MERCURY, 137. Supposed planet Vulcan, 137. Visibility, 138. Period &c., 138. Elongations, 138. Amateur’s first view, 139. Phases, 139. Atmosphere, 139. Telescopic observations, 140. Schiaparelli’s results, 141. Observations of Schröter and W. Herschel, 142. Surface-markings, 142. Transits across the Sun, 143. Occultations, 144. Messier, The Comet-hunter, 249. Messier’s lists of Nebulæ, 327. —— large Comet of 1769, 232. METEORS AND METEORIC OBSERVATIONS, 260. Ancient ideas, 260. Meteoric apparitions, 261. Radiation of Meteors, 262. Identity of Meteors and Comets, 262. Aerolites, 264. Fireballs, 267. Heights of Fireballs, 268. Meteorite from Biela’s Comet, 270. Differences of motion, 271. Nomenclature of Meteor-systems, 271. Meteor-storms, 271. Telescopic Meteors, 272. Meteor-showers, 274. Varieties of Meteors, 276. Meteor of Dec. 28, 1888, 277. Average heights of Meteors, 277. Computation of Meteor-heights, 278. Meteoric observations, 279. Meteors and terrestrial objects, 284. —— and gales of wind, 285. Method, 78. Milky Way or Galaxy, 2, 295. Minimum of Sun-spots, 347. Mirrors, Dewing of, 62. MOON, Attractive aspect of the, 113. Diameter and distance, 114. Crateriform aspect, 114. Absence of air and water, 115. Only one hemisphere visible, 115. Earthshine, 116. Telescopic observations, 116. Eclipses, 118. Physical changes, 120. Active volcanoes, 120. Crater Aristarchus, 120. —— Linné, 121. —— near Hyginus, 122. General description of formations, 123. Description of special objects, 125-132. Objects near terminator, 133. Occultation of Stars, 135. Visibility of new and old Moon, 136. Moonlight and planetary definition, 187. Motion of light, 190. Motion of Stars in the line of sight, 300. —— of Sun-spots, Proper, 106. Mounting of Telescopes, 45. Naked-eye views of Comets, 248. —— —— of Jupiter in daylight, 170. —— —— of Jupiter’s satellites, 188. —— —— of Mercury, 139. —— —— of Sun-spots, 89. —— —— of Uranus, 217. —— —— of Venus in transit, 105. —— —— of Vesta, 168. Names of the Stars, Learning the, 287. Nasmyth and Carpenter describe Plato, 126. Nasmyth’s Telescopes, 16. —— “Willow-leaves,” 101. Nature of Cometary apparitions, 229. —— of the red spot on Jupiter, 177.