History of Geography. Sir John Scott Keltie
and in literary usage came to signify the uttermost north. Pytheas also obtained an idea of the Baltic Sea, and is considered by some to have entered it; he is stated to have reached the River Tanais; but if that is to be considered as one of the north European rivers, and not the known Tanais of the Black Sea basin, its identity is doubtful. Pytheas was a trained astronomer; he was one of the first to calculate latitudes, and had that of Massilia nearly correct; he heard of the unbroken summer daylight and winter darkness of the far north, and he noted various features of geographical interest, such as the decrease in the number of different grain crops observed as he travelled northward. He appears, in fact, from the references in other authors, which alone furnish us with knowledge of his work, in the light of a scientific traveller of a type rare in his time.
Mathematical geography was carried a long step forward by Eratosthenes (c. 276–194 B.C.), a native of Cyrene, who became chief librarian at Alexandria under Ptolemy III Euergetes. He calculated the circumference of the earth. He considered Syene to be situated on the tropic (which it was not, precisely), because at noon on the day of the summer solstice the sun appeared to shine directly down a deep well there. He therefore observed the zenith distance of the sun at Alexandria at the same time, and obtained his result from this and the measured distance between Alexandria and Syene. His result was to make the earth’s circumference only about one-seventh greater than it actually is. He also estimated the size of the habitable earth (œcumene), and considered it, as a result, to be about double as long from west to east as it was broad from north to south. But his estimate of the distance from what is now the extremity of Brittany to the known eastern limit of India was about one-third too great. On a map of the world he drew seven parallels, using the few points of which the latitudes had been worked out, and also seven meridians at irregular distances apart. Hipparchus (middle and second half of the second century), an astronomer, native of Nicæa in Bithynia, who worked in Rhodes, drew an elaborate series of parallels, and made the division into 360 degrees; the spaces between the lines he called climata, or zones. The problem presented by meridians was more difficult, for there was no instrument for the calculation of longitude like the gnomon for that of latitude. A well-recognised line was that taken to lie from the mouth of the Danube to that of the Nile—Herodotus had used this—and southward up the latter river; but not only the line itself, but also the ideas of intermediate points lying on it, were rather far from the truth.
Eratosthenes in his writings also dealt with the history of geography and with physical geography. This last branch attracted a number of students about this period and later, as, for example, Agartharchides or Agatharchus of Cnidus (middle of the second century B.C.). Crates of Mallus, in the first half of the same century, expressed the view of the Stoic philosophers that the spherical earth was divided into four inhabited quarters—the Œcumene (the known world), the Antipodes, the Periœci, and the Antœci. Posidonius the Stoic (c. 130–50 B.C.), among his studies in various departments of knowledge, included such subjects as the ocean, volcanoes, and earthquakes; he observed the interaction of the sun and moon in their influence on tides. He recalculated the circumference of the earth, but obtained an underestimate considerably further from the truth than Eratosthenes’s overestimate; and, owing to his high scientific reputation, his error persisted in much later work. Posidonius, before settling at Rhodes, had travelled widely in Africa, Spain, and western Europe generally; and both he and Agartharchides, like other writers of this period, and Aristotle before them, recognized the importance of the human side of geography, and the influence of physical environment on the political and social régime. Polybius (c. 204–122 B.C.) of Megalopolis in Arcadia, historian, statesman, and military commander, was inspired by extensive travel to introduce the results of topographical and geographical studies throughout his history. Among travellers who rank more nearly among explorers there may be mentioned at this period Eudoxus of Cyzicus (fl. c. 130 B.C.), who went on a trading expedition to India, in command of a fleet which was despatched by Ptolemy Euergetes of Egypt with the specific object of exploring the Arabian Sea. Eudoxus subsequently tried without success to circumnavigate Africa, making at least two voyages along the east coast. Finally, it must be remembered that at this period the extension of the knowledge of the world was mainly due no longer to Greek, but to Roman, activities, and Roman conquests were pushed beyond the confines of accurate Greek knowledge in various directions. Much geographical material was made available by writers on Roman military expeditions. Thus Pompey was accompanied in the Caucasian region by Theophanes of Mytilene, as historian of his campaigns; Julius Cæsar wrote his own account of lands into which he carried his arms (Gaul, etc.).
From all this it appears that, according to the lights of knowledge at the time, a fair conception existed of geographical study along the main lines which it follows to-day. There was therefore occasion for a general review of the whole subject; and this occasion was seized by Strabo, a native of Amasia in Pontus, who was born c. 63 B.C., and died in the second or third decade of the following century. He was educated partly at Rome, but his language and outlook were Greek. He travelled much, as far as Etruria, the Black Sea, and the borders of Ethiopia, as well as in Asia Minor, though he knew comparatively little of Greece. His geography, which was not finally completed till towards the close of his life, was the first attempt at covering the whole geographical field—mathematical, physical, and human—and his range was thus wider than that of Eratosthenes. Strabo used the recent Roman authorities to some extent, such as Cæsar’s Commentaries (in part) and a map of the Roman Empire by M. Vipsanius Agrippa, son-in-law of Augustus, which was set up in Rome; and he also preferred the authority of Polybius to that of Pytheas, but his sources were mostly Greek. His appreciation of them was not always wise. He ranked the Homeric poems highly, but discredited Herodotus, who on some points had better information than he. He added nothing to the mathematical branch, in which Eratosthenes was his master. He thus accepted the spherical form of the earth, its dimensions as laid down by his predecessors, and its division into five zones. He recognized Hipparchus’s view that further astronomical observations were essential to precision in earth-measurement and the position of points on the surface; but it was outside his province to add to those existing. His work in the physical field, however, improved upon that of his predecessors, and his surveys of the features and products of the various lands must have been singularly valuable for reference. The apportionment of the seventeen books of his geography is not without interest as a rough guide to the distribution of available material and to the author’s outlook. He devoted two books to introductory matter, to Spain and France two, to Italy two, to northern and eastern Europe one, to Greece and adjacent lands three, to the main divisions and remoter parts of Asia one, to Asia Minor three, to India and Persia one, to Syria and Arabia one, to Egypt and the rest of Africa one.
Rome did not carry on the Greek tradition of the study of geographical theory. H. F. Tozer, quoting J. Partsch, writes: “It has been aptly remarked that the task which Eratosthenes set himself of measuring the earth by means of the heavenly bodies, and that of Agrippa, who measured the Roman provinces by milestones, may be taken as typical of the genius of the two nationalities respectively.” Thus Pomponius Mela, purporting to survey the world in his De Chorographia (written c. 50 A.D.), followed the coast and described various countries in passing, but by no means all, and added very little to geographical knowledge at large. Pliny the Elder (c. 23–79) devoted three books and part of another of his Historia Naturalis to geography; but his geography may (at least in considerable part) be compared with the arid text-book of a generation ago, though in some instances his descriptions (as of features in Palestine, Syria, and Armenia) are valuable. As bearing on the quotation made above, it may be said here that the famous Roman system of road building gave rise to two classes of road-books (as they may be termed), one consisting of lists of stations and distances, such as the Antonine Itinerary (probably, in its original form, of the late third or fourth century), the other diagrammatic, such as the Peutinger Table (probably of the first half of the third century, though named after a scholar of the sixteenth), on which roads, stations, and other details were presented in a map-like form, but independently of true scale or direction. The Roman agrimensores were skilled surveyors.
It is not, then, surprising that the two great theoretical geographers next to be considered are not associated with the capital of the Roman Empire. Of the work of Marinus of Tyre nothing is known beyond what is recorded by his immediate successor, Ptolemy, who used and acknowledged his