if the flow of water could be perfectly controlled. In practice it cannot. The clepsydra has an honourable history from perhaps 1400 BC in Egypt, through Greece and Rome and the Arab civlizations and China, and even up to the 16th century in Europe. But it is more of a toy than a timepiece.

The hourglass, using sand on the same principle, has an even longer career. It is a standard feature on 18th-century pulpits in Britain, ensuring a sermon of sufficient length. In a reduced form it can still be found timing an egg.


Glazed ceramics: 9th - 1st century BC

In all the early civilizations, from Mesopotamia and Egypt onwards, pottery is a highly developed craft. An outstanding achievement is the Greek ceramic tradition of the 6th and 5th century BC. But technically all these pots suffer from a major disadvantage. Fired earthenware is tough but it is porous. Liquid will soak into it and eventually leak through it. This has some advantages with water (where evaporation from the surface cools the contents of the jug) but is less appropriate for storing wine or milk.

The solution is the addition of a glaze. This technological breakthrough is made in Mesopotamia in the 9th century BC for decorative tiles. It is not adapted for practical everyday purposes until many centuries later.

A glaze is a substance, applied to the inner or outer surface of an unfired pot, which vitrifies in the kiln - meaning that it forms a glassy skin, which fuses with the earthenware and makes it impermeable to liquids.

But glazes, which can be of any colour, also have a highly decorative quality. It is for this purpose that they are first developed, as a facing for ceramic tiles, in Mesopotamia from the 9th century BC. The most famous examples are from the 6th century palace of Nebuchadnezzar in Babylon.

Glazed pots make their appearance in the Middle East in about the 1st century BC, possibly being developed first in Egypt. The characteristic colour is green, from copper in the glaze. Pottery of this kind is common in imperial Rome a century later.

By this time glazed pottery is also being manufactured in Han dynasty China. It may be that the development occurs independently in the Middle East and in China, but by now there could also be a direct influence in either direction. Rome and China are already linked by the Silk road, and glazed ceramics are attractive commodities.

Lock and key: c.710 BC

In Assyria, at Khorsabad, an expensive wooden bolt is installed in the new palace of Sargon II. It is the world's earliest surviving lock.

Within the bolt are several holes. When the bolt is pushed home, wooden pins fall down into these holes from within the frame of the door, holding the bolt fast. The only way of releasing it is to insert a key, shaped like a tooth brush, into a hollow cavity in the bolt below the pin holes. The key has projecting pins in the necessary pattern. When pressed upwards they will raise the other pins, allowing the bolt to be withdrawn.

6th century BC


Persian carpets: 6th century BC

Persian emperors of the 6th century BC are among the first to make a display of lavish floor coverings. Carpets becomes one of the characteristic art forms of people living on the high plateau of west Asia, from Turkey through Iran, where winters can be extremely cold.

They are a particularly important form of wealth and comfort for the nomadic tribes which live in these regions and in the steppes to the north. One of the earliest true carpets to survive (woven with a knotted pile, and Persian in origin) belongs to a tribal ruler in about 500 BC. It is discovered in his frozen tomb at Pazyryk.

Lacquer: c.500 BC

The Chinese discover that the sap of a tree, Rhus vernicifera, has unusual qualities. It can be applied in successive layers to wooden objects, such as dishes and boxes, and each layer can be hardened by exposure to moisture.

The resulting surface, so hard that it is not corroded by acid, can be brought to a very smooth polish, or decorated with gold and silver dust, or delicately carved to reveal the successive layers beneath. This technique of lacquer, adopted also in Japan by the 6th century AD, provides one of the most highly valued commodities of the orient.

Greece


Electricity and magnetism: 5th century BC

Two natural phenomena, central to the study of physics, are observed and speculated upon by Greek natural scientists - probably in the 5th century BC, though Aristotle gives credit for the first observation of each to the shadowy figure of Thales.

One such phenomenon is the strange property of amber. If rubbed with fur it will attract feathers or bits of straw. Modern science, in its terms for the forces involved, acknowledges this Greek experiment with amber (electron in Greek). The behaviour of the amber is caused by what we call Electricity, resulting from the transfer of what are now known as electrons.

The other natural phenomenon, observed in lodestone rather than Amber, also derives its scientific name from Greek experiments. Lodestone is a naturally occurring mineral (formed of iron oxide), and it will surprisingly attract small pieces of iron. .

The Greeks find this mineral in a region of Thessaly called Magnesia. They call it lithos magnetis, the 'stone of Magnesia'. Thus the magnet is identified and named, though like rubbed Amber it will only be a source of interest and amusement for the next 1000 years and more - until a practical purpose is found for it in the form of the Compass.

Distillation: 4th century BC

The principle of distillation is probably in use long before it is applied to the production of alcohol. Greek sailors of the 4th century BC know how to derive fresh water from the sea, by boiling salt water and suspending a sponge in the steam (pure water condenses in the sponge).

The distillation of alcohol is possible because it boils at a lower temperature than water. In the simplest form of still, the alcohol vapour condenses on a cold surface held in the steam. Subsequent improvements, achieved at various places and different times, involve channelling the steam into a separate condenser and cooling it in such a way as to separate any intrusive water vapour from the alcohol.

Pulley: 4th century 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 with more pulleys.

Mechanical organ: 3rd century BC

Pipes of varying sorts are among the earliest of musical instruments, and pipers must often have imagined a pipe too large for human lungs. A scientist in Alexandria, by the name of Ctesibius, is credited with being the first to invent an organ - with a hand-operated pump sending air through a set of large Pipes. Each pipe is played by pressing a note on a board. This is the beginning of Keyboard instruments.

By the time of the Roman empire, a few centuries later, the organ is a familiar and popular instrument - playing a prominent part in public games and circuses as well as private banquets. The emperor Nero, an enthusiastic performer, is proud of his talents on the organ.

Archimedes: water and specific gravity c.250 BC

Archimedes, working in Syracuse in the 3rd century BC, features in popular tradition as one of the most practical of Greek mathematicians. His study of spirals is reflected in the simple irrigation machine known as the Screw of Archimedes.

The legend is that the king of Syracuse, Hiero II, is troubled by the problem of how to get water out of the hold of a large ship. He turns to the local genius, who devises a spiral watertight tube, inclined at an angle with its lower end in the water. When it is turned, the effect of the spiral is to raise the water. As if by magic, it pours out at the top end.

Another problem confronting the king proves equally stimulating to the scientist's inventive faculties. Hiero suspects that he may have been cheated by his goldsmiths. He has ordered a crown of pure gold. How can he be certain, when it is delivered, that it has not been adulterated with some cheaper silver?

He asks Archimedes, who - the story goes - is nonplussed until he steps into his bath.

The overflow of water from the bath gives Archimedes the solution to the problem. His body displaces a certain amount of water. Another object, of the same weight but more dense, will displace less water. Archimedes only has to immerse an ingot of pure gold of the same weight as the crown. If it and the crown displace the same amount, then the crown too is pure gold.

The popular legend accurately reflects an important discovery about specific gravity - and naturally dresses it up in lively detail. The scientist is so excited that he leaps from his bath and runs naked down the street crying eureka (Greek for 'I have found it').

Cement: c.200 BC

Builders in Greek cities on the coast of Turkey (and in particular Pergamum) evolve cement in about 200 BC as a structural material, in place of weaker mortars such as gypsum plaster (used in Egypt) or bitumen (in Mesopotamia). The secret of the new material is the lime which binds sand, water and clay.

The Romans subsequently use finely ground volcanic lava in place of clay, deriving it mainly from the region of Pozzuoli. Their cement, known for this reason as pozzolanic, is the strongest mortar in history until the development of Portland cement. When small fragments of volcanic rubble are included, the result is concrete - making possible the great arches and aqueducts of Roman architecture, and playing its part in Roman roads.

Development of the stirrup: 2nd century BC - 7th century AD

It is probable that early Nomadic horsemen, such as the Scythians, use some form of looped fabric to support their feet. But the first direct evidence of a stirrup is a loop for the big toe used by Indian cavalry from the 2nd century BC. Suitable only for use by barefoot warriors in warm climates, this device spreads gradually through southeast Asia.

At some time before the 5th century AD the Chinese, who need to keep their boots on, transform the toe loop into a metal stirrup for the whole foot. From China this crucial device moves westwards, through Iran to the Muslim world in the 7th century, and then through the Byzantine empire to western Europe.

Pergamum and parchment: 2nd century BC

During the 2nd century BC people in the region of the Mediterranean begin using a much more expensive alternative to papyrus. Tradition credits its invention to Eumenes II, who rules in Pergamum on the west coast of Turkey from 197 to 159 BC. The substance is parchment (the word derives from a variation of Pergamum). It is a form of leather.

Ordinary leather has occasionally been used for these purposes since about 2500 BC, but only one side can be written on. With parchment both sides are treated and rubbed until smooth, to form a flexible double surface.

It is not until much later, in the second century AD, that parchment becomes a serious rival to papyrus. But from the 4th until the 15th centuries it is the standard writing surface of medieval European scribes. It is the material used in all the famous illuminated manuscripts produced in the monasteries.

For the most expensive books a softer and finer version is often used, known as vellum and made from the hides of young or sometimes unborn calves, kids and lambs.

Parchment is strong and flexible enough for separate pages of a manuscript to be sewn together down one side, to form the spine of a book. This shape, whether in a manuscript codex or printed book, represents a massive advance in the efficiency of written communication.

