Book Vi.--Mechanics.

PRINCIPLES AND PROBLEMS.

Significance of Analytical Mechanics. 536 Strength of Materials. 538 Roofs--Arches--Vaults. 541

BOOK VII.--PHYSICAL ASTRONOMY.

PRELUDE TO NEWTON.

The Ancients. 544 Jeremiah Horrox. 545 Newton's Discovery of Gravitation. 546 {22}

THE PRINCIPIA.

Reception of the Principia. 548 Is Gravitation proportional to Quantity of Matter? 549

VERIFICATION AND COMPLETION OF THE NEWTONIAN THEORY.

Tables of the Moon and Planets. 550 The Discovery of Neptune. 554 The Minor Planets. 557 Anomalies in the Action of Gravitation. 560 The Earth's Density. 561 Tides. 562 Double Stars. 563

INSTRUMENTS.

Clocks. 565

{{23}} INDEX OF PROPER NAMES.

The letters a, b, indicate vol. I., vol. II., respectively.

Abdollatif, b. 443. Aboazen, a. 222. Aboul Wefa, a. 180. Achard, b. 174. Achillini, b. 445. Adam Marsh, a. 198. Adanson, b. 404, 405. Adelbold, a. 198. Adelhard Goth, a. 198. Adet, b. 279. Achilles Tatius, a. 127. Æpinus, b. 197, 203, 209. Agassiz, b. 429, 521, 540. Agatharchus, b. 53. Airy, a. 372, 442, 477; b. 67, 120. Albategnius, a. 177, 178. Albertus Magnus, a. 229, 237; b. 367. Albumasar, a. 222. Alexander Aphrodisiensis, a. 206. Alexander the Great, a. 144. Alfarabi, a. 209. Alfred, a. 198. Algazel, a. 194. Alhazen, a. 243; b. 54. Alis-ben-Isa, a. 169. Alkindi, a. 211, 226. Almansor, a. 177. Almeric, a. 236. Alpetragius, a. 179 Alphonso X., a. 151, 178. Amauri, a. 236. Ammonius Saccas, a. 206, 212. Ampère, b. 183, 243, 244, 246, 284. Anaxagoras, a. 78; b. 53. Anaximander, a. 130, 132, 135. Anaximenes, a. 56. Anderson, a. 342. Anna Comnena, a. 207. Anselm, a. 229. Arago, b. 72, 81, 100, 114, 254. Aratus, a. 167. Archimedes, a. 96, 99, 312, 316. Arduino, b. 514. Aristarchus, a. 137, 259. Aristyllus, a. 144. Aristophanes, a. 120. Aristotle, a. 57, 334; b. 24, 58, 361, 412, 417, 420, 438, 444, 455, 583. Arnold de Villâ Novâ, a. 228. Arriaga, a. 335. Artedi, b. 423. Artephius, a. 226. Aryabatta, a. 260. Arzachel, a. 178. Asclepiades, b. 439. Asclepigenia, a. 215. Aselli, b. 453. Avecibron, a. 232. Averroes, a. 194, 210. Avicenna, a. 209. Avienus, a. 169. Aubriet, b. 387. Audouin, b. 483. Augustine, a. 197, 220, 232. Autolycus, a. 130, 131. Auzout, a. 474.

Babbage, Mr. b. 254, 555. Bachman, b. 386. Bacon, Francis, a. 278, 383, 412; b. 25, 32, 165. Bacon, Roger, b. 55. Bailly, a. 199, 445. Baliani, a. 326, 347. Banister, b. 380. Barlow, b. 67, 223, 245, 254. {24} Bartholin, b. 70. Barton, b. 125. Bauhin, John, b. 381. Bauhin, Gaspard, b. 381. Beaumont, Elie de, b. 527, 532, 533, 539, 583, 588. Beccaria, b. 199. Beccher, b. 268. Bede, a. 198, 232. Bell, Sir Charles, b. 463. Bélon, b. 421, 476. Benedetti, a. 314, 321, 324, 336. Bentley, a. 422, 424. Berard, b. 154. Bergman, b. 266, 281, 321. Bernard of Chartres, a. 229. Bernoulli, Daniel, a. 375, 378, 379, 380, 430; b. 32, 37, 39. Bernoulli, James, a. 358. Bernoulli, James, the younger, b. 42. Bernoulli, John, a. 359, 361, 363, 366, 375, 393, 430; b. 32. Bernoulli, John, the younger, b. 32. Berthollet, b. 267, 278, 281. Berzelius, b. 284, 289, 304, 335, 347, 348. Bessel, a. 272. Betancourt, b. 173. Beudant, b. 348. Bichat, b. 463. Bidone, a. 350. Biela, a. 452. Biker, b. 174. Biot, b. 75, 76, 81, 223, 249. Black, b. 160, 272, 281. Blair, b. 67. Bloch, b. 425. Blondel, a. 342. Bock, b. 371. Boëthius, a. 197, 208. Boileau, a. 390. Bonaparte, b. 241, 296. Bonaventura, a. 233. Bontius, b. 422. Borelli, a. 323, 387, 393, 405, 406. Bossut, a. 350. Boué, Ami, b. 523. Bouguer, a. 377. Bouillet, b. 166. Bourdon, b. 461. Bournon, b. 326. Bouvard, a. 443. Boyle, a. 395; b. 80, 163, 263. Boze, b. 198. Bradley, a. 438, 441, 456, 463, 465. Brander, b. 508, 516. Brassavola, b. 368. Brewster, Sir David, b. 65, 75, 81, 113, 119, 123, 331, 332. Briggs, a. 276. Brisbane, Sir Thomas, a. 478. Brocchi, b. 519, 576, 589. Brochant de Villiers, b. 527, 532. Broderip, b. 562. Brongniart, Alexandre, b. 516, 530. Brongniart, Adolphe, b. 539. Brook, Taylor, a. 359, 375; b. 31. Brooke, Mr., b. 325. Brougham, Lord, b. 80, 112. Brown, Robert, b. 409, 474. Brunfels, b. 368. Bruno, Giordano, a. 272. Buat, a. 350. Buch, Leopold von, b. 523, 527, 539, 557. Buckland, Dr., b. 534. Budæus, a. 74. Buffon, b. 317, 460, 476. Bullfinger, a. 361. Bullialdus, a. 172, 397. Burckhardt, a. 442, 448. Burg, b. 443. Burkard, b. 459. Burnet, b. 559, 584.

