The Story of Geographical Discovery: How the World Became Known by Joseph Jacobs - HTML preview

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CHAPTER I

THE WORLD AS KNOWN TO THE ANCIENTS

Before telling how the ancients got to  know that part of the world  with which they finally became acquainted  when the Roman Empire was at its greatest extent,  it is as well to get some idea of the successive stages of their knowledge,  leaving for the next chapter the story of how that knowledge was obtained.  As in most  branches of organised  knowledge,  it  is to  the  Greeks that we  owe our acquaintance with ancient views of this subject.  In the early stages they possibly learned  something from the Phœnicians, who were the great traders and sailors of antiquity, and who coasted along the Mediterranean, ventured through the Straits of Gibraltar, and traded with the British Isles, which they visited  for the  tin found  in Cornwall.  It  is even said  that  one of their admirals,  at  the command  of Necho, king of Egypt, circumnavigated  Africa, for Herodotus reports that on the homeward voyage the sun set  in the sea on  the right hand.  But  the Phœnicians kept their  geographical knowledge to themselves as a trade secret, and the Greeks learned but little from them.

The first  glimpse that we  have of the  notions which  the Greeks possessed  of the shape  and  the inhabitants of the earth is afforded by the poems passing under the name of HOMER. These poems show an  intimate knowledge  of Northern Greece  and  of the western coasts  of Asia  Minor,  some acquaintance with Egypt,  Cyprus,  and  Sicily; but all the rest, even of the Eastern Mediterranean,  is only  vaguely  conceived  by  their  author.  Where  he  does  not  know  he  imagines,  and  some  of his imaginings have had a most important influence upon the progress of geographical knowledge. Thus he conceives of the world as being a sort of flat shield, with an extremely wide river surrounding it, known as Ocean. The centre of this shield was at Delphi, which was regarded as the "navel" of the inhabited world.  According to  Hesiod,  who  is but little later than  Homer,  up  in the far  north were placed  a people  known as  the Hyperboreani,  or those  who  dwelt  at the  back  of the north  wind; whilst  a corresponding place in the south was taken by  the Abyssinians.  All these four conceptions had  an important influence upon the views that men had of the world up to times comparatively recent. Homer also  mentioned  the pigmies  as living in Africa.  These were regarded  as  fabulous,  till they were re- discovered by Dr. Schweinfurth and Mr. Stanley in our own time.

It is probably from the Babylonians that the Greeks obtained  the idea  of an all-encircling ocean. Inhabitants of Mesopotamia would find themselves reaching the ocean in almost any direction in which they travelled, either the Caspian, the Black Sea, the Mediterranean, or the Persian Gulf. Accordingly, the oldest map of the world which has been found is one accompanying a cuneiform inscription, and representing  the   plain  of  Mesopotamia  with  the   Euphrates  flowing  through  it,  and   the  whole surrounded  by two  concentric circles,  which are  named  briny waters.  Outside these,  however,  are  seven detached  islets,  possibly representing  the seven  zones or climates  into  which the  world  was divided according to the ideas of the Babylonians, though afterwards they resorted to the ordinary four cardinal points. What was roughly true of Babylonia did  not in any way answer to  the geographical position of Greece,  and it is therefore probable that in the first place they obtained  their ideas of the surrounding ocean from the Babylonians.

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THE EARLIEST MAP OF THE WORLD

It was after  the period  of Homer and  Hesiod  that the first great expansion  of Greek  knowledge about the world began, through the extensive colonisation which was carried on by the Greeks around the Eastern Mediterranean. Even to this day the natives of the southern part of Italy speak  a Greek dialect, owing to  the wide extent of Greek colonies in that country, which used to  be called "Magna Grecia," or "Great Greece." Marseilles also one of the Greek colonies (600 B.C.), which, in its turn, sent out other colonies along the Gulf of Lyons. In the East, too, Greek  cities were dotted along the coast of the Black Sea,  one of which, Byzantium,  was destined  to be of world-historic importance. So, too, in North Africa, and among the islands of the Ægean Sea, the Greeks colonised throughout the sixth and  fifth centuries B.C., and in almost every case communication was kept up between the colonies and the mother-country.

