istoryworld
HISTORY OF GEOGRAPHY
Surface of the earth
Pangaea: 250 - 200 million years ago
In the shifting story of the face of the earth, the land surface merges into one single continent about 250 million years ago. It is from this land mass that our own geography has gradually emerged.
This continent has been given the name Pangaea (Greek for 'all earth'). About 200 million years ago Pangaea splits into two parts, north and south, separated by water - the Tethys Sea. The area north of the Tethys Sea, named Laurasia, includes the future north America, Europe and most of Asia. South of the sea, a continent named Gondwanaland is made up of what will be South America, Antarctica, Africa, India and Australia.
This continent has been given the name Pangaea (Greek for 'all earth'). About 200 million years ago Pangaea splits into two parts, north and south, separated by water - the Tethys Sea. The area north of the Tethys Sea, named Laurasia, includes the future north America, Europe and most of Asia. South of the sea, a continent named Gondwanaland is made up of what will be South America, Antarctica, Africa, India and Australia.
From one continent to six: 200 - 20 million years ago
The reshaping of the surface of the earth, into the pattern now familiar to us, takes place between 200 and 20 million years ago.
First south America splits from Africa and drifts westwards (it is the snug fit between their coast lines which suggests the idea of continental drift to Alfred wegener in 1912). Then Antarctica, India and Australia separate from Africa. Antarctica moves to the south, while India and Australia drift north and east.
First south America splits from Africa and drifts westwards (it is the snug fit between their coast lines which suggests the idea of continental drift to Alfred wegener in 1912). Then Antarctica, India and Australia separate from Africa. Antarctica moves to the south, while India and Australia drift north and east.
Africa and India move slowly but forcefully towards Europe and Asia, reducing the Tethys Sea to its present-day remnant (the Mediterranean) and throwing up the Alps and the Himalayas from the force of the collision.
Finally north America splits from Europe and Asia (though remaining almost linked at its northern tip), thus forming the Atlantic ocean and completing the disposition of The continents as we know them.
Finally north America splits from Europe and Asia (though remaining almost linked at its northern tip), thus forming the Atlantic ocean and completing the disposition of The continents as we know them.
To the 14th century AD
The geographers of Miletus: 6th century BC
Nothing is known of the map of the world supposedly produced in Miletus by Anaximander in the mid-6th century BC. But by the end of the century, also in Miletus, another geographer writes a book of which sufficient details survive for his ideas to be reconstructed. He is Hecataeus.
Like most early mapmakers, Hecataeus puts the most important place at the centre of the world. For medieval Christian cartographers this is Jerusalem. For Hecataeus it is the Aegean Sea, on the east coast of which stands Miletus.
Like most early mapmakers, Hecataeus puts the most important place at the centre of the world. For medieval Christian cartographers this is Jerusalem. For Hecataeus it is the Aegean Sea, on the east coast of which stands Miletus.
The shape of the world according to Hecataeus has a geometrical simplicity. It is a flat circle, with a continuous ocean forming the rim. The circular land mass is divided into two parts by an almost unbroken stretch of water linked with the ocean on the west at the straits of Gibraltar, then running east the length of the Mediterranean, through the Black Sea and (after a short land bridge) into the Caspian Sea, which joins the ocean on the east.
The semicircle of land above this belt of water is Europe, while the semicircle below is Asia. The part west of the Nile has the subsidiary name of Libya, standing in for Africa.
The semicircle of land above this belt of water is Europe, while the semicircle below is Asia. The part west of the Nile has the subsidiary name of Libya, standing in for Africa.
Hecataeus is at the end of a pioneering century of Greek science in Miletus, which lies to the east of mainland Greece. At the same period a new centre of Greek scientific speculation is being developed far to the west, in the Pythagorean tradition of southern Italy.
Greek philosophy is strongly associated with Athens, because of Socrates, Plato and Aristotle. But scientific history testifies rather more to the colonial spread of Greek culture round the Mediterranean. Ionia and Samos, Italy and Sicily, Alexandria; these are the places where Greeks will establish the rational traditions of western science.
Greek philosophy is strongly associated with Athens, because of Socrates, Plato and Aristotle. But scientific history testifies rather more to the colonial spread of Greek culture round the Mediterranean. Ionia and Samos, Italy and Sicily, Alexandria; these are the places where Greeks will establish the rational traditions of western science.