Cabanis, b. 489. Cæsalpinus, b. 316, 371, 373. Calceolarius, b. 508. Calippus, a. 123, 140. Callisthenes, a. 144. Camerarius, Joachim, b. 372. Camerarius, Rudolph Jacob, b. 458, 459. Campanella, a. 224, 237. Campani, a. 474. Camper, b. 476. Canton, b. 197, 198, 219. Capelli, a. 435. Cappeller, b. 318. {25} Cardan, a. 313, 319, 330, 335. Carlini, a. 456. Carne, b. 538. Caroline, Queen, a. 422. Carpa, b. 445. Casræus, a. 326. Cassini, Dominic, a. 454, 462, 479; b. 33. Cassini, J., a. 439, 463. Castelli, a. 340, 342, 346, 348. Catelan, a. 358. Cavallieri, a. 430. Cavendish, a. 456; b. 204, 273, 278. Cauchy, a. 379; b. 43, 127. Caus, Solomon de, a. 332. Cesare Cesariano, a. 249. Chalid ben Abdolmalic, a. 169. Chatelet, Marquise du, a. 361. Chaussier, b. 463. Chladni, b. 40, 41. Christie, b. 254. Christina, a. 390. Chrompré, b. 304. Cicero, a. 119. Cigna, a. 376; b. 202. Clairaut, a. 367, 377, 410, 437, 451, 454; b. 67. Clarke, a. 361, 424. Cleomedes, a. 161, 167. Clusius, b. 378. Cobo, b. 379. Colombe, Ludovico delle, a. 346. Colombus, Realdus, b. 446, 450. Columna, Fabius, b. 381. Commandinus, a. 316. Comparetti, b. 79. Condamine, a. 453. Constantine of Africa, b. 367. Conti, Abbé de, a. 360. Conybeare, b. 519, 525. Copernicus, a. 257. Cosmas Indicopleustes, a. 196. Cotes, a. 366, 425. Coulomb, b. 204, 207, 209, 221. Crabtree, a. 276, 302, 304. Cramer, b. 35. Cronstedt, b. 341. **Cruickshank, b. 240. Cumming, Prof., b. 252. Cunæus, b. 196. Cuvier, b. 421, 422, 466, 478, 481, 487, 492, 516, 517, 520, 522.

D'Alembert, a. 361, 365, 367, 372, 374, 376, 378, 446; b. 33, 37. D'Alibard, b. 198. Dalton, Dr. John, b. 157, 169, 174, 285 &c., 288, &c. Daniell, b. 178, 554. Dante, a. 200. D'Arcy, a. 380. Davy, b. 291, 293, 295, 301. Daubenton, b. 476. Daubeny, Dr., b. 550. Daussy, a. 459. De Candolle, Prof., b. 408, 473. Dechen, M. von, b. 533. Defrance, b. 516, 518. Degerando, a. 194, 228. De la Beche, Sir H., b. 519. Delambre, a. 442, 447. De la Rive, Prof., b. 187. Delisle, a. 431. De Luc, b. 167, 177. Démeste, b. 319. Democritus, a. 78; b. 360. Derham, b. 165. Desaguliers, b. 193. Descartes, a. 323, 328, 338, 343, 354, 387, 423; b. 56, 59, 220. Des Hayes, b. 519. Desmarest, b. 512, 515. Dexippus, a. 208. Digges, a. 331. Dillenius, b. 402. Diogenes Laërtius, a. 187. Dioscorides, b. 364, 367. Dollond, a.475; b. 67. Dominis, Antonio de, b. 59. Dubois, b. 445. Dufay, b. 194, &c., 201. Du Four, b. 79. Dufrénoy, b. 527, 532. Dulong, b. 150, 187. Duns Scotus, a. 233, 237. Dunthorne, a. 435. Dupuis, a. 125. Durret, a. 288. {26} Dutens, a. 82. Duvernay, b. 475.

Ebn Iounis, a. 177. Encke, a. 451, 467, 483. Eratosthenes, a. 158. Ericsen, b. 167. Eristratus b. 453. Etienne, b. 445. Evelyn, a. 422. Euclid, a. 100, 101, 131, 132. Eudoxus, a. 140, 143. Euler, a. 363, 367, 370, 377, 380, 437; b. 32, 40. Eusebius, a. 195. Eustachius, b. 445, 453. Eustratus, a. 207.

Fabricius, a. 207. Fabricius of Acquapendente, b. 456. Fabricius, David, a. 300. Fallopius, b. 445. Faraday, Dr., b. 245, 254, 291, 292, 296, 302. Fermat, a. 341, 353. Fitton, Dr., b. 524. Flacourt, b. 379. Flamsteed, a. 304, 409, 410, 419, 427, 435. Fleischer, b. 57. Fontaine, a. 372. Fontenelle, a. 439; b. 265, 509. Forbes, Prof. James, b. 155. Forster, Rev. Charles, a. 243. Fourcroy, b. 278, 281. Fourier, b. 141, 147, 152, 180. Fowler, b. 242. Fracastoro, b. 507. Francis I. (king of France), a. 237. Franklin, b. 195, 197, 202. Fraunhofer, a. 472, 475; b. 68, 98. 128. Frederic II., Emperor, a. 236. Fresnel, b. 72, 92, 96, 102, 114, 115, 179. Fries, b. 418. Frontinus, a. 250. Fuchs, b. 334, 369. Fuchsel, b. 513.