In a Papyrus scroll a quick glance at another part of the text involves much unrolling and rolling up. Within a codex or book the reader can move about freely. Modern habits of information retrieval become possible (index references to numbered pages, slips of paper inserted to mark one's place). They will remain familiar in the west for a millennium and a half - until eventually improved upon by digital methods.

Astrolabe: c.140 BC

The astrolabe (meaning 'star taker') is arguably the world's oldest scientific instrument. It is often credited as an invention to Hipparchus, a leading Greek astronomer of the 2nd century BC.

The astrolabe measures the angle of the sun or of a star above the horizon and provides a chart (in later examples often beautifully engraved in metal) showing the heavens at differing latitudes and times. The altitude of the Pole Star will reveal the observer's latitude, in relation to which the position of sun and stars will give the time of day or night. The instrument is therefore of great use to sailors, until eventually replaced in the 18th century by the Sextant.

Glassblowing: c.50 BC

The craftsmen of Phoenicia maintain their pre-eminence in Glass technology when they discover, in the 1st century BC, how to produce glass vessels in large quantities. Instead of the laborious processes of building up molten glass around a core, or casting it in prepared moulds, the new method is one of startling originality. And it offers potential for very skilled work.

The Phoenicians discover that if a blob of molten glass is fixed to the end of a tube, air blown through the tube will form the blob into a hollow vessel. By turning the tube and controlling the pressure of his breath, the glassblower can vary the shape of the developing vase.

The new technology comes within a few years of Pompey bringing this region of the Middle East under Roman control, as the province of Syria. As a result, glass spreads rapidly through the Roman empire.

As a standard household commodity, produced in fairly large quantities, this glass is often of relatively poor quality. But at the top end of the market the skills of the glass-blowers rapidly reach extraordinary standards - making, for example, glass in which one colour is blown within another and the outer skin is partially engraved away to provide a cameo scene. The famous Portland Vase, dating from about 25 BC, is an outstanding example of this technique.

Greek atmospheric devices: 1st century AD

Hero, a mathematician in Alexandria in about AD 75, enjoys inventing mechanical gadgets, which he describes in his work Pneumatica. Whether he has the technology to make them we do not know, but his scientific principles are correct.

One such gadget is a primitive version of a steam turbine. Hero says steam should be directed into a hollow globe with outlets through nozzles on opposite sides of the circumference. The nozzles are directed round the rim of the globe. As the steam rushes out, like sparks from a catherine wheel, the globe spins.

Hero makes another significant use of atmospheric pressure in a magic altar, putting to work the expansion and contraction of air. A fire heats the air in a container, causing it to expand and force water up a tube into a bucket. The increased weight of the bucket opens the doors of an altar. When the fire is extinguished, the air contracts, the water in the bucket is sucked out and the doors close.

Any temple managing to work this trick is certain to attract more pilgrims, and more money, than its rivals.

The discovery of paper: AD 105

Chinese tradition attributes one of the most wide-reaching of inventions to a eunuch at the imperial court, by the name of Cai Lun, in the year AD 105.

Cai Lun may merely have presented the emperor with a report on the new substance, but certainly paper is produced in China in the second century AD. Fragments of it survive, made from rags and the fibres of mulberry, laurel and Chinese grass.

To make a sheet of paper these substances are repeatedly soaked, pounded, washed, boiled, strained and bleached. The mush is left to drain in a mesh frame and then dried. The result is thinner and more flexible than Papyrus or Parchment, and much more adaptable to methods of large-scale production.

This desirable secret takes 1000 years to reach Europe.

Knitting: from the 3rd century AD

Knitting, as a concept, is very simple but extremely hard to imagine. It is likely, therefore, to be one of the few technological developments in ancient history to have an actual inventor. As a challenge to the inventive mind, the problem ('Transform a continuous thread into a piece of fabric without at any point cutting the thread') still seems difficult.

The likelihood of a single moment of invention is also made more probable by the late arrival of knitting. Even though it makes no technological demands (neolithic communities could provide a skein of wool and two long needles), civlization is 3000 years old before the first row is knitted.

Knitting first appears in the Roman empire, in the 3rd century AD. The earliest examples to survive are socks (found in tombs in Egypt), and it is in footwear that the advantages of the new technology are most obvious.

Until this time feet have usually been kept warm and protected within the shoe by wrapping them in strips of cloth or leather. In the 2nd century AD the Romans evolve a tailored sock, made of pieces of cloth sewn together. But these lack the elasticity of a knitted fabric. Eventually the demand for knitted stockings is so great that the first Knitting machine, devised in 1589, is an early landmark of the Industrial Revolution.

Middle Ages


Windmills: 9th - 15th century AD

The first practical windmills are constructed in or before the 9th century in a region spanning eastern Iran and western Afghanistan. They are descibed in a manuscript by Estakhri, a Persian georgrapher of that period, as having horizontal sails, like the blades of a helicopter, directly linked by a vertical shaft to the millstones turning below. The date of the first windmill is often given as 644 or earlier, because a 9th-century document says that the man who in that year assassinated the caliph Omar in the mosque at Medina was a Persian builder of windmills. But a first mention of this two centuries after the event makes it unlikely to be true.

Windmills are first mentioned in Europe in the 12th century. There is a reference to one in France in 1180, and a few years later to another in England. Since this is the time of the crusades, it is likely that the idea has been brought from the Middle East.

The European windmills of the 12th and 13th century have upright sails, of the kind still familiar today. They require simple gearing, to transmit the power to the vertical shaft which will turn the millstones. And they have to be able to turn through 360 degrees so that the sails can face the wind.

In these first versions the entire working mill, complete with the millstones, has to be turned into the wind by pressure from ground level on a long pole. For this to be possible the mill structure has to sit on a sturdy vertical post, giving such mills their name - post mills.

By the 14th century there are windmills of a new design in France. Known as tower mills, they can be larger and more rigid than the earlier post mills. Now only the top part of the structure rotates. Holding the horizontal axle of the sails, it sits like a loose cap on top of the mill tower. It can be turned either by the traditional pole, from outside, or by a lever within the cap.

By the 15th century windmills are common in Europe, though rarely as economical as the watermill. The exception is the Netherlands, where there is plenty of wind and a great deal of surplus water to be lifted from low-lying areas - the original purpose of the Dutch windmills.

Greek fire: AD 674

In 674 a Muslim fleet enters the Bosphorus to attack Constantinople. It is greeted, and greatly deterred, by a new weapon which can be seen as the precursor of the modern flamethrower. It has never been discovered precisely how the Byzantine chemists achieve the jet of flame for their 'Greek fire'. The secret of such a lethal advantage is jealously guarded.

Contemporary accounts imply that the inflammable substance is petroleum-based, floats on water, and is almost impossible to extinguish. It can be lobbed in a canister. But in its most devastating form it is projected, as a stream of liquid fire, from a tube mounted in the prow of a ship. Sprayed among a wooden fleet, its destructive potential is obvious.

Printed Buddhist texts in Korea and Japan: AD 750-768

The invention of printing is a striking achievement of Buddhists in east Asia. Korea takes the lead. The world's earliest known printed document is a sutra printed on a single sheet of paper in Korea in750.

This is closely followed in Japan by a bold experiment in mass circulation (precisely the area in which printed material has the advantage over manuscript). In768, in devoutly Buddhist Nara, the empress commissions a huge edition of a lucky charm or prayer. It is said that the project takes six years to complete and that the number of copies printed, for distribution to pilgrims, is a million. Many have survived.

Gunpowder: 11th century

In about 1040 a Chinese manual on warfare is issued under the title Compendium of Military Technology. It is the first document to describe gunpowder. This black powder, formed by pounding a mixture of saltpetre, charcoal and sulphur (a dangerous process if the pounding is overdone), seems to have been developed in the small chemical laboratories attached to the temples of Daoists where research is conducted mainly on the secret of eternal life.

At this early stage in China the military use of gunpowder is limited to grenades and bombs lobbed at the enemy from catapults. Its real destructive force will only emerge when the explosion is confined, in the development of Artillery.

Movable type: from the 11th century

Movable type (separate ready-made characters or letters which can be arranged in the correct order for a particular text and then reused) is a necessary step before Printing can become an efficient medium for disseminating information.

The concept is experimented with in China as early as the 11th century. But two considerations make the experiment unpractical. One is that the Chinese script has so many characters that type-casting and type-setting become too complex. The other is that the Chinese printers cast their characters in clay and then fire them as pottery, a substance too fragile for the purpose.

Compass: 11th century

At some time before 1100 it is discovered that a magnet, if allowed to move freely, will turn so that one end points to the north. Free movement is difficult to achieve, since the natural source of magnetism is a heavy mineral (Lodestone or magnetite).

But a fine iron needle can be magnetized by contact with a Lodestone, and such a needle is light enough to be attached to a sliver of wood and floated on water. It will then drift into a position which identifies the north - providing invaluable information to seafarers in cloudy weather.

There has been much argument about where the compass is first developed. The earliest reference to such a device is in a Chinese manuscript of the late 11th century; within the next 150 years it features also in Arabic and European texts. This is too short a time span to prove the priority of China, given the random nature of the surviving references.

The crucial fact is that this instrument is available to make possible the great age of Maritime exploration which begins in the 15th century - though as yet no-one understands why a magnet Points to the north.

A tower clock in China: AD 1094

After six years' work, a Buddhist monk by the name of Su Song completes a great tower, some thirty feet high, which is designed to reveal the movement of the stars and the hours of the day. Figures pop out of doors and strike bells to signify the hours.

The power comes from a water wheel occupying the lower part of the tower. Su Song has designed a device which stops the water wheel except for a brief spell, once every quarter of an hour, when the weight of the water (accumulated in vessels on the rim) is sufficient to trip a mechanism. The wheel, lurching forward, drives the machinery of the tower to the next stationary point in a continuing cycle.

