NOTES

The beginnings of astronomical and of geographical science.—Primitive attempts at map construction, as seen in the Babylonian plan of the world.—Anaximander probably the first scientific cartographer.—Statements of Herodotus.—The place of Hecataeus, Hipparchus, Marinus, Ptolemy.—The Romans as map makers.—The earliest beliefs in a globular earth.—Thales, the Pythagoreans, Aristotle.—Eratosthenes and his measurements of the earth.—Crates probably the first to construct a terrestrial globe.—Statements of Strabo.—Ptolemy’s statements concerning globes and globe construction.—The allusions of Pliny.

THEbeginnings of the science of astronomy and of the science of geography are traceable to a remote antiquity. The earliest records which have come down to us out of the cradleland of civilization contain evidence that a lively interest in celestial and terrestrial phenomena was not wanting even in the day of history’s dawning. The primitive cultural folk of the Orient, dwellers in its great plateau regions, its fertile valleys, and its desert stretches were wont, as we are told, to watch the stars rise nightly in the east, sweep across the great vaulted space above, and set in the west as if controlled in their apparent movement by living spirits. To them this exhibition was one marvelous and awe-inspiring. In the somewhat strange grouping of the stars they early fancied they could see the forms of many of the objects about them, of many of their gods and heroes, and we find their successors outlining these forms in picture in their representations of the heavens onthe material spheres which they constructed. Crude and simple, however, were their astronomical theories relative to the shape, the structure, and the magnitude of the great universe in which they found themselves placed.1

Then too, as stated, there was something of interest to the people of that early day in the simple problems of geography; problems suggested by the physical features of their immediate environment; problems arising as they journeyed for trade or traffic, or the love of adventure, to regions now near, now remote. Very ancient records tell us of the attempts they made, primitive indeed most of them were, to sketch in general outline small areas of the earth’s surface, usually at first the homeland of the map maker, but to which they added as their knowledge expanded. The early Egyptians, for example, as we long have known, made use of rough outline drawings (Fig.1)2to represent certainfeatures of special sections of their country, and recently discovered tablets in the lower Mesopotamian valley (Fig.2) interestingly show us how far advanced in the matter of map making the inhabitants of that land were two thousand years before the Christian era.3We are likewise assured, through references in the literature of classical antiquity, that maps were made by the early Greeks and Romans, and perhaps in great numbers as their civilization advanced, though none of their productions have survived to our day. To the Greeks indeed belongs the credit of first reducing geography and map making to a real science.4No recent discovery by archaeologist or by historian, interesting as many of their discoveries have been, seems to warrant an alteration of this statement, long accepted as fact.

Fragment Map of Egyptian Gold Mines.Fig. 1. Fragment Map of Egyptian Gold Mines.

Fig. 1. Fragment Map of Egyptian Gold Mines.

Tablet Representing Babylonian World-Plan.Fig. 2. Tablet Representing Babylonian World-Plan.

Fig. 2. Tablet Representing Babylonian World-Plan.

The credit of being the first scientific cartographer has been generally assigned to the Greek Anaximander of Miletus (610-547 B. C.).5While there is not a detaileddescription extant of the maps he is reputed to have made, we know that he accepted the so-called Homeric idea, that the earth has the form of a circular disc,6and is surrounded by the Ocean Stream, an idea generally approved by the Ionic School of Philosophers.7It is not improbable that we have an allusion to the work of Anaximander in the History of Herodotus (484-400? B. C.), wherein we are told that Aristagoras, the tyrant of Miletus, when on a mission to Cleomenes, the King of Sparta, carried with him “a copper plate on which was engraved the whole circuit of the earth, and likewise all the Seas and Rivers.”8In another passage, Herodotus takes occasion to criticise maps of this circular character. “I laugh,” he says, “when I see that, though many before this have drawn maps of the Earth, yet no one has set the matter forth in an intelligent way; seeing that they draw the Ocean flowing round the Earth, which is circular as if drawn with compasses, and they make Asia equal in size to Europe. In a few words I shall declare the size of each division and of what nature it is as regards outline.”9It is, however, interesting to observe that the father of historical geography and of history nowhere records his idea of a properly constructed map, and further that the circular form, which he condemned, is one which found wide acceptance even to the close of the middle ages.

