Ancient Greek Geography
Anaximander of Miletus, 570 BC, is credited with the invention of charts and maps. This is improbable, as the necessities of the Egyptians in measuring and dividing their Nile-irrigated and artificially irrigated lands must have made land-surveying and plotting a principal mode of determining the allotment of taxes. The revenue was derived from the use of water during the overflow of the Nile, and afterward of that which, was stored in reservoirs during high water, — the simplest form of taxation upon property ; the eminent domain of water being vested in the sovereign. The Egyptians, says Eustathius, "recorded their marches in maps."
The popular idea of the earth in the time of Homer, 900 BC, consisted of a strip of land around the Pontus Pelagus, and even the boundaries were not known toward the northwest. Cimmerian darkness brooded upon the deep which surrounded the land. The world as known to Hecateus about 500 BC, finds the borders of the Mediterranean defined ; the Iberi and Celtse are known ; the pillars of Hercules on the west and the Caspian on the east mark the longitudinal extent; back of Asia Minor is a greater Asia, which extends westward to the Nile.
As far back as 570 BC, Anaximander believed that the earth was a cylinder whose height was three times the diameter of the base. Anaxagoras was of the same opinion. Plato in 400 BC also believed that he lived on a flat earth, only he supposed the surface was a square, and that the earth itself was a cube. In 340 BC came the first to advance the theory of the spherical form of the earth. This was Aristotle. He reported that mathematicians had already computed the circumference, and found that it was 400,000 stadia. The term stadia comes from the plural of the Greek stadion, the word for a distance of 185 to 192 meters (607-630 ft), the length of the track of the running event which was the only competition of the first Olympic Games. The circumference of the earth at the equator is actually 24,900 statute miles (40,075 kilometers), about half the 47,000 statute miles of Aristotle.
Observations accumulated which could not be reconciled with the flatness of the Earth. A traveller, journeying from a mountain range, found on looking back that the mountains not only grew smaller and smaller but that they sank and at last dropped down altogether out of sight. When sailors began to go down to the sea in ships and ventured far out on the waters, the new land to which they sailed appeared first as one little peak, then as a range, and at last the whole land stood above the water. These observations were difficult to reconcile with the idea of a flat Earth, but easy to explain if it was round. The sinking of ships below the horizon is not a proof that the earth is a globe, but it does indicate that the surface is curved.
Two facts known to the ancients prove indisputably that the earth is nearly, if not quite, spherical. One is the appearance of the moon when she is eclipsed. From time to time the full moon passes into a shadow and loses its light for a couple of hours. The outline of the shadow which appears on the lunar disc, is always circular. This is a very important circumstance. Only one figure throws a round shadow under all conditions, and that is a globe. The shadow into which the moon passes must therefore be the shadow of a large ball. Early astronomers knew that an eclipse of the moon was caused by the moon entering the shadow of the earth. With this knowledge, and the facts of observation, it was possible to place the earth's globularity beyond the possibility of doubt.
Another fact which results from the earth's spherical form is that the same stars have different altitudes when observed from different latitudes. If the earth were flat, the altitudes of stars would be the same from whatever place they were viewed, but the earliest navigators found that this was not the case. When sailing southwards the stars in the northern sky appear lower and lower every night, and stars not previously seen shine out in the south.
In the geography of Democritus, 300 BC, Europa, Asia, and Libya are acknowledged divisions. In the world of Herodotus, the Caspian was changed from an indentation in the land to a lake. Asia extends to the Atlantic; Libya is a subdivision. "Aristogoras, the tyrant of Miletus, showed to King Cleomencs of Sparta a bronze tablet, on which the whole circuit of the earth was engraved, with its seas and rivers" [Herodotus, V. 49]. In the maps cited by Herodotus and other geographers of his time, the grand division now known as Africa was called Libya. The term Europe is from a Semitic word Ereb, the west, selling, darkness, etc. Asia signifies the opposite, — the east, rising, etc. The origin of the term Libya is lost in obscurity. The same, except as to period, may lie said of the Latin word Africa. Its derivation was a mystery 2,300 years ago.
"For my part I cannot conceive why three names, and women's names especially, should ever have been given to a tract which is in reality one nor can I even say who gave the three tracts their names, or whence they took the epithets. According to the Greeks in general, Libya was so called after a certain Libya, a native woman, and Asia' after the wife of Prometheus. The Lydiaus, however, put in a claim to the latter name, 'as being from Asius, the son of Cotys.' . . As for Europa, no one can say whether it is surrounded by the sea or not, neither is it known whence the name of Europa is derived, nor who gave it name, unless we say that Europa was so called after the Tyrian Europn, and before her time was nameless. . . However let us quit these matters. We shall ourselves continue to use the names which custom sanctions." [Herodotus, IV. 45].
