Variable stars, 108-115 Venus, mode of rotation, 96 Vogel, stellar development, 219, 225 Whewell, status of nebulæ, 54 Whittaker, undulatory theory of gravity, 178-9 Wilson, radium in the sun, 34 Wolf, C., motion of Phobos, 48; solar tidal friction, 67; criticism of Faye's cosmogony, 73 Wolf, Max, photographs of the zodiacal light, 263 World Soul, function in cosmogony, 8-9 Wright, theory of the Milky Way, 16-17, 18, 20 Zodiacal light, origin, 256-7, 261, 264; triple aspect, 257-60; transversal dimensions, 260; constitution, 262; plane of extension, 262-3 BILLING AND SONS, LTD., PRINTERS, GUILDFORD