Inclined plane, law of, 140-141. Incomprehensible, the, 186. Indian, his modes of conception and interpretation, 218 et seq. Individual, a thread on which pearls are strung, 234-235. Industrial arts, economy of the, E. Hermann on, 192. Inertia, law of, 143 et seq., 146 et seq., 216, footnote, 283 et seq. Innate concepts of the understanding, Kant on, 199. Innervation, visual, 99. Inquirer, his division of labor, 105; compared to a shoemaker, 105-106; what constitutes the great, 191; the true, seeks the truth everywhere, 63 et seq.; the, compared to a wooer, 45. Instinctive knowledge, 189, 190. Instruction, aim of, the saving of experience, 191; in the classics, mathematics, and sciences, 338-374; limitation of matter of, 365 et seq. Insulators, 130. Integrals, 195. Intellectual development, conditions of, 286 et seq. Intentions, acts of nature compared to, 14-15. Interconnexion of nature, 182. Interdependence, of properties, 361; of the sensuous elements of the world, 179. Interference experiments with the head-wave of moving projectiles, 327-328. International intercourse, established by Latin, 341. International measures, 108. Invention, discovery and, distinction between, 269. Inventions, requisites for the development of, 266, 268 et seq. Iron-filings, 220, 243. Italian art, 234. Jacobi, C. G. J., on mathematics, 280. James, W., 275, 299. Java, 163. Jews and Christians, monotheism of the, 187. Jolly, Professor von, 112, 274. Joule, J. P., on the conservation of energy, 163-165, 167, 183; his conception of energy, 245; his metaphysics, 183, 246; his method of thought, 247; also 137, 138. Journée, 317. Judge, criminal, the natural philosopher compared to a, 48. Judgment, essentially economy of thought, 201-202; sharpened by languages and sciences, 357-358; also 232-233, 238. Juliet, Romeo and, 87. Jupiter, its satellites employed in the determination of the velocity of light, 51 et seq. Jurisprudence, Latin and Greek unnecessary for the study of, 346, footnote. Kant, his hypothesis of the origin of the planetary system, 5; his _Critique of Pure Reason_, 188; on innate concepts of the understanding, 199; on time, 204; also footnote, 93. Kepler, 187, 270. Kinetic energy, 177. Kirchhoff, his epistemological ideas, 257-258; his definition of mechanics, 236, 258, 271, 273. Knight, 289. Knowledge, a product of organic nature, 217 et seq., 235; instinctive, 190; made possible by economy of thought, 198; our first, derived from the economy of self-preservation, 197; the theory of, 203; our primitive acts of the foundation of science, 190. Kocher, 328. Koenig, measurement of the velocity of sound, 57 et seq. Kölliker, 19. Kopisch, 61. Kreidl, 299, 302, 306; his experiments, 272. Krupp, 319.