This device (which in Su Sung's tower must feel like a minor earthquake every time it slams the machinery into action) is an early example of an escapement - a concept essential to mechanical Clockwork. In any form of clock based on machinery, power must be delivered to the mechanism in intermittent bursts which can be precisely regulated. The rationing of power is the function of the escapement. The real birth of mechanical Clockwork awaits a reliable version, developed in Europe in the 13th century.

Meanwhile Su Sung's tower clock, ready for inspection by the emperor in 1094, is destroyed shortly afterwards by marauding Barbarians from the north.

Spectacles: from the 13th century AD

During the 13th century it is discovered that a crystal with a curved surface can help the elderly to read. Mounted in a holder, such a lens is simply a small magnifying glass. The philosopher-scientist Roger Bacon refers to the use of a lens in a text of 1268. At this time it would be shaped and smoothed from a lump of quartz.

Soon (probably in Florence during the 1280s) the idea evolves of placing two lenses in a frame which can be held in front of the eyes. It is a natural next step to perch this frame on the nose. Spectacles, hinged at the centre to grip the nose, appear quite frequently in paintings of the 15th century.

As demand increases, glass replaces quartz as the material for lenses and the trade of the lens-grinder becomes one of great skill and importance.

Early spectacles all use convex lenses to redress long sight (difficulty in seeing things which are close). By the 16th century it is discovered that concave lenses will compensate for short sight (difficulty in seeing distant objects). The two everyday forms of spectacle have been achieved.

Clockwork in Europe: 13th - 14th century AD

Europe at the end of the Middle Ages is busy trying to capture time. The underlying aim is as much astronomical (to reflect the movement of the heavenly bodies) as it is to do with the more mundane task of measuring everybody's day. But the attraction of that achievement is recognized too. A textbook on astronomy, written by 'Robert the Englishman' in 1271, says that 'clockmakers are trying to make a wheel which will make one complete revolution' in each day, but that 'they cannot quite perfect their work'.

What prevents them even beginning to perfect their work is the lack of an escapement. But a practical version of this dates from only a few years later.

A working escapement is invented in about 1275. The process allows a toothed wheel to turn, one tooth at a time, by successive teeth catching against knobs projecting from an upright rod which oscillates back and forth. The speed of its oscillation is regulated by a horizontal bar (known as a foliot) attached to the top of the rod. The time taken in the foliot's swing can be regulated by moving weights in or out on each arm.

The function of the foliot is the same as that of the pendulum in modern clocks, but it is less efficient in that gravity is not helping it to oscillate. A very heavy weight is needed to power the clock, involving massive machinery and much friction.

Nevertheless the foliot works to a degree acceptable at the time (a clock in the Middle Ages is counted a good timekeeper if it loses or gains only a quarter of an hour a day), and in the 14th century there are increasingly frequent references to clocks in European cities. A particularly elaborate one is built between 1348 and 1364 in Padua by Giovanni de' Dondi, a professor of astronomy at the university who writes a detailed description of his clock. A 14th-century manuscript of his text has the earliest illustration of a clock mechanism with its escapement.

The world's three oldest surviving examples of clockwork date from the last years of the 14th century.

The famous clock in Salisbury cathedral, installed by 1386 and still working today with its original mechanism, is a very plain piece of machinery. It has no face, being designed only to strike the hours. Striking is the main function of all early clocks (the word has links with the French cloche, meaning 'bell').

In 1389 a great clock is installed above a bridge spanning a street in Rouen. It remains one of the famous sights of the city, though its glorious gilded dial is a later addition and its Foliot has been replaced by a pendulum (in 1713). The historical distinction of the Rouen clock is that it is the first machine designed to strike the quarter-hours.

In 1392 the bishop of Wells instals a clock in his cathedral. The bishop has previously been in Salisbury, and the same engineer seems to have made the new clock. It not only strikes the quarters. It steals a march on Rouen by having a dial, showing the movement of astronomical bodies.

With escapements, chiming mechanisms and dials, clocks are now set to evolve into their more familiar selves. And the telling of time soon alters people's perceptions of time itself. Hours, minutes and seconds are units which only come into existence as the ability to measure them develops.

Artillery: 14th - 16th century AD

The most significant development in the story of warfare is the use of Gunpowder to propel a missile. There has been much debate as to where the first experiments are made. Inconclusive and sometimes mistranslated references from early documents appear to give the priority variously to the Chinese, the Hindus, the Arabs and the Turks.

It is likely that the matter can never be resolved. The earliest incontrovertible evidence of artillery is a drawing of a crude form of cannon in a manuscript dated 1327 (now in the library of Christ Church, Oxford). There is a reference to a gun Mounted on a ship in 1336, and the possibility of cannon of some kind in use at Crécy and Calais in 1346-7.

The problem confronting early makers of artillery is how to construct a tube strong enough to contain an explosion which will propel a missile out of one end (or, in other words, how to make a gun rather than a bomb). An early solution gives us our word 'barrel'. The tube is built up of metal strips welded to each other along their straight edges - just as a barrel is constructed of similar strips of wood. This rather fragile structure is given greater strength by being encased in a series of tightly fitting metal rings.

With luck, a round stone (or later a ball of cast iron) will hurtle from the open end of this tube when Gunpowder is ignited behind it.

The laborious loading and firing of such weapons limits their effective use to sieges - either inside a castle defending an entrance, or outside lobbing heavy objects at the walls. The size of the missile rather than its speed is the crucial factor. A breakthrough in this respect, in the late 14th century, is the discovery of how to cast gun barrels from molten Iron.

Cannon, during the next two centuries, become progressively larger. There are some impressive surviving examples. Mons Meg, dating from the 15th century and now in Edinburgh castle, could hurl an Iron ball, 18 inches in diameter, as far as a mile. The even larger Tsar Cannon in Moscow, cast in 1586 with a bore of 3 feet, weighs nearly 40 tons. Mobility is not one of its features.

One of the most remarkable of early cannon is a proud possession of Mehmed, the Turkish conqueror of Constantinople. Before his final attack in 1453 he terrifies the inhabitants by trundling close to their city a massive 19-ton bombard of cast Iron. It requires 16 oxen and 200 men to manoeuvre it into its firing position. Once there, it settles down to a slow but devastating bombardment. A stone weighing as much as 600 pounds can be lobbed against the great city walls. The rate of fire is seven stones a day.

In this same same year, at Castillon in France, another potential of gun power is demonstrated - in the effect of light artillery on the battlefield.

Hand guns: 14th - 17th century AD

Portable guns are developed shortly after the first cannons. When first mentioned, in the 1360s, such a gun is like a small version of a cannon. A metal tube, up to a foot long, is attached to the end of a pole about six feet in length - an early and very basic version of the barrel and stock of a rifle.

The gunner has to apply a glowing coal or a red-hot wire to a touchhole in the loaded barrel, and then somehow get far enough away from the explosion. There is clearly not much opportunity for rapid aiming. Most such weapons are probably fired by two men, or are carried to a new position and fixed there before being loaded and ignited by one.

Refinements follow surprisingly fast. During the 15th century the barrel of such weapons is lengthened, giving more reliable aim. The wooden stock acquires a curve, so that the recoil raises the barrel rather than driving backwards with full force. A length of rope known as a 'match' replaces the hot coal or wire for igniting the charge in the touchhole; it is soaked in a substance which causes it to burn with a steady glow.

And a device called a 'lock' is developed - a curving arm of metal which holds the glowing match and will plunge it into the touchhole, when a pull on a trigger releases a spring. The 'matchlock' becomes the standard form of musket until the arrival of the Flintlock in the 17th century.

Type foundry in Korea: c. 1230

In the early 13th century, more than 200 years before Gutenberg’s innovation in Europe, the Koreans establish a foundry to cast movable type in bronze. Unlike earlier Chinese experiments with pottery, bronze is sufficiently strong for repeated printing, dismantling and resetting for a new text.

With this technology the Koreans create, in 1377, the world’s earliest known book printed from movable type. Known as Jikji, it is a collection of Buddhist texts compiled as a guide for students. Only the second of the two published volumes survives (held at present in the National Library of France). It reveals not only the date of its printing but even the names of the priests who assisted in the compiling of the type.

The Koreans at this time are using the Chinese script, so they have the problem of an unwieldy number of characters. They solve this in 1443 by inventing their own national Alphabet, known as han'gul. By one of the strange coincidences of history this is precisely the decade in which Gutenberg is experimenting with movable type far away in Europe, which has enjoyed the advantage of an Alphabet for more than 2000 years.

A keyboard for strings: AD 1397

In a manuscript of 1397 it is reported that a certain Hermann Poll has invented a clavicembalum or harpsichord. In doing so he has adapted the keyboard (long familiar in the Organ) to the playing of strings. Whether or not Poll is its actual inventor, the harpsichord rapidly becomes a successful and widespread instrument. It stands at the start of the tradition which will eventually make keyboard music a part of everyday life.

But the harpsichord has one limitation. However hard or softly the player strikes the key, the note sounds the same; the action merely releases a device to pluck the string. For playing soft or loud, a further development is needed - the Pianoforte.

15th - 16th century


Gutenberg and western printing: AD 1439 - 1457

The name of Gutenberg first appears, in connection with printing, in a law case in Strasbourg in 1439. He is being sued by two of his business partners. Witnesses, asked about Gutenberg's stock, describe a press and a supply of metal type. It sounds as though he is already capable of printing small items of text from movable type, and it seems likely that he must have done so in Strasbourg. But nothing from this period survives.