Gærtner, b. 404. Galen, b. 440, 443, 444, 445, 462, 464. Galileo, a. 276, 319, 322, 324, &c., 336, 342, 345. Gall, b. 463, 465. Galvani, b. 238, 240. Gambart, a. 451. Gascoigne, a. 470. Gassendi, a. 288, 341, 390, 392; b. 33. Gauss, a. 372, 448. Gay-Lussac, b. 158, 169, 179, 283, 290. Geber, a. 178, 224. Gellibrand, b. 219. Geminus, a. 118, 143, 166. Generelli, Cirillo, b. 587. Geoffroy (botanist), b. 459. Geoffroy (chemist), b. 265. Geoffroy Saint-Hilaire, b. 477, 480, 483. George Pachymerus, a. 207. Gerbert, a. 198. Germain, Mlle. Sophie, b. 43. Germanicus, a. 168. Gessner, b. 316, 372, 508. Ghini, b. 376. Gibbon, a. 242. Gilbert, a. 274, 394; b. 192, 217, 219, 224. Giordano Bruno, a. 272, 273. Girard, a. 350. Girtanner, b. 169. Giseke, b. 398. Glisson, b. 466. Gmelin, b. 348. Godefroy of St. Victor, a. 231. Goldfuss, b. 519. Göppert, b. 578. Göthe, b. 63, 469, 473. Gough, b. 171. Graham, a. 471; b. 219. Grammatici, b. 435. Grazia, Vincenzio di, a. 346. Greenough, b. 527. Gregory, David, a. 426, 435. Gregory VII., Pope, a. 227. Gregory IX., Pope, a. 237. Gren, b. 174. Grew, b. 457, 475. Grey, b. 194. Grignon, b. 319. Grimaldi, a. 341; b. 60, 79. {27} Grotthuss, b. 304. Guericke, Otto, b. 33, 193. Guettard, b. 510. Gulielmini, b. 317. Guyton de Morveau, b. 278, 281.

Hachette, b. 350. Hadley, a. 474. Haidinger, b. 330. Halicon, a. 150. Haller, b. 401, 466. Halley, a. 354, 355, 396, 398, 421, 426, 435, 443, 450, 454, 480; b. 225. Haly, a. 222. Hamilton, Sir W. (mathem.), b. 124, 130. Hampden, Dr., a. 228. Hansen, a. 372, 374. Hansteen, b. 219. Harding, a. 448. Harris, Mr. Snow, b. 209. Harrison, a. 473. Hartsoecker, a. 474. Harvey, b. 446, 449, 456. Hausmann, b. 329. Haüy, b. 320, &c., 325, 342. Hawkesbee, b. 193, 195. Hegel, a. 415. Helmont, b. 262. Henckel, b. 318. Henslow, Professor, b. 474. Heraclitus, a. 56. Herman, Paul, b. 379. Hermann, Contractus, a. 198. Hermann, James, a. 359, 362, 363; b. 386, 387. Hermolaus Barbarus, a. 75. Hernandez, b. 379. Herodotus, a. 57; b. 361, 506. Herophilus, b. 441. Herrenschneider, b. 145. Herschel, Sir John, a. 467; b. 67, 81, 254, 333, 555, 559. Herschel, Sir William, a. 446; b. 80. Hevelius, a. 450, 471, 480. Higgins, b. 287. Hill, b. 319, 403. Hipparchus, a. 144. Hippasus, a. 107. Hippocrates, b. 438. Hoff, K. E. A. von, b. 545, 550. Hoffmann, b. 527. Home, b. 518. Homer, b. 438. Hooke, a. 324, 353, 354, 387, 395, 396, 401, 406; b. 29, 41, 62, 77, 79, 85. Hopkins, Mr. W., b. 40, 557. Horrox, a. 276, 303, 395. Hoskins, a. 355. Howard, Mr. Luke, b. 179. Hudson, b. 403. Hugo of St. Victor, a. 231. Humboldt, Alexander von, b. 219, 523, 538, 549. Humboldt, Wilhelm von, b. 240. Hunter, John, b. 476. Hutton (fossilist), b. 519. Hutton (geologist), a. 456; b. 515, 584. Huyghens, a. 337, 343, 353, 357, 377, 387, 412; b. 33, 62, 70, 86, 87. Hyginus, a. 168.

Iamblichus, a. 214. Ideler, a. 113. Ivory, a. 372.

Jacob of Edessa, a. 209. Jameson, Professor, b. 338, 514. Job, a. 124. John of Damascus, a. 206. John Philoponus, a. 206. John of Salisbury, a. 232, 234. John Scot Erigena, a. 229. Jordanus Nemorarius, a. 314, 331. Joseph, a. 226. Julian, a. 215. Jung, Joachim, b. 384. Jussieu, Adrien de, b. 407. Jussieu, Antoine Laurent de, b. 406. Jussieu, Bernard de, b. 406.

Kæmpfer, b. 379. Kant, b. 490. Kazwiri, b. 583. Keckerman, a. 235. Keill, a. 367, 426; b. 264. Kelland, Mr. Philip, b. 127, 130. {28} Kempelen, b. 47. Kepler, a. 263, 271, 290, 353, 383, &c., 415, 462; b. 55, 56. Kircher, a. 218. Kirwan, b. 274, 278. Klaproth, b. 279. Klingenstierna, a. 475; b. 67. Knaut, Christopher, b. 386. Knaut, Christian, b. 386. König, b. 519. Krafft, b. 142, 225. Kratzenstein, b. 166. Kriege, b. 380.

Lacaille, a. 442, 454. Lactantius, a. 195. Lagrange, a. 367, 369, 375, 381, 444; b. 35, 37, 39. Lamé, b. 129. La Hire, a. 439, 463. Lalande, a. 440, 447. Lamarck, b. 408, 478, 518. Lambert, b. 40, 142, 221. Landen, a. 375. Lansberg, a. 288, 302, 303. Laplace, a. 370, &c., 444, 457; b. 36, 140, 147, 184. Lasus, a. 107. Latreille, b. 485. Lavoisier, b. 274, 275, 276, &c., 280. Laughton, a. 424. Launoy, a. 236. Laurencet, b. 484. Lawrence, b. 565. Lecchi, a. 350. Leeuwenhoek, b. 457, 460. Legendre, b. 223. L'Hôpital, a. 358. Leibnitz, a. 360, 391. Le Monnier, a. 435, 437, 463. Leonardo da Vinci, a. 251, 318; b. 507, 586. Leonicenus, b. 368. Le Roi, b. 167, 178. Leslie, b. 145, 151, 181. Levy, b. 331. Leucippus, a. 78, 84. Lexell, a. 447, 452. Lhwyd, b. 508. Libri, b. 151. Lindenau, a. 440. Lindley, b. 474, 519. Linnæus, b. 318, 388, 423. Linus, b. 61. Lister, b. 509, 511. Littrow, a. 477. Lloyd, Professor, b. 125, 130. Lobel, b. 381, 408. Locke, a. 422. Longomontanus, a. 297, 302. Louville, a. 431, 439. Lubbock, a. 372, 373, 459. Lucan, a. 190. Lucas, b. 62. Lyell, b. 500, 529, 545, 560, 562, 590.

