CXXX1V KOTES* 



result of laborious observations by William Herschel (between 1777 and 1781), 

 which gave 24 hours, 39 minutes, 21 '7 seconds. Kunowsky found, in 1821, 

 24 hours, 36 minutes, 40 seconds, which is very near to Madler's result. 

 Cassini's earliest observation of the rotation of a spot of Mars (Delambre, 

 Hist, de 1'Astr. moderne, T. ii. p. 694), appears to have been made soon after 

 the year 1670; but in the very rare treatise (Kern, Diss. de Scintillatione 

 Stellarum, Wittenb. 1686, 8), I find Salvator Serra and Father ^gidiua 

 Franciscus de Cottignez, Astronomer of the Collegio Romano, named as the 

 discoverers of the rotation of Mars and Jupiter. 



( 598 ) p. 369. Laplace, Expos, du Syst. du Monde, p. 36. Schroter's very 

 imperfect measurements of the diameters of the planet gave the ellipticity of 

 Mars as only -fa. 



( 599 ) p. 370. Beer und Madler, Beitrage, S. 111. 

 C 300 ) p. 370. Sir John Herschel, Outlines, 510. 



C 501 ) p. 370. Beer und Madler, Beitrage, S. 117125. 



t 602 ) p. 370. Madler, in Schumacher's Astr. Nachr. No. 192. 



C 503 ) p. 371 Kosmos, Bd. iii. S. 427429 ; Eugl. ed. p. 304306. 

 Compare also, for what has been said in the present volume respecting the 

 chronology of the discoveries of the small planets, S. 426 and 460 ; Engl. ed. 

 p. 303 and 338 ; respecting the proportion of their magnitudes to that of 

 meteoric asteroids or aerolites, S. 432 ; Engl. ed. p. 309 ; and respecting 

 Kepler's conjecture of the existence of a planet in the great planetary gap 

 between Mars and Jupiter (a conjecture which yet was by no means the 

 occasion of the discovery of the first discovered of the small planets, Ceres), 

 S. 439444, and Anm. 3133, S. 483 ; Engl. ed. p. 317322, and Notes 

 523 525, p. cxix. cxx. The bitter censure which has been expressed against a 

 highly esteemed philosopher, " because at a time when he might indeed have 

 known Piazzi's discovery for five months, but did not know it, he denied, not 

 so much the probability, but rather only the necessity, of there being a planet 

 .situated between Mars and Jupiter," appears to me but little justified. 

 Hegel, in his Dissertatio de Orbitis Planetarum, written in the spring and 

 summer of 1801, discusses the ideas of the ancients respecting the distances of 

 the planets ; and in remarking the series of which Plato speaks in the Timceus 

 (p. 35, Steph.) : 1.2. 3. 4. 9. 8. 27.... (compare Kosmos, Bd. iii. S. 477, 

 Anm. 21 ; Engl. ed. p. cxv. Note 513) says, he denies the possibility of a gap. 

 He says merely, ' Qiue series si verior naturae ordo sit, quam arithmetira 

 progressio, inter quart um et quiuturn locum magnum esse spatiurn, neque ibi 

 planetam desidcrari apparet" (Hegel's Wcrkc, Bd. xvi. 1834, S. 28; and 



