NOTES rxli 



( W1 ) p. 393. The first letter in which Lassell announced the discovery was 

 dated the 6th of August, 1847. (Schumacher's Astr. Nach. No. 611, S. 1 65). 



f 42 ) p. 393. Otto Struve, in the Astr. Nachr. No. 629. August Struve, 

 at Dor pat, computed the orbit of the first satellite of Neptune from the obser- 

 vations at Pulkowa. 



( 643 ) p. 393. W. C. Bond, in the Proceedings of the American Academy 

 of Arts and Sciences, Vol. ii. p. 137 and 140. 



C 644 ) p. 393. Schum. Astr. Nachr. No. 729, S. 143. 



C 646 ) p. 395. Kant says: "The last planets beyond Saturn will be found 

 to bear an increasing resemblance to comets, until one class of bodies is con- 

 nected with or passes by gradual transition into the other. This supposition 

 is supported by* the law according to which the excentricity of the planetary 

 orbits increases with their distance from the Sun. The remoter planets ap- 

 proach thereby nearer to the definition of comets. The last planet, and first 

 comet, may be the body which at its perihelion shall be found to intersect 

 the orbit of the next planet, perhaps Saturn. Our theory of the mechanical for- 

 mation of the heavenly bodies is also clearly proved (!) by the magnitude of the 

 planetary masses increasing with their distance from the Sun." Kant, Natur- 

 gesch. des Himmels (1755) in his Sammtl. Werken, Th. vi. S. 88 and 195. 

 In the beginning of the 5th Part (S. 131) he had spoken of the " earlier 

 comet-like nature which Saturn had laid aside." 



( W6 ) p. 396. Stephen Alexander " on the Similarity of Arrangements of 

 the Asteroids and the Comets of Short Periods, and the Possibility of their 

 Common Origin," in Gould's Astron. Journal, No. 19, p. 147, and No. 20, 

 p. 181. The author distinguishes, with Hind (Schum. Astr. Nachr. No. 

 724) " the comets of short period, whose semi-axes are all nearly the same 

 with those of the small planets between Mars and Jupiter ; and the other 

 class, including the comets, whose mean distance or semi-axis is somewhat 

 less than that of Uranus." He concludes the first memoir wifh the statement 

 that " different facts and coincidences agree in indicating a near appulse, if 

 not an actual collision, of Mars with a large comet in 1315 or 1316 ; that the 

 comet was thereby broken into three parts, whose orbits (it may be presumed) 

 received even then their present form, viz. that still presented by the comets 

 of i 812, 1815, and 1846, which are fragments of-the dissevered comet." 



l tfi7 ) p. 397. Laplace, Expos, du Syst. du Monde (ed. 1824), p. 414. 