The coast of northwest Europe: c.310 BC
Pytheas, an explorer from the Greek city of Massilia (now Marseilles), voyages past Gibraltar and turns north up the European coast. Off Brittany he veers west to visit Cornwall, where he describes the trade in tin. He then sails up the west coast of Britain and continues beyond it for six days to reach a land which he calls Thule. It is inhabited but uncomfortable and strange. At midsummer the sun never sets, and beyond here the sea is frozen.
As a result of this report Thule (presumably Norway) becomes for all Greek and Roman geographers the most northerly place in the world.
As a result of this report Thule (presumably Norway) becomes for all Greek and Roman geographers the most northerly place in the world.
The circumference of the earth: calculated in about 220 BC
Eratosthenes, the librarian of the Museum at alexandria, has more on his mind than just looking after the scrolls. He is making a map of the stars (he will eventually catalogue nearly 700), and he is busy with his search for prime numbers; he does this by an infinitely laborious process now known as the Sieve of Eratosthenes.
But his most significant project is working out the circumference of the earth.
But his most significant project is working out the circumference of the earth.
Eratosthenes hears that in noon at midsummer the sun shines straight down a well at Aswan, in the south of Egypt. He finds that on the same day of the year in Alexandria it casts a shadow 7.2 degrees from the vertical. If he can calculate the distance between Aswan and Alexandria, he will know the circumference of the earth (360 degrees instead of 7.2 degrees, or 50 times greater).
He discovers that camels take 50 days to make the journey from Aswan, and he measures an average day's walk by this fairly predictable beast of burden. It gives him a figure of about 46,000 km for the circumference of the earth. This is, amazingly, only 15% out (40,000 km is closer to the truth).
He discovers that camels take 50 days to make the journey from Aswan, and he measures an average day's walk by this fairly predictable beast of burden. It gives him a figure of about 46,000 km for the circumference of the earth. This is, amazingly, only 15% out (40,000 km is closer to the truth).
A grid before its time: 2nd century BC
One of the most rigorous of Greek scientists, the astronomer Hipparchus, foresees in the 2nd century BC the requirements of a modern map. He is critical of mapmaking efforts by his Greek contemporaries, based on measurements taken on the ground. Instead he proposes a grid of 360° of latitude and of longitude (a number relating back to Babylonian systems), on which places will be plotted according to astronomical readings taken on location.
The necessary instruments of measurement (in particular for the accurate recording of time) are not available to Hipparchus. But his bold idea prefigures the principle of scientific cartography.
The necessary instruments of measurement (in particular for the accurate recording of time) are not available to Hipparchus. But his bold idea prefigures the principle of scientific cartography.
The influential errors of Ptolemy: 2nd century AD
Ptolemy, working in Alexandria in the 2nd century AD, is one of the great synthesizers of history. In several important fields (cosmology, astronomy, geography) he brings together in encyclopedic form an account of the received wisdom of his time.
His influence derives from the accident that his predecessors' works are lost while his have survived. Their achievements are known only through him, and when he disagrees with them it is usually he who is wrong. Just as in astronomy he wrongly adjusts the degree of Precession of hipparchus, so in geography he rejects Eratosthenes, whose calculation of the circumference of the earth is very close, and prefers instead another estimate which is 30% too small.
His influence derives from the accident that his predecessors' works are lost while his have survived. Their achievements are known only through him, and when he disagrees with them it is usually he who is wrong. Just as in astronomy he wrongly adjusts the degree of Precession of hipparchus, so in geography he rejects Eratosthenes, whose calculation of the circumference of the earth is very close, and prefers instead another estimate which is 30% too small.
Ptolemy's astronomical work is divided into thirteen books. The first proves that the earth is the immovable centre of the universe; the last five describe the movement of the sun, moon and five planets, each attached to its own crystal sphere. By adding adjustments to reflect the erratic behaviour seen in the sky, Ptolemy achieves a system capable of satisfying scientific enquiry in the unscientific centuries of the Middle Ages.
His book becomes known as Ho megiste astronomas (Greek for 'the greatest astronomer'), or Megiste for short. The Arabs call it Al Megiste (the Megiste). Reaching northern Europe through the Arab civilization in Spain, it acquires its eventual title - as Ptolemy's Almagest.
His book becomes known as Ho megiste astronomas (Greek for 'the greatest astronomer'), or Megiste for short. The Arabs call it Al Megiste (the Megiste). Reaching northern Europe through the Arab civilization in Spain, it acquires its eventual title - as Ptolemy's Almagest.
In practical terms the Ptolemaic system proves adequate for everyday purposes. Indeed its very complexity makes it attractive to the exclusive minority of learned men. The details may be hard to master, but once understood they will reveal future positions of the planets. Ptolemy himself prepares charts of the moon's behaviour, more accurate than any previously available, which remain in everyday use until the Renaissance.