Macleay, b. 418. Magini, a. 270. Mairan, a. 361. Malpighi, b. 456. Malus, b. 71, 74. Manilius, a. 168. Maraldi, a.439; b. 79. Marcet, b. 187. Margrave, b. 422. Marinus (anatomist), b. 462. Marinus (Neoplatonist), a. 215. Marriotte, a. 343. Marsilius Ficinus, a. 238. Martianus Capella, a. 259. Martyn, T., b. 402. Mæstlin, a. 271, 287. Matthioli, b. 381. Maupertuis, a. 367, 431, 453. Mayer, Tobias, a. 165; b. 146, 206, 221. Mayo, Herbert, b. 464. Mayow, b. 277. Mazeas, b. 80, 199. MacCullagh, Professor, b. 123, 130. Meckel, b. 486. Melloni, b. 154. Menelaus, a. 167. Mersenne, a. 328, 342, 347, 390; b. 28. Messa, b. 445. Meton, a. 121. Meyranx, b. 484. Michael Scot, a. 226. Michell, b. 511. {29} Michelotti, a. 350. Miller, Professor, b. 331. Milton, a. 200, 275, 340. Mitscherlich, b. 334. Mohs, b. 326, 329, 345, &c., 349, 351. Mondino, b. 445. Monge, b. 274. Monnet, b. 510. Monnier, b. 197. Monteiro, b. 331. Montfaucon, b. 196. Morin, a. 288. Morison, b. 383. Moro, Lazzaro, b. 587. Morveau, Guyton de, b. 278, 281. Mosotti, b. 211. Munro, b. 476. Murchison, Sir Roderic, b. 530. Muschenbroek, b. 166.

Napier, a. 276, 306. Naudæus, a. 226. Naumann, b. 331, 352. Newton, a. 343, 349, 353, 355, 363, 399, &c., 420, 432, 463; b. 33, 39, 59, 70, 73, 77, 88, 142, 450. Nicephorus Blemmydes, a. 207. Nicholas de Cusa, a. 261. Nicomachus, a. 104. Nigidius Figulus, a. 219. Nobili, b. 154. Nollet, b. 196. Nordenskiöld, b. 350. Norman, b. 218. Norton, a. 331. Numa, a. 118, 261.

Odoardi, b. 513, 515. Oersted, Professor, b. 243. Œyenhausen, b. 533. Oken, Professor, b. 477. Olbers, a. 448. Orpheus, a. 214. Osiander, a. 268. Ott, b. 145. Otto Guericke, b. 193, 195. Ovid, b. 506.

Pabst von Ohain, b. 341. Packe, b. 509. Pallas, b. 476, 513. Papin, b. 173. Pappus, a. 188. Paracelsus, a. 226; b. 262. Pardies, b. 61. Pascal, a. 346. Paulus III., Pope, a. 267. Pecquet, b. 453. Pepys, a. 422. Perrier, a. 348. Peter of Apono, a. 226. Peter Bungo, a. 217. Peter Damien, a. 231. Peter the Lombard, a. 231. Peter de Vineis, a. 237. Petit, b. 149, 187. Petrarch, a. 237. Philip, Dr. Wilson, b. 454. Phillips, William, b. 325, 343, 525. Philolaus, a. 259. Photius, a. 208. Piazzi, a. 447, 485. Picard, a. 404, 464, 470; b. 33. Piccolomini, a. 336. Pictet, b. 168. Picus of Mirandula, a. 226, 238. Plana, a. 372. Playfair, a. 423. Pliny, a. 150, 187, 219; b. 316, 359, 364. Plotinus, a. 207, 213. Plunier, b. 380. Plutarch, a. 77, 187. Poisson, a. 372, 377; b. 40, 43, 182, 208, 222. Polemarchus, a. 141, 142. Poncelet, a. 350. Pond, a. 477. Pontanus, Jovianus, b. 458. Pontécoulant, a. 372. Pope, a. 427. Porphyry, a. 205, 207. Posidonius, a. 169. Potter, Mr. Richard, b. 126, 130. Powell, Prof., b. 128, 130, 154. Prevost, Pierre, b. 143. Prevost, Constant, b. 589. Prichard, Dr., b. 500, 565. {30} Priestley, b. 271, 273, 279. Proclus, a. 204, 207, 214, 217, 222. Prony, a. 350; b. 174. Proust, b. 267. Prout, Dr., b. 289, 454. Psellus, a. 208. Ptolemy a. 149, &c.; b. 26 Ptolemy Euergetes, a. 155. Purbach, a. 299. Pythagoras, a. **65, 78, 127, 217. Pytheas, a. 162.

Quetelet, M., b. 130.

Raleigh, b. 378. Ramsden, a. 471. Ramus, a. 237, 301. Raspe, b. 514, 516. Ray, b. 384, 422. Raymund Lully, a. 226. Reaumur, b. 509. Recchi, b. 379. Redi, b. 475. Reichenbach, a. 472. Reinhold, a. 269. Rennie, Mr. George, a. 350. Rheede, b. 379. Rheticus, a. 266, 269. Riccioli, a. 288, 341. Richman, b. 142, 199. Richter, b. 286. Riffault, b. 304. Riolan, b. 448. Rivinus, b. 386. Rivius, a. 250, 326. Robert Grostête, a. 198, 226. Robert of Lorraine, a. 198. Robert Marsh, a. 199. Roberval, b. 33. Robins, a. 342. Robinson, Dr., a. 477. Robison, a. 169. 173, 206. Roger Bacon, a. 199, 226, 244. Rohault, a. 391, 423. Romé de Lisle, b. 318, 319, 320, 324, 328. Römer, a. 464, 480; b. 33. Rondelet, b. 421. Roscoe, b. 409. Ross, Sir John, b. 219. Rothman, a. 264. Rouelle, b. 512, 515. Rousseau, b. 401. Rudberg, b. 127. Ruellius, b. 368. Rufus, b. 441. Rumphe, b. 379.