By the time he is next heard of in connection with printing, he is in Mainz. He borrows 800 guilders in 1450 from Johann Fust with his printing equipment as security. The resulting story of Gutenberg and Fust is a saga in itself.

Gutenberg's great achievement in the story of printing has several components. One is his development of the printing Press, capable of applying a rapid but steady downward pressure. The concept of the Press is not new. But existing presses (for wine, oil or paper) exert slow pressure - uneconomical in printing.

More significant are Gutenberg's skills with metal (his original trade is that of a goldsmith). These enable him to master the complex stages in the manufacture of individual pieces of Type, which involve creating a master copy of each letter, devising the moulds in which multiple versions can be cast, and developing a suitable alloy (Type metal) in which to cast them.

No date appears in the Gutenberg Bible (known technically as the 42-line Bible), which was printed simultaneously on six presses during the mid-1450s. But at least one copy is known to have been completed, with its initial letters coloured red by hand, by 24 August 1456. The first dated book from these same presses, in 1457, is even more impressive. Known as the Mainz psalter, it achieves outstanding colour printing in its two-colour initial letters.

These first two publications from Germany's presses are of an extraordinary standard, caused no doubt by the commercial need to compete with manuscripts. The new technology, so brilliantly launched, spreads rapidly.

All this skilful technology precedes the basic work of printing - that of arranging the individual letters, aligned and well spaced, in a forme which will hold them firm and level to transfer the ink evenly to the paper.

The printing process involves complex problems at every stage, and the brilliance of the first known products from Gutenberg's Press suggest that earlier efforts must have been lost. If not, the decision to make his first publication a full-length Bible in Latin (the Vulgate), printed to the standards of the best Black-letter manuscripts, is a bold one indeed.

Domestic clocks: 15th century AD

After the success of the clocks in Europe's cathedrals in the late 14th century, and the introduction of the clock face in places such as Wells, kings and nobles naturally want this impressive technology at home.

The first domestic clocks, in the early 15th century, are miniature versions of the cathedral clocks - powered by hanging weights, regulated by escapements with a Foliot, and showing the time to the great man's family and household by means of a single hand working its way round a 12-hour circuit on the clock's face. But before the middle of the 15th century a development of great significance occurs, in the form of a spring-driven mechanism.

The earliest surviving spring-driven clock, now in the Science Museum in London, dates from about 1450. By that time clockmakers have not only discovered how to transmit power to the mechanism from a coiled spring. They have also devised a simple but effective solution to the problem inherent in a coiled spring which steadily loses power as it uncoils.

The solution to this is the fusee.

The fusee is a cone, bearing a spiral of grooves on its surface, which forms part of the axle driving the wheels of the clock mechanism. The length of gut linking the drum of the spring to the axle is wound round the fusee. It lies on the thinnest part of the cone when the spring is fully wound and reaches its broadest circumference by the time the spring is weak. Increased leverage exactly counteracts decreasing strength.

These two devices, eliminating the need for weights, make possible clocks which stand on tables, clocks which can be taken from room to room, even clocks to accompany a traveller in a carriage. Eventually, most significant of all, they make possible the Pocket watch.

The first globe: AD 1492

One of the most unfortunate innovators in the history of invention is Martin Behaim, the creator of the world's first globe - made in Nuremberg in 1492.

His idea is excellent. A globe is the only accurate way of representing the surface of the earth. His misfortune is to base his globe on Ptolemy (who postulates a single ocean between Spain and China) and to achieve his three-dimensional version of this notion in the very year in which it is disproved - by Columbus reaching America. But Behaim shows the reason for Columbus's confidence in sailing west. The distance on his globe between Spain and China is only half what it should be.

Stocking frame: AD 1589

The world's first piece of industrial machinery is invented in 1589 by an English clergyman in Nottinghamshire. Tradition maintains that his inspiration derives from annoyance at his loved one being so busy with her knitting whenever he comes courting. The frustrated lover, William Lee, duly invents a knitting machine.

His device, known as the stocking frame, depends upon a needle with a hook which opens and closes at successive stages of the process to imitate the procedure of the hand-knitter. Lee's type of needle (known as the beard or bearded spring needle) is still a feature of the machines used in modern industrial knitting.

Elizabeth I refuses Lee a patent for his stocking frame, partly on the far-sighted grounds that it may damage the trade of hand-knitters. Lee then takes his machines to France, on the invitation of Henry IV, but they are brought back to England after the assassination of the French king in 1610.

Framework knitting gradually becomes established, and the Worshipful Company of Framework Knitters is given a charter by Charles II in 1663. The growth in the number of machines over the next two centuries reflects the gathering pace of the Industrial revolution. There are some 650 stocking frames in Britain in 1660, and about 43,000 in 1844.

The knitting machine also provides an early instance of the Luddite tendency, as the threat predicted by Elizabeth becomes an increasingly evident reality.

As early as 1710, in Spitalfields in London, stocking frames are thrown out of the window of a small factory during a dispute between the knitters and the owners of the frames.

Microscope and telescope: AD 1590-1608

The principle of the microscope and of the telescope is identical - that two lenses, placed in line at the correct focal distance, will enlarge a detail of what is being looked at. With the microscope this enlargement reveals features too small for the unaided human eye to focus on and perceive. With the telescope the enlargement brings closer an object too distant for the naked eye to see with any precision.

This effect is a likely one for lens grinders and specacle makers to stumble upon in the course of their business. Its discovery seems to have been made in this way in the Netherlands in the late 16th or early 17th century.

Tradition credits the discovery of the microscope to Zacharias Janssen in 1590 and of the telescope to Hans Lippershey in 1608. Both men are spectacle makers in the town of Middelburg. Tradition even provides the happy event which brings to Lippershey's notice the concept of the telescope.

One day, with a lens in each hand, Lippershey happens to hold them in line with the steeple of a nearby church. On looking more closely at the nearer lens, he sees the weathercock in surprising detail.

Once the principle has been recognized, it is a simple matter to mount two lenses in a sealed tube to make a telescope (from words meaning 'far' and 'look at' in Greek). Such toys, for such they must have seemed, are soon on sale in large numbers in Amsterdam. But when news of this invention reaches Galileo in Venice, in 1609, he rapidly turns the idea to more serious purposes.

The microscope has to wait rather longer until it is put to the service of science - by the Italian biologist Malpighi in 1661.

The flintlock: 16th - 18th century AD

From the middle of the 16th century there are attempts to ignite the powder in the pan of a musket by means of a spark rather than from an already burning match. The flintlock is poised to replace the Matchlock.

In a flintlock the spark is created by striking a sharp flint obliquely against a surface of slightly roughened steel (the device is already in domestic use in the Tinderbox). Just as the trigger in a Matchlock brings down the smouldering match, so it now uses the same action to strike the flint down sharply above the pan with its charge of gunpowder.

European countries develop their own differing versions of the flintlock. The one which eventually becomes standard is designed in France in about 1610 - possibly by Marin Le Bourgeoys, whose name is on a flintlock in the private collection of Louis XIII.

The French flintlock has the advantage of a halfcock position (with the gun ready to fire but safe), and its method of directing the spark into the pan proves reliable. By the 18th century it is the standard musket throughout most of Europe and in the American colonies. Spanish armies are the only ones to retain their own variety of flintlock, known as the miquelet.

17th century


Barometer and atmospheric pressure: AD 1643-1646

Like many significant discoveries, the principle of the barometer is observed by accident. Evangelista Torricelli, assistant to Galileo at the end of his life, is interested in why it is more difficult to pump water from a well in which the water lies far below ground level. He suspects that the reason may be the weight of the extra column of air above the water, and he devises a way of testing this theory.

He fills a glass tube with mercury. Submerging it in a bath of mercury, and raising the sealed end to a vertical position, he finds that the mercury slips a little way down the tube. He reasons that the weight of air on the mercury in the bath is supporting the weight of the column of mercury in the tube.

If this is true, then the space in the glass tube above the mercury column must be a vacuum. This plunges him into instant controversy with traditionalists, wedded to the ancient theory - going as far back as Aristotle - that 'nature abhors a vacuum'. But it also encourages Von guericke, in the next decade, to develop the vacuum pump.

The concept of variable atmospheric pressure occurs to Torricelli when he notices, in 1643, that the height of his column of mercury sometimes varies slightly from its normal level, which is 760 mm above the mercury level in the bath. Observation suggests that these variations relate closely to changes in the weather. The barometer is born.

With the concept thus established that air has weight, Torricelli is able to predict that there must be less atmospheric pressure at higher altitudes. It is not hard to imagine an experiment which would test this, but the fame for proving the point in 1646 attaches to Blaise Pascal - though it is not even he who carries out the research.

Having a weak constitution, Pascal persuades his more robust brother-in-law to carry a barometer to different levels of the 4000-foot Puy de Dôme, near Clermont, and to take readings. The brother-in-law descends from the mountain with the welcome news that the readings were indeed different. Atmospheric pressure varies with altitude.

The pendulum clock: AD 1656-1657

Christiaan Huygens spends Christmas day, in the Hague in 1656, constructing a model of a clock on a new principle. The principle itself has been observed by Galileo, traditionally as a result of watching a lamp swing to and fro in the cathedral when he is a student in Pisa. Galileo later proves experimentally that a swinging suspended object takes the same time to complete each swing regardless of how far it travels.

This consistency prompts Galileo to suggest that a pendulum might be useful in clocks. But no one has been able to apply that insight, until Huygens finds that his model works.

