“quella foce stretta, Ov’ Ercule segnò li suoi riguardi, Acciochè l’uom più oltre non si metta.”[422]
Through these Ulysses sailed, never to return.[423]
It is difficult to believe that a lunar eclipse had ever been observed simultaneously, and the local time compared, on the Ganges and at Gibraltar, as the above quotation from the Quæstio declares: and if it had been, the astrologers, the cosmographers, and the naturalists would have found out that they were greatly mistaken, for the distance is little more than half what they thought. All that Ptolemy had said was that this was the right method for calculating longitudes, and he gave as an example an eclipse which had been seen at Arbela at the fifth hour and at Carthage at the second hour.[424] It was, in fact, an excellent method, and the only one before the day of chronographs and telegraphs; and it seems to have been assumed that Ptolemy’s guess of 180° for the extent in longitude of the inhabited earth was based upon it.
Then this 180° was considered, in the Middle Ages, as divided into two equal parts, the western half containing Europe and Africa, the eastern containing Asia. On the western front of Asia lay Jerusalem, thus holding the central position in the inhabited earth which was thought to be her right, on the authority of certain Scripture texts, as we saw.[425] This gave the Mediterranean a length of 90°, which of course is vastly too great. Even Ptolemy had only estimated it at 62°, and the Alfonsine Tables made it 52°, while the true distance is only about 42°.
Latitude, however, was much more easily measured than longitude, for it was only necessary to take the height of the pole star above the horizon with an astrolabe; and the latitude of Jerusalem is really just about midway between the supposed limits of the habitable earth, the equator and arctic circle, for it is nearly 32° north.
Some daring spirits ventured to suggest that the dry land stretched much further round the globe than was commonly supposed, so that one might sail from Spain to Asia in quite a short time, and they sheltered themselves behind the great names of Aristotle, Seneca, Pliny, and Esdras.[426] Albertus Magnus quotes Aristotle to this effect, although in another part of the same book (his De Cælo et Mundo), he repeats the usual phrase about the habitable Earth being all contained within one of the northern quadrants of earth. Roger Bacon expresses himself more boldly, and it is possible that he was impressed by the long journey of the Franciscan friar Rubruquis, on his mission to Central Asia, from St. Louis of France to the Emperor of the Mongols. Besides relating the story of this journey, Bacon speaks of men who were known to live in tropical Taprobane (Ceylon), and if there, why not also south of Capricorn? There may be delightful countries there, since it is the better and nobler part of the world, as Aristotle and Averroës taught.
Moreover, Dante’s own countryman, the learned Pietro d’Abano, maintained that there are habitable lands on, and even beyond the equator, and did not hesitate to quote conversations with Marco Polo as evidence, although this “most extensive traveller and most diligent enquirer” was accounted a romancer by most of his contemporaries. Had not Messer Marco told him that in islands south of the equator he had seen not only great rams with coarse stiff wool like the bristles of pigs, but human beings?[427]
Roger Bacon was banished from Oxford on a charge of heresy and witchcraft: Pietro d’Abano escaped the Inquisition by dying, in 1316. Men such as these belonged to the new age that was coming, the age that would throw away the old lesson-books, and begin to discover for itself—and they suffered in consequence. Dante belonged heart and soul to his own era, and clung passionately to its ideals and traditions. For him the Ganges still flowed into the all-surrounding ocean on the east coast of Asia, 90 degrees from Jerusalem, as Orosius had pictured it, and there is not the faintest echo in his writings of the voyages of his countrymen, Corvino and his bishops, or Polo and his companions,[428] between “Greater India” and “Zayton” (Amoy harbour), although they surely must have recognized, when they praised the great rivers of China, that these flowed into a sea many days’ journey beyond that into which the Ganges rolled its waters. Nor is there, on the other hand, any hint of the monstrous races with which Dark-Age superstition had peopled the remote regions of the earth, although they were regularly represented on the maps of that time. It is true that the “portolani,” or handy charts, of which the earliest known date from Dante’s life-time, showed none of these things, but depicted the coast-lands of the Mediterranean and Black Seas with marvellous accuracy: but they were only for pilots and merchant captains, and had nothing to do with scholars. The maps Dante would see were hung on church or monastery walls, or illustrated learned books; and the mappe-monde of Cardinal Heinrich of Mainz may be taken as typical of them all. It much resembles our great Hereford Map of the World, and was probably copied from the same original design.
It is two hundred years older than Dante, but so stationary was geography throughout the Middle Ages that it might have been executed in his day, or, except for a few details, several centuries earlier.
Mediæval maps are as fascinating as a fairy tale, which indeed they much resemble. The shape is conventional, and not supposed to represent the true shape of the habitable earth; it is sometimes circular, sometimes quadrilateral, occasionally oval, as in the present instance. The east is here, as usual, at the top, and there we see the Paradise of Adam and Eve, and close beside it, to the north, the River Ganges, flowing into the great ocean which surrounds all the land. At the opposite or western extremity are the Pillars of Hercules, which two angels appear to be guarding. In the centre, but not so exactly or conspicuously central as in some other maps, we find “Hierusalem.” Along the south is the long narrow continent of Africa, with the Atlas and Ethiopian mountains; and the Nile, rising far in the south-west, after mysterious submergences and reappearances, finally flows into the Mediterranean, past the pictured Pyramids, here strangely called (according to Dark-Age myth) the Barns of Joseph. In the north another Angel points to the country where dwell the Gog-Magogs, and not far off are the lands of the Hyperboreans, here described as untroubled by disease or discord, of the “most wicked” Gryphons, and of the Dog-headed folk, adjoining the Arctic Ocean.