Saluces, a. 376. Salusbury, a. 276. Salviani, b. 421 Santbach, a. 325. Santorini, b. 462. Saron, a. 446. Savart, b. 40, 44, 245. Savile, a. 205. Saussure, b. 177, 513. Sauveur, b. 30, 37. Scheele, b. 271. Schelling, b. 63. Schlottheim, b. 514, 519. Schmidt, b. 557. Schomberg, Cardinal, a. 267. Schweigger, b. 251. Schwerd, b. 125. Scilla, b. 508. Scot, Michael, b. 367. Scrope, Mr. Poulett, b. 550. Sedgwick, Professor, b. 533, 538. Sedillot, M., a. 179. Seebeck, Dr., b. 75, 81, 252. Segner, a. 375. Seneca, a. 168, 259, 346. Sergius, a. 209. Servetus, b. 446. Sextus Empiricus, a. 193. S'Gravesande, a. 361. Sharpe, b. 174. Sherard, b. 379. Simon of Genoa, b. 367. Simplicius, a. 204, 206. Sloane, b. 380. Smith, Mr. Archibald, b. 130. Smith, Sir James Edward, b. 403. Smith, William, b. 515, 521. Snell, b. 56, 57. Socrates, b. 442. Solomon, a. 227**; b. 361. {31} Sorge, b. 38. Sosigenes, a. 118, 168. Southern, b. 174. Sowerby, b. 519. Spallanzani, b. 454. Spix, b. 477. Sprengel, b. 473. Stahl, b. 268. Stancari, b. 29. Steno, b. 317, 507, 512. Stephanus, b. 445. Stevinus, a. 317, 336, 345, 357. Stillingfleet, b. 403. Stobæus, a. 208. Stokes, Mr. C. b. 578. Strabo, a. 203; b. 363, 587. Strachey, b. 511. Stukeley, b. 511. Svanberg, b. 149. Surian, b. 380. Sylvester II. (Pope), a. 198, 227. Sylvius, b. 263, 445, 446. Symmer, b. 202. Syncellus, a. 117. Synesius, a. 166.

Tacitus, a. 220. Tartalea, b. 315, 321, 325. Tartini, b. 38. Taylor, Brook, a. 359, 375; b. 31. Tchong-Kang, a. 135, 162. Telaugé, a. 217. Tennemann, a. 228. Thales, a. 56, 57, 63, 130. Thebit, a. 226. Thenard, b. 283. Theodore Metochytes, a. 207. Theodosius, a. 168. Theophrastus, a. 205; b. 360, 362, 363, 370. Thomas Aquinas, a. 226, 232, 237. Thomson, Dr., b. 288, 289. Tiberius, a. 220. Timocharis, a. 144. Torricelli, a. 336, 340, 347, 349. Tournefort, b. 386, 458. Tostatus, a. 197. Totaril, Cardinal, a. 237. Tragus, b. 368. Trithemius, a. 228. Troughton, a. 471. Turner, b. 289. Tycho Brahe, a. 297, 302; b. 55, 56.

Ubaldi, a. 313. Ulugh Beigh, a. 178. Ungern-Sternberg, Count, b. 550. Uranus, a. 209. Ure, Dr., b. 174. Usteri, b. 473.

Vaillant, Sebastian, b. 459. Vallisneri, b. 508. Van Helmont, b. 262. Varignon, a. 344; b. 454. Varolius, b. 463. Varro, Michael, a. 314, 319, 326, 332. Vesalius, b. 444, 445, 462. Vicq d'Azyr, b. 463, 476. Vieussens, b. 463. Vincent, a. 355. Vincent of Beauvais, b. 367. Vinci, Leonardo da, a. 251, 318; b. 507. Virgil (bishop of Salzburg), a. 197. Virgil (a necromancer), a. 227. Vitello, b. 56. Vitruvius, a. 249, 251; b. 25. Viviani, a. 337, 340. Voet, a. 390. Voigt, b. 473. Volta, b. 238, 240. Voltaire, a. 361, 431. Voltz, b. 533. Von Kleist, b. 196.

Wallerius, b. 319. Wallis, a. 276, 341, 343, 387, 395; b. 37. Walmesley, a. 440. Warburton, a. 427. Ward, Seth, a. 276, 396. Wargentin, a. 441. Watson, b. 195, 196, 202. Weber, Ernest and William, b. 43. Weiss, Prof., b. 326, 327. Wells, b. 170, 177, 242. Wenzel, b. 286. {32} Werner, b. 318, 337, 341, 514, 520, 521, 528, 584. Wheatstone, b. 44. Wheler, b. 379. Whewell, a. 459; b. 330. Whiston, a. 424. Wilcke, b. 161, 198, 204. Wilkins (Bishop), a. 275, 332, 395. William of Hirsaugen, a. 198. Willis, Rev. Robert, a. 246; b. 40, 47. Willis, Thomas, b. 462, 463, 465. Willoughby, b. 422, 423. Wolf, Caspar Frederick, b. 472. Wolff, a. 361; b. 165. Wollaston, b. 68, 70, 71, 81, 288, 325. Woodward, b. 508, 511, 584. Wren, a. 276, 343, 395; b. 421. Wright, a. 435.

Xanthus, b. 360.

Yates, b. 219. Young, Thomas, a. 350; b. 43, 92, &c., 111, 112.

Zabarella, a. 235. Zach, a. 448. Ziegler, b. 174. Zimmerman, b. 557.

{{33}} INDEX OF TECHNICAL TERMS.

