HELLENISTIC PERIOD 



Most interesting and frequently cited is the bronze 

 planetarium said to have been made by Archimedes 

 and described in a tanlaHsingly fragmentary fashion 

 by Cicero and by later authors. Because of its im- 

 iwrtance as a protot\pe, we give the most relevant 

 passages in full." 



Cicero's descriptions of Archimedes" planetarium 

 are (italics supplied): 



Gaius Sulpieius Gallus ... at a liinc when ... he 

 happened to be at the house of Marcus Marcellus, his 

 colleague in the consulship [i66 B.C.], ordered the celestial 

 globe to be brought out which the grandfather of Marcellus 

 liad carried off from Syracuse, when that very rich and 

 beautiful city was taken [212 B.C.]. . . . Though I had 

 heard this globe (sphaerac) mentioned quite frequently 

 on account of the fame of .Xrchimedes, when I saw it I did 

 not particularly admire it; for that other celestial globe, also 

 constructed by Archimedes, which the same Marcellus 

 placed in the temple of Virtue, is more beautiful as well 

 as more widely known among the people. But when 

 Gallus began to give a very learned explanation of the 

 device. I concluded that the famous .Sicilian had been 

 endowed with greater genius than one would imagine 

 possible for human being to possess. For Gallus 

 told us that the other kind of celestial globe, which 

 was solid and contained no hollow space, was a very 

 early invention, the first one of that kind having been 

 constructed by Thales of Miletus, and later inarked by 

 Eudo.xus of Cnidus — a disciple of Plato, it was claimed — with 

 constellations and stars which are fixed in the sky. He also 

 said that many years later Aratus . . . had described it 

 in verse. . . . But this newer kind of globe, he said, on 

 which were delineated the motions of the sun and moon and 

 of those five stars which are called wanderers, or, as we 

 might say, rovers [;'. e., the five planets], contained more than 

 could be shown on the solid globe, and the invention of 

 Archimedes deserved special admiration because he had 

 thought out a way to represent accurately by a single device 

 for turning the globe, those various and divergent move- 

 ments with their different rales of speed. .-\nd when Gallus 

 moved [i.e., set in motion] the globe, it was actually true 

 that the moon was always as many revolutions behind the 

 sun on the bronze contrivance as would agree with the 

 number of days it was behind in the sky. Thus the .same 

 eclipse of the sun happened on the globe as would actually 

 happen, and the moon came to the point where the shadow 

 of the earth was at the very time when the sun (appeared?) 



" For these tran.slations from classical authors I am indebted 

 to Professor Loren MacKinney and Miss Harriet Lattin, who 

 had collected them for a history, now abandoned, of planc- 

 tariums. I am grateful for the opportunity of giving thcin here 

 the mention they deserve. 



out of the region . . . [several pages are missing in the 

 manuscript; there is only one], 



De republica, I, xiv (21-22), Keycs' translation. 



When Archimedes put logclhcr in a globe the movemcnis 

 of the moon, sun and five wandering [planets], he brought 

 about the same eflfecl as that which the god of Plato did in 

 the Timaeus when he made the world, so that one revolution 

 produced dissimilar movements of delay and acceleration. 



Tusculanae dispulaliones, I, 63. 



Later descriptions from Ovid, Lactantius, C.laudian, 

 Sextus Empiricus, and Pappus, respectively, are 

 (italics su])plied) : 



There stands a globe suspended by a Syracusan's skill 

 in an enclosed bronze [frame, or sphere — or perhaps, in 

 enclosed air], a small image of the immense vault [of 

 heaven]; and the earth is equally distant from the top and 

 bottom; that is brought about by its [/. c, the outer bronze 

 globe's] round form. The form of the temple [of Vesta] 

 is similar. . . . 



Ovid, l-'asli (ist century, .\.D.), VI, 277-280, 

 Frazer's translation. 



The Sicilian Archimedes, was able to make a reproduction 

 and model of the world in concave brass (concavo aerc 

 similitudinem mundi ac figuram); in it he so arranged 

 the .fun and moon and resembling the celestial revolutions 

 (caelcstibus similes conversionibus); and while it revolved 

 it exhibited not only the accession and recession of the sun 

 and the waxing and waning of the moon (incrementa 

 deminutionesque lunae), but also the unequal courses of 

 the stars, whether fixed or wandering. 

 Lactantius, Inslitutiones divinae (4th century, A.D.). H, 5, 18. 



.Archimedes' sphere. When Jove looked down and saw 

 the heavens figured in a sphere oi glass, he laughed and said 

 to the other gods: "Has the power of mortal effort gone so 

 far? Is my handiwork now mimicked in a fragile globe?" 

 .•\n old man of Syracuse had imitated on earth the laws of the 

 heavens, the order of nature, and the ordinances of the gods. 

 Some hidden influence within the sphere directs the various 

 courses of the stars and actuates the lifelike mass with 

 definite motions. A false zodiac runs through a year of its 

 ow-n and a toy moon waxes and wanes month by month. 

 Now bold invention rejoices to make its own heaven revolve 

 and sets the stars [planets?] in motion by human wit . . . 

 Claudian, Carmina minora (ca. A.D. 400), LI (LWIII), 



Platnaure"s translation. 



The things that move by themselves are more wonderful 

 than those which do not. .-\t any rate, when we behold an 

 .Archimedean sphere in which the sun and the rest of the 

 stars move, we arc immensely impressed b\- it, not by Zeus 

 because we are amazed at the uood. or at the movemcnis 

 of these [bodies], but by the devices and causes of the 

 moveinents. 



Sextus Empiricus, . 1(7; (•r.(iismaMcma//i-o.f (3rd century, A,D.). 



1\. 115. Epps' translation. 



I'APER 6: CLOCKWORK, PERPETUAL MOTION DEVICES, AND THE COMPASS 



89 



