219 



Space, conjectures regarding, 29 ; com- | its influence 

 pared to the mythic period of history, I 37. 

 29; fallacy of attempts at measurement , Temporary stars, 



the climate of the earth, 



t of, 155 ; notoe to, 



of, 30 ; po'rtions between cosmical bod- I 155-160." 

 jes not void, 31 ; its probable low tem- Ternary stars, 210. 



perature, 35. 



Spectra, the prismatic, 44 ; difference of 

 the dark lines of, according to their 

 sources, 45. 



" Sphtera aplanes" of Macrobiue, 27. 



Spurious diameter of stars, 130. 



Star of the Magi, Ideler's explanation of 

 the, 154. 



Star of St. Catharine, 137. 



Star systems, partial, in which several 

 suns revolve about a common center 

 of gravity, 204. 



Stars, division into wandering and non- 

 wandering, dates at least from the early 

 Greek period, 27 ; magnitude and visi- 



Timur Ulugh Beg, improvements in prac- 

 tical astronomy in the time of, 91. 



Translation in space of the whole solar 

 system, 195; first hinted by Bradley, 

 195 ; verified by actual observation by 

 William Herschel, 196; Argelander. 

 Strove, and Gauss's views, 196. 



Trapezium in the great nebula of Orion, 

 investigated by Sir Wm. Herschel, 203. 



Tycho Brahe, his vivid description of the 

 appearance of a new star, 152 ; his the- 

 ory of the formation of such, 154. 



Ultimate mechanical cause" of all mo- 

 tion, unknown, 24, 25. 



bility of the, 48 ; seen through shafts I Undulation of the stars, 58, 59. 



of chimneys, 57 ; undulation of the, 58, ' Undulations of rays of light, various 



59 ; observation of, by daylight, 66 ; ! lengths of, 84. 



scintillation of the, 73 ; variations in its Unity of nature distinctly taught by Aris- 



intensity, 76 ; the brightest the earliest totle, 13-15. 



named, 89; rays of, 52, 127, 128 ; color Uranological and telluric domain of the 

 Cosmos, 26. 



of, 130 ; distribution of, 140 ; concentric 

 rings of, 149 ; variable, 161 ; vanished, 

 163 ; periodically changeable, 164 ; non- 

 luminous, of doubtful existence, 187 ; 

 ratio of colored stars, 209. 



Steinheil's experiments on the velocity 

 of the transmission of electricity, 87 ; 

 his photometer, 93. 



Stellar clusters or swarms, 140. 



Struve on the velocity of light, 82 ; his 

 estimate of the number of tine fixed 

 stars, 1 17 ; on the Milky Way, 139 ; his 

 Dorpat Tables, 205 ; on the contrasted 

 colors of multiple stars, 207 ; calcula- 

 tion of the orbits of double stars by, 211. 



Sun, the, described as " a perpetual north- 

 ern light" by Sir William Herschel, 34 ; 

 in intensity of light merely one of the 

 fainter fixed stars, 95 ; its place prob- 

 ably in a comparatively desert region 

 of the starry stratum, and eccentric, 150. 



Suns, self-luminous cosmical bodies, 199. 



Uranus observed as a star by Flamstead 

 and others, 114. 



Vanished stars, 163; statements about 

 such to be received with great caution, 

 163. 



Variable brightness of multiple and dou- 

 ble stars, 209. 



Variable stars, 160-161 ; mostly of a red 

 color, 165; irregularity of their periods, 

 167 ; table of, 172. 



Velocity of light, 79 ; methods of determ- 

 ining, 80 ; applied to the determination 

 of the parallax, 195. 



Visibility of objects, 55 ; how modified, 56. 



Vision, natural and telescopic. 41 ; aver- 

 age natural, 47, 48; remarkable in- 

 stances of acute natural, 52, 55. 



Wheatstone's experiments with revolv- 

 mirrors,45; velocity of electrical 



ing IT 



light determined by, 86." 

 Table of photometric arrangement of 190 White Ox, name given to the nebula now 

 fixed stars, 100 ; of 17 stars of first mag- known as one of the Magellanic clouds, 



nitude, 102; of the variable stars, by 



91. 



Argelander, 172, and explanatory re- Wollaston's photometric researches, 95. 



marks, 172-177; of ascertained paral- Wright, of Durham, his view of the origin 



laxes, 193 : of the elements of the or- of the form of the Milky Way, 149. 

 bits of double stars, 213. 



Telescope, the principle of, known to the Yggdrasil, the World-tree of the Edda- 



Arabs, and probably to the Greeks and Songs, 8. 

 Romans, 42, 43 ; di 



:overies by its 



means, 61 ; successive improvements ' Zodiac, period of its introduction into the 

 Greek sphere, 119; its origin among the 

 Chaldeans, 120 ; the Greeks borrowed 

 from them only the idea of the division, 

 and filled its signs with their own cataa- 

 toriems, 120; great antiquity of the In- 



of the, 62; enormous focal lensrth of 

 som.', 63; Lord Rosse's, 65; Bacon's 

 comparison of, to discovery ships, 130; 

 penetrating power of the, 145, 146. 

 Telesio, Bernardino, of Cosenza, his v: 



of the 



iews 

 phenomena of inert matter, 16. 



Temperature, low, of cclcstiiil 

 uncertainty of results "el obta 



space, 35; 

 ained, 36 ; 



dian ver 



130; great 

 y doubtful, 



-ID. 

 THE END. 



Zodiacal light, Sir John Herschel on the, 