But in the long run the complexity is unconvincing (the alternative proposed by Copernicus is simpler); and the orbiting planets of Jupiter, revealed by Galileo's telescope, inconsiderately smash through one of Ptolemy's crystal spheres.
But in the long run the complexity is unconvincing (the alternative proposed by Copernicus is simpler); and the orbiting planets of Jupiter, revealed by Galileo's telescope, inconsiderately smash through one of Ptolemy's crystal spheres.
In geography Ptolemy seems to offer what Hipparchus had proposed - the location of the world's natural and man-made features on a grid of 360° of latitude and longitude. He lists and places some 8000 towns, islands, rivers and mountains. But he is no more capable of providing accurate data, astronomically based, than Hipparchus was. The relative positions of his named features are calculated by collating travellers' accounts of the number of days taken on their journeys.
The results are wildly inaccurate. But the great prestige of Ptolemy means that with the revival of classical learning, in the Renaissance, his errors become enshrined in the earliest Printed maps.
The results are wildly inaccurate. But the great prestige of Ptolemy means that with the revival of classical learning, in the Renaissance, his errors become enshrined in the earliest Printed maps.
The medieval world: 5th - 15th century
The temperate belt of the northern hemisphere, from Britain to China, is reasonably familiar from Trade and travel by the time of the late Roman empire. From the 7th century the spread of Islam provides further detail, as subsequently do travellers such as Marco polo or Ibn batuta. Much information is forgotten or becomes confused; the mysterious regions of northern Asia and southern Africa remain full of monsters; and the medieval love of a marvellous tale will cloud many issues. But the known world is seen as a rectangular chunk of continuous land, like a belt round most of the earth, with a single ocean dividing western Europe from eastern Asia.
This view of geography prevails until the decade of Exploration - the 1490s.
This view of geography prevails until the decade of Exploration - the 1490s.
15th - 16th century
Ptolemy and the Renaissance: 15th century
In the gradual spread of ancient Greek texts to medieval Europe, manuscripts of Ptolemy become known by 1400. His account of world geography is widely available after it is translated into Latin in 1410.
With the arrival of printing later in the century, a world map based on Ptolemy's information is a natural project for the publishers. The first printed version, done from engraved copper plates, appears in Bologna in 1477. The projection of the map is redrawn and made clearer in the 1482 German edition, printed in Ulm from wood blocks.
With the arrival of printing later in the century, a world map based on Ptolemy's information is a natural project for the publishers. The first printed version, done from engraved copper plates, appears in Bologna in 1477. The projection of the map is redrawn and made clearer in the 1482 German edition, printed in Ulm from wood blocks.
The Ptolemaic map shows the known world, from the Atlantic coast in the west to China and India in the east. India stretches on through what we now call Indonesia, to reach the edge of the map below China. The supposed ocean separating Europe from China and India is the unseen region behind the map.
Luckily for the story of exploration, this ocean is assumed to be relatively small (Ptolemy greatly reduces the more accurate figure for the circumference of the earth arrived at by Eratosthenes). The unseen ocean is small on the world's First globe. And it is on this same assumption that Columbus sails west, just fifteen years after the first printed edition of Ptolemy, confident that he will soon reach the coast of India or China.
Luckily for the story of exploration, this ocean is assumed to be relatively small (Ptolemy greatly reduces the more accurate figure for the circumference of the earth arrived at by Eratosthenes). The unseen ocean is small on the world's First globe. And it is on this same assumption that Columbus sails west, just fifteen years after the first printed edition of Ptolemy, confident that he will soon reach the coast of India or China.
Another Ptolemaic error is disproved by the explorers just a few years later. Even though Herodotus reported that a Ptolemy had sailed round the southern tip of Africa, the Ptolemaic map shows south Africa extending east through terra incognita to join up with India in the far East, making the Indian Ocean a vast inland sea.
In 1497 Phoenician fleet makes his way round the Cape of Good Hope, pioneering the sea route to India which he reaches in 1498. Rarely until the 20th century has new technology, in this case the printed map, been so rapidly outdated.
In 1497 Phoenician fleet makes his way round the Cape of Good Hope, pioneering the sea route to India which he reaches in 1498. Rarely until the 20th century has new technology, in this case the printed map, been so rapidly outdated.
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.
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.
Columbus and the Catholic monarchs: AD 1492
In Santa Fe, a royal encampment from which the siege of Granada is conducted, the Spanish monarchs Ferdinand and isabella debate whether to accept a proposal put to them by a visionary explorer, Christopher Columbus.