A craftsman in the Hague makes the first full-scale clock on this principle for Huygens in 1657. But it is in England that the idea is taken up with the greatest enthusiasm.

By 1600 London clockmakers have already developed the characteristic shape which makes best use of the new mechanism - that of the longcase clock, more affectionately known as the grandfather clock.

The pocket watch: AD 1675

Nineteen years after making his model of the pendulum clock, Huygens invents a device of equal significance in the development of the watch. It is the spiral balance, also known as the hairspring (an invention also claimed, less convincingly, by Robert Hooke). This very fine spring, coiled flat, controls the speed of oscillation of the balance wheel. For the first time it is possible to make a watch which is reasonably accurate - and slim.

Both elements are important, for the sober gentlemen of the late 17th century are less inclined than their ancestors to wear Jewels round the neck. A watch which will keep the time and slip into a waistcoat pocket is what they require.

Thomas Tompion, the greatest of English clock and watchmakers, is one of the first to apply the hairspring successfully in pocket watches (of which his workshop produces more than 6000 in his lifetime). The new accuracy of these instruments prompts an addition to the face of a watch - that of the minute hand.

The familiar watch face, with two concentric hands moving round a single dial, is at first considered confusing. There are experiments with several other arrangements of the hour and minute hand, before the design which has since been taken for granted is widely accepted.

Cartridges: 17th - 19th century AD

The efficiency of the Flintlock mechanism is accompanied by a similar improvement in the loading of a musket. In the early years of hand-guns the soldier carries a powder flask, from which he tips a small charge of gunpowder into the pan of the gun and then a larger quantity down the barrel - following it with a round metal ball and sufficient wadding to hold it in place, before ramming the whole charge tight with his ramrod.

During the 17th century time is saved by providing the soldier with the correct charge, together with the ball, wrapped in a paper tube - the whole package being called a cartridge.

On the battlefield the soldier bites off the end of the paper tube, tips a small amount of powder into the pan of his Flintlock and then pours the rest down the barrel, following it with the remains of the cartridge (the ball and the paper) which he rams tightly home.

This remains the standard procedure on the battlefield as long as muzzle-loading muskets are in use. Only in the 19th-century does it finally become obsolete, supplanted by Breech-loading guns and metal cartridges with internal Percussion caps.

Pressure cooker and piston: AD 1685-1690

In about 1685 Denis Papin, a French scientist working in England, demonstrates his 'digester'. It is a device familiar three centuries later as the pressure cooker. Papin's version is a cast-iron cylinder, about 6 inches in diameter and 18 inches long - much like a short length of drainpipe. The top section, which can be removed, is provided with a tight seal.

Papin places meat, bones and water in his digester. The tube can contain atmospheric pressure up to the point at which tin melts (about 210° C). To everyone's delight and amazement, the food is cooked very much sooner than the onlookers expect.

The digester includes an important mechanical innovation. Anticipating the danger that his scalding concoction of meat, bones and water may explode over the assembled company, Papin takes a crucial precaution. He provides the first recorded safety valve.

In addition to the main seal at the end of the cylinder, there is a second smaller aperture with its own seal. This smaller seal is held in place by a lever with an adjustable weight exerting the pressure.

By 1690 Papin is professor of mathematics at the university of Marburg. Here he makes a working model of a steam engine which is the first to incorporate one crucial element - the piston, forced up in its cylinder by the energy of expanding steam and then sucked down again by the vacuum when the steam cools and condenses.

Papin's machine is extremely leisurely because he uses the same container as both boiler and cylinder. A small amount of water is boiled in the vessel, forcing up the piston; the heat is removed and the steam cools, condensing and eventually pulling down the piston. The pace is unbearably slow, but the principle has a great future.

Piano and forte: AD c.1698

A maker of keyboard instruments in Florence, Bartolomeo Cristofori, begins work in about 1698 on a Harpsichord che fa il piano e il forte (which can do soft and loud). He achieves this by devising a mechanism which will strike the strings rather than pluck them. In doing so, he greatly extends the range of effects available to the performer on the traditional Harpsichord.

Early accounts emphasize this 'piano e forte' element of the new instrument, and from them it derives the name of pianoforte - or, in a more recent abbreviation, simply piano. By the end of the 18th century the piano occupies the central place in both professional and amateur music which it has held ever since.

18th century


Steam pump: AD 1698-1702

Thomas Savery has grown up in a mining district of Devon and knows the problem of flooded mines. In 1698 he obtains a patent for an engine to raise water 'by the Impellent Force of Fire'. It turns out to be the world's first practical steam engine. Designed purely as a pump, it has no piston but relies on the power of a vacuum.

A metal cylinder is filled with steam from a boiler. Cold water is poured over the outside, condensing the steam within and creating a vacuum which sucks water up through a pipe at the base. When the cylinder is full of water, the valve from below is closed. Steam is again introduced, forcing the water out of the cylinder through another valve. With the cylinder again full of steam, the process is repeated.

In 1702 Savery publishes a book about his invention, entitled The Miner's Friend. In it he describes how the idea came to him. One evening, after finishing his wine, he threw the empty bottle into the fire and prepared to wash his hands in a basin of water. Noticing steam coming out of the neck of the bottle, he plucked it from the fire and stuck it neck down in the basin. As the bottle cooled, it sucked up the water.

The story sounds improbable, and it may be Savery's way of trying to justify his patent - for the principles involved are already well known to contemporary scientists. What the pamphlet does show is that Savery intends to make money from his invention by supplying pumps to mines.

As it turns out, the maximum levels of pressure and vacuum achieved by Savery cannot lift water more than about twelve yards - too little for most mines.

Instead he finds his main customers among progressive country landowners, who are attracted by being at the cutting edge of technology. They use Savery's pumps to raise water for their houses and gardens.

Boiler cylinder and piston: AD 1704-1712

Two Devon metalworkers - Thomas Newcomen, a Dartmouth blacksmith, and his assistant John Calley, a glassblower and plumber - are making good progress in some potentially very profitable experiments. They know the high cost of the horse-driven pumps which raise water from the copper and tin mines of Devon and Cornwall. So they are working on a steam pump.

Though probably unaware of this, they are combining two elements pioneered separately by Denis Papin and Thomas Savery - Papin's piston and Savery's separation of the boiler (providing the supply of steam) from the cylinder (where the steam does its work).

In Newcomen's engine the piston, emerging from the top of the cylinder, is attached by an iron chain to one end of a beam which seesaws on a central pivot. At the other end of the beam another chain leads down to the water-pumping mechanism.

Steam released from the boiler into the cylinder pushes up the piston. When the cylinder is full of steam, the same procedure follows as in Savery's engine. Cold water poured on the outside condenses the steam and creates the vacuum. But in this case, instead of directly sucking up water, the vacuum causes the piston to descend in the cylinder. The chain drags down one end of the beam, activating the pump at the other end.

As so often in the advance of science and technology, an accident provides Newcomen with the refinement which brings his pump up to an economic speed. A flaw develops in one of the seams of his cylinder. As a result some cold water, intended only to flow down the outside, gets into the cylinder when it is full of steam. It creates a vacuum so rapid and so powerful that it snaps the chain attaching the piston to the beam.

With this event another lasting feature of the steam engine is discovered. In all Newcomen's developed engines, which soon start work in England's mines, the steam is condensed by a jet of cold water injected into the cylinder.

The first of Newcomen's working engines is installed in 1712 at a colliery near Dudley Castle. It operates successfully here for some thirty years, as the first of many in the mining districts of Britain. Newcomen's machine undoubtedly infringes Savery's patent, for there is no denying that it works 'by the Impellent Force of Fire'. But Savery is having no great commercial success with his own machine. The two men come to an amicable arrangement, the details of which are not known.

Even with Newcomen's improvements, these machines are suitable only for the slow relentless work of pumping in the mines. Proof of the wider potential of the steam engine must await the inventive genius of James Savery.

Mercury thermometer: AD 1714-1742

Gabriel Daniel Fahrenheit, a German glass-blower and instrument-maker working in Holland, is interested in improving the design of thermometer which has been in use for half a century. Known as the Florentine thermometer, because developed in the 1650s in Florence's Accademia del Cimento, this pioneering instrument depends on the expansion and contraction of alcohol within a glass tube.

Alcohol expands rapidly with a rise in temperature, but not at an entirely regular speed of expansion. This makes accurate readings difficult, as also does the sheer technical problem of blowing glass tubes with very narrow and entirely consistent bores.

By 1714 Fahrenheit has made great progress on the technical front, creating two separate alcohol thermometers which agree precisely in their reading of temperature. In that year he hears of the researches of a French physicist, Guillaume Amontons, into the thermal properties of mercury.

Mercury expands less than alcohol (about seven times less for the same rise in temperature), but it does so in a more regular manner. Fahrenheit sees the advantage of this regularity, and he has the glass-making skills to accomodate the smaller rate of expansion. He constructs the first mercury thermometer, of a kind which subsequently becomes standard.

There remains the problem of how to calibrate the thermometer to show degrees of temperature. The only practical method is to choose two temperatures which can be independently established, mark them on the thermometer and divide the intervening length of tube into a number of equal degrees.

In 1701 Newton has proposed the freezing point of water for the bottom of the scale and the temperature of the human body for the top end. Fahrenheit, accustomed to Holland's cold winters, wants to include temperatures below the freezing point of water. He therefore accepts blood temperature for the top of his scale but adopts the freezing point of salt water for the lower extreme.

