_Aqua regia_, 51, 132. Aqueducts, 33. Aqueous vapor, 157 _et seq._ Arago, 184. Archimedes, 27. Architecture, 30 _et seq._ Archytas, 18. Aristotle, 20 _et seq._, 49, 51, 53, 266. Arithmetic, 6, 11, 48. Arnold, Matthew, 273. Astrology, 10. Astronomy, (Egyptian and Babylonian) 2 _et seq._; (Greek) 16; (Roman) 34; (Alexandrian) 45; (Hindu) 48; (Arabian) 49, 50; (Copernican) 55; (Tycho Brahe and Kepler) 87 _et seq._; (Newton) 110 _et seq._; (nebular hypothesis) 142 _et seq._; (discovery of Neptune) 184 _et seq._ Atmosphere, 157. Atomic Theory, 158 _et seq._, 250. Atoms, 17, 148, 158, 253. Augustus Cæsar, 36. Averroës, 51 _et seq._ Avicenna, 51. Avogadro, 165. Babylonia, 1 _et seq._ Bacon, Francis, 57 _et seq._, 80 _et seq._, 105; Baconian principles, 211. Bacon, Roger, 54. Bacteria, 93. Bacteriology, 213 _et seq._ Bagdad, 49. Barbarians, 46. Barometer, 94 _et seq._ Basalt, 131, 132, 136, 137, 201. Becquerel, 233, 246 _et seq._ Beddoes, 173. Beer, 223, 226. Berzelius, 162. Bessel, 187. Biology, 6, 7, 23 _et seq._, 37, 53, 78, 109, 197 _et seq._, 213. Biot, 215 _et seq._ Black, 129, 133. _Bode's Law_, 189. Botany, 6, 26, 37, 39, 53, 231 _et seq._ Bouvard, Alexis, 185. Bouvard, Eugène, 187. Boyle, 96, 107. Buffon, 130, 135. Building material, 32. Cabanis, 258. Cairo, 49. Calendar, 9, 36. Carbonic acid, 138, 155, 157, 217. Carlisle, 177. Cato, 35, 38. Challis, 189. Charlemagne, 52. Charles II, 105. Chemical affinity, 159, 253. Chemistry, 6, 8, 50, 51, 155 _et seq._, 170 _et seq._, 245 _et seq._ Chicken cholera, 225. Chlorine, 180. Clocks, 89, 94. Collinson, 123. Columbus, 26, 54. Columella, 38. Comenius, 100. Comets, 10, 40, 149. Conservation of energy, 168. Constantine, 37. Copernicus, 55. Coral reefs, 203. Cordova, 50. Counting, 6, 11, 34, 49, 86. Cowley, 104 _et seq._ Cronstedt, 130. Curie, P. and S., 247 _et seq._ D'Alembert, 58. Dalton, 155, 157 _et seq._ Darwin, Charles, 198 _et seq._ Darwin, Erasmus, 199. Davy, 122, 163, 170 _et seq._ Deduction, 82. Defoe, 116. Democratic culture, 44, 270 _et seq._ Democritus, 17, 48, 148. Descartes, 57, 72, 82 _et seq._ Desmarest, 132. _Dialogues_ of Plato, 19. Diderot, 58. Dioscorides, 39. Dyes, 24, 33, 71, 181. Earthquakes, 40, 137. Ebers papyrus, 7. Eclipses, 10, 16, 49. Education, 19, 35, 36, 40, 44, 52, 53, 100 _et seq._, 116, 122, 123, 171-72, 198, 213, 214, 216, 270 _et seq._ Egypt, 1 _et seq._ Electricity, 75, 123 _et seq._, 177, 231. Electrolysis, 178. Elements, 17, 20, 22, 155. Ellipse, 20. Embalmers, 7. Empedocles, 17, 40. _Encyclopaedia_, 58. Ethics, 21, 40, 41. Euclid, 18, 19. Evelyn, 109. Experiment, 72 _et seq._ Extinction, 206. Faraday, 181. Fermentation, 216 _et seq._ Fitzroy, 198. Flacherie, 221. Flamsteed, 110, 111, 184. Fossils, 140.