For eight years Columbus has been pestering European courts, particularly those of Portugal and Spain, to sponsor him in an undertaking which obsesses him. The Portuguese explorers have had notable success in their attempts to sail east round Africa towards India and China, but Columbus has become convinced that he can achieve the same more easily by sailing west.
For eight years Columbus has been pestering European courts, particularly those of Portugal and Spain, to sponsor him in an undertaking which obsesses him. The Portuguese explorers have had notable success in their attempts to sail east round Africa towards India and China, but Columbus has become convinced that he can achieve the same more easily by sailing west.
It has long been the accepted view, deriving from Ptolemy, that nothing but sea separates Europe from India and China round the back of a spherical world. During the 15th century the notion has developed that the unseen distance by sea is much less than the known distance between Europe and China by land.
Columbus believes that he has found mathematical proof of this in an apocryphal text of the Old Testament where the prophet Esdras states that the earth is six parts land to one part sea. Columbus argues, first to the king of Portugal in 1484 and then to the Spanish monarchs, that India is therefore within reach of a Caravel sailing west from the Canaries.
Columbus believes that he has found mathematical proof of this in an apocryphal text of the Old Testament where the prophet Esdras states that the earth is six parts land to one part sea. Columbus argues, first to the king of Portugal in 1484 and then to the Spanish monarchs, that India is therefore within reach of a Caravel sailing west from the Canaries.
The Portuguese court rejects his argument. The Spanish monarchs delay for years while a commission investigates his claims. Finally, in the camp near Granada, they accept his somewhat exorbitant terms regarding the honours which will be heaped upon him if he reaches India or China, and his share of whatever is found.
Once agreement is reached, after so many years, Columbus moves fast. With his partners (brothers from a Spanish ship-owning family named Pinzón) he prepares vessels for the great adventure.
Once agreement is reached, after so many years, Columbus moves fast. With his partners (brothers from a Spanish ship-owning family named Pinzón) he prepares vessels for the great adventure.
Santa Maria Pinta and Niña: AD 1492-1493
On 3 August 1492 a little fleet of three vessels sets sail from the small Spanish harbour of Palos. Columbus is in command of the largest, the Santa Maria; the captains of the other two, the Pinta and the NiÑa, are the brothers Martin Alonso and Vicente Yañez Pinzón.
Three weeks are spent loading stores in the Canaries until, on September 6, the three ships sail west into the unknown. During the next month there are several sightings of coastlines which turn out to be illusions. At last, on October 12, a look-out on the Pinta spies real land.
Three weeks are spent loading stores in the Canaries until, on September 6, the three ships sail west into the unknown. During the next month there are several sightings of coastlines which turn out to be illusions. At last, on October 12, a look-out on the Pinta spies real land.
Atlantic and Pacific: AD 1492-1519
The Atlantic ocean begins to acquire a western edge and a definable shape after the discovery of the Caribbean by Columbus in 1492, followed by the exploration of the coast of Venezuela by a Spaniard (Alonso de Ojeda) in 1499-1500 and then Landfall in brazil in 1500 by a Portuguese navigator (Pedro Cabral).
This coastline is still believed (following the theories of Ptolemy and columbus) to be part of Asia. That theory is not necessarily disproved by news which begins to reach the Spaniards as they make contact with the Indians of central America. The Indians speak of another sea not far away to the west.
This coastline is still believed (following the theories of Ptolemy and columbus) to be part of Asia. That theory is not necessarily disproved by news which begins to reach the Spaniards as they make contact with the Indians of central America. The Indians speak of another sea not far away to the west.
Such a sea, if this land is indeed Asia, would consist of a huge bay somewhere south of China. It becomes known as the mar del sur ('south sea'). To be the first to find it is any explorer's dream.
An expedition to find the south sea is mounted, in a mood of urgency, by Vasco Núñez de Balboa in 1513. Balboa is the governor of a Spanish colony which he has established, in 1510, at Santa María la Antigua on the west shore of the gulf of Uraba (a region known then as Darién). He comes to believe that the south sea, with its fabled riches, could be reached from here in a fairly short expedition with a force of 1000 fighting men.
An expedition to find the south sea is mounted, in a mood of urgency, by Vasco Núñez de Balboa in 1513. Balboa is the governor of a Spanish colony which he has established, in 1510, at Santa María la Antigua on the west shore of the gulf of Uraba (a region known then as Darién). He comes to believe that the south sea, with its fabled riches, could be reached from here in a fairly short expedition with a force of 1000 fighting men.