Now, the one quality which has made the Greeks so distinguished  in the world's history was their curiosity; and it was natural that they should desire to know, and to put on record, the large amount of information brought to  the mainland  of Greece from the innumerable Greek  colonies.  But to  record geographical knowledge,  the  first  thing  that  is  necessary  is  a  map,  and  accordingly  it  is  a  Greek philosopher named  ANAXIMANDER of Miletus,  of the sixth century B.C.,  to whom we owe the invention of map-drawing.  Now,  in order to  make  a map  of one's own country,  little astronomical knowledge is required. As we have seen, savages are able to draw such maps; but when it comes to describing the relative positions of countries divided from one another by seas, the problem is not so easy. An Athenian would know roughly that Byzantium (now called Constantinople) was somewhat to the east and to the north of him, because in sailing thither he would have to sail towards the rising sun, and  would  find  the  climate getting colder  as he  approached  Byzantium.  So,  too,  he  might roughly guess that Marseilles was somewhere to the west and north of him; but how was he to fix the relative position of Marseilles and Byzantium to one another? Was Marseilles more northerly than Byzantium? Was it very far away from that city? For though it took  longer to get to Marseilles, the voyage was winding, and might possibly bring the vessel comparatively near to Byzantium,  though there might be no direct road between the two cities. There was one rough way of determining how far north a place stood: the very slightest observation of the starry heavens would show a traveller that as he moved towards the north, the pole-star rose higher up in the heavens. How much higher, could be determined by the angle formed by a stick pointing to the pole-star, in relation to one held horizontally. If, instead of two  sticks, we cut out a piece of metal or wood  to fill up  the enclosed angle,  we get the earliest form of the sun-dial, known as the gnomon, and according to the shape of the gnomon the latitude of a place is determined. Accordingly, it is not surprising to find that the invention of the gnomon is also attributed to Anaximander, for without some such instrument it would have been impossible for him to have made any map worthy of the name. But it is probable that Anaximander did not so much invent as introduce the gnomon,  and,  indeed,  Herodotus, expressly states that this instrument was derived from  the  Babylonians,  who  were  the  earliest  astronomers,  so  far  as  we  know.  A  curious  point confirms this, for the measurement of angles is by degrees, and degrees are divided into sixty seconds, just as minutes are. Now this division into sixty is certainly derived from Babylonia in the case of time measurement, and is therefore of the same origin as regards the measurement of angles.

We have no longer any copy of this first map of the world drawn up by Anaximander, but there is little   doubt  that  it  formed   the   foundation  of  a  similar  map   drawn  by  a  fellow-townsman  of Anaximander, HECATÆUS of Miletus, who seems to  have written the first formal geography. Only fragments of this are extant, but from them we are able to see that it was of the nature of a periplus, or seaman's guide,  telling how many days'  sail it was from one point to another,  and in what direction. We know also that he arranged his whole subject into two books,  dealing respectively with Europe and  Asia,  under  which  latter  term he  included  part  of what  we  now  know  as  Africa.  From the fragments  scholars have  been  able to  reproduce  the rough  outlines of the  map  of the  world  as  it presented itself to Hecatæus. From this it can be seen that the Homeric conception of the surrounding ocean formed a chief determining feature in Hecatæus's map. For the rest, he was acquainted with the Mediterranean, Red, and Black  Seas, and with the great rivers Danube,  Nile, Euphrates, Tigris, and Indus.

The next great name in the history of Greek geography is that of HERODOTUS of Halicarnassus, who  might  indeed  be  equally  well  called  the  Father  of  Geography  as  the  Father  of History.  He travelled  much  in  Egypt,  Babylonia,  Persia,  and  on  the  shores  of  the  Black  Sea,  while  he  was acquainted with Greece, and passed the latter years of his life in South Italy. On all these countries he gave  his  fellow-citizens  accurate  and  tolerably  full  information,  and  he  had  diligently  collected knowledge about  countries in their  neighbourhood.  In  particular he gives  full details of Scythia (or Southern  Russia),  and  of the satrapies  and  royal roads  of Persia.  As  a rule,  his  information is  as accurate as could  be expected at such an early date,  and he rarely tells marvellous stories,  or if he does, he points out himself their untrustworthiness. Almost the only traveller's yarn which Herodotus reports without due scepticism is that of the ants of India that were bigger than foxes and burrowed out gold dust for their ant-hills.

