DISCOVERIES IX THE CELESTIAL SPACES. 693 



ancients, those which appeared to exercise the greatest influence 

 on the direction and gradual development of the ideas of 

 Copernicus, are expressed, according to Gassendi, in a passage 

 in the encyclopaedic work of Martianus Mineus Capella, 

 written in a half- barbarous language, and in the System of 

 the World of Apollonius of Perga. According to the opinions 

 described by Martianus Mineus of Madaura, and which have 

 been veiy confidently ascribed, sometimes to the Egyptians, 

 and sometimes to the Chaldeans,* the earth is immovcably 



* See the profound treatment of this subject in Martin, Etudes sur 

 Timee, t. ii. p. Ill Cosmographie des Egyptiens], and pp. 129-133 

 (Antecedents du Systeme de Copernic). The assertion of this learned 

 philologist, that the original system of Pythagoras differed from that of 

 Philolaus, and that it regarded the earth as fixed in the centre of the 

 universe, does not appear to me to be entirely conclusive (t. ii. pp. 103 

 and 107). I would here explain myself more fully respecting the remark- 

 able statement of Gassendi, regarding the similarity of the systems of 

 Tycho Brahe and Apollonius of Perga, to which I have referred in the text. 

 We find the following passage in Gassendi's biographies : " Magnam 

 imprimis ratiouem habuit Copernicus duarum opinionum affinium, 

 quarum unain Martiano Capellse, alteram Apollonio Pergaco attribuit. 

 Apollonius solem delegit, circa quern, ut centrum, non modo Mercurius 

 et Venus, verum etiam Mars, Jupiter, Saturnus suas obirent periodos, 

 dum Sol interim, uti et Luna, circa Terrum, ut circa centrum, quod 

 foret Afiixarum mundique centrum, moverentur; quse deinceps quoque 

 opinio Tychonis propemodum fuit. Rationem autem magnam harum 

 opinionum Copernicus habuit, quod utraque eximie Mercurii ac Veneris 

 circuitiones rcprajsentaret, eximieque causam retrogradationum, direc- 

 tionum, stationum in iis apparentium exprimeret et posterior (Pergsei) 

 quoque in tribus Planetis superioribus prsestaret." (Gassendi, Tychonis 

 JSrahei Vita, p. 296.) My friend the astronomer Galle, to whom 

 I applied for information, agrees with me in thinking that nothing could 

 justify Gassendi's decided statement. " In the passages" he writes to 

 me, "to which you refer in Ptolemy's Almagest (in the commence- 

 ment of Book XII.), and in the works of Copernicus (lib. v. cap. 3, 

 p. 141, a; cap. 35, p. 179, a and b; cap. 36, p. 181, b), the onjy 

 questions considered are the retrogressions and stationary conditions of 

 the planets in which Apollonius' assumption of their revolution round 

 the sun, is indeed referred to, (and Copernicus himself mentions expressly 

 the assumption of the earth's standing still) but it cannot be deter- 

 mined when he became acquainted with what he supposes to have been 

 derived from Apollonius. We can only therefore conjecture that he 

 assumed, on some later authority, that Apollonius of Perga had con- 

 structed a system similar to that of Tycho> . although I do not find, even 

 in Copernicus, any clear exposition of such a system, or any reference 

 to ancient passages in which it may be spoken of. If lib. XH. of the 



