Sagittarius, nebula in, 333. 



Sanscrit names of planets. 409. 



Satellites, general considerations 

 on, 462. 



Saturn, numerical data, 517; rings, 

 519; ex centric position, 521. 



Saturn's satellites, numerical data, 

 523. 



Schwabe's observations on the solar 

 spots, 397 ; on the excentric posi- 

 tion of Saturn, 521. 



Scythian myth of a fall of gold 

 (meteors), 589. 



Seas (so-called) of the Moon, 491. 



Secondary planets, 462. 



Shooting stars, upper limits of the 

 height of, unascertained, 583; 

 various colours, 583; magni- 

 tudes, 586. 



Sidera Borbonia and Sidera Aus- 

 triaca, 367. 



Sidereal aggregation, theory of, 303. 



Sidereal periods of revolution and 

 axial rotation of the planets, 448. 



Sirius, and other fixed stars, esti- 

 mates of the distance of, 353. 



Small planets, 504. 



Snow spots in Mars, 504. 



Solar system, difference between, 

 and the system of double stars, 

 351 ; its limits indicated by the 

 orbits of comets, 356 ; its con- 

 stituents, 357. 



South, Sir James, nebulae resolved 

 by, 304. 



South polar star, search for a, 315. 



Southern Catalogue of the Her- 

 schels, 309. 



Southern Cross, planetary nebula 

 in, 320 ; black spot in, 340, 

 347. 



Southern hemisphere, with fewer 

 nebulae, possesses relatively more 

 clusters of stars than the northern, 

 314 ; the Magellauic Clouds, 294, 

 339. 



Spiral nebula in Asterion, 334. 



Spots, solar, 377, 398; lunar, 488; 

 on Mars, 504. 



Star catalogues, early, 341; the 



HersehoV, 309; the Northera, 

 309 ; the Southern, 310. 



Star clusters, 297 ; predominate in 

 the southern hemisphere, 311. 



Star-formation theory, the, 303 

 independentof the nebular theory 

 303. 



Stellar clusters, probably no essei* 

 tial physical difference between, 

 and nebulae, 305 ; in the north- 

 ern and the southern hemispheres, 

 311. 



Sternhaufen, star clusters, 297. 



Suhel, a vague term of the Arabian 

 astronomers, 340. 



Sun, domain of the, 351 ; its con- 

 stituents, 357; translatory mo- 

 tion, 466. 



Sun, considered as the central body, 

 359; numerical data, 361; con- 

 jectures as to its physical charac- 

 ter, 362 ; envelopes, 363 ; pe- 

 numbras, 371; protuberances, 

 375, 468 ; distribution of solar 

 spots, 377; chronological list of 

 remarkable appearances of, 38 1 ; 

 intensity of solar light, 388; com- 

 parison of artificial light, 393; 

 rays of light and rays of heat, 

 395; Schwabe's table of occur- 

 rence of solar spots, 398. 



Telescope, discoveries of planets 

 since the invention of the, 420; 

 the Earl of Rosse's, 304. 



Tethys, a satellite of Saturn, 523. 



Titan, a satellite of Saturn, 523. 



Titius, on the law of planetary dis- 

 tances, 442. 



Transits of Venus, 474. 



Trapezium of Orion, discovery of 

 new stars in, 330. 



Uranus, numerical data, 524. 

 Uranus, satellites of, peculiarity of 



their motion, 526; their number 



undetermined, 527. 

 Ursa Major, planetary nebula ill, 



320. 

 Ursa Minor, /3 and y, 316. 



