Galileo, on the motion of pendulums, 21; his attempted measurement of the velocity of light, 50 et seq.; his exclusion of a perpetual motion, 143; on velocities acquired in free descent, 143-147; on the law of inertia, 146-147; on virtual velocities, 150; on work, 172; his laws of descent, 193; on falling bodies, 225; great results of his study of nature, 214 et seq.; his rude scientific implements, 215; selections from his works for use in instruction, 368; also 105, 182, 187, 237, 272, 274, 283. Galle, observes the planet Neptune, 29. Galvanic, electricity, 134; current, 132; dizziness, 291; vertigo, 298. Galvanoscope, 135. Galvanotropism, 291. Garda, Lake, 239. Gas, the word, 264; mass of, enclosed in a cylinder, 179. Gases, tensions of, for scales of temperature, 174. Gauss, on the foundations of dynamics, 154; his principle, 154; also, 108, 274. Genius, 279, 280. Geography, comparison in, 239. Geometers, in our eyes, 72. Geotropism, 289. German schools and gymnasiums, 372, 373, 338, footnote. Ghosts, photographic, 73. Glass, invisible in a mixture of the same refrangibility, 312; powdered, visible in a mixture of the same refrangibility, 312. Glove, in a mirror, 93. Goethe, quotations from, 9, 31, 49, 88; on the cause of harmony, 35. Goltz, 282, 291. Gossot, 332. Gothic cathedral, 94. Gravitation, discovery of, 225 et seq. Gravity, how to get rid of the effects of, in liquids, 4; also 228. Gray, Elisha, his telautograph, 26. Greased plate, drop of water on a, 8. Great minds, idiosyncrasies of, 247. Greek language, scientific terms derivedfrom, 342-343; common words derived from, 343, footnote; still necessary for some professions, 346; its literary wealth, 347-348; narrowness and one-sidedness of its literature, 348-349; its excessive study useless, 349-350; its study sharpens the judgment, 357-358; a knowledge of it not necessary to a liberal education, 371. Greeks, their provinciality and narrow-mindedness, 349; now only objects of historical research, 350. Griesinger, 184. Grimaldi, 270. Grimm, 344, footnote. Grunting fishes, 306. Habitudes of thought, 199, 224, 227, 232. Haeckel, 222, 235. Hamilton, deduction of the conical refraction of light, 29. Hankel, 364. Harmonics, 38, 40. Harmony, on the causes of, 32 et seq.; laws of the theory of, explained, 30; the investigation of the ancients concerning, 32; generally, 103. See _Consonance_. Harris, electrical balance of, 127, footnote. Hartwich, Judge, 343, 353, footnote. Hat, a high silk, 24. Hats, ladies', development of, 64. Head-wave of a projectile, 323 et seq. Hearing and orientation, relation between, 304 et seq.