that a globe to be serviceable should be of large size, and his reasoning can readily be understood, for what at that time was really known of the earth’s surface was small indeed in comparison with what was unknown. Should one not make use of a sphere of large dimensions, the habitable regions (Fig. 6), in comparison with the earth’s entire surface, would occupy but small space. What Strabo states in his geography is interesting and may here well be cited. “Whoever would represent the real earth,” he says, “as near as possible by artificial means, should make a sphere like that of Crates, and upon this draw the quadrilateral within which his chart of geography is to be placed. For this purpose however a large globe is necessary since the section mentioned, though but a very small portion of the entire sphere, must be capable of containing properly all the regions of the habitable earth and of presenting an accurate view of them to those who wish to consult it. Any one who is able will certainly do well to obtain such a globe. But it should have a diameter of not less than ten feet; those who can not obtain a globe of this size, or one nearly as large, had better draw their charts on a plane surface of not less than seven feet. Draw straight lines for the parallels, and others at right angles to these. We can easily imagine how the eye can transfer the figure and extent (of these lines) from a plane surface to one that is spherical. The meridians of each country on the globe have a tendency to unite in a single point at the poles; nevertheless on the surface of a plane map there would be no advantage if the right lines alone which should represent the meridians were drawn slightly to converge.”27
Fig. 6. Globe according to Strabo.
It is not at all improbable that Strabo and Ptolemy made considerable advance in the practical construction of terrestrial globes, for it seems reasonable to conclude that they were in possession of such objects when writing, as they did, concerning them.
Ptolemy, we may note, expressly allowed that the size of a globe should be that which one might desire, and that it was not necessary it should be of large size. It was this great Alexandrian cosmographer who first demonstrated the scientific value of drawing on the surface of a globe or map the network of parallels and meridians, and of establishing by means of the two geographical coördinates the true geographical position of every known place. To the end of making globes more serviceable he suggested the use of a meridian circle, such as is today employed in globe construction, passing through both poles, within which circle the globe might be made to move freely on its axis. He, however, in this connection, did not give technical directions for the construction of terrestrial globes, but he says enough to assure us that the art of globe construction was measurably well understood in his day, and that the Greeks and the Romans considered them very useful instruments in the study of the heavens and the earth.28
The allusions of the naturalist Pliny (23–79 AD) to the spherical shape of the earth give us no particular intimation that he knew of the existence of terrestrial globes, but they are interesting as indicating a belief of his time in its spherical form, a belief, judging from the nature of the argument, apparently drawn from Aristotle. Referring to the shape of the earth, he observes that “everyone agrees it has the most perfect figure. We always speak of the ball of the earth, and we admit it to be a globe bounded by the poles. It has not indeed the form of an absolute sphere, from the number of lofty mountains and flat plains; but if the termination of the lines be bound by a curve, this would compose a perfect sphere. And this we learn from arguments drawn from the nature of things, although not from the same considerations which we have made use of with respect to the heavens. For in the heavens the hollow convexity everywhere bends on itself and leans upon the earth as a center, whereas the earth rises up solid and dense like something that swells up and is protruded outward. The heavens bend toward the center, while the earth goes out from the center, the continual rolling of the heavens about it forcing its immense mass into the form of a sphere.”29
NOTES
1 Most of the larger general works presenting an historical survey of the science of astronomy give consideration to its beginnings, noting the interest in the subject exhibited by the early Egyptians, Assyrians, Babylonians, and by other Eastern peoples. See the introductory pages of such works as Dalambre, M. Histoire de l’astronomie ancienne. Paris, 1817; Lockyer, J. N. The Dawn of Astronomy. New York, 1894; Allan, H. A. Star Names and their Meanings; Wolf, R. Geschichte der Astronomie. München, 1877; Mädler, J. H. Geschichte der Himmelskunde von den ältesten bis auf die neuste Zeit. Braunschweig, 1873. 2 vols.; Narrien, J. N. An Historical Account of Origin and Progress of Astronomy. London, 1833.
2 Chabas, F. Ouvres diverses publiées par G. Maspero. Paris, 1902. Tome deuxième, Plate II, p. 208, “Carte Egyptienne de mines d’or.”
3 Cuneiform Texts from Babylonian Tablets, etc., in British Museum. London, 1906. Vol. 22, Plate 48. This Babylonian plan of the world illustrates the idea concerning the world which was current in the late Babylonian period. It represents the region of Babylonia, Assyria, and the neighboring districts as a circular plain surrounded by the Persian Gulf (Ma-ra-tum). The city Babylon (Babylu) is indicated near the center, and next to it the land of Assyria (Ashshur). The position of certain other cities is indicated. The district toward the south, bordering the Persian Gulf, is represented as being full of canals and marshes. Toward the north is marked a district which is referred to as mountainous. Beyond the circle is represented the Persian Gulf, and a number of triangles pointing outward from the circular zone, each being labeled “region,” indicating a vague conception concerning the same.
4 Numerous works have been published referring to the geography of the ancients. Mention may here be made of the following as being important. In each may be found extensive bibliographical references. Berger, H. Geschichte der wissenschaftlichen Erdkunde der Griechen. Leipzig, 1887–1894. This work was issued in four parts. Forbiger, A. Handbuch der alten Geographie nach den Quellen bearbeitet. Hamburg, 1877; Schmidt, M. C. P. Zur Geschichte der geographischen Litteratur bei den Griechen und Römern. Berlin, 1887; Bunbury, E. H. History of Ancient Geography. London, 1883. 2 vols.; Tozer, H. F. A History of Ancient Geography. Cambridge, 1897. See also The History of Herodotus; The Geography of Strabo; The Natural History of Pliny; The Geography of Ptolemy.
5 Schmidt, op. cit., p. 12; Bunbury, op. cit., Vol. I, p. 122; Berger, op. cit., pt. 1, p. 8–14.
6 Iliad, XVIII, 446–447; XXI, 225–228; Odyssey, V, 282; XII, 380.
7 They indulged much in speculation concerning the physical constitution of the world.
8 Herodotus. Historia. Bk. V, chap. 49. Citation from translation by Macaulay, G. C. The History of Herodotus. London, 1890. 2 vols.
9 Herodotus, op. cit., Bk. IV, chap. 8, 36; II, 21, 23.
10 Bunbury, op. cit., Vol. I, chap. v; Schmidt, op. cit., p. 13; Berger, op. cit., pt. 1.
