612 BIBLIOGRAPHY OF HERSCHEL's WRITINGS. 



Subject-Index. Philosophical Teaksactions. Year. Page. 



Clusters: their relative distances 1818 429 



Clusters of stars : see Catalogue of, etc. 



Clustering power : its analogy witli the gravitating principle in nebulse. 1814 271 



Coma of a comet : definition 1808 151 



Comet: [1786, II] observed 1787 4 



: [1788, II] 1789 151 



Comets: [1792,1] 1792 23 



: [1796,1] ■. 1796 133 



: [1806,11] 1807 260 



: [1807, I] 1808 145 



: [1811,1] 1812 115 



: it was self-luminous 1812 119 



: it -was transparent and elastic 1812 122 



: its tail compared with the milky way 1812 126 



: its real construction 1812 133 



: [1811, II] 1812 226 



Comet of 1807 and 1811 : their relative age 1812 141 



Comets : the sun's effect on them 1812 236 



: their light is reflected sunlight 1812 234 



: defined 1802 Mzo 



: definitions of Nucleus, Head, Coma, etc 1808 146 



: may become asteroids 1802 230 



: may restore to the sun the light it loses by emission 1795 60 



: out of 16 comets, 14 had no nucleus 1807 266 



: that of 1807, I, did not shine by reflected sunlight only 1808 156 



: the sun's influence on their phenomena 1812 136 



: the tail and coma of 1807, I, obstructed the light of stars 1808 157 



Construction of the heavens 1784 237 



: 1785 213 



: 1789 212 



: 1791 71 



: 1795 46 



: 1802 477 



: 1811 269 



: '. 1814 248 



: 1817 302 



: 1818 429 



Diameters of the Sfars : see Stars. 



Dione : observations 1790 450 



Diurnal motion of the earth : see Earth 1781 115 



DOLLAND (J.) 1780 518 



Double nebula; 1811 285 



Double star observations : effect of practice 1803 346 



Double stars : account of changes that have happened in their relative 



situation, and of the cause of these changes 1803 339 



: change their rehitive situation as proved by observation . . . 1802 486 



: changes that have happened in their relative situation 1804 353 



: see Stars. 



Drawings of Mars, Jupiter, etc. : see Mars, Jupiter, etc. 



Earth : is its diurnal motion equable ? 1781 115 



Enceladns: discovered 1789, August 28 [ ^''^^ '^^^ 



" ( 1790 10 