We are not definitely informed as to just the course of improvement or advancement in early scientific map making among the Greeks, yet not a few names are known to us of those who made it a matter of special endeavor, as they specifically stated, to improve the work of their predecessors. We, for example, are told that Hecataeus (550-480 B. C.),10likewise a native of Miletus, improved the maps of Anaximander, and that scientists of his day were astonished at his results; that Dicaearchus of Massina (350-290 B. C.)11was the first to employ a central line of orientation on a map, one passing through the Mediterranean east and west, and that he represented on his map all the lands known sincethe expedition of Alexander the Great into the Far East; and further, that Eratosthenes, the librarian of Alexandria (276-196 B. C.),12was the first to attempt a representation of the curved surface of the earth on a plane in accord with geometrical rules. The scientific cartographical ideas of Eratosthenes were further developed by Hipparchus (180-125 B. C.),13who is generally referred to as the greatest astronomer of antiquity, and by Marinus of Tyre (fl. ca. 100 A. D.),14who introduced the idea of inscribing lines of latitude and longitude on a map, crossing the same at right angles, which lines could be made to serve the useful purpose of orientation and be of assistance in giving proper location to all known places on the earth’s surface.

Map making in that early period reached its climax in the work of Claudius Ptolemy of Alexandria (ca. 87-150 A. D.).15His ideas, however, seem not to have found general favor with his contemporaries, nor with the geographers of the middle ages. (Fig.3.) It was not until the so-called period of great geographical discoveries and explorations in the fifteenth century that he became a real teacher within his chosen field.

Ptolemy World Map.Fig. 3. Ptolemy World Map.

Fig. 3. Ptolemy World Map.

Map making and the science of geography were continuously progressive among the Greeks. Imperial Rome witnessed little progress in either field. Among those who wrote in the Latin language, Pomponius Mela (fl. ca. 43 A. D.)16and Pliny (ca. 23-79 A. D.)17alone have rank of importance. In the matter of map construction the Romans held to many of the cruder methods and ideas of the Greeks, a fact which we learn from the fragmentary references in their literature, and from the itinerary or road maps (Fig.4), of the period of the emperors, which have come down to us.18

Sections of Peutinger Tables.Fig. 4. Sections of Peutinger Tables.

Fig. 4. Sections of Peutinger Tables.

The idea of a globular earth was at first accepted by the geographers of antiquity with some hesitancy. That Thales (640-548 B. C.),19one of the earliest astronomers and cosmographers, openly supported this theory, as is sometimesasserted, is hardly probable. It is rather to be assumed that according to his idea the earth has the form of a cylinder, and that it moves within a hollow sphere, an idea upheld by Anaximander, his disciple and successor, to whom reference has been made above. It was the Pythagorean philosophers who appear to have first transferred to the earth that which had already been accepted as a theory relative to the heavens, including the imaginary circles and the circular or spherical form, apparently arguing that the earth is a sphere because that is the most perfect form, that it is located in the center of the universe because that is the place of honor, and that it is at rest because rest is more dignified than motion.20It however was Aristotle who undertook, in the manner of a philosopher, an elaborate defense of the Pythagorean doctrine of a globular earth, supporting his arguments, first, through a reference to such positive proof as may be found in gravitation or “the tendency of all particles of matter to form themselves about the middle and thus make a sphere,” and secondly, through a reference to the appearance of the earth’s shadow cast during an eclipse of the moon.21A third proof, so familiar to us today, that distant objects as we approach them gradually reveal themselves above the horizon, seems not to have occurred to Aristotle, but was first employed by Strabo. “It is evident,” says the latter, “that, when persons on shipboard are unable to see at a distance lights which are on a level with the eye, the cause of this is the curvature of the sea; for if those lights are raised to a higher level, they become visible, even though the distance is increased; and in like manner, if the beholder attains a greater elevation he sees what was previously hidden.... Again, when men are approaching the land from the sea, the parts nearest the shore-line come more and more into view, and objects which at first appeared low attain a greater elevation.”22

After the attempt had been made to determine the circumference of the earth, as was done by Eratosthenes withmore or less satisfactory results, the thought, very naturally, was suggested of making an artificial representation of the entire earth, so far as then understood, that is, of making a terrestrial globe. There is no intimation, however, in any early allusion to Eratosthenes that he was a globe maker, or that he knew anything about globe construction. We know that he thought of the earth as a sphere placed in the center of the universe, around which the celestial sphere revolves every twenty-four hours.23Strabo, at a much later date, in referring to the geographical ideas of Eratosthenes, censured him for his unnecessarily elaborate proofs of the earth’s spherical character, apparently thinking the fact one too well known to require demonstration.

