introduction into the Greek 

 sphere, 162. 



Light, always refracted, 54; pris- 

 matic spectra differ in number of 

 dark lines according to their 

 source, 55, 56; polarisation of, 

 57; velocity of, 105; ratio of 

 solar, lunar, and stellar, 126; 

 variation of, in stars of ascer- 

 tained and unascertained period- 

 icity, 228, 240. 



Light of the sun and moon, Euler's 

 and Michelo's estimates of the 

 comparative, 127. 



Limited transparency of the celestial 

 regions, 46. 



Macrobius, " Sphsera aplanes" of, 

 31. 



Madler, on Jupiter's satellites, 67; 

 on the determined periods of 

 variable stars, 225; on future 

 polar stars, 245 ; on non-lumi- 

 nous stars, 255; on the centre of 

 gravity of the solar system, 269. 



Magellanic clouds, known to the 

 Arabs, 122. 



Magnitude of the stars, classes of, 

 120, 121. 



Malus, his discoveries regarding 

 light, 57. 



"Mappa coelestis" of Schwinck, 

 189. 



Ma-tuan-lin, a Chinese astrono- 

 mical record of, 146. 



Mayer, Christian, the first special 

 observer of the fixed stars, 275. 



Melville Island, temperature of, 43. 



Michell, John, 126; applies the 

 calculus of probabilities to small 

 groups of stars, 274; little re- 

 liance to be placed in its indivi- 

 dual numerical results, 275. 



Michelo's comparative estimate of 

 the light of the sun and moon, 

 177. 



Milky Way, average number of stars 

 in, and beyond the, according to 

 Struve, 188; intensity of its light 

 in the vicinity of the Southern 



Cross, 198; its course and direc- 

 tion, 199; most of the new stars 

 have appeared in its neighbour- 

 hood, 220. 



Morin proposes the application of 

 the telescope to the discovery of 

 the stars in daylight, 51, 86. 



Motion, proper, of the fixed stars, 

 248; variability of, 252. 



Multiple stars, 175, 271; variable 

 brightness of, difference of opinion 

 regarding, 286. 



Nebulse, probably closely crowded 

 stellar swarms, 44. 



Neptune, the planet, its orbit used 

 as a measure of distance of 61 

 Cygni, 277. 



New stars, 204 ; their small num- 

 ber, 204 ; Tycho Brahe's descrip- 

 tion of one, 205; its disappear- 

 ance, 206; speculations as to 

 their origin, 218; most have ap- 

 peared near the Milky Way, 

 220. 



Newton, embraces by his theory of 

 gravitation the whole uranological 

 portion of the Cosmos, 23. 



Non-luminous stars, problematical 

 existence of, 254. 



Numerical results, exceeding the 

 grasp of the comprehension, fur- 

 nished alike by the minutest 

 organisms and the so-called fixed 

 stars, 34 ; encouraging views on 

 the subject, 35. 



Optical and physical double stars, 

 272; often confounded, 272. 



Orbits of double stars, calculation 

 of the, 287; their great eccentri- 

 city, 287; hypothesis, that the 

 brighter of the two stars is at 

 rest, and its companion revolves 

 about it, probably correct, and a 

 great epoch in cosmical know- 

 ledge, 288. 



Orion, the six stars of the trapezium 

 of the nebula of, probably subject 

 to peculiar physical attraction, 287. 



