NOTES. CXX1X 



minds already disturbed this might appear ominous of misfortune as it was 

 the circumstaiice of the Moon's varying colours blood-red, black, and other 

 mournful hues which filled their souls with uneasy apprehensions." 



( 574 ) p. 357. Schroter, Seleuotopographische Fragmente, Th. i. 1791, S. 

 668 ; Th. ii. 1802, S. 52. 



( 5 ~ 5 ) p. 357. Bessel, "iiber eine angenommene Atmosphare des Mondes," 

 in Schumacher's Astron. Nachr. No. 263, S. 416420. Compare also 

 Beer und Madler, "der Mond," 83 and 107, S. 138 and 158 ; as well as 

 Arago, ill the Annuaire for 1846, p. 346353. The argument taken from 

 the greater or less distinctness with which the smaller features of the Moon's 

 surface can be recognised, so often adduced in proof of the reality of a lunar 

 atmosphere, and of " passing lunar mists in the valleys of the Moon," is the 

 most untenable of all, seeing the changes continually taking place in the 

 upper strata of our own atmosphere. Considerations respecting the shape of 

 one of the Moon's horns in the solar eclipse of the 5th of September, 1793, 

 led William Herschel to form even at that time a decided opinion against the 

 hypothesis of a lunar atmosphere. (Phil. Trans. Vol. Ixxxiv. p. 167.) 



( 5 ? 6 ) p. 358. Madler, in Schumacher's Jahrbuch fiir 1840, S. 188. 



( 5 77) p. 358. Sir John Herschel (Outlines, p. 247) calls attention to the 

 immersion of double stars, which, from the great proximity of the indivi- 

 duals of which they consist, cannot be separated by the telescope. 



( 578 ) p. 358. Plateau, " sur Tlrradiation," in the Mem. de 1'Acad. royale 

 des Sciences et Belles-Lettres de Bruxelles, T. xi. p. 142 ; and " Erganzungs- 

 band (supplementary volume) zu PoggendorfFs Annalen, 1842, S. 79 128, 

 193232, and 405 *43. "The phenomenon of irradiation is probably 

 caused by the stimulus produced by light extending itself on the retina a little 

 beyond the outline of the image." 



( 5 '~ 9 ) p. 358. Arago, in the Comptes rendus, T. viii. 1839, p. 713 and 

 883. " Les pheuomeues d'irradiation signales par Mr. Plateau sont regardea 

 par Mr. Arago comme les effets des aberrations de refrangibilite et de sphe- 

 ricite de 1'oeil, combines avec 1'iudistiuction de la vision, consequence des cir- 

 constances dans lesquelles les observateurs se sont places. Des mesures 

 exactes prises sur des disques noirs a fciid blanc et des disques blancs a fond 

 noir, qui etaient places au Palais du Luxembourg, vmblcs a 1'Observatoirc, 

 n'ont pas indique les effets de 1'irradiation." 



(*') p. 359. Plut. Moral, ed. W; ,teub. T. iv. p. 786789. The shadow 

 of Mount Athos, as has also been remarked by the traveller, Pierre Belon 

 (Observations de Singularites trouvees en Giec e, As e etc. 1554, livre i. 