One of the stories he relates is of interest, as seeming to show an anticipation of one of Mr. Stanley's journeys. Five young men of the Nasamonians started from Southern Libya, W. of the Soudan, and journeyed for many days west till they came to a grove of trees, when they were seized by a number of men of very small stature, and conducted through marshes to a great city of black men of the same size,  through  which  a  large  river  flowed.  This  Herodotus  identifies  with  the  Nile,  but,  from  the indication of the journey given by him, it would seem more probable that it was the Niger, and that the Nasamonians had visited  Timbuctoo! Owing to this statement of Herodotus, it was for long thought that the Upper Nile flowed east and west.

After Herodotus, the date of whose history may be fixed at the easily remembered number of 444 B.C., a large increase of knowledge was obtained of the western part of Asia by the two expeditions of Xenophon and of Alexander, which brought the familiar knowledge of the Greeks as far as India. But besides these military expeditions we have still extant several log-books of mariners, which might have  added  considerably  to  Greek  geography.  One of these  tells the  tale  of an  expedition of the Carthaginian  admiral named  Hanno,  down the  western  coast of Africa,  as far  as  Sierra Leone,  a voyage which was not afterwards undertaken for sixteen hundred  years.  Hanno brought back  from this voyage hairy skins, which,  he stated, belonged  to men and women whom he had  captured, and who were known to the natives by the name of Gorillas. Another log-book is that of a Greek named Scylax, who gives the sailing distances between nearly all ports on the Mediterranean and Black Seas, and the number of days required to pass from one to another. From this it would seem that a Greek merchant  vessel could  manage on  the  average  fifty  miles  a  day.  Besides this,  one  of Alexander's admirals, named Nearchus, learned to carry his ships from the mouth of the Indus to the Arabian Gulf. Later on, a Greek sailor, Hippalus, found out that by using the monsoons at the appropriate times, he could  sail direct  from Arabia  to  India without  laboriously coasting  along  the shores  of Persia  and Beluchistan,  and  in consequence the Greeks gave his name to  the monsoon.  For information about India  itself,  the  Greeks  were,  for  a  long  time,  dependent  upon  the  account  of  Megasthenes,  an ambassador sent by Seleucus, one of Alexander's generals, to the Indian king of the Punjab.

While knowledge was thus gained of the East, additional information was obtained about the north of Europe by the travels of one PYTHEAS, a native of Marseilles, who  flourished about the time of Alexander the Great (333 B.C.), and he is especially interesting to us as having been the first civilised person who can be identified  as having visited  Britain. He seems to have coasted  along the Bay of Biscay,  to have spent some time in England,—which he reckoned as 40,000 stadia (4000 miles) in circumference,—and he appears also to have coasted along Belgium and Holland, as far as the mouth of the Elbe. Pytheas is, however, chiefly known in the history of geography as having referred to the island of Thule, which he described as the most northerly point of the inhabited earth, beyond which the sea became thickened, and of a jelly-like consistency. He does not profess to have visited Thule, and his account probably refers to the existence of drift ice near the Shetlands.

All this new information was gathered together, and made accessible to the Greek reading world, by ERATOSTHENES,  librarian  of Alexandria  (240-196  B.C.),  who  was  practically  the  founder  of scientific geography. He was the first to attempt any accurate measurement of the size of the earth, and of its inhabited portion. By his time the scientific men of Greece had become quite aware of the fact that the  earth was  a globe,  though they considered  that it  was fixed  in  space at  the centre  of the universe.  Guesses had  even been made at the size of this globe,  Aristotle fixing its circumference at 400,000  stadia (or  40,000  miles),  but  Eratosthenes  attempted  a  more  accurate measurement.  He compared  the length  of the  shadow  thrown by  the sun  at Alexandria  and  at Syene,  near the  first cataract of the Nile, which he assumed to be on the same meridian of longitude, and to be at about 5000 stadia (500 miles) distance. From the difference in the length of the shadows he deduced that this distance represented  one-fiftieth of the circumference of the earth, which would  accordingly be about 250,000 stadia,  or 25,000  geographical miles. As the actual circumference is 24,899  English miles,  this  was  a  very  near  approximation,  considering  the  rough  means  Eratosthenes  had  at  his disposal.

