612 BIBLIOGRAPHY OF HERSCHEL's WRITINGS. 



Subject-Index. Philosophical Teaksactioks. Year. Page. 



Clusters: their relative distances 1818 429 



Clusters of stars : see Catalogue of, etc. 



Clustering power : its analogy with the gravitating principle in nebulas . 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, I] 1796 133 



: [1806,11] 1807 260 



: [1807,1] 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 226 



: 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 j)henomena 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 Stars : see Stars. 



Dione : observaitions 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 relative 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 



Enceladus : discovered 1789, August 28 < ' ^ 



' " < 1790 19 