Balboa proves his point in 1513. He sets off from a Spanish colony on the Atlantic coast, in the gulf of Uraba. Four weeks later he climbs to the top of a hill and sees water to the distant horizon. He claims for the king of Spain the entire south sea, stretching away beyond the Asian promontory on which Balboa believes himself to be standing.
Somewhere in this south sea there must lie the Spice Islands, or Moluccas, already discovered by the Portuguese travelling eastwards (the first local treaties signed by the Portuguese in these islands date from 1512). The final discovery of the extent of the Pacific derives from a bold geographical theory, held by the navigator Ferdinand Magellan, as to where precisely the Moluccas might be.
Somewhere in this south sea there must lie the Spice Islands, or Moluccas, already discovered by the Portuguese travelling eastwards (the first local treaties signed by the Portuguese in these islands date from 1512). The final discovery of the extent of the Pacific derives from a bold geographical theory, held by the navigator Ferdinand Magellan, as to where precisely the Moluccas might be.
Magellan's theory: AD 1518
Ferdinand Magellan learns the craft of navigator, between 1505 and 1512, voyaging to and around the East Indies in the service of his native Portugal. In 1516 his request for promotion is refused by the Portuguese king, who informs him that he may offer his services elsewhere.
The only alternative employment for a man of his skills is with Spain, Portugal's great rival on the oceans. As it happens, Magellan now holds a theory which could prove greatly to Spain's advantage.
The only alternative employment for a man of his skills is with Spain, Portugal's great rival on the oceans. As it happens, Magellan now holds a theory which could prove greatly to Spain's advantage.
The pope has granted to Spain all newly found territory lying west of the Tordesillas line, and to Portugal everything to the east of it. In terms of modern longitude, the line is approximately 50° W. In 1518 Magellan persuades the Spanish king that the spice islands, or Moluccas, may be less than half way round the globe travelling west from the Tordesillas line. If that is the case, the islands would belong to Spain.
He is almost right. The longitude of the Moluccas is about 125° E. They are therefore 185° west of the Tordesillas line, or just 5° more than half way round the globe. Spain will have a valid case, for instruments of the time cannot be so precise. But first Magellan has to reach his destination sailing westwards.
He is almost right. The longitude of the Moluccas is about 125° E. They are therefore 185° west of the Tordesillas line, or just 5° more than half way round the globe. Spain will have a valid case, for instruments of the time cannot be so precise. But first Magellan has to reach his destination sailing westwards.
Magellan and Del Cano: AD 1519-1522
With a fleet of five ships, carrying 265 men, Magellan sails in September 1519 from Seville. In mid-December he reaches Rio de Janeiro. For the next ten months he explores southwards along the coast, searching for a channel through to the 'south sea' (sighted seven years earlier by Balboa).
The broad estuary of the river Plate delays him, falsely raising his hopes, and it is not until October 1520 that he begins to explore west and then south through the straits which now bear his name. The fleet is now reduced to three ships. One has been wrecked on the south American coast. The captain of another deserts and sails home from the straits.
The broad estuary of the river Plate delays him, falsely raising his hopes, and it is not until October 1520 that he begins to explore west and then south through the straits which now bear his name. The fleet is now reduced to three ships. One has been wrecked on the south American coast. The captain of another deserts and sails home from the straits.
On November 28 the three Caravels begin their journey across an unknown ocean. The crossing lasts ninety-nine days, without replenishment of food or water. The explorers finally make landfall, at Guam in the Marianas, on March 6. It has been three months of nightmarish deprivation, with the crew reduced in the end to eating leather from the rigging. But the sea itself has been sufficiently friendly for Magellan to give it a name which sticks - the Pacific ocean.
The next landfall is in the Philippines.
The next landfall is in the Philippines.
On the island of Cebu Magellan and his party rapidly convert the ruler to Christianity, beginning a Spanish link with the Philippines which will last until 1898. But in April Magellan is killed in a skirmish with natives on the island of Mactan.
He is already west (and slightly north) of his destination in the Moluccas, and he has achieved the hardest part of the undertaking - coaxing his often mutinous crews across a vast unknown expanse of ocean. But the glory of leading the first complete circumnavigation of the globe falls to one of his officers, Juan Sebastian del Cano.
He is already west (and slightly north) of his destination in the Moluccas, and he has achieved the hardest part of the undertaking - coaxing his often mutinous crews across a vast unknown expanse of ocean. But the glory of leading the first complete circumnavigation of the globe falls to one of his officers, Juan Sebastian del Cano.
