Siebenkees and Heeren (De Fontibus Geographicorum Strabonis) have examined the authorities to which Strabo had, or might have had, access, and Groskurd has availed himself of their researches.
The following is a short summary of the seventeen books from these sources, but for a more detailed account of their contents the translation itself must be referred to.
The first two books may be considered as an independent treatise, and by themselves form a remarkable contrast with the rest of the work, in the manner of treating the subjects, and in the difficulties which they present both of language and matter.
In the 1st book, the author enters into a long discussion on the merits of Homer, whom he considers to have been the earliest geographer, and defends him against the errors and misconceptions of Eratosthenes. He corrects some faults of Eratosthenes, and, in his inquiry concerning the natural changes of the earth’s surface defends Eratosthenes against Hipparchus. In conclusion, he again corrects Eratosthenes as regards the magnitude and divisions of the inhabited world. The most remarkable passage in this book is that in which he conjectures the existence of the great Western Continents.[15]
The 2nd book is chiefly occupied with some accounts of mathematical geography, and the Author defends against Hipparchus the division of the inhabited world adopted by Eratosthenes into sections. Then follows a criticism of the division of the earth into six zones, as taught by Poseidonius and Polybius. The pretended circumnavigation of Africa by Eudoxus is referred to, as well as some geographical errors of Polybius. He makes observations of his own on the form and size of the earth in general, as well as of the inhabited portion of it, describing the method of representing it on a spherical or plane surface. A short outline is given of seas, countries, and nations; and he concludes with remarks on the system of climates,[16] and on the shadows projected by the sun.
The 3rd book commences with Iberia, and the subject of Europe is continued to the end of the 10th book. His references are the Periplus of Artemidorus, Polybius, and Poseidonius; all three of whom wrote as eye-witnesses. For descriptions and measurement of distances, Artemidorus is chiefly depended upon. The information possessed by Eratosthenes of these countries was meagre and uncertain. For the nations of southern Iberia, he adopts the account of Asclepiades of Myrlea, who had lived and been educated there. Some statements also are borrowed from Roman authors.
The 4th book contains Gallia, according to the four divisions then existing, viz. Gallia Narbonensis, Acquitanensis, Lugdunensis, and the Belgæ; also Britain, with Ierne, and Thule; and lastly, the Alps.
Here Eratosthenes and Ephorus are of little service. His chief guide is Julius Cæsar, whom he frequently quotes verbatim. Polybius is his guide for the Alps. Pytheas is the source of some scanty information respecting Ierne and Thule. Throughout his description he adds accounts obtained at Rome from travellers.
The 5th book commences with a general sketch of Italy, and refers principally to northern Italy. Dividing its history into ancient and modern, his chief reference for the former is Polybius, and for the latter we are indebted to the observations of the author himself, or to accounts received from others. Still the description of Upper Italy is poor and unsatisfactory, from the author not sufficiently availing himself of Roman resources. Then follows some account of Etruria with its neighbouring islands, Umbria, Samnium, Latium, and Rome, chiefly the result of the author’s own researches and observations. The book concludes with some remarks on the inhabitants of the mountainous districts of Samnium and Campania.
The 6th book is a continuation of the same subject. Magna Græcia, Sicily, and the adjacent islands, are noticed, and the author concludes with a short discussion on the extent of the Roman Empire. Descriptions of some places are from his own observations; but the sources whence he takes his other account of Italy and the islands are the works of Polybius, Eratosthenes, Artemidorus, Ephorus, Fabius Pictor, Cæcilius (of Cale Acte in Sicily), and some others, besides an anonymous chorographer, supposed to be a Roman, from the circumstance of his distances being given, not in stadia, but in Roman miles.