Globe according to Crates.Fig. 5. Globe according to Crates.

Fig. 5. Globe according to Crates.

It appears to have been the grammarian Crates of Mallos, a contemporary of Hipparchus, and a member of the Stoic School of Philosophers, who made the first attempt to constructa terrestrial globe (Fig.5), and that he exhibited the same in Pergamum, not far from the year 150 B. C.24It seems to have been Crates’ idea that the earth’s surface, when represented on a sphere, should appear as divided into four island-like habitable regions. On the one hemisphere, which is formed by a meridional plane cutting the sphere, lies our own oecumene or habitable world, and that of the Antoecians in corresponding longitude and in opposite latitude; on the other hemisphere lies the oecumene of the Perioecians in our latitude and in opposite longitude, and that of the Antipodes in latitude and longitude opposite to us.25Through the formulation and expression of such a theory the idea of the existence of an antipodal people was put forth as a speculative problem, an idea frequently discussed in the middle ages, and settled only by the actual discovery of antipodal regions and antipodal peoples in the day of great transoceanic discoveries.26That Strabo, at a later date, had this Pergamenian example in mind when stating certain rules to be observed in the construction of globes seems probable, since he makes mention of Crates’ globe. Strabo alone among ancient writers, so far as we at present know, treats of terrestrial globes, practically such as we find in use at the present day. He thought 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, thoughbut 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

Globe according to Strabo.Fig. 6. Globe according to Strabo.

Fig. 6. Globe according to Strabo.

It is not at all improbable that Strabo and Ptolemy madeconsiderable 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 A. D.) 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 thesame 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

1Most 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.

2Chabas, F. Ouvres diverses publiées par G. Maspero. Paris, 1902. Tome deuxième, Plate II, p. 208, “Carte Egyptienne de mines d’or.”

3Cuneiform 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.

4Numerous 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 Griechenund 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.

5Schmidt, op. cit., p. 12; Bunbury, op. cit., Vol. I, p. 122; Berger, op. cit., pt. 1, p. 8-14.

6Iliad, XVIII, 446-447; XXI, 225-228; Odyssey, V, 282; XII, 380.

7They indulged much in speculation concerning the physical constitution of the world.

8Herodotus. Historia. Bk. V, chap. 49. Citation from translation by Macaulay, G. C. The History of Herodotus. London, 1890. 2 vols.

9Herodotus, op. cit., Bk. IV, chap. 8, 36; II, 21, 23.

10Bunbury, op. cit., Vol. I, chap. v; Schmidt, op. cit., p. 13; Berger, op. cit., pt. 1.

11Cicero. Epistolae ad Atticum. vi. 2; Bunbury, op. cit., Vol. I, p. 617.

12Berger, op. cit., pt. 3; Bunbury, op. cit., Vol. I, chap. xvi.

13Berger, op. cit., pt. 3; Bunbury, op. cit., Vol. II, chap. xvii, sec. 1.

14Bunbury, op. cit., Vol. II, chap. xxvi. Marinus is known to us only at second-hand. Ptolemy extols him in the highest terms, but he undertook to reform his maps just as Marinus had undertaken to reform the maps of his predecessors.

15Bunbury, op. cit., Vol. II, chaps. xxviii-xxix; Mollweide, S. Die Mappierungskunst des Ptolemaus. (In: Zachs Monatliche Korrespondence zur Beförderung der Erd- und Himmelskunde. Weimar. Bd. 11, pp. 322 ff.); Nordenskiöld, A. E. Facsimile Atlas. Stockholm, 1889. This last-named work gives consideration to the Atlas of Ptolemy, to the numerous editions of his Geographia, to his geographical errors. The twenty-seven maps printed in the 1490 Rome edition of the Atlas are reproduced. See also the printed lists of the editions of Ptolemy’s Atlas by Eames, W., Winsor, J., Philipps, P. L.