Del Cano finally reaches Spain in September 1522 with a single ship (the Victoria, only survivor of the fleet of five) and seventeen Europeans from the original crew of 265, together with four Indians. He is granted by the Spanish king, Charles V, a suitable addition to his coat of arms - the device of a globe and the inscription Primus circumdedisti me (Latin for 'you first encircled me').
With this achievement, humans at last know the extent of the planet on which we live (Copernicus, at this same moment, is beginning to think the unthinkable - that it may indeed be only a planet). But the Pacific still has surprises in store.
With this achievement, humans at last know the extent of the planet on which we live (Copernicus, at this same moment, is beginning to think the unthinkable - that it may indeed be only a planet). But the Pacific still has surprises in store.
Problems of projection: 16th century AD
The European discovery of America and of the Pacific coincides with an increase in ocean travel and with the new Printing techniques of woodcut and engraving. The result is a great demand for maps which can be cheaply produced and which, unlike a globe, will take little space - lying flat, and capable of being folded or even bound into book form.
The printed map is in its vigorous infancy during the 16th century. But a globe remains the only accurate way of representing the land masses on the surface of the spherical earth. How are the newly discovered facts of world geography to be represented on a flat surface?
The printed map is in its vigorous infancy during the 16th century. But a globe remains the only accurate way of representing the land masses on the surface of the spherical earth. How are the newly discovered facts of world geography to be represented on a flat surface?
The problem is real, and in a real sense insoluble. Imagine a rubber globe, hollow like a football. The information on its surface is accurate. But try cutting the globe in half and laying each half out flat, as on a page. It is impossible to do so. Distortion is inevitable. The particular distortion chosen is known as the map's projection. One of the best known is that used by Gerardus Mercator.
His framework is far from new. The grid system of latitude and longitude dates back to Hipparchus in the 2nd century BC, and the prime meridian (or 0° longitude) has run through the Canaries since the second century AD, placed there by Ptolemy. But Mercator's projection is based on new scientific principles.
His framework is far from new. The grid system of latitude and longitude dates back to Hipparchus in the 2nd century BC, and the prime meridian (or 0° longitude) has run through the Canaries since the second century AD, placed there by Ptolemy. But Mercator's projection is based on new scientific principles.
Mercatow's projection and atlas: AD 1569-1595
Mercator publishes in 1569 a map of the world specifically stated, in its title, to be intended as an aid to navigation. It is laid out on the projection now known by Mercator's name, though it has been used by one or two others before him.
Mercator's projection has the effect of greatly enlarging territories as they recede from the equator. India, for example, appears smaller than Tierra del Fuego. The Moghul emperor Jahangir is understandably displeased at the diminutive size of his empire when the British ambassador, Thomas Roe, presents him with a copy of Mercator's world map.
Mercator's projection has the effect of greatly enlarging territories as they recede from the equator. India, for example, appears smaller than Tierra del Fuego. The Moghul emperor Jahangir is understandably displeased at the diminutive size of his empire when the British ambassador, Thomas Roe, presents him with a copy of Mercator's world map.
The distortion of Mercator's projection is a benefit to navigators. By gradually lengthening the lines of longitude towards the poles, Mercator achieves a matching scale for longitude and latitude in every section of the map (the northern degrees of latitude, being shorter in reality, are exaggerated on a regular grid). A compass course can be plotted at the same angle on any part of Mercator's map. As a result marine charts still use this projection.
From 1569 Mercator devotes himself to a vast project, producing a series of maps of Europe which compare Ptolemy's version with improvements based on modern knowledge (much as Vesalius has to measure his own anatomical discoveries against the yardstick of Galen).
From 1569 Mercator devotes himself to a vast project, producing a series of maps of Europe which compare Ptolemy's version with improvements based on modern knowledge (much as Vesalius has to measure his own anatomical discoveries against the yardstick of Galen).
By the time of his death Mercator has either published or prepared large engraved maps, designed for binding into volume form, of France, Germany, Italy, the Balkans and the British Isles.
A year after his death, in 1595, Mercator's son issues the entire series under the title Atlas sive Cosmographicae Meditationes ('Atlas, or cosmographic meditations'). It is the first collection to bear the title 'atlas'. Probably based on the Greek mythological character Atlas, whose task is to support the heavens, the name becomes the standard European word for a volume of maps.
A year after his death, in 1595, Mercator's son issues the entire series under the title Atlas sive Cosmographicae Meditationes ('Atlas, or cosmographic meditations'). It is the first collection to bear the title 'atlas'. Probably based on the Greek mythological character Atlas, whose task is to support the heavens, the name becomes the standard European word for a volume of maps.