Aberration, a. 464. Absolute and relative, a. 69. Accelerating force, a. 326. Achromatism, b. 66. Acid, b. 263. Acoustics, b. 24. Acronycal rising and setting, a. 131. Action and reaction, a. 343. Acuation, b. 319. Acumination, b. 319. Acute harmonics, b. 37. Ætiology, b. 499. Affinity (in Chemistry), b. 265. " (in Natural History), b. 418. Agitation, Centre of, a. 357. Alidad, a. 184. Alineations, a. 158, 161. Alkali, b. 262. Almacantars, a. **181. Almagest, a. 170. Almanac, a. **181. Alphonsine tables, a. 178. Alternation (of formations), b. 538. Amphoteric silicides, b. 352. Analogy (in Natural History), b. 418. Analysis (chemical), b. 262. " (polar, of light), b. 80. Angle of cleavage, b. 322. " incidence, b. 53. " reflection, b. 53. Animal electricity, b. 238. Anïon, b. 298. Annus, a. 113. Anode, b. 298. Anomaly, a. 139, 141. Antarctic circle, a. 131. Antichthon, a. 82. Anticlinal line, b. 537. Antipodes, a. 196. Apogee, a. 146. Apotelesmatic astrology, a. 222. Apothecæ, b. 366. Appropriate ideas, a. 87. Arctic circle, a. 131. Armed magnets, b. 220. Armil, a. 163. Art and science, a. 239. Articulata, b. 478. Artificial magnets, b. 220. Ascendant, a. 222. Astrolabe, a. 164. Atmology, b. 137, 163. Atom, a. 78. Atomic theory, b. 285. Axes of symmetry (of crystals), b. 327. Axis (of a mountain chain), b. 537. Azimuth, a. **181. Azot, b. 276.

Ballistics, a. 365. Bases (of salts), b.264. Basset (of strata), b. 512. Beats, b. 29.

Calippic period, a. 123. Caloric, b. 143. Canicular period, a. 118. Canon, a. 147. Capillary action, a. 377. Carbonic acid gas, b. 276 Carolinian tables, a. 304. Catasterisms, a. 158. Categories, a. 206. Cathïon, b. 298. Cathode, b. 298. Catïon, b. 298. Causes, Material, formal, efficient, final, a. 73. {34} Centrifugal force, a. 330. Cerebral system, b. 463. Chemical attraction, b. 264. Chyle, b. 453. Chyme, b. 453. Circles of the sphere, a. 128. Circular polarization, b. 82, 119. " progression (in Natural History), b. 418. Civil year, a. 117. Climate, b. 146. Coexistent vibrations, a. 376. Colures, a. 131. Conditions of existence (of animals), b. 483, 492. Conducibility, b. 143. Conductibility, b. 143. Conduction, b. 139. Conductivity, b. 143. Conductors, b. 194. Conical refraction, b. 124. Conservation of areas, a. 380. Consistence (in Thermotics), b. 160. Constellations, a. 124. Constituent temperature, b. 170. Contact-theory of the Voltaic pile, b. 295. Cor (of plants), b. 374. Cosmical rising and setting, a. 131. Cotidal lines, a. 460. Craters of elevation, b. 556.

Dæmon, a. 214. D'Alembert's principle, a. 365. Day, a. 112. Decussation of nerves, b. 462. Deduction, a. 48. Deferent, a. 175. Definite proportions (in Chemistry), b. 285. Delta, b. 546. Dephlogisticated air, b. 273. Depolarization, b. 80. " of heat, b. 155. Depolarizing axes, b. 81. Descriptive phrase (in Botany), b. 393. Dew, b. 177. Dichotomized, a. 137. Diffraction, b. 79. Dimorphism, b. 336. Dioptra, a. 165. Dipolarization, b. 80, 82. Direct motion of planets, a. 138. Discontinuous functions, b. 36. Dispensatoria, b. 366. Dispersion (of light), b. 126. Doctrine of the sphere, a. 130. Dogmatic school (of medicine), b. 439. Double refraction, b. 69.

Eccentric, a. 145. Echineis, a. 190. Eclipses, a. 135. Effective forces, a. 359. Elective attraction, b. 265. Electrical current, b. 242. Electricity, b. 192. Electrics, b. 194. Electrical tension, b. 242. Electro-dynamical, b. 246. Electrodes, b. 298. Electrolytes, b. 298. Electro-magnetism, b. 243. Elements (chemical), b. 309. Elliptical polarization, b. 122, 123. Empiric school (of medicine), b. 439. Empyrean, a. 82. Enneads, a. 213. Entelechy, a. 74. Eocene, b. 529. Epicycles, a. 140, 145 Epochs, a. 46. Equant, a. 175. Equation of time, a. 159. Equator, a. 130. Equinoctial points, a. 131. Escarpment, b. 537. Evection, a. 171, 172. Exchanges of heat, Theory of, b. 143.

Facts and ideas, a. 43. Faults (in strata), b. 537. Final causes, b. 442, 492. Finite intervals (hypothesis of), b. 126. First law of motion, a. 322. Fits of easy transmission, b. 77, 89. Fixed air, b. 272. Fixity of the stars, a. 158. {35} Formal optics, b. 52. Franklinism, b. 202. Fresnel's rhomb, b. 105. Fringes of shadows, b. 79, 125. Fuga vacui, a. 347. Full months, a. 122. Function (in Physiology), b. 435.

Galvanism, b. 239. Galvanometer, b. 251. Ganglionic system, b. 463. Ganglions, b. 463. Generalization, a. 46. Geocentric theory, a. 258. Gnomon, a. 162. Gnomonic, a. 137. Golden number, a. 123. Grave harmonics, b. 38. Gravitate, a. 406.

Habitations (of plants), b. 562. Hæcceity, a. 233. Hakemite tables, a. 177. Halogenes, b. 308. Haloide, b. 352. Harmonics, Acute, b. 37. " Grave, b. 38. Heat, b. 139. " Latent, b. 160. Heccædecaëteris, a. 121. Height of a homogeneous atmosphere, b. 34. Heliacal rising and setting, a. 131. Heliocentric theory, a. 258. Hemisphere of Berosus, a. 162. Hollow months, a. 122. Homoiomeria, a. 78. Horizon, a. 131. Horoscope, a. 222. Horror of a vacuum, a. 346. Houses (in Astrology), a. 222. Hydracids, b. 283. Hygrometer, b. 177. Hygrometry, b. 138. Hypostatical principles, b. 262.