16Bunbury, op. cit., Vol. II, chap. xxviii, sec. 2; Fink. Mela und seine Geographie. Rosenheim, 1881. Mela titled his work, “De situ orbis.” Excellent tr. into English by Golding, Arthur. London, 1585. Various printed editions, first in 1471.

17Bunbury, op. cit., Vol. II, chap. xxiv. Various editions of original; various English translations. Pliny titled his work, “Naturalis historia.”

18Miller, K. Die Weltkarte des Castorius, genannt Peutingersche Tafel. Ravensburg, 1887; Porena, F. Orbis pictus d’Agrippa. Roma, 1883; Desjardins, E. La Table de Peutinger d’après l’original conservé à Vienne. Paris, 1896.

19Lewis, G. C. Historical survey of the Astronomy of the Ancients. London, 1862. pp. 80 ff.; Berger, op. cit., pt. 1.

20Bunbury, op. cit., Vol. I, chap. iv, secs. 4, 5.

21A scientific foundation for the spherical theory seems not to antedate Aristotle. See especially his work, De Coelo, Bk. II, chap. 14, and for a good translation of this work by Taylor, T., bearing title, On the Heavens, from the Greek with copious elucidations. London, 1807. Plato’s statement in Phaedo merely observes that the earth, if like a ball, must be suspended without support in the interior of a hollow sphere. See also the Book of Job, chap. xxvi, v. 7, where reference is made to the earth hanging upon nothing. There is here probably the expression of an early Assyrian or Babylonian belief in a spherical earth.

22Strabo. Geographia. Bk. I, chap. 1, §20. See translation by Jones, H. L. The Geography of Strabo. New York, 1917. 8 vols.

23Bunbury, op. cit., Vol. I, pp. 619-620.

24Wachsmuth, C. De Cratte Mallota. Leipzig, 1860; Berger, H. Entwickelung der Geographie der Erdkugel bei den Hellenen. (In: Grenzboten, Vol. xxxiv, pp. 408 ff.); Müllenhoff, C. (In: Deutsche alterthumskunde. Berlin, 1895. p. 248.) Diodorus Siculus attributes the discovery of the use of the globe to Atlas of Libya.

25Berger. Geschichte, pt. 2, p. 135; Friedrich, R. Materialien zur Begriffsbestimmung des Orbis Terrarum. Leipzig, 1887.

26A belief in the existence of antipodal peoples, very clearly was accepted by Pythagoras, Eratosthenes, Crates, Posidonius, Aristotle, Strabo, and later by Capella. Numerous others presupposed the earth to be globular in shape. See Kretschmer, K. Die physische Erdkunde im christlichen Mittelalter. Wien, 1889. pp. 54-59, wherein the author gives consideration to the doctrine of the antipodes as held in the middle ages. Berger. Geschichte, pt. 3, p. 129, notes that the idea of the earth’s division into four parts or quarters persisted for centuries after Crates’ day, if not among scientific geographers, at least among those who could be said to have possessed general culture. Cleomedes, Ampelius, Nonnus, and Eumenius mention the idea as one to be accepted. See in this connection the world map of Macrobius, a reproduction of which may be found in Nordenskiöld, op. cit., pl. XXXI. See also Miller, K. Die Weltkarte des Beatus, 776 nach Christus. Stuttgart, 1895. p. 28.It was thought that Africa did not extend to the equator, or at least was not habitable to the equator. Below the equator there was thought to be water but beyond the uninhabitable and impassable torrid zone a habitable region. The map of Lambertus well represents this early theory. Pomponius Mela called the inhabitants of this southern region “Antichthoni,” their country being unknown to us because of the torrid zone intervening. Pliny, and after him Solinus, says that for a long time the island of Taprobana (Ceylon) was thought to be the region occupied by the Antichthoni.

It was thought that Africa did not extend to the equator, or at least was not habitable to the equator. Below the equator there was thought to be water but beyond the uninhabitable and impassable torrid zone a habitable region. The map of Lambertus well represents this early theory. Pomponius Mela called the inhabitants of this southern region “Antichthoni,” their country being unknown to us because of the torrid zone intervening. Pliny, and after him Solinus, says that for a long time the island of Taprobana (Ceylon) was thought to be the region occupied by the Antichthoni.

