compression of Uranus, 304

Satellites, discoveries, 110, 282, 293;
transits, 291, 292;
variability, 292, 302;
origin, 309, 318

Saturn, low specific gravity, 298;
rotation, 302;
spectrum, 303

Saturn's rings, first disclosure, 85;
dusky ring, 86;
stability, 298, 300;
meteoric constitution, 300;
eventual dispersal, 301

Savary, orbits of double stars, 46

Savelieff, solar radiation, 164, 225

Sawerthal, discovery of a comet, 366

Schaeberle, discovery of Procyon's satellite, 42;
coronal photographs, 187, 188;
theory of corona, 191;
meteoric photography, 339;
discovery of a comet, 355

Schaeberle and Campbell, observations of Jupiter's satellites, 292

Scheiner, Father, nature of sun-spots, 52, 54;
equatoreal instrument, 120 _note_;
solar rotation, 146;
darkening of sun's limb, 221

Schiener, Dr. J., photospheric structure, 165;
spectrographic researches, 384, 405;
spectrum of Andromeda nebula, 403;
stars and nebulae in Orion, 407

Schiaparelli, rotation of Mercury, 247;
of Venus, 251, 252;
spots on Mars, 275;
snow-cap, 277;
canals, 278-280;
compression of Uranus, 304;
comets and meteors, 327, 331, 332, 338;
anomalous tail of great comet, 364;
Pons's comet, 365;
origin of comets, 370;
measures of double stars, 419

Schmidt, A., circular refraction in sun, 159

Schmidt, J., sun-spot period, 126;
lunar rills, 263;
lunar maps, 265;
disappearance of Linne, 267;
cometary appendages, 363;
new stars, 393

Schoenfeld, extension of Bonn Durchmusterung, 412, 414

Schrader, construction of reflectors, 243

Schroeter, a follower of Herschel, 5;
motions of sun-spots, 146;
biographical sketch, 243, 244;
observations on Mercury, 244, 246, 247;
on Venus, 250-253, 255;
on the moon, 263;
a lunar city, 265;
Linne, 267;
spots on Mars, 275;
Jovian markings, 290

Schuelen, perspective effects in sun-spots, 54

Schuster, photographs of corona, 178, 185;
spectra of oxygen, 214

Schwabe, sun-spot periodicity, 125, 126

Secchi, chromosphere, 70;
Biela's comet, 97;
cyclonic movements in sun-spots, 144;
distribution, 148;
profundity, 154;
nature, 156, 158;
constitution of photosphere, 151;
eclipse observations, 166, 167;
reversing layer, 171;
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