THE PLANETS. 405 



that the Moon was included in the series of the seven planets, 

 since, with the exception of a memorable theory of attrac- 

 tion put forward by Anaxagoras (Cosmos, vol. ii. p. 690, 

 and note 27), its more intimate connexion with the Earth 

 was scarcely ever suspected by the ancients. On the contrary, 

 according to an opinion respecting the system of the world 

 which Vitruvius 8 and Martianus Capella 9 quote, without stat- 



8 Vitruv. de ArcldL ix. 4 (eel. Rode, 1800, p. 209). Nei- 

 ther Vitruvius nor Martianus Capella mention the Egyptians 

 as the originators of a system, according to which Mercury 

 and Venus are considered as satellites of the planetary sun. 

 The former says, "Mercurii autem et Veneris stelke circum 

 Solis radios, solem ipsum, uti centrum, itineribus coronantes, 

 regressus retrorsum et retardationcs faciunt." " But Mer- 

 cury and Venus, which encircle in their orbits the Sun itself 

 as a centre, retrogress and proceed slowly round its rays." 



9 Martianus Mineus Felix Capella, De, Nuptiis Philos. et 

 Mercurii, lib. viii. (ed. Grotii, 1599, p. 289): "For though 

 Venus and Mercury appear to rise and set daily, yet their 

 orbits do not, however, go round the Earth, but revolve round 

 the Sun in a wider orbit. In fact, the centre of their orbits 

 is in the Sun, so that they are sometimes above it ... ." 

 "Nam Venus Mercuriusque licet ortus occasusque quoti- 

 dianos ostendant, tamcn eorum circuli Terras omnino non 

 ambiunt, sed circa Solem laxiorc ambitu circulantur. De- 

 nique circulorum suorum centrum in Sole constituunt, ita ut 

 supra ipsum aliquando . . ." As this place is written over, 

 * 4 Quod Tellus non sit centrum omnibus planetis," "Because 

 the Earth is not the centre of all the planets," it may cer- 

 tainly, as Gassendi asserts, have had an influence upon the 

 first views of Copernicus, in ore than the passages attributed 

 to the great geometer, Apollonius of Perga. However, 

 Copernicus only says, '" Minime contemnendum arbitror, 

 quod Martianus Capella scripsit, existimans quod Venus 

 et Mercurius circumerrant Solem in medio cxistentem." 

 " I by no means think that we should despise what Mar- 

 tianus Capella has written, who supposes that Venus and 



i 2 