27Strabo, op. cit., Bk. II, chap. v, §10.

28Ptolemy. Geographia. Bk. I, chap. 22.

29Pliny, op. cit., Bk. II, chap. 64; Bk. II, chap. 2.

Thales’ ideas, probably not a globe maker.—Eudoxus.—The Atlante Farnese.—Archimedes.—Allusion of Lactantius.—Pappus’ allusions.—Armillary spheres.—The astronomer Hipparchus.—Ptolemy.—Globes used for decorative purposes by the Romans.—Roman coins.—The Byzantine Leontius Mechanicus.

THOUGHwe find but an occasional reference to terrestrial globes in the literature of classical antiquity, numerous statements appear therein which assure us that celestial globes, solid balls as well as armillary spheres, were constructed in those early centuries, for both practical and ornamental purposes. There exists, however, considerable uncertainty as to the exact character of the earliest of these globes.

The information we have concerning the Ionic School of Philosophers, of which school Thales is reputed to have been the founder, does not give us any satisfactory evidence that attempts were made by any of their number at a material representation of their astronomical or geographical theories. They were content, in the main, with mere philosophical or cosmical speculations. The statement, therefore, that Thales himself constructed a celestial globe, on which to represent his notion of the crystal sphere, is not well authenticated.30

While not assured to us by any positive statement, there appears to be good reason for believing the astronomer Eudoxus of Cnidos (409-356 B. C.) made use of a celestialglobe on which to represent certain astronomical theories which he entertained.31He traveled in Egypt in his later life, where he carried on his studies, and where he seems to have learned the construction of star catalogues. On his return to his own country he is reported to have undertaken the representation of the several constellations known to him, on a celestial sphere. The astronomical poem of Aratus (fl. 270 B. C.),32so frequently cited and copied in following centuries, is considered to be a description of the constellations according to Eudoxus.

In the Royal Museum of Naples there may be found a large marble celestial globe, 65 cm. in diameter (Fig.7), which the mythical Atlas bears on his shoulders, the statue itself being 1.86 m. in height, resting on one knee.33This very interesting and artistic object was transferred to Naples museum from the Farnese Palace in Rome, hence is generally referred to as the Atlante Farnesiano. Forty-two constellations are represented on its surface (Fig.8), and the five wanting, including Ursa Major and Ursa Minor, probably owe their absence to the obliteration which time has brought about. From the position of the several constellations, relative to the intersecting points of the ecliptic with the equator, it is thought that it must have been constructed at least three hundred years before the Christian era. It seems therefore to date from about the time of Eudoxus, being then the oldest extant globe.

Atlante Farnese, ca. 200 B. C.Fig. 7. Atlante Farnese, ca. 200 B. C.

Fig. 7. Atlante Farnese, ca. 200 B. C.

Atlante Farnese Constellation Figures.Fig. 8. Atlante Farnese Constellation Figures.

Fig. 8. Atlante Farnese Constellation Figures.

We learn from Cicero and from other early writers that Archimedes (ca. 287-212 B. C.), the celebrated geometrician of Syracuse, constructed a globe or contrivance for the purpose of demonstrating the movements of the heavenly bodies. Cicero’s statements imply that the work of Archimedes was well known in his day, yet he thought it merited a special word of commendation from himself. “I shall propose nothing new to you,” he says, “nor that which I have invented or discovered; but I remember C. Sulpicius Gallus, a very learned man, as you know, when this appearance(in the heavens) was spoken of, and he was, by chance, at the house of Marcellus, who had been consul with him, he described a globe among the spoils of that opulent and magnificent city of Syracuse, when captured, as the only thing among all the spoils which he ordered to be carried to his own house; about which globe I have often heard, on account of the fame of Archimedes, although the work itself was not very remarkable, for there was another far more beautiful and more honored by the common people, made by the same Archimedes, and placed in the Temple of Virtue by the same Marcellus. But afterward when Gallus began to explain scientifically the object of the machine, I thought there was more ingenuity in that Sicilian than human nature was capable of. For Gallus informed me that there was another ancient invention of a solid and elaborately formed globe which was made by Thales, the Milesian, to revolve. And afterward the same was, by Eudoxus of Cnidos, the disciple of Plato, adorned with the fixed stars of heaven, and with every ornament and embellishment, as described by Eudoxus, and was many years afterward celebrated by Aratus, not exactly in the scientific language of astronomy, but with the graces of poetry. This species of globe indeed, in which the sun and moon were made to revolve, and five of those stars which have been called travelers, and as it were wanderers, could not possibly be exhibited on that solid sphere. And more especially was that invention of Archimedes to be admired, for he had so contrived that one revolution of the machine served somehow to produce unequal and varied movements through their different paths. For when Gallus set the globe in motion, the moon succeeded the sun by as many turns of the brass wheel of the machine as days in the heavens, so that the globe represented in the heavens the same eclipse of the sun, when the moon arrived at a certain place or point, as the shadow of the earth did when the sun shone from the opposite region.”34

