336;
size of, 337;
tailless, 370;
tails of, 337, 361;
Bredichin's researches, 365;
Cheseaux's, 367;
composition of, 365, 369;
condensation of, 369;
electricity and, 368;
gradual growth of, 363;
law of direction of, 362;
repelled by the Sun, 364;
repulsive force of, 364, 368;
various types of, 365;
Tebbutt's (1881), 353;
tenuity of, 357

Common, Dr., constructor of reflectors, 21;
and the comet of 1882, 354;
and the nebula in Orion, 469

Cook, Captain, and the transit of Venus, 184

Copeland, Dr., and Schmidt's star, 489;
and the lunar crater, Tycho, 92;
and the spectra of nebula, 473;
and the transit of Venus, 189

Copernicus and Mercury, 156;
confirmation of his theory by the discovery of Jupiter's satellites, 267;
his theory of astronomy, 7;
lunar crater called after him, 89

Copper in the Sun, 50

Cor scorpionis, 423

Corona Borealis, 423, 488

Corona of Sun, during an eclipse, 62-64, 151

Coronium, 64

Cotopaxi and meteorites, 401

Crab, the, 422

Crabtree, and the transit of Venus, 180

Crape ring of Saturn, 281

Craters in the Moon, 83-85, 87-98

Critical velocity, 103, 104, 237

Crown, the, 423

Cryptograph of Huyghens, the, 277

Cygni, b, 439

Cygni 61, annual parallax of, 450;
Bessel's measurement of distance of, 442, 446, 447;
Bruennow's observations of, 449;
distance from the Sun of, 452;
disturbing influence of, 452;
double, 446;
Professor A. Hall's measurement of, 449;
Professor Pritchard's photographic researches concerning, 449;
proper motion of, 446;
Struve's observations of, 448, 449;
velocity of, 452

Cygnus, 424

Cyrillus, 92

Cysat, and the Belt of Orion, 467

D

D line in solar spectrum, 48

Darwin, Professor G.H., and tidal evolution, 531

Dawes, Professor, and Saturn's third ring, 281

Day, length of, and the Moon, 542;
and the tides, 541

Deimos, 226, 558

Denebola, 423

Diffraction, 56

Dione, 559

Dispersion of colours, 47

Distances, astronomical, 558, 559

Doerfel, and comets, 339

Dog star (_see_ Sirius)

Dog, the Little, 420

Donati's comet, 353, 358;
tails, 366

Double stars, 434-440

D Q, 236

Draco, nebula in, 470

Dragon, the, 415

Draper, Professor, and the nebula in Orion, 469

Dunsink Observatory, 12, 184, 447, 449

Dynamical stability, 547;
theory of Newton, 214

Dynamics and the Earth-Moon system, 546

Dynamics, Galileo