In former times the geographers were undecided where to draw the dividing line between Asia and Libya. The Egyptians were of known Asiatic origin, and it was considered more logical to include them in Asia. The eastern border of the land abutting upon Libya, was for a time adopted. Afterwards the 1'auais and the Nile were the limits of Asia, one half of Egypt being ascribed to Africa. Herodotus considered it absurd to divide the country of one people between two continents. Ptolemy, the geographer, defined the Red Sea and the Isthmus of Suez as the boundary between the continents.
Eratosthenes (276-196 BC) of Alexandria was the discoverer of the obliquity of the ecliptic, and was the founder of geodesy. He determined the circumference of the earth by measuring a degree of the meridian. Measurements of an arc of the meridian have been made by the Chaldeans, by Eratosthenes, by Al Maimon, by Pire, and more lately by the French, English, Germans, and others; in Peru, Lapland, British India, and elsewhere. Eratosthenes was the author of the science of geography, and the name thereof. The extent of each zone ne determined by the length of the solstitial day, and called them climates. The map of Eratosthenes was merely a plane exemplification, and that lie was fully aware of the spherical form of the earth.
To Eratosthenes is due the honor of being the first of whom there is any record to make an estimate of the circumference of the earth based upon measurement. His geodetic measures consisted in noting that at Syene, at the time of the summer solstice, the sun passed through the zenith of the place, was shown by a vertical object casting no shadow; while at the same time at Alexandria such an object cast a shadow of such a length as to show that the sun's rays made an angle with the vertical equal to one-fiftieth of a whole circumference. He concluded, then, that as the two places were nearly on the same meridian the distance between them is one-fiftieth of the whole circumference of the earth. The distance being estimated at 5,000 stadia, the circumference of the earth becomes 250,000 stadia. As the precise length of his stadium is not known, it is not possible to estimate the accuracy of this determination, which would be about 29,500 statute miles [rather larger than the actual 24,900 statute miles]. The longitudes of the two places differed by 3°; also the amplitude of his arc was too small by 15'. Notwithstanding these sources of inaccuracy, however, great credit is due to him for inaugurating a correct method for determining the dimensions of the earth.
The "map of the world" by Hipparchus (150 BC) is founded on the discoveries of Eratosthenes, and is the first recorded attempt to assign geographical jwsitions by longitudes and latitudes, obtained, the former from lunar eclipses, and the latter from lengths of the shadow measured by the gnomon. In Strabo's time, about the Christian era, it was customary to draw a meridian and parallel for each important place whose position was considered as determined.
A new measurement of the circumference of the earth by Posidonius (born about the end of Hipparchus's life) may also be noticed; he adopted a method similar to that of Eratosthenes, and arrived at two different results. The later estimate, to which he seems to have attached most weight, was 180,000 stadia [about 21,000 statute miles, rather less than the actual 24,900 statute miles], a result which was about as much below the truth as that of Eratosthenes was above it.
Ptolemy, about AD 150, simplified the method, and probably introduced the regular plan of dividing the area by lines. Geographia of Claudius Ptolemy (ca. 87-150 CE), by Wilibald Pirkheimer [1525, Nuremberg]. Ptolemy's map showed the inhabited world as it was known to the Greeks and Romans of about 100-150 CE. Ptolemy, who gave Greeek astronomy its final form in the second century A.D., did the same--and more -- for geography and cartography. His massive work on the subject, which summed up and criticized the work of earlier writers, offered instruction in laying out maps by three different methods of projection, provided coordinates for some eight thousand places, and treated such basic concepts as geographical latitude and longitude. In Byzantium, in the thirteenth century, Ptolemic maps were reconstructed and attached to Greek manuscripts of the text. And in the fifteenth century, a Latin translation of this text, with maps, proved a sensation in the world of the book. A best seller both in the age of luxurious manuscripts and in that of print, Ptolemy's Geography became immensely influential. Columbus -- one of its many readers -- found inspiration in Ptolemy's exaggerated value for the size of Asia for his own fateful journey to the west. Even the familiar territory of the Mediterranean demonstrated that insufficient contemporary knowledge was available. Ptolemy erred in many important cartographical details, as his Mare Nostrum is about 20° too long, and even after correcting his value of a degree it was still about 500 geographical miles too long. His Mediterranean, from Marseilles to the opposite point on the coast of Africa, is 11° of latitude instead of the actual 6.5°.
The maps of Eratosthenes and Ptolemy show a marked advance in geographical knowledge, especially in the bounds of Asia and Libya, the latter receiving in the map of Ptolemy its new name of "Africa." The old belief in a circumscribing sea is evident in the upper map, where Libya is apparently extended merely to balance the newly discovered extent of Asia, the insular character towards the south being assumed, as in the earlier maps. In the [very poorly attested] map of Democritus, the Mesopotamian rivers flow into the ocean and mark the extent of geographic knowledge, in an eastern direction, of the Mediterranean nations [in most respects, this infrequently cited map represents a retrogression relative to the map of Herodotus of some 150 years earlier]. In other maps these rivers debouch into the Persian Gulf; and India with its marginal rivers, the Indus and the Ganges, forms an eastern extension. Taprobane (Ceylon) is also shown.