17th - 18th century
Terra Australis: 16th-18th century
From the early 16th century European merchants are sailing the seas of southeast Asia. Often they make unexpected landfall, raising hopes of unknown territories rich in gold, silver or spice. The discovery of the Solomon Islands by a Spanish vessel in 1568 prompts interest in a so-called Terra Australis Incognita ('unknown southern land'). Part of the brief given to Francis Drake, when he sets off in 1577 to sail across the Pacific, is that he should search for this supposed land of treasure (see Drake's voyage).
Interest is maintained in the early 17th century when Dutch ships, sailing to and from the Moluccas, sight stretches of the western Australian coast. Are these places perhaps connected to the southern land?
Interest is maintained in the early 17th century when Dutch ships, sailing to and from the Moluccas, sight stretches of the western Australian coast. Are these places perhaps connected to the southern land?
The governor general of the Dutch East Indies, Antonio van Diemen, decides to investigate. He chooses for the purpose an experienced navigator, Abel Tasman, who is instructed to sail far south in the Indian Ocean and then to strike east, hoping to discover whether there is an open passage to South America. In the process he may also perhaps discover Terra Australis.
Tasman leaves Batavia in August 1642. He sails to Mauritius before continuing south and then east. He first makes landfall in November. He calls the place Van Diemen's Land, after the governor who has appointed him. Not until 1856 is the island renamed Tasmania, in honour of its discoverer.
Tasman leaves Batavia in August 1642. He sails to Mauritius before continuing south and then east. He first makes landfall in November. He calls the place Van Diemen's Land, after the governor who has appointed him. Not until 1856 is the island renamed Tasmania, in honour of its discoverer.
Keeping to the southern coast of this large island, Tasman continues eastwards. In December he reaches New Zealand. Sailing northeast along the coast of both South and North Island, he concludes that this must be the northwest corner of Terra Australis. Tasman discovers Tonga in January 1643, and the Fiji islands in February. He then continues northwest, passing north of New Guinea and returning to Batavia in June.
Remarkably, in his ten-month voyage, Tasman has sailed all the way round the real Terra Australis without noticing it. It will be another century before the continent of Australia is properly discovered and charted.
Remarkably, in his ten-month voyage, Tasman has sailed all the way round the real Terra Australis without noticing it. It will be another century before the continent of Australia is properly discovered and charted.
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 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.
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'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.
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.
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.
Three voyages of Captain Cook: AD 1768-1779
The voyages of James Cook are the first examples of exploration undertaken on scientific principles. His first expedition, sailing in the Endeavour from Plymouth in 1768, has a scientific task as its central mission. It is known to the astronomers of the day that in June 1769 the planet Venus will pass directly between the earth and the sun. An international effort is made to time the precise details of this transit, as seen from different parts of the world, in the hope of calculating the earth's distance from the sun.
Cook first mission is to sail to Tahiti, set up a telescope for this purpose and take the necessary readings.
Cook first mission is to sail to Tahiti, set up a telescope for this purpose and take the necessary readings.
Cook's second purpose is exploration. He is to continue the search for the supposed southern land, Terra australis, and he is to chart the coast of the known territory of New zealand. He has among his passengers scientists of another discipline. The botanists Joseph Banks and his Swedish colleague Daniel Solander are eager to collect specimens of Pacific flora.
Cook observes the transit of Venus in the summer of 1769 and then spends the next eighteen months charting the entire coast of New zealand's two main islands and the east coast of Australia. The Endeavour is back in Britain in July 1771.
Cook observes the transit of Venus in the summer of 1769 and then spends the next eighteen months charting the entire coast of New zealand's two main islands and the east coast of Australia. The Endeavour is back in Britain in July 1771.
The original astronomical purpose proves the least significant part of the voyage (the data proves inadequate for the intended purpose). But Cook's charting of these important coast lines is carried out to a scientific standard previously unattempted. As the first Europeans to visit Australia's congenial eastern coast, the reports of Cook and his distinguished passengers are instrumental in encouraging the notion of forming British settlements. And the botanical specimens of Banks and Solander prove of immense value.
One issue not resolved is whether there is an unknown southern continent south of New zealand. Cook now proposes another voyage to more southerly latitudes.
One issue not resolved is whether there is an unknown southern continent south of New zealand. Cook now proposes another voyage to more southerly latitudes.
The original astronomical purpose proves the least significant part of the voyage (the data proves inadequate for the intended purpose). But Cook's charting of these important coast lines is carried out to a scientific standard previously unattempted.
