xvm NOTES. 



N. 300302, S. 188, 192, 197, 200, 202, and 230; and in Schum. 

 Jahrbuch, 1837, S. 149168. William Herechel considered that in Ms 

 observations of the fine comet of 1811, he found evidences of the rotation of 

 the nucleus and tail. Phil. Trans. 1812, Ft. i. p. 140. Dunlop, at Para- 

 matta, thought the same respecting the third comet of 1825. 



( l ?) p. 96. Bessel, in the Astr. Nachr. 1836, N. 302, S. 231 ; Schum. 

 Jahrb. 1837, S. 175. Also compare Lehmann iiber Cometenschweife, in 

 Bode's Astron. Jahrb. filr 1826, S. 168. 



H p. 96. Aristot. Meteor, i. 8, 1114 and 1921 (ed. Ideler, T. L 

 p. 3234). Biese, Phil, des Aristoteles, Bd. ii. S. 86. The great influence 

 which the writings of Aristotle exercised on the whole of the middle ages, 

 renders it a cause of extreme regret that he should have been so opposed to 

 the grander and juster views of the fabric of the universe entertained by the 

 more ancient Pythagorean school. He pronounces comets to be transitory 

 meteors belonging to our atmosphere, in the same book in which he mentions 

 the Pythagorean opinion, that they were planets of long revolution (Aristot. 

 i. 6, 2). This Pythagorean doctrine, which, according to the testimony of 

 Appollonius Myndius, had been still more anciently held by the Chaldeans, 

 descended to the Romans, who here, as elsewhere, merely repeated the lesson 

 learnt from others. The Myndian describes the path of comets as extending 

 far into the upper celestial spaces. Hence Seneca says, in the Nat. Quaest. 

 vii. 17 : " Cornetes non est species falsa, sed proprium sidus sicut solis et 

 lunse : altiora mundi secat et tune demum apparet quum in imum cursum sui 

 venit ; and (vii. 27) : " Cometas seternas esse et sortis ejusdem, cujus ccetera 

 (sidera), etiamsi faciem illis non habent similem." Pliny (ii. 25) likewise ob- 

 viously refers to Appollonius Myndius, when he says : " Sunt qui et hsec sidera 

 perpetua esse credant suoque ambitu ire, sed non nisi relicta a sole cerni." 



( 49 ) p. 96.-01bers, in the Astr. Nachr. 1828, S. 157 und 184. Arago 

 de la Constitution physique des Cometes, Annuaire, 1832, p. 203 208. 

 The ancients had been struck by the circumstance that it is possible to see 

 through comets as through flame. The oldest testimony to stars having been 

 seen through them is that of Democritus (Aristot. Meteor, i. 6, 11) ; and it 

 led Aristotle to make the not unimportant remark, that he had himself observed 

 one of the stars of Gemini occulted by Jupiter. Seneca only speaks decidedly 

 * the transparency of the tail. He says (Nat. Qusest. vii. 18) that stars are 

 *eefl tnrough comets as through a cloud; not indeed through , the body of the 

 comet, bnt through the rays of the tail : non in ea parte qua sidus ipsmn est 

 pissi et solidi ignis, sed qua rarus splendor oceurrit et in crines dispergitiir. 



