clxii INDEX. 



and xxiii. (Note 117.) Earl of Rosse's great, and results thereof as respects 

 our knowledge of nebulae, p. 6364, 225226, and Ixxx. Ixxxiii. (Notes 382 

 and 383.) 



Temperature of space, and its relation to that of the Earth, p. 3639, and xii. 

 xiii. (Notes 7177). How the, of the Earth may have been or would be 

 affected, if our Sun were a variable star, p. 177 ; by the spots, &c. of the 

 Sun's disk, p. 277278 and 293 ; by the present or a different obliquity of the 

 ecliptic, p. 327331 ; and by the change of position of the line of the Aspides, 

 p. 334 336. Supposed temperature of the Moon, p. 338. Of Comets at their 

 perihelion, p. 401402. 



Tubes, long, their employment in astronomical observations before the invention 

 of telescopes, p. 4445 and xv.-xvi. p. 133136. (Note 94.) 



Variable stars, p. 147, 152-177, and Ixviii. Ixx. (Notes 274289). Periodically, 

 p. 153172 (Notes 155281). Table of, by Argelander, p. 161 ; and com- 

 mentsthereon by the same astronomer, p. 162171. " Periods within periods," 

 p. 156160. Not having any determinate periods, and more especially 

 i} Argfts, p. 172177. May our Sun have been a variable star? p. 177. 



Venus, varying brightness of, p. 311. Numerical data, spots, &c. p. 348 351 

 and cxxv. cxxvi. (Notes 557560.) 



Vesta, magnitude of, p. 309. 



Visibility of distant objects, remarkable instance of, p. 5152. How affected by 

 the form of the object, &c. and minimum requisite difference of light between 

 the object and the back ground, p. 50 53 and latter part of p. xxvii. 



Vision, natural and telescopic, p. 43 71. Limits to ordinary visual power, p. 

 4749 and xviii. (Note 103.) Extraordinary instances, p. 49 and xix. xx. 

 (Note 105.) Imperfections of the visual organs causing the appearance of 

 " rays," &c. p. 50, 100 11 1, xviii. xix. xx. and Ivi. Ivii. (Notes 104105, and 

 205), and of factitious diameters of stars, p. 50110, and (Note 106.) Natural 

 vision of stars, as affected by the use of long tubes, p. 4445, 55, 8688. 

 From the bottom of deep cavities or on high mountains, p. 5355 and xxii. 

 Notes 109 110. Progress of astronomy while limited to " natural vision," 

 p. 5758. Transition to telescopic, and astronomical progress consequent 

 thereon, p. 5859. Telescopic, of stars in the daytime, p. 6567 and xxiv. 

 (Note 127.) Arago, MS. on an effect of telescopic, p. xxv. xxvii. (Note 128.) 



Uranology, p. 26446. Divided under two heads, p. 2627. 

 Uranus, p. 387388. Satellites of, 388390 and 457. 



Zodiac, p. 103105, Hi. liii. (Notes 193196.) 

 Zodiacal light, p. 413-418. 



END OF VOL. III. 



WILSON AND OOILVY, 57, SETS HER STTtEET, SNOWHILL, LONDON, 



