Radiata, _b._ 478. Radiation, _b._ 139. Rays, _b._ 58. Realists, _a._ 238. Refraction, _b._ 54. " of heat, _b._ 155. Remora, _a._ 190. Resinous electricity, _b._ 195. Rete mirabile, _b._ 463. Retrograde motion of planets, _a._ 139. Roman calendar, _a._ 123. Rotatory vibrations, _b._ 44. Rudolphine tables, _a._ 270, 302. Saros, _a._ 136. Scholastic philosophy, _a._ 230. School philosophy, _a._ 50. Science, _a._ 42. Secondary rocks, _b._ 513. " mechanical sciences, _b._ 23. Second law of motion, _a._ 330. Seconds, _a._ 163. Secular inequalities, _a._ 370. Segregation, _b._ 558. Seminal contagion, _b._ 459. " proportions, _a._ 79. Sequels of epochs, _a._ 47. Silicides, _b._ 352. Silurian rocks, _b._ 530. Simples, _b._ 367. Sine, _a._ 181. Solar heat, _b._ 145. Solstitial points, _a._ 131. Solution of water in air, _b._ 166. Sothic period, _a._ 118. Spagiric art, _b._ 262. Specific heat, _b._ 159. Sphere, _a._ 130. Spontaneous generation, _b._ 457. Statical electricity, _b._ 208. Stationary periods, _a._ 48. " planets, _a._ 139. Stations (of plants), _b._ 562. Sympathetic sounds, _b._ 37. Systematic Botany, _b._ 357. Systematic Zoology, _b._ 412. Systems of crystallization, _b._ 328. Tables, Solar, (of Ptolemy), _a._ 146. " Hakemite, _a._ 177. " Toletan, _a._ 177. " Ilchanic, _a._ 178. " Alphonsine, _a._ 178. " Prutenic, _a._ 270. " Rudolphine, _a._ 302. " Perpetual (of Lansberg), _a._ 302. " Philolaic, _a._ 304. " Carolinian, _a._ 304. Tangential vibrations, _b._ 45. Tautochronous curves, _a._ 372. Technical terms, _b._ 389. Temperament, _b._ 47. Temperature, _b._ 139. Terminology, _b._ 389. Tertiary rocks, _b._ 513. Tetractys, _a._ 77. Theory of analogues, _b._ 483. Thermomultiplier, _b._ 154. Thermotics, _b._ 137. Thick plates. Colors of, _b._ 79. Thin plates. Colors of, _b._ 77. Third law of motion, _a._ 334. Three principles (in Chemistry), _b._ 261. Toletan tables, _a._ 177. Transition rocks, _b._ 530. Transverse vibrations, _b._ 44, 93, 101. Travertin, _b._ 546. Trepidation of the fixed stars, _a._ 179. Trigonometry, _a._ 167. Trivial names, _b._ 392. Trivium, _a._ 199. Tropics, _a._ 131. Truncation (of crystals), _b._ 319. Type (in Comparative Anatomy), _b._ 476. Uniform force, _a._ 327. Unity of Composition (in Comparative Anatomy), _b._ 483. Unity of plan (in Comparative Anatomy), _b._ 483. Variation of the moon, _a._ 179, 303. {38} Vegetable alkali, _b._ 264. Vertebrata, _b._ 478. Vibrations, _b._ 44. Vicarious elements, _b._ 334. " solicitations, _a._ 359. Virtual velocities, _a._ 333. Vitreous electricity, _b._ 195. Volatile alkali, _b._ 264. Volta-electrometer, _b._ 299. Voltaic electricity, _b._ 239. " pile, _b._ 239. Volumes, Theory of, _b._ 290. Voluntary, violent, and natural motion, _a._ 319. Vortices, _a._ 388. Week, _a._ 127. Year, _a._ 112. Zenith, _a._ 181. Zodiac, _a._ 131. Zones, _a._ 136.