Measurement is conventionally done in multiples of 2, 3 and 4, so Fahrenheit splits his scale into 12 sections, each of them divided into 8 equal parts. This gives him a total of 96 degrees, zero being the freezing point of brine and 96° (in his somewhat inaccurate reading) the average temperature of human blood. With his thermometer calibrated on these two points, Fahrenheit can take a reading for the freezing point (32°) and boiling point (212°) of water.

A more logical Swede, Anders Celsius, proposes in 1742 an early example of decimilization. His centigrade scale takes the freezing and boiling temperatures of water as 0° and 100°. In English-speaking countries this less complicated system takes more than two centuries to prevail.

Chronometer: AD 1714-1766

Two centuries of ocean travel, since the first European voyages of discovery, have made it increasingly important for ships' captains - whether on naval or merchant business - to be able to calculate their position accurately in any of the world's seas. With the help of the simple and ancient Astrolabe, the stars will reveal latitude. But on a revolving planet, longitude is harder. You need to know what time it is, before you can discover what place it is.

The importance of this is made evident when the British government, in 1714, sets up a Board of Longitude and offers a massive £20,000 prize to any inventor who can produce a clock capable of keeping accurate time at sea.

The terms are demanding. To win the prize a chronometer (a solemnly scientific term for a clock, first used in a document of this year) must be sufficiently accurate to calculate longitude within thirty nautical miles at the end of a journey to the West Indies. This means that in rough seas, damp salty conditions and sudden changes of temperature the instrument must lose or gain not more than three seconds a day - a level of accuracy unmatched at this time by the best clocks in the calmest London drawing rooms.

The challenge appeals to John Harrison, at the time of the announcement a 21-year-old Lincolnshire carpenter with an interest in clocks. It is nearly sixty years before he wins the money. Luckily he lives long enough to collect it.

By 1735 Harrison has built the first chronometer which he believes approaches the necessary standard. Over the next quarter-century he replaces it with three improved models before formally undergoing the government's test. His innovations include bearings which reduce friction, weighted balances interconnected by coiled springs to minimize the effects of movement, and the use of two metals in the balance spring to cope with expansion and contraction caused by changes of temperature.

Harrison's first 'sea clock', in 1735, weighs 72 pounds and is 3 feet in all dimensions. His fourth, in 1759, is more like a watch - circular and 5 inches in diameter. It is this machine which undergoes the sea trials.

Harrison is now sixty-seven, so his son takes the chronometer on its test journey to Jamaica in 1761. It is five seconds slow at the end of the voyage. The government argues that this may be a fluke and offers Harrison only £2500. After further trials, and the successful building of a Harrison chronometer by another craftsman (at the huge cost of £450), the inventor is finally paid the full prize money in 1773.

He has proved in 1761 what is possible, but his chronometer is an elaborate and expensive way of achieving the purpose. It is in France, where a large prize is also on offer from the Académie des Sciences, that the practical chronometer of the future is developed.

The French trial, open to all comers, takes place in 1766 on a voyage from Le Havre in a specially commissioned yacht, the Aurore. The only chronometer ready for the test is designed by Pierre Le Roy. At the end of forty-six days, his machine is accurate to within eight seconds.

Le Roy's timepiece is larger than Harrison's final model, but it is very much easier to construct. It provides the pattern of the future. With further modifications from various sources over the next two decades, the marine chronometer in its lasting form emerges before the end of the 18th century. Using it in combination with the Sextant, explorers travelling the world's oceans can now bring back accurate information of immense value to the makers of maps and charts.

Sextant: AD 1731-1757

The 18th-century search for a way of discovering longitude is accompanied by refinements in the ancient method of establishing latitude. This has been possible since the 2nd century BC by means of the Astrolabe. From the beginning of the European voyages in the 15th century practical improvements have been made to the Astrolabe - mainly by providing more convenient calibrated arcs on which the user can read the number of degrees of the sun or a star above the horizon.

The size of these arcs is defined in relation to the full circle. A quadrant (a quarter of the circle) shows 90°, a sextant 60° and an octant 45°.

The use of such arcs in conjunction with the traditional Astrolabe is evident from a text of 1555 about voyaging to the West Indies. The author talks of 'quadrant and Astrolabe, instruments of astronomy'.

The important development during the 18th century is the application of optical devices (mirrors and lenses) to the task of working out angles above the horizon. Slightly differing solutions, by instrument makers in Europe and America, compete during the early decades of the century. The one which prevails - largely because it is more convenient at sea - is designed as an octant in 1731 by John Hadley, an established English maker of reflecting telescopes.

Hadley's instrument, like others designed by his contemporary rivals, uses mirrors to bring any two points into alignment in the observer's sight-line. For the navigator these two points will usually be the sun and the horizon. To read the angle of the sun, the observer looks through the octant's eyepiece at the horizon and then turns an adjusting knob until the reflected orb of the sun (through a darkened glass) is brought down to the same level.

The double reflection means that the actual angle of the sun above the horizon is twice that on the octant's arc of 45%. So Hadley's instrument can read angles up to 90%.

In 1734 Hadley adds an improvement which becomes standard, installing a spirit level so that the horizontal can be found even if the horizon is not visible. In 1757, after Hadley's death, a naval captain proposes that the arc in the instrument be extended from 45° to 60°, making possible a reading up to 120°.

With this Hadley's octant becomes a sextant, and the instrument in use ever since finds its essential form.

This History is as yet incomplete.

The Leyden jar: AD 1745-1746

The researches of William Gilbert, at the start of the 17th century, lead eventually to simple machines with which enthusiasts can generate an electric charge by means of friction. The current generated will give a stimulating frisson to a lady's hand, or can be discharged as a spark.

In 1745 an amateur scientist, Ewald Georg von Kleist, dean of the cathedral in Kamien, makes an interesting discovery. After partly filling a glass jar with water, and pushing a metal rod through a cork stopper until it reaches the water, he attaches the end of the nail to his friction machine.

After a suitable amount of whirring, the friction machine is disconnected. When Kleist touches the top of the nail he can feel a slight shock, proving that static electricity has remained in the jar. It is the first time that electricity has been stored in this way, for future discharge, in the type of device known as a capacitor.

In 1746 the same principle is discovered by Pieter van Musschenbroek, a physicist in the university of Leyden. As a professional, he makes much use of the new device in laboratory experiments. Though sometimes called a Kleistian jar, it becomes more commonly known as the Leyden jar.

Within a year or two an improvement is made which gives the capacitor its lasting identity. The water in the vessel is replaced by a lining of metal foil, with which the metal rod projecting from the jar is in contact. Another layer of metal foil is wrapped round the outside of the jar. The two foils are charged with equal amounts of electricity, one charge being positive and the other negative.

The principle of plates bearing opposite charges, and separated only by a narrow layer of insulation, remains constant in the development of capacitors - much used in modern technology.

James Watt and the condenser: AD 1764-1769

In 1764 a model of a Newcomen steam engine is brought for repair to the young James Watt, who is responsible for looking after the instruments in the physics department of the university of Glasgow. In restoring it to working order, he is astonished at how much steam it uses and wastes.

The reason, he realizes, is that the machine's single cylinder is required to perform two opposing functions. It must receive the incoming steam at maximum pressure to force the piston up (for which it needs to be as hot as possible), and it must then condense the steam to form a vacuum to pull the cylinder down (for which it needs to be as cool as possible).

The solution occurs to Watt when he is walking near Glasgow one Sunday in May 1765. The two functions could be separated by providing a chamber, outside the cylinder but connecting with it, in which a jet of cold water will condense the steam and cause the vacuum.

This chamber is the condenser, for which Watt registers a patent in 1769. The principle has remained an essential part of all subsequent steam engines. It is the first of three major improvements which Watt makes in the basic design of steam-driven machinery. The other two are the Double-acting engine and the Governor, developed in the 1780s.

Early in the 1770s Watt goes into business with Matthew Boulton, an entrepreneur with a large factory at Soho near Birmingham. Boulton has the capacity to manufacture steam engines to Watt's patented design, and the first two are delivered to customers in 1776.

One of them, installed by Watt himself at John Wilkinson's ironworks at Broseley in Shropshire, is of special significance. Wilkinson is the only ironmaster in the country capable of producing cylinders of sufficiently accurate dimensions to deliver the potential benefits of Watt's improved engine.

Machine tools gun barrels and cylinders: AD 1774-1800

John Wilkinson, an ironmaster in Staffordshire and Shropshire, has been building up a lucrative arms trade. In 1774 he invents a machine, powered by a water wheel, which can drill with unprecedented accuracy through the length of a cast-iron cylinder to create the barrel of a cannon. It is a turning point in the development of machine tools.

James Watt realizes that Wilkinson's new machine is capable of the precision required for an efficient steam-engine cylinder. In 1775 Wilkinson delivers to Birmingham the first of the thousands of cylinders he will bore for the firm of Boulton and Watt. Boulton finds them 'almost without error; that of 50 inches diameter doth not err the thickness of an old shilling' in any part.

The Boulton and Watt engine delivered to Wilkinson in the following year is intended for a new purpose. Instead of the usual pumping of water, it is to undertake a more sophisticated role - working the bellows which pump air into one of Wilkinson's blast furnaces of molten iron.

The owners of the mills and mines of the young Industrial Revolution have many tasks to which a source of mechanical power, other than the traditional water of a mill race, could be usefully applied. They await with interest reports of this new type of engine. And the reports are good. By the time Watt's patent expires, in 1800, more than 500 Boulton and Watt engines have been installed around the country and abroad.

The increased efficiency of the new engines, compared with the previous Newcomen version, enables Boulton and Watt to charge by a novel and very profitable method. The machines are provided and installed free, and customers pay a royalty of one-third of the amount saved on fuel. One group of merchants interested in the Boulton and Watt machines, the London brewers, have no previous machine use for comparison. They present Watt with an interesting billing problem which results in the concept of horsepower.

