Refraction, atmospheric, 31;
effects looked for in comets, 106, 353;
Cytherean, 235, 253, 254;
lunar 263, 264

Reichenbach, foundation of Optical Institute, 28, 34, 122

Repsold, astronomical circles, 41, 122;
Cape heliometer, 416

Resisting medium, 93, 94, 360

Respighi, slitless spectroscope, 173;
prominences and chromosphere, 194, 196, 199;
solar uprushes, 205;
spectrum of Gamma Argus, 380

Reversing layer, detected, 171, 172;
photographed, 172, 189;
depth, 173

Riccioli, secondary light of Venus, 255

Ricco, trials with coronagraph, 180;
distribution of prominences, 199;
spectrum of Venus, 254;
spot on Jupiter, 294;
spectrum of great comet, 364

Richer, distance of the sun, 228

Ristenpart, solar translation, 40

Ritchey, nebula round Nova Persei, 401;
photographs of nebulae, 432

Ritter, development of stars, 375

Roberts, A. W., southern variables, 392

Roberts, Isaac, search for ultra-Neptunian planet, 306;
photographs of Orion nebula, 408;
of Andromeda nebula, 409;
of the Pleiades, 411

Roberval, structure of Saturn's rings, 299

Robinson, reflectors and refractors, 431

Roche, inner limit of satellite-formation, 301;
modification of nebular hypothesis, 321

Roemer, star places, 10;
invention of equatoreal and transit instrument, 120;
of altazimuth, 121;
velocity of light, 231;
satellite transit on Jupiter, 291

Rosenberger, return of Halley's comet, 101

Rosetti, temperature of the sun, 219

Rosse, third Earl of, biographical sketch, 114;
great specula, 115-117;
discovery of spiral nebulae, 118;
resolution of nebulae, 119;
climate and telescopes, 434

Rosse, fourth Earl of, experiments on lunar heat, 269

Rost, nature of sun-spots, 54

Roszel, mass of asteroids, 287

Rowland, photographic maps of solar spectrum, 210, 440;
elements in run, 213;
concave gratings, 439, 440

Ruemker, observation of Encke's comet, 90

Russell, H. C., red spot on Jupiter, 295;
change in Argo nebula, 404;
photographs of Nubeculae, 425

Russell, H. N., atmosphere of Venus, 254

Rutherfurd, lunar photography, 268;
star spectra, 372;
photographs of the Pleiades, 410;
diffraction gratings, 439

Sabine, magnetic and sun-spot periods, 127, 128, 130

Safarik, secondary light of Venus, 256;