Lactantius’ allusion to Archimedes, at a later date, is perhaps derived from Cicero, but it is none the less interesting as indicating a belief that such a globe had existed. In his characteristic vein he refers to the mechanical device, finding therein a support for his theological arguments. “Was Archimedes of Sicily able to contrive a likeness and representation of the universe in hollow brass,” he inquires, “in which he so arranged the sun and moon, that they effected, as it were every day, motions unequal and resembling the revolutions of the heavens, and that sphere, while it revolved, exhibited not only the approaches and with drawings of the sun or the increase and waning of the moon, but also the unequal course of the stars, whether fixed or wandering? Was it then impossible for God to plan and create the original, when the skill of man was able to represent them by imitation? Would the stoic, therefore, if he should have seen the figures of the stars painted and fashioned in that brass, say that they moved by their own design, and not by the genius of the artificer?”35Günther notes that at the beginning of the seventh book of the collection of Pappus, geometrician of Alexandria, may be found a reference to those skilled in mechanical devices in which it is stated that “Mechanicians are those who understand how to construct celestial globes and to represent the heavens and the course of the stars moving in circles by means of like circular movements of water.”36It has been thought that in this passage we have a reference to a globe such as was probably constructed by Archimedes, although the reference is not to any particular example. It seems not improbable that the globe of Archimedes was made to revolve by an hydraulic contrivance, and that it resembled a planetarium or orrery.37That the science of hydrostatics had been developed by Archimedes’ time to a high degree is very certain.

Instruments for measuring angles and distances were very early employed in the field of astronomy as well as in thefield of geography. Of these instruments the Egyptiangnomonappears to have been the oldest.38In its best form it consisted of a bowl having a perpendicular rod or staff erected at the central point of the inner curved surface. This rod cast a shadow upon the inner surface of the bowl, which had been graduated, giving a reading in degrees which furnished to the observer the information desired. Time brought improvements and variations in the construction of simple instruments of this character. As early as the third century before the Christian era, adjustable rings, or armillae, for example, were employed by astronomers to aid them in the solution of their problems, which instruments later developed, as noted below, into the more elaborate and complex armillary spheres. The simplest form of such an instrument appears to have been but a single graduated circle. To this, at a very early date, a second was added, thus providing an instrument in which one of the circles was regarded as fixed in the plane of the equator, the other, intersecting this at right angles, served as a meridian circle, being movable around an axis which could be called the world axis, the axis of the celestial sphere, or the axis of the universe. The position of a celestial body in declination could be determined on the meridian circle, and its right ascension on the fixed or horizon circle.39It seems altogether probable that Eratosthenes made use of such an instrument in his efforts to measure the obliquity of the ecliptic. He tells us that in his time one of large dimensions hung in the portico of the academy of Alexandria.40With the addition of other circles, and of an adjustable view-tube, that more accurate and detailed measurements might be made, this device, in Hipparchus’ day, came to be known as an astrolabe, and, after the addition of other rings in later years, to be known as an armillary sphere. Even in this last development it was not a true sphere on which could be represented the starry constellations, but an arrangement of circles forming a sort of imaginary sphere, the circles beingintended to represent the relative position of the principal celestial circles. This instrument seems, at first, to have been suspended, when in use, but later was made to rest upon a base, the whole adjusted to revolve around an axis and within a graduated horizon circle. In the earliest examples, the earth at the center of the circles, it represented the Ptolemaic system (Fig.9); in the later examples, having the sun at the center, it represented the Copernican system.

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