Iatro-chemists, b. 263. Ideas of the Platonists, a. 75. Ilchanic tables, a. 178. Impressed forces, a. 359. Inclined plane, a. 313. Induction (electric), b. 197. " (logical), a. 43. Inductive, a. 42. " charts, a. 47. " epochs, a. 46. Inflammable air, b. 273. Influences, a. 219. Intercalation, a. 118. Interferences, b. 86, 93. Ionic school, a. 56. Isomorphism, b. 334. Isothermal lines, b. 146, 538. Italic school, a. 56.

Joints (in rocks), b. 537. Judicial astrology, a. 222. Julian calendar, a. 118.

Lacteals, b. 453. Latent heat, b. 160. Laws of motion, first, a. 322. " " second, a. 330. " " third, a. 334. Leap year, a. 118. Leyden phial, b. 196. Librations (of planets), a. 297. Libration of Jupiter's Satellites, a. 441. Limb of an instrument, a. 162. Longitudinal vibrations, b. 44. Lunisolar year, a. 120. Lymphatics, b. 453.

Magnetic elements, b. 222. " equator, b. 219. Magnetism, b. 217. Magneto-electric induction, b. 256. Matter and form, a. 73. Mean temperature, b. 146. Mechanical mixture of gases, b. 172. Mechanico-chemical sciences, b. 191. Meiocene, b. 529. Meridian line, a. 164. Metals, b. 306, 307. Meteorology, b. 138. Meteors, a. 86. Methodic school (of medicine), b. 439. {36} Metonic cycle, a. 122. Mineral alkali, b. 264. Mineralogical axis, b. 537. Minutes, a. 163. Miocene, b. 529. Mollusca, b. 478. Moment of inertia, a. 356. Momentum, a. 337, 338. Moon's libration, a. 375. Morphology, b. 469, 474. Movable polarization, b. 105. Multiple proportions (in Chemistry), b. 285. Music of the spheres, a. 82. Mysticism, a. 209, 211.

Nadir, a. **182. Nebular hypothesis, b. 501. Neoplatonists, a. 207. Neutral axes, b. 81. Neutralization (in Chemistry), b. 263. Newton's rings, b. 77, 124. " scale of color, b. 77. Nitrous air, b. 273. Nomenclature, b. 389. Nominalists, a. 238. Non-electrics, b. 194. Numbers of the Pythagoreans, a. 82, 216. Nutation, a. 465. Nycthemer, a. 159.

Octaëteris, a. 121. Octants, a. 180. Oolite, b. 529. Optics, b. 51, &c. Organical sciences, b. 435. Organic molecules, b. 460. Organization, b. 435. Oscillation, Centre of, a. 356. Outcrop (of strata), b. 512. Oxide, b. 282. Oxyd, b. 282. Oxygen, b. 276.

Palæontology, b. 519. Palætiological sciences, b. 499. Parallactic instrument, a. 165. Parallax, a. 159. Percussion, Centre of, a. 357. Perfectihabia, a. 75. Perigee, a. 146. Perijove, a. 446. Periodical colors, b. 93. Phases of the moon, a. 134. Philolaic tables, a. 304. Phlogisticated air, b. 273. Phlogiston, b. 268. Phthongometer, b. 47. Physical optics, b. 52. Piston, a. 346. Plagihedral faces, b. 82. Plane of maximum areas, b. 380. Pleiocene, b. 529. Plesiomorphous, b. 335. Plumb line, a. 164. Pneumatic trough, b. 273. Poikilite, b. 530. Polar decompositions, b. 293. Polarization, b. 72, 74. " Circular, b. 82, 119. " Elliptical, b. 122, 124. " Movable, b. 105. " Plane, b. 120. " of heat, b. 153. Poles (voltaic), b. 298. " of maximum cold, b. 146. Potential levers, a. 318. Power and act, a. 74. Precession of the equinoxes, a. 155. Predicables, a. 205. Predicaments, a. 206. Preludes of epochs, a. 46. Primary rocks, b. 513. Primitive rocks, b. 513. Primum calidum, a. 77. Principal plane (of a rhomb), b. 73. Principle of least action, a. 380. Prosthapheresis, a. 146. Provinces (of plants and animals), b. 562. Prutenic tables, a. 270. Pulses, b. 33. Pyrites, b. 352.

Quadrant, a. 164 Quadrivium, a. 199. Quiddity, a. 234. {37} Quinary division (in Natural History), b. 418. Quintessence, a. 73.

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.

{{39}} A HISTORY OF THE INDUCTIVE SCIENCES.

INTRODUCTION.

"A just story of learning, containing the antiquities and originals of KNOWLEDGES, and their sects; their inventions, their diverse administrations and managings; their flourishings, their oppositions, decays, depressions, oblivions, removes; with the causes and occasions of them, and all other events concerning learning, throughout all ages of the world; I may truly affirm to be wanting.

"The use and end of which work I do not so much design for curiosity, or satisfaction of those that are the lovers of learning: but chiefly for a more serious and grave purpose; which is this, in few words--that it will make learned men more wise in the use and administration of learning." BACON, Advancement of Learning, book ii.

{{41}} INTRODUCTION.

IT is my purpose to write the History of some of the most important of the Physical Sciences, from the earliest to the most recent periods. I shall thus have to trace some of the most remarkable branches of human knowledge, from their first germ to their growth into a vast and varied assemblage of undisputed truths; from the acute, but fruitless, essays of the early Greek Philosophy, to the comprehensive systems, and demonstrated generalizations, which compose such sciences as the Mechanics, Astronomy, and Chemistry, of modern times.

The completeness of historical view which belongs to such a design, consists, not in accumulating all the details of the cultivation of each science, but in marking the larger features of its formation. The historian must endeavor to point out how each of the important advances was made, by which the sciences have reached their present position; and when and by whom each of the valuable truths was obtained, of which the aggregate now constitutes a costly treasure.