Britannia and Ierne come upon the scene with the Cassiterides or Tin Islands, which had been known to the Phoenicians for 1,000 years. There is also an indication of a land across the Baltic. Aristotle had said, 100 vears before, that it was possible that Spain and India were only separated by the sea. Eratosthenes said that only the extent of the Atlantic Ocean prevented sailing from Spain to India along the same parallel. In the map of Ptolemy, the land grows toward sunrise, with the peninsula of Malacca coming into view, with some traces of an eastern archipelago, and a country beyond India of unknown and undefined extent; so much land in this direction, indeed, that the sea is suppressed. Taprobane is still there.
From the most distant ages, the products of India were conveyed to the West; but the course was chiefly a land one, from the coast of Arabia Felix, or the head of the Persian Gulf, and the trade was almost entirely in the hands of the Phoenicians. At length, when Alexander the Great had built the city named from himself in Egypt, and that country formed an independent kingdom, under the Ptolemies, the Indian trade began to take a new direction, and vessels leaving the vicinity of the modern Suez proceeded down the Red Sea, along the coast of Arabia, whence they sometimes sailed across the mouth of the Persian Gulf to the Indus, and thence round Cutch and Guzerat to the mouth of the Nerbudda, and then occasionally along the coast of Malabar. When they had obtained their cargoes, they returned by the same circuitous route, and the commodities, being conveyed by land to Alexandria, were thence distributed over the West. This, however, was not the common course, for the ships of Egypt in general went no further than the coast of Arabia, where they purchased the goods which Arabian or Indian vessels had brought thither.
It seems strange that, in this long-continued intercourse with India, the phenomenon of the Monsoons, and their applicability to the purposes of trade, should never have engaged the thoughts of any of the navigators. It was not till about the middle of the first century of our era, that a mariner named Hippalus, observing the regularity with which the one blows for six months, from the south-west, and the other for an equal period, from the north-east, drew the natural conclusion, that if a vessel were to sail with the former, from the mouth of the Red Sea, she must be carried to some point on the coast of India, and that the other then would bring her back to the place from which she had started. He had the courage to put his theory into practice, and the event fully justified his anticipations. The Indian trade now took a new course; but Alexandria continued to be its great emporium.
Ptolemy put upon his map the interior lakes of Africa where Livingstone found them to be, would not take the sea for granted on the southern confines of Africa more than he would on the eastern regions of Asia. Africa assumes large proportions, and the name Libya becomes local ; indeed, a dotted line uniting a hypothetical eastern land with a possible extension of Africa is suggested as the termination of salt water southwardly. Herodotus had characterized as incredible the statement "that those who sailed around Libya, in sailing from, east to west, had the sun on their riight hand," as in sailing eastwardly in the Mediterranean the sun at noon is always to the left. He farther states that Neeho commanded the Phoenicians to make their return to Egypt by the pillars of Hercules. Strabo, while discrediting the accounts of circumnavigations previously said to have been accomplished, does not deny the possibility of the circumnavigation, but affirms that from the cast to the west there was but little wanting to its completion.
The Greek philosophers before the time of Christ had discovered that the world is a globe, or ball, and had even computed rudely its circumference. But in the Middle Ages this knowledge had been disputed and contradicted by a geographer named Cosmas, who held that the world was a vast plane, twice as long as it was broad and surrounded by an ocean. This belief was generally adopted by churchmen, who were the only scholars of the Middle Ages, and came to be the universal belief of Christian Europe.
The geographical theory of the Greeks, that the world is round, was revived towards the end of the 15th Century. The geographers, however, in making their calculations of the earth’s circumference, had fallen into an error of some thousands of miles; that is, instead of finding that it is fully twelve thousand miles from Europe around to the East Indies, they had supposed it about four thousand, or even less. Marco Polo too had exaggerated the distance he had traveled and from his accounts men had been led to believe that China, Japan, and the Spice Islands lie much further to the east than they actually do.
By sailing west across one wide ocean, with no intervening lands, it was thought that one could arrive at the island-world off the continent of Asia. This was the theory that was revived in Italy and which clung in men’s minds for years and years, even after America was discovered. An Italian, named Toscanelli, drew a map showing how this voyage could be made, and sent Columbus a copy. By sailing first to the Azores, a considerable portion of the journey would be passed, with a convenient resting-stage. Then about thirty-five days’ favorable sailing would bring one to the islands of “Cipango,” or Japan, which Marco Polo had said lay off the continent of Asia. From here the passage could readily be pursued to Cathay and India.
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