About the time that Alexander was annexing the whole of the eastern world, men were becoming very much interested in the west. Over seven hundred years had passed since the Phoenicians first came to an island in the Northern Sea where there was tin to be had for the mining; but the Phoenicians had kept their secret well. They did not want their competitors to know the route to the tin-bearing islands. But the existence of England could not remain hidden from the world forever. The great traveler Pytheas of Marseilles visited it in about 300 B. C., and reported an island named Thule, six days sail to the north, where there was unbroken daylight in the summer and long winter darkness. That might refer to the Faeroe Islands, or even Iceland or Norway, we do not know; but Pytheas was the first of the really scientific travelers, and his remarks are not to be dismissed lightly. He had established a training course for astronomers, and determined a substantially correct latitude for his home town.
Soon after Pytheas, the Romans came in contact with the Carthaginians, who were the natural heirs of the Phoenicians, and from them discovered the secret. There was an island to the north, an island which bore not only tin, but pearls as well. The Gallic people had named the high mountains which separated their country from Italy, by their own word for hills, and called those mountains the "Alps." The little island received the same name, a name that meant a high white hill--and all the early travelers called it Albion--from the first view they had of it--the chalk cliffs of Dover.
The rumor of pearls, as well as his incurable habit of conquering, took Julius Caesar to that coast. The ladies of Rome were very fond of jewelry. He gave the same account of Britain that most travelers give when they spend only a few weeks in a country and return to impress the people at home: "Hopelessly primitive natives they have there--why they don't even know how wonderful our country is." As a matter of fact the people were more than moderately civilized, and if they acknowledged Phoenician and Gallic customs more than Roman, that is hardly remarkable. The Phoenicans and the Gauls had acknowledged them.
In the meantime scientific geography had progressed in Greece with great rapidity. Eratosthenes, who had all the resources of the Library of Alexandria at his command, had measured the circumference of the Earth, and drawn a map with seven parallels of latitude and seven meridians. His main parallel ran through the Cape of Saint Vincent, the Straits of Messina, the Island of Rhodes, to Issus on the Gulf of Iskanderus. His prime meridian stretched from the first Cataract on the Nile, through Alexandria to Rhodes and the city of King Byzas, which was later to be called Constantinople or Istambul. His great book was divided into three parts: a history of geography and its physical features, a mathematical treatise on the nature of the world, and a history of political and social geography.
Eratosthenes was also the first man to recognize the implications of a spherical Earth. "If it were not that the vast extent of the Atlantic sea rendered it impossible," he wrote, "one might even sail from the coast of Spain to that of India along the same parallel." More than fifteen hundred years were to pass before such an attempt was made, and even then the first man who tried to go from Spain westward to India did not believe in the vastness of the Atlantic.
Only fifty years after Eratosthenes, Hipparchus, the famous astronomer, undertook to show all the fallacies which his predecessor had committed. The latitudes, Hipparchus said, should be drawn at equal intervals, say at half an hour's difference in the length of the day; and the longitudes should be likewise regulated, preferably from observation of eclipses. The length of the degree, which Eratosthenes had computed, Hipparchus accepted without question (it was wrong), but he accused the librarian in no uncertain terms of reckoning by travelers' tales instead of science. "And as for his claim that the ocean surrounds the Earth--it makes no more sense than to say that the Red Sea is surrounded by land!"
His whole argument was just a little unfair and capricious. It was hard enough for anyone to calculate longitudes with the poor timekeepers available, without wandering over the Earth in those perilous days of sea voyages; and eclipses hardly came often enough for one man to use them exclusively for his measurements. Hipparchus had made an excellent map of the sky so he thought he know all about the business of cartography. He never tried to make a map of the Earth.
The work of Eratosthenes was for the most part copied by Strabo, who lived from 50 B. C. to 24 A. D. Strabo however rejected the idea of Thule and decided that the most northerly habitable land was Ieme ( Ireland) which he set far to the north of Britain, where some of the Irish Free-staters might well wish it set today. But in something far more important, Strabo agreed with Eratosthenes. He insisted that there was much more water than land on the globe. He was right; but perhaps it was not a pity that he was judged wrong. As usual in geography, the wrong theory led further.