β Aurigae, 54, 58 β-particles, 112, 113, 116, 145 and Plate XIII (p. 113) β-rays, 111, 145 B.D. 6° 1309, _see_ Plaskett’s star Bacon, Roger, 1 Becquerel, H., 110 Bentley, R., 197 Berenice’s hair, 39 Bessel, F. W., 33 Betelgeux (α Orionis), 259, 272, 278 Bickerton, A. W., 235 Biela’s comet, 251 Binary systems, 39, 40, 52, 54 birth of, 217 eclipsing, 54, 58 loss of weight in, 188, 228 orbits of, 46, 47, 167 origins of, 169, 219, 297 relative weights of components in, 188 subdivision in, 228 weights of, 48, 55 Birth of binary systems, 217 of nebulae, 204 of planets, 232, 237 of satellites, 232, 241 of stars, 209 Blackett. P. M. S., 117, 118 Blue stars, 62 Bode’s law, 19, 20, 252 Bohr, Niels, 124, 128, 129, 131, 304, 305 Bowen, J. S., 143 Boys, C. V., 44 Brownian movements, 159, 163 Bruno, Giordano, 3, 4, 344 Buffon, G. L. L., 235 Bumstead, H. A., 113 Burton, E. F., 143 γ-rays, 111, 114, 122, 139, 144, 145 Cameron, G. H., 143 Campbell, W. W., 321 Candle-power of stars, 49, 55, 179, 188; _see_ Luminosity Capella, 278 Cassini, D., 23 Cavity-radiation, 123, 255 Cepheid variables, 55, 56, 57, 59, 60, 70, 209 mechanism of, 223 Ceres (asteroid), 17 Chamberlin, T. C., 235, 236 Chaos, primaeval, density of, 202 evolution from, 202, 204, 229, 230 Charlier, C. V. L., 67 Clusters, globular, 63, 64, 68, 213, 216 moving, 39, 173, 216, 217 Coal, combustion of, 175, 191 Coal sack, 30 Comets, 247, 251 origin of, 238 Condensation-chamber of C. T. R. Wilson, 113, 117 Condensations in a gas, 198, 200, 203, 209, 237 Configurations of rotating masses, 221 Conservation, of angular momentum, 205, 217, 232 of energy, 99, 189, 326, 328 of matter, 189 Constellations, 36, 39 Cooke, H. L., 143 Copernican astronomy, 3, 5, 6, 27, 32 Copernicus, 3 Creation, of matter, 336 of universe, 79, 337 Crookes, Sir W., 106 Cycles and epicycles (Ptolemaic), 2, 3, 4 Cyclic processes in nature, 325, 329, 331