Having thus estimated the size of the earth, Eratosthenes then went on to determine the size of that portion which the ancients considered to  be habitable.  North and south of the lands known to  him, Eratosthenes and  all the ancients considered  to  be either  too  cold  or  too  hot to  be  habitable; this portion  he  reckoned  to  extend  to  38,000  stadia,  or  3800  miles.  In  reckoning  the  extent  of the habitable  portion from east  to  west,  Eratosthenes  came  to  the conclusion  that  from the Straits  of Gibraltar to the east of India was about 80,000 stadia, or, roughly speaking, one-third of the earth's surface.  The  remaining  two-thirds were  supposed  to  be  covered  by the  ocean,  and  Eratosthenes prophetically  remarked  that  "if  it  were  not  that  the  vast  extent  of  the  Atlantic  Sea  rendered  it impossible,  one might almost sail from the coast of Spain to  that of India along the same parallel." Sixteen hundred years later, as we shall see, Columbus tried to carry out this idea. Eratosthenes based his  calculations on  two  fundamental lines,  corresponding  in a  way to  our equator  and  meridian  of Greenwich: the first stretched, according to him, from Cape St. Vincent, through the Straits of Messina and  the island  of Rhodes, to  Issus (Gulf of Iskanderun); for his starting-line in reckoning north and south he used a meridian passing through the First Cataract, Alexandria, Rhodes, and Byzantium.

The next two  hundred  years after Eratosthenes'  death  was filled  up  by the spread  of the Roman Empire, by the taking over by the Romans of the vast possessions previously held by Alexander and his successors and by the Carthaginians, and by their spread into Gaul, Britain, and Germany. Much of  the increased knowledge thus obtained was summed up in the geographical work of STRABO, who wrote  in  Greek  about  20  B.C.  He  introduced  from  the  extra  knowledge  thus  obtained  many modifications of the system of Eratosthenes, but, on the whole, kept to his general conception of the world.  He rejected,  however,  the existence of Thule,  and  thus made the world  narrower; while he recognised  the  existence of Ierne,  or  Ireland; which he regarded  as the most northerly  part of the habitable world, lying, as he thought, north of Britain.

Between the time of Strabo  and  that of Ptolemy, who  sums up  all the knowledge of the ancients about the habitable earth, there was only one considerable addition to men's acquaintance with their neighbours,  contained  in a  seaman's manual for  the navigation  of the Indian  Ocean,  known  as the Periplus of the Erythræan Sea. This gave very full and tolerably accurate accounts of the coasts from Aden to the mouth of the Ganges, though it regarded Ceylon as much greater, and more to the south, than it really is; but it also  contains an account of the more easterly parts of Asia, Indo-China,  and China itself, "where the silk comes from." This had an important influence on the views of Ptolemy, as we shall see, and indirectly helped long afterwards to the discovery of America.

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PTOLEMAEI ORBIS

It was left to PTOLEMY of Alexandria to sum up for the ancient world all the knowledge that had been accumulating from the time of Eratosthenes to his own day, which we may fix at about 150 A.D. He took  all the information he  could  find  in  the writings of the preceding four hundred  years,  and reduced it all to  one uniform scale; for it is to  him that we owe the invention of the method  and the names of latitude and  longitude. Previous writers had been content to say that the distance between one point and another was so many stadia, but he reduced all this rough reckoning to so many degrees of latitude and  longitude,  from fixed  lines  as starting-points.  But,  unfortunately,  all these reckonings were  rough  calculations,  which  are  almost  invariably  beyond  the  truth;  and  Ptolemy,  though  the greatest of ancient astronomers, still further distorted  his results by assuming that a degree was 500 stadia,  or  50  geographical  miles.  Thus  when  he  found  in  any  of  his  authorities  that  the  distance between one port and another was 500 stadia, he assumed, in the first place, that this was accurate, and,  in the second,  that  the distance between the two  places was equal to  a degree of latitude or longitude, as the case might be. Accordingly he arrived at the result that the breadth of the habitable globe was, as he put it, twelve hours of longitude (corresponding to 180°)—nearly one-third as much again as the real dimensions from Spain to China. The consequence of this was that the distance from Spain to China westward  was correspondingly diminished  by sixty degrees (or nearly 4000  miles), and it was this error that ultimately encouraged Columbus to attempt his epoch-making voyage.

