Terrestrial and Celestial Globes Vol I

Globes i

of Lactantius.-Pappus' allusions.-Armillary spheres.-The astronomer Hipparchus.-Ptolemy.-Glo

ein which assure us that celestial globes, solid balls as well as armillary spheres, were constructed in those early centuries, for both p

tempts 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 cos

ined.31 He 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 th

m 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 posi

nte Farnese,

Farnese Conste

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 Aratu

rawings 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?"35 Günther 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 i

he 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.39 It 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.40 With the addition of other circles, and of an adjustable

ry Sphere accor

er of spherical trigonometry,41 and Pliny tells us that Hipparchus was the inventor of the astrolabe,42 which statement proba

hich is likewise an axis of the globe proper. In marking the position of the fixed stars, we are told that the proper method is to commence at some constant and invariable point of a certain constellation, and he suggests that the best starting point is the fixed star in Canis Major, that is, the so-called dog star, or Sirius. "The position of the other fixed stars, as they follow in the list, could easily be determined," he says, "by making the globe to turn upon the poles of the zodiac, thus bringing the graduated circle to the proper point of each. The stars could be marked with yellow or with such other color as one might choose, having due regard for their brilliancy and magnitude. The outline of each of the constellations should be made as simple as possible, indicating with light strokes, differing but little in color from that of the surface of the globe, the figures which the stars in the several constellations represent, preserving in this manner the chief advantage of such representation, w

an a scientific value. In the year 1900 there was found in a villa at Boscoreale, not far from Pompeii, an interesting fresco (Fig. 10), this being acquired by the Metropolitan Museum of New York in the year 1903. It has been referred to as a sundial, but was clearly intended to represent, in outline, a globe exhibiting the prominent parallels and a certain number of the meridians. It is

Reale Roman Fre

reek and R

2. Rom

friends such description he now proposed to write. This appears to be the raison d'être for his treatise. The importance of adhering closely to the statements of Aratus he insists upon, though admitting that writer's errors, being convinced that most of the globes of which one had knowledge in his day agreed neither with him nor with Ptolemy. Leontius first directs attention to Aratus' threefold plan in describing the several constellations, in which description that author speaks first of the relation which part bears to part in each; second, of the position of each constellation relative to the celestial circles, as, for example, to the tropics, and third, its position in the heavens relative to the constellations in the zodiac. He follows this statement with a somewhat lengthy reference to the constellation Ophiuchus, or the Serpent, in explanation of the method of description. After having the surface of the globe portioned out for the representation of the several constellations and the important circles, he then proceeds, as he states, to consider the execution, by which he means representing in proper color and outline the several figures, and the mounting of the globe. Upon a properly constructed support should first be placed the horizon circle, through which a second circle should be made to pass; this second circle will serve as a meridian. These circles, he observes, will enclose the ball, all the points of the surface of which should be equally distant from

O

es, cited p. 16, is probably

p. 193; Gassendi, P. Opera Omnia. Leipzig, 1658. Vol.

ranslation of the astronomy and meteorology of Aratus. Lewes, 1895. In his "Bibliographical remarks," the translator refers to

hesaurus gemmarum antiquarum astriferarum. Firenze, 1750. Vol. III.); Denza, P. F. Globi celest

The citation is from the translation by H

titutiones divinae

Edited by Commandino. Urbino, 1588. Bk

atik und Physik. Leipzig, 1878. Bd. 22. Hist. Litt. Abteilung, p. 106.); Same aut

p. cit., p

p. cit., p

op. cit

. This work was first printed in Venice, 1496; the first Greek text in

Historia

my mentions by name forty-eight constellations, all of which he probably obtained

Zo

er Libra C

o Scorpio

go Sagitta

hern Hem

Corona Lyr

us Ophiuchu

phinus Peg

Draco

a Equuleu

ercules T

ern Const

us Crat

Centaurus E

a Australis Hydra

nor Corv

marmo porino. Roma, 1835; Gaedechens, R. Der marmorne Himmelsglobus de

Gesetzgebungswerk des Kaisers Justinian. München, 1890. Se

to the imperial insignia, a part of which was a globe, which the emperor was represented, in the pictures o

ed in the eighth century, p. 201; Susemihl. Geschichte der Griechischen Litteratur der alexandriner Zeit.

les Scholies de Théon, les catasterismes d'Eratosthenes et la sphère de Le