As the first Europeans to visit Australia's congenial eastern coast, the reports of Cook and his distinguished passengers are also instrumental in encouraging the notion of forming British settlements.
As the first Europeans to visit Australia's congenial eastern coast, the reports of Cook and his distinguished passengers are also instrumental in encouraging the notion of forming British settlements.
Cook sails from England in 1772 (now in the Resolution) and spends the three antarctic summers of 1772, 1773 and 1774 in a complete circumnavigation of the ice mass of the south pole - proving finally that there is no unknown habitable continent in the south (though Cook suspects, rightly, that there may be land under the ice).
Back in England in 1775, Cook reveals another scientific aspect to his explorations. His crew have remained surprisingly healthy in these long voyages, avoiding the sailor's debilitating disease of scurvy. Cook publishes a paper on his method for avoiding this condition. His men are given a regular ration of lemon juice.
Back in England in 1775, Cook reveals another scientific aspect to his explorations. His crew have remained surprisingly healthy in these long voyages, avoiding the sailor's debilitating disease of scurvy. Cook publishes a paper on his method for avoiding this condition. His men are given a regular ration of lemon juice.
Cook has discovered the importance of vitamin C, long before the substance itself is identified. The navy adopts his method, later substituting lime juice for lemon (causing British sailors in foreign ports to be known as 'limeys').
Cook's aim on his third voyage (again in the Resolution, from 1776) is to explore the Pacific coast of north America. He sails through the British settlements as far as the pack ice of the north pole. On his outward journey he discovers the Hawaiian group of islands, and here - wintering in Bering strait itself - he is killed in a skirmish with natives. He has spent all but two of the past ten years at sea, making an unprecedented contribution to knowledge of the Antarctic seas and the Pacific.
Cook's aim on his third voyage (again in the Resolution, from 1776) is to explore the Pacific coast of north America. He sails through the British settlements as far as the pack ice of the north pole. On his outward journey he discovers the Hawaiian group of islands, and here - wintering in Bering strait itself - he is killed in a skirmish with natives. He has spent all but two of the past ten years at sea, making an unprecedented contribution to knowledge of the Antarctic seas and the Pacific.
19th - 20th century
The challenge of Africa: from AD 1788
The ability of European ships to sail anywhere on the oceans of the world - culminating in the great voyages of Captain cook in 1768-79 - means that by the end of the 18th century the coast lines of the continents are familiar. So, from many centuries of to and fro, are the interior regions of Europe and Asia.
The interiors of the other three continents remain largely a mystery. North America will soon have heroic tales of exploration (particularly that of Lewis and clark in 1804-6) and Australia's fearsome outback will claim tragic victims (such as Burke and wills). But it is the ancient continent of Africa which now most fires the imagination of explorers, particularly in Britain.
The interiors of the other three continents remain largely a mystery. North America will soon have heroic tales of exploration (particularly that of Lewis and clark in 1804-6) and Australia's fearsome outback will claim tragic victims (such as Burke and wills). But it is the ancient continent of Africa which now most fires the imagination of explorers, particularly in Britain.
The mouths of Africa's great rivers - the Nile, the Niger, the Congo, the Zambezi - are familiar to European traders. And there are reliable reports of great stretches of inland river (particularly the Niger, linked in history with several important African kingdoms). But no one has any idea how it all joins up. Where do the inland rivers reach the sea? Where do the estuary waters come from? These questions tantalize explorers from the late 18th century to the heady days of Livingstone, Burton and speke, Baker and Stanley.
In 1788 an African Association is founded in London. Trade is one of its aims. Another is exploration, and specifically the discovery of the course of the Niger.
In 1788 an African Association is founded in London. Trade is one of its aims. Another is exploration, and specifically the discovery of the course of the Niger.
The mouths of Africa's great rivers - the Nile, the Burton and speke, the Congo, the Zambezi - are familiar to European traders. And there are reliable reports of great stretches of inland river. But no one has any idea how it all joins up. Where do the inland rivers reach the sea? Where do the estuary waters come from? These questions tantalize explorers from the late 18th century to the heady days of Livingstone, Burton and speke.
By the time the discoveries of these intrepid adventurers have been passed to the cartographers, the maps of the world have few blank areas left. Improved techniques of surveying will refine the detail. But geography, in a schoolroom sense, is complete by the late 19th century.
By the time the discoveries of these intrepid adventurers have been passed to the cartographers, the maps of the world have few blank areas left. Improved techniques of surveying will refine the detail. But geography, in a schoolroom sense, is complete by the late 19th century.
Improvements: 18th - 20th century AD
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