Ptolemy's errors of calculation would not have been so extensive but that he adopted  a method of measurement which made them accumulative. If he had chosen Alexandria for the point of departure in measuring longitude, the errors he made when reckoning westward would have been counterbalanced by those reckoning eastward, and  would not have resulted  in any serious distortion of the truth; but instead  of this,  he adopted  as his point of departure the Fortunatæ  Insulæ,  or Canary Islands,  and every degree measured to the east of these was one-fifth too great, since he assumed that it was only fifty miles in length. I may mention that so great has been the influence of Ptolemy on geography, that, up to the middle of the last century, Ferro, in the Canary Islands, was still retained as the zero-point of the meridians of longitude.

Another point in which Ptolemy's system strongly influenced modern opinion was his departure from the previous assumption that the world was surrounded by the ocean, derived from Homer. Instead of Africa  being  thus  cut  through  the  middle  by  the  ocean,  Ptolemy  assumed,  possibly  from  vague traditional knowledge,  that  Africa  extended  an unknown  length  to  the south,  and  joined  on to  an equally unknown continent far to the east, which, in the Latinised versions of his astronomical work, was termed "terra australis incognita," or "the unknown south land." As, by his error with regard to the breadth of the  earth,  Ptolemy led  to  Columbus; so,  by his mistaken notions as to  the "great south land," he prepared  the way for the discoveries of Captain Cook.  But notwithstanding these errors, which were  due partly  to  the roughness  of the materials  which he  had  to  deal with,  and  partly to scientific caution, Ptolemy's work is one of the great monuments of human industry and knowledge. For the Old World it remained the basis of all geographical knowledge up to the beginning of the last century, just as his astronomical work was only finally abolished by the work of Newton. Ptolemy has thus  the  rare  distinction  of being  the  greatest  authority  on  two  important  departments  of  human knowledge—astronomy  and  geography—for  over  fifteen  hundred  years.  Into  the  details  of  his description of the world it is unnecessary to go. The map will indicate how near he came to the main outlines of the Mediterranean, of Northwest Europe, of Arabia, and of the Black Sea. Beyond these regions he could only depend upon the rough indications and guesses of untutored merchants. But it is worth while referring to his method of determining latitude, as it was followed up by most succeeding geographers. Between the equator and the most northerly point known to him, he divides up the earth into horizontal strips, called by him "climates," and determined by the average length of the longest day in each. This is a very rough method of determining latitude, but it was probably, in most cases, all that Ptolemy had to depend upon, since the measurement of angles would be a rare accomplishment even in modern  times,  and  would  only  exist among a  few mathematicians and  astronomers  in Ptolemy's days. With him the history of geographical knowledge and discovery in the ancient world closes.

In  this  chapter I  have  roughly  given the  names  and  exploits of the  Greek  men of science,  who summed up in a series of systematic records the knowledge obtained by merchants, by soldiers, and by travellers of the extent of the world known to  the ancients.  Of this knowledge,  by far the largest amount  was gained,  not  by  systematic investigation  for  the purpose  of geography,  but by  military expeditions for the purpose of conquest. We must now retrace our steps, and give a rough review of the various stages of conquest. We must now retrace our steps, and give a rough review of the various stages of conquest by which the different regions of the Old World became known to the Greeks and the Roman Empire, whose knowledge Ptolemy summarises.

[Authorities: Bunbury, History of Ancient Geography, 2 vols., 1879; Tozer, History of Ancient Geography, 1897.]