"It would seem as if the mind of the great discoverer must combine contradictory attributes. He must be fertile in theories and hypotheses, and yet full of facts and precise results of experience. He must entertain the feeblest analogies, and the merest guesses at truth, and yet he must hold them as worthless till they are verified in experiment. When there are any grounds of probability he must hold tenaciously to an old opinion, and yet he must be prepared at any moment to relinquish it when a clearly contradictory fact is encountered." INDEX Aberration, 105-109, 111, 112, 117, 118, 185, 188, 192, 214, 215 Accidental discovery, 15, 73, 121-154 Adams, 12, 45-85; resolution, 55 Airy, 32, 40-85, 214 Algiers, 130 Alleghenia, 26 Almucantar, 180, 181 Alphabet used for planets, 27 Anderson, Dr. T. C., 8, 142, 143, 144, 146 Anthelm, 142 Apollo, 9 Argon, 109 Ascension, 34 Assumption, forgotten, 196 Astræa, 22, 23, 219 Astrographic chart, 122, 125, 130 _Astronomical Journal_, 177-217 _Astronomische Nachrichten_, 52, 158 Astrophil, 143 Auwers, 142 Ball, Sir R., 24 Balliol College, 87 Banks, Sir J., 9 Barnard, E. E., 146, 220 Berlin, 181, 183, 184, 188, 193 Berlin star-map, 45, 66, 83, 124 Bessel, 192 Bettina, 26, 27 Birmingham, 142 "Black Drop" (in transit of Venus), 30 Bliss, 114 Board of Visitors of Greenwich Observatory, 63 Bode, 11, 14, 15, 22 Bode's Law, 12, 13, 38, 43, 45, 52, 72, 76, 77, 84 Bourdeaux, 130 Bouvard, 39, 40, 42, 48, 49, 50, 61 Bradley, 39, 86-120, 188-192, 213, 214, 218, 219 Bradley, John, 115 Bremen, 20 Bridstow, 87, 88, 94 Briggs, 119 Brinkley, 192 British Association, 63 Brünnow, 193 California, 26 Cambridge (Mass.), 180, 184, 188 Cambridge Observatory, 23, 42, 49, 52, 63, 65, 66, 135, 193 Cambridge University, 68-71, 114 Cape Observatory, 123, 124, 130 Cards, 11 Cassini II., 156 Catania, 130 Ceres, 14-22 Chacornac, 124 Challis, 49-54, 63-68, 71, 85, 218 Chandler, S. C., 118, 177-217 Chapman's "Homer," 2 Chicago, 157 Chromosphere, 170 Clarke, C. C., 2 Coelostat, 94 Columbus, 63 Comet, 4-8, 88, 108, 117, 123, 125 Commission, planetary, 27 Common, A. A., 124, 127 _Compte Rendu_, 62 Comstock, 202 Conference, Astrographic, 125-136 Copernicus, 79, 95 Cordoba, 130, 199 Cornu, 210-213 Corona, 170-175 _Cosmos_ (Humboldt's), 160 Delambre, 157 Deviation of Pole, 187 Disc of Neptune, 44, 64, 79 Disc of Uranus, 4-7 Dorpat, 192 Doublet (photographic), 127-129 Draconis, [gamma], 96-104 Draconis, [beta], 193 Driessen, 23 Dry plate, 122 Dublin, 192 Earthquakes, 215 Earth's Pole, 177-217 Eccentricity, 41, 83 Eclipses, 170-176 Edinburgh, 143 Eduarda, 26 Egeria, 22 Endymion, 25 Eriphyla, 26