Such a task, if fitly executed, must have a well-founded interest for all those who look at the existing condition of human knowledge with complacency and admiration. The present generation finds itself the heir of a vast patrimony of science; and it must needs concern us to know the steps by which these possessions were acquired, and the documents by which they are secured to us and our heirs forever. Our species, from the time of its creation, has been travelling onwards in pursuit of truth; and now that we have reached a lofty and commanding position, with the broad light of day around us, it must be grateful to look back on the line of our vast progress;--to review the journey, begun in early twilight amid primeval wilds; for a long time continued with slow advance and obscure prospects; and gradually and in later days followed along more open and lightsome paths, in a wide and fertile region. The historian of science, from early periods to the present times, may hope for favor on the score of the mere subject of his narrative, and in virtue of the curiosity which the men {42} of the present day may naturally feel respecting the events and persons of his story.

But such a survey may possess also an interest of another kind; it may be instructive as well as agreeable; it may bring before the reader the present form and extent, the future hopes and prospects of science, as well as its past progress. The eminence on which we stand may enable us to see the land of promise, as well as the wilderness through which we have passed. The examination of the steps by which our ancestors acquired our intellectual estate, may make us acquainted with our expectations as well as our possessions;--may not only remind us of what we have, but may teach us how to improve and increase our store. It will be universally expected that a History of Inductive Science should point out to us a philosophical distribution of the existing body of knowledge, and afford us some indication of the most promising mode of directing our future efforts to add to its extent and completeness.

To deduce such lessons from the past history of human knowledge, was the intention which originally gave rise to the present work. Nor is this portion of the design in any measure abandoned; but its execution, if it take place, must be attempted in a separate and future treatise, On the Philosophy of the Inductive Sciences. An essay of this kind may, I trust, from the progress already made in it, be laid before the public at no long interval after the present history.[1\1]

Though, therefore, many of the principles and maxims of such a work will disclose themselves with more or less of distinctness in the course of the history on which we are about to enter, the systematic and complete exposition of such principles must be reserved for this other treatise. My attempts and reflections have led me to the opinion, that justice cannot be done to the subject without such a division of it.

To this future work, then, I must refer the reader who is disposed to require, at the outset, a precise explanation of the terms which occur in my title. It is not possible, without entering into this philosophy, to explain adequately how science which is INDUCTIVE differs from that which is not so; or why some portions of knowledge may properly be selected from the general mass and termed SCIENCE. It will be sufficient at present to say, that the sciences of which we have {43} here to treat, are those which are commonly known as the Physical Sciences; and that by Induction is to be understood that process of collecting general truths from the examination of particular facts, by which such sciences have been formed.

There are, however, two or three remarks, of which the application will occur so frequently, and will tend so much to give us a clearer view of some of the subjects which occur in our history, that I will state them now in a brief and general manner.

Facts and Ideas.[2\1]--In the first place then, I remark, that, to the formation of science, two things are requisite;--Facts and Ideas; observation of Things without, and an inward effort of Thought; or, in other words, Sense and Reason. Neither of these elements, by itself can constitute substantial general knowledge. The impressions of sense, unconnected by some rational and speculative principle, can only end in a practical acquaintance with individual objects; the operations of the rational faculties, on the other hand, if allowed to go on without a constant reference to external things, can lead only to empty abstraction and barren ingenuity. Real speculative knowledge demands the combination of the two ingredients;--right reason, and facts to reason upon. It has been well said, that true knowledge is the interpretation of nature; and therefore it requires both the interpreting mind, and nature for its subject; both the document, and the ingenuity to read it aright. Thus invention, acuteness, and connection of thought, are necessary on the one hand, for the progress of philosophical knowledge; and on the other hand, the precise and steady application of these faculties to facts well known and clearly conceived. It is easy to point out instances in which science has failed to advance, in consequence of the absence of one or other of these requisites; indeed, by far the greater part of the course of the world, the history of most times and most countries, exhibits a condition thus stationary with respect to knowledge. The facts, the impressions on the senses, on which the first successful attempts at physical knowledge proceeded, were as well known long before the time when they were thus turned to account, as at that period. The motions of the stars, and the effects of weight, were familiar to man before the rise of the Greek Astronomy and Mechanics: but the "diviner mind" was still absent; the act of thought had not been exerted, by which these facts were bound together under the form of laws and principles. And even at {44} this day, the tribes of uncivilized and half-civilized man, over the whole face of the earth, have before their eyes a vast body of facts, of exactly the same nature as those with which Europe has built the stately fabric of her physical philosophy; but, in almost every other part of the earth, the process of the intellect by which these facts become science, is unknown. The scientific faculty does not work. The scattered stones are there, but the builder's hand is wanting. And again, we have no lack of proof that mere activity of thought is equally inefficient in producing real knowledge. Almost the whole of the career of the Greek schools of philosophy; of the schoolmen of Europe in the middle ages; of the Arabian and Indian philosophers; shows us that we may have extreme ingenuity and subtlety, invention and connection, demonstration and method; and yet that out of these germs, no physical science may be developed. We may obtain, by such means, Logic and Metaphysics, and even Geometry and Algebra; but out of such materials we shall never form Mechanics and Optics, Chemistry and Physiology. How impossible the formation of these sciences is without a constant and careful reference to observation and experiment;--how rapid and prosperous their progress may be when they draw from such sources the materials on which the mind of the philosopher employs itself;--the history of those branches of knowledge for the last three hundred years abundantly teaches us.

Accordingly, the existence of clear Ideas applied to distinct Facts will be discernible in the History of Science, whenever any marked advance takes place. And, in tracing the progress of the various provinces of knowledge which come under our survey, it will be important for us to see that, at all such epochs, such a combination has occurred; that whenever any material step in general knowledge has been made,--whenever any philosophical discovery arrests our attention,--some man or men come before us, who have possessed, in an eminent degree, a clearness of the ideas which belong to the subject in question, and who have applied such ideas in a vigorous and distinct manner to ascertained facts and exact observations. We shall never proceed through any considerable range of our narrative, without having occasion to remind the reader of this reflection.

Successive Steps in Science.[3\1]--But there is another remark which we must also make. Such sciences as we have here to do with are, {45} commonly, not formed by a single act;--they are not completed by the discovery of one great principle. On the contrary, they consist in a long-continued advance; a series of changes; a repeated progress from one principle to another, different and often apparently contradictory. Now, it is important to