From 1783 the saving (and the royalty) is even greater, because in that year Watt puts on the market another major innovation - his Double-acting engine.

Double-acting engine and governor: AD 1782-1787

Just as James Watt applied a rational approach to improve the efficiency of the steam engine with the Condenser, so now he takes a logical step forward in a modification patented in 1782. His new improvement is the double-acting engine.

Watt observes that the steam is idle for half of each cycle. During the downward stroke, when the vacuum is exerting atmospheric force on the piston, the valve between boiler and cylinder is closed. Watt takes the simple step of diverting the steam during this part of the cycle to the upper part of the cylinder, where it joins with the atmospheric pressure in forcing the cylinder down - and thus doubles its effective action.

The most elegant contraption devised by Watt is in use from 1787. It is the governor - the first example of the type of controlling device required in industrial automation, and a feature of all steam engines since Watt's time.

Watt's governor consists of two arms, hinged on a central pivot and rotated by the action of the steam engine. Each arm has a heavy ball at the end. As the speed increases, centrifugal force moves the balls and the arms outwards. This action narrows the aperture of a valve controlling the flow of steam to the engine. As the power is slowly cut off, the speed of the engine reduces and the balls subside nearer to the central column - thus slightly opening the valve again in a permanent process of adjustment.

Watt's many improvements to the steam engine leave it poised to undertake a whole new range of tasks. Its new efficiency means that it can become mobile. Each engine can now generate more power than is required merely to move itself.

By the time of his death in 1819, in quiet retirement near Birmingham, Watt has seen the introduction of commercially successful steam boats and the dawn of the railway age. In each case the vehicles are powered by engines of the type which he has developed.

This History is as yet incomplete.

Year of the balloon - hot air: AD 1783

Although hydrogen has been isolated by Cavendish in the 1760s, and shown to be fourteen times lighter than air, it is not until the early 1780s that Europe's inventors are suddenly gripped with a feverish interest in using the concept to achieve a form of flight. In 1781-2 scientists in both England and Switzerland fill soap bubbles with hydrogen and see them rise rapidly to the ceiling, but similar experiments with animal bladders prove disappointing.

In the event a more elementary idea, requiring none of the achievements of recent researches, provides the breakthrough.

In November 1782 a French manufacturer of paper, Joseph Montgolfier, wonders whether the simple fact of smoke rising might not be used to carry a balloon aloft. With his brother Etienne he begins making experiments. By June 1783 they are sufficiently confident to give a public demonstration in the town of Annonay.

They light a bonfire of straw and wool under a canvas and paper balloon with a diameter of about 35 feet. An astonished crowd sees the apparatus inflate and then drift into the sky. It rises, they estimate, to more than 3000 feet, stays in the air for ten minutes, and descends gently to earth 1500 yards away.

A report is immediately sent by the representatives of the local assembly to the Academy of Sciences in Paris. The news causes a sensation. The Montgolfiers are invited to the capital to demonstrate their invention.

Etienne makes the journey on their joint behalf and constructs a balloon to be launched at Versailles on September 19 in the presence of Louis XVI. This time the flying globe or aerostatic sphere (both are contemporary phrases) carries living passengers - a sheep, a cock and a duck. The trio travel more than two miles and land unharmed, except that the cock has been kicked by the sheep. The king, watching it all through his telescope, raises the Montgolfier family into the ranks of the nobility.

The final Montgolfier triumph takes place in November. A larger balloon is constructed, 46 feet in diameter, with a metal container (to hold the burning straw) hanging on chains just inside it. A basket, suspended below, is large enough to carry two people. Rigorous tests take place in a Paris garden. The tethered balloon, now bearing a passenger (Pilâtre de Rozier), is allowed to rise to successively greater heights.

At last, on November 21, all is considered ready. Four hands will be needed to stoke the fire with bundles of straw. Pilâtre is joined by a fellow passenger, the marquis d'Arlandes.

An excited crowd attempts to follow the path of the balloon as it rises and drifts away across Paris. In spite of alarming moments (such as their basket catching fire), the aeronauts make a successful flight, travelling about six miles in twenty-five minutes. They land safely, narrowly missing a windmill.

Those who have followed on horses are immediately on the scene. In the excitement Pilâtre's jacket, which he has taken off in the heat of the work, is torn to shreds and distributed as souvenirs. History has its first aviators.

Year of the balloon - hydrogen: AD 1783

News of the astonishing event at Annonay, in June 1783, prompts a Parisian physicist, Jacques Alexandre César Charles, to take serious steps to harness the property of hydrogen. He commissions from a silk merchant a balloon with a diameter of about 13 feet, and has it varnished with a gum solution.

To provide enough hydrogen Charles acquires 500 lb. of sulphuric acid and 1000 lb. of iron filings. The resulting gas is passed for four days through lead pipes into the slowly inflating balloon. At last, on August 27, a cannon is fired to signal the launch. The balloon rises rapidly to about 3000 feet in front of an ecstatic crowd on the Champ de Mars.

The contraption travels fifteen miles in forty-five minutes before springing a leak and crashing to the ground near a village. The first peasants on the scene, alarmed at the arrival of this monster from the sky, take the precaution of beating it until it seems undeniably dead.

Just as the hydrogen balloon is behind the hot-air version in the first ascent of any kind, so it is in the first manned ascent - but only by a very small margin. On December 1, ten days after the achievement of Pilâtre de rozier, Charles and a colleague rise into the air from the circular pond in front of the Tuileries. After a trouble-free journey of more than two hours, the aeronauts land about twenty-seven miles from Paris.

Charles's balloon, as befits that of a scientist, is more controllable than the Montgolfier version. It has a valve to release gas and descend, and it carries ballast which can be thrown overboard to rise again. The basket to carry the aeronauts is now a sturdy construction, looking like a small ship or gondola. And there is a Barometer on board to measure altitude.

After the first landing, Charles takes off alone for a second flight. The Barometer reveals that with the lighter load the balloon reaches the impressive height of about 10,000 feet, or two miles.

The hydrogen balloon soon prevails over the hot-air variety, because of its greater sophistication in an age when heat depends on burning bales of straw. Magnificent feats are achieved, beginning with a flight in 1785 across the English Channel by Jean Pierre Blanchard and an American doctor, John Jeffries. They throw out every loose item in the gondola, including their own clothes, to stay aloft long enough to arrive naked in France.

Impressive though these adventures are, the basic problem remains that there is no way of guiding a balloon.

Bifocals: AD 1784

As he advances in years, Benjamin Franklin needs two pairs of Spectacles - one for reading and one for distance. Like everyone else, he finds changing his Spectacles tiresome. The other pair is invariably mislaid when needed.

At the age of seventy-eight this most practical of scientists finds the obvious solution. He commissions from his spectacle-maker semicircular lenses of each variety and a frame which will hold a pair of these semicircles tightly together for each eye - the concave half at the top for the distance, the convex at the bottom for reading. The bifocal lens is born.

Cotton gin: AD 1793

The mechanization of spinning and weaving in England, between 1733 and 1785, greatly speeds up the industrial process and rapidly leads to a shortage of cotton. During most of the century the bulk of raw cotton arriving at Liverpool for the Lancashire mills is from India. The cotton grown in the southern states of America is commercially less viable because it is short-fibred.

The cotton fibres, which will be spun into cotton, have to be separated from the seeds which they protect and enmesh. This process, known as cotton picking, is done entirely by hand. The short fibres make it a slow and expensive task.

In 1793 Eli Whitney, a graduate of Yale, invents a machine which solves this problem. It consists of a hand-turned roller with projecting spikes. Each spike passes through a slot in a grid, wide enough to allow the spike to drag the cotton fibres through but too narrow for the cotton seeds to pass. They fall out into a separate container, while a revolving brush cleans the fibres, or lint, off the spikes.

Whitney's machine immediately trebles the speed at which cotton can be ginned, with major effects on the economy of the southern states of America. About forty times as much cotton (now established as 'king cotton') is produced in 1810 as in 1793. Vast new areas are taken in hand as plantations. The demand for slaves increases accordingly.

Lithography: AD 1798-1875

In 1798 an unsuccessful dramatist, Alois Senefelder, makes a discovery of profound significance in the history of artists' prints and later of commercial printing too. He has been attempting for some while to print from stone (prompted by a famous incident of 1796 when he jots down his mother's laundry list in greasy ink on a slab of limestone). What he comes to realize, in 1798, is that the antipathy between grease and water, familiar in any kitchen, can be used as a basis for printing.

In lithography marks are made on a stone surface in greasy crayon or ink. The stone is then wetted. Newly applied ink will stick only to the greasy marks. Paper pressed against the stone will pick up those marks and nothing else.

England is the first country in which artists take an interest in Senefelder's technique. As early as 1803 a collection of six lithographs by various painters (including Benjamin West, the president of the Royal Academy) is published under the title Specimens of Polyautography. By 1807 there are six issues, making thirty-six lithographs in all. They are mostly simple drawings in a pen-and-ink style.

In the long run the less restricting crayon style of lithography proves of more interest to artists. It is harder to achieve, but four early masterpieces in this medium are produced in 1825 by the elderly Goya in his series the Bulls of Bordeaux.

The example of these pioneers is not much followed during the main part of the 19th century except in the field of caricature, where artists such as Daumier use the immediacy of the medium to devastating effect in satirical journals. But by the final decades of the century the lithograph returns to fashion, along with etching, in a revival of interest in artists' prints which has never since slackened.

Meanwhile lithography makes steady inroads in the field of commercial printing. Topographical views in crayon lithography become common from the 1820s. Soon they acquire a tint or two, in fawn or pale blue from a second and third stone, to make them look more colourful.

The next stage in this progression is the chromolithograph printed in several colours, each from a separate stone. Bright and cheerful, the chromolithograph is a characteristic feature of 19th-century commercial printing - seen in posters, as book plates and eventually (following the example of the Illustrated London News in its Christmas issue of 1855) in weekly magazines.

The 1850s also see the first attempts to use photography in the making of lithographic plates. In the 1870s the process of offset lithography is invented. Senefelder's invention is poised to become, by the late 20th century, the standard method of printing.

This History is as yet incomplete.

Jenner and vaccination: AD 1796-1798

Working as a country doctor in the Gloucestershire village of Berkeley, Edward Jenner is aware of a local theory that people who have suffered a mild form of pox - caught from the infected udders of cows - never catch the much more dangerous smallpox.

Cowpox is a relatively rare disease, unrecognized at the time by the medical profession, and it is not until 1796 that Jenner has an opportunity to test this theory of immunity. In that year a dairymaid develops the symptoms. Jenner takes material from an eruption on her hand and (using a thorn) inoculates an 8-year-old boy, James Phipps, with the substance. Phipps develops cowpox and soon recovers.

The principle of Inoculation has become well established since the efforts of Lady Mary Wortley Montagu to encourage the use of infected matter from smallpox victims as a preventive measure. Six weeks after the cowpox Inoculation, Jenner gives James Phipps a conventional smallpox Inoculation. The expectation would be that he develops a mild attack of smallpox, survives it and becomes immune. In the event, as Jenner hopes, Phipps shows no sign at all of being infected by the smallpox virus.

Continuing his experiments, Jenner proves that even in a long line of Inoculation (taking new vaccine from each successive patient suffering from cowpox) the procedure still confers immunity.

Jenner publishes his findings in 1798 in the splendidly titled An Inquiry into the Causes and Effects of the Variolae Vaccinae, a disease discovered in some of the Western Counties of England, particularly Gloucestershire, and known by the name of Cow Pox.

Variolae Vaccinae, meaning literally 'smallpox of cows', is Jenner's scholarly name for cowpox. The phrase soon provides the word vaccination (initially coined in France as a term of mockery) for this new form of Inoculation against smallpox. After some initial opposition from the medical establishment, vaccination proves its merits and the use of it rapidly spreads. As early as 1807 it is made compulsory in Bavaria (though not till 1853 in Britain).

In 1806 the president of the USA, Thomas Jefferson, writes to Jenner: 'Future generations will know by history only that the loathsome smallpox existed and by you has been extirpated.' He is right, but the process takes longer than the president probably expects - even though the immediate effects are impressive. In Britain the annual death rate from smallpox falls during the 19th century from about 2000 per million to well under 100. But diseases are difficult to extirpate on a worldwide basis.

Nevertheless smallpox is the first disease with which that aim is eventually achieved. After intensive international vaccination programmes, there is by 1980 no case of smallpox on the planet.

Sections are as yet missing at this point.

Percussion: from AD 1807

Alexander Forsyth, a Scottish clergyman who enjoys shooting wildfowl, finds that the flash from his Flintlock often alerts the sitting ducks which are his target. Sometimes they even fly away or dive before his ball reaches them.

Searching for a priming substance which will ignite without a spark, he discovers that potassium chlorate will do the job if struck a sharp blow. He successfully builds himself a fowling piece which fires by percussion. When his gun comes to the attention of the military, he is installed in the Tower of London to continue his experiments. By 1807 he has shown that his powder will work in any size of musket or cannon. His discovery is a turning point in the story of gunfire.

Forsyth's compound makes possible the development of the breech-loading bolt-action rifle which eventually becomes the standard infantry weapon - after many other inventors have also made their contribution.

The value of breech-loading is the time saved in inserting the cartridge into the breech (the back end of the barrel) rather than down the Muzzle. Experiments in this direction go back to the 17th century, when a breech-loading musket is produced in Italy (possibly invented in Florence by Michele Lorenzoni). Practical versions are later developed in Britain by Patrick Ferguson (in 1776) and in the United States by John Hall (in 1811).

These are all flintlocks, and the clumsy firing mechanism reduces the advantage of the faster loading system. The first really effective breech-loading rifle is made possible by Forsyth's system of percussion. It is developed from 1827 in Germany by Johann von Dreyse.

Dreyse's extremely influential weapon, adopted by the Prussian army in 1848, has several new features. It uses a needle-like point to pierce the cartridge and strike the percussion cap, giving it the name 'needle-gun' (a short and blunt version of this needle later becomes the pin, the standard percussion device).

The Dreyse rifle also introduces the bolt, another standard feature of subsequent rifles. In this first application the bolt is merely a quick way of opening the breech and ramming in the next cartridge.

The eventual double-action bolt (pulling out the empty case when drawn back and inserting the live bullet on the forward movement) has to await the invention of the self-contained metal cartridge, with the percussion cap in its base. The first bullet of this kind is patented in 1846 by a Paris gunsmith named Houiller.

With these various elements, beginning with percussion, the standard rifle of the infantryman is in existence; its 20th-century form is merely a refinement. The principle of rifling (cutting grooves within the barrel to cause the bullet to spin for a straighter trajectory) has been experimented with since the 15th century. It comes into its own once ways are found, mainly during the 18th century, of making the bullet fit tightly in the barrel.

The obvious next development, in use by the 1870s, is the magazine, loaded with several bullets, which can be clipped on below the breech of the rifle. Beyond that there lies only mechanization - in the automatic rifle and the machine gun.

This History is as yet incomplete.

19th century


Laënnec and the stethoscope

René Laënnec, a physician at the Necker Hospital in Paris, specializes in diseases of the chest. Two events in 1816 give him the idea for a significant contribution to medical practice.

Walking in a courtyard of the Louvre he sees children playing an acoustic game with a long strip of wood. A boy scratches one end of the wood; his friend, with the other end to his ear, hears the sound clearly. Soon after this Laënnec is visited by a female patient too plump for her heartbeat to be easily discernible but too young for him to press his ear to her chest with decorum. Following the example of the boys, he rolls a sheet of paper into a tube. He places one end gently on the lady's bosom and the other to his ear.

Laënnec is surprised to discover that through the tube he hears the heart with much greater clarity than with his ear to a patient's chest. He has stumbled upon the principle of the stethoscope (from Greek stethos chest, scopein to observe).

Laënnec now constructs a hollow wooden tube, about nine inches long with ends designed to fit snugly against the chest and into the ear. He spends three years analysing the weird and often tumultuous sounds which reach him as patients breathe. At first he has no way of interpreting them. But he notes the variety of noises heard in terminally ill patients, and in subsequent post mortems he observes the condition of their lungs and heart.

By this means Laënnec is able to identify and describe the characteristic sounds of various stages of bronchitis, pneumonia and - increasingly important as one of the most prevalent diseases of the 19th century - tuberculosis. Laënnec's researches are published in 1819 in Traité de l'auscultation médiate (Treatise on Mediate Auscultation). Auscultation, or listening to the body for diagnostic purposes, has until now always been 'immediate' - with the physician's ear pressed to the patient's body. The stethoscope becomes the mediating instrument.

Later in the century a tube of rubber is found to be more convenient. And in 1852 the familiar modern version is introduced, enabling the physician to use both his ears.

This History is as yet incomplete.

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Contact lenses: AD 1887

A German physiologist, Adolf Fick, grinds glass lenses in 1887 to a very precise and unusual shape. They are to fit exactly over the surface of a patient's eyes. This pair of Spectacles, instead of being supported on the nose, clings to the eyes themselves.

Contact lenses remain an oddity (and no doubt a very alarming one) until they begin to be made of plastic in the 1940s. Thereafter Fick's boldly simple idea proves its worth in a bewildering range of adaptations - such as soft lenses, extended-wear lenses, disposable lenses, lenses to change the colour of the eyes, and even Bifocals.

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20th century


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Continental drift: AD 1912

Alfred Wegener, a German geophysicist, gives a lecture in which he proposes a radical theory. He begins from a geographical oddity often previously commented on - the neat way the coast of south America fits, like a piece of a jigsaw puzzle, into the coast of West Africa. He elaborates by pointing out how identical types of rock and fossil are found in different continents.

Wegener's hypothesis, to explain this state of affairs, is that all our present land masses were at one time joined together as one; and that they have reached their present positions by a process of continental drift.

Wegener's hypothesis provokes violent controversy, with strong views expressed for and against. But by the time of his death, in 1930, the consensus of scientific opinion is against such a radical notion.

However, from the 1950s confirmation seems to come from several areas of research - into the earth's magnetic field in past times, and into the ocean beds - and the new science of Plate tectonics evolves, providing a feasible explanation of how Continental drift can occur. More recently satellite observations have provided direct evidence. The Atlantic is growing wider at the rate of about 7 cm every year.

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A spreading seafloor: from the 1960s

During the 1960s there are major changes in scientists' understanding of the behaviour of the earth's crust. It is discovered that the crust beneath the oceans is thinner than beneath the land, and that it is composed of much younger rock formations. It is also proved that in parts of the oceans there are submerged mountain ranges with great rift valleys in them.

The explanation is that molten material (or magma) from the earth's mantle is forced up through these rifts to form new ocean floor. Where this happens, the seafloor spreads and the continents drift apart - by a process known as plate tectonics.

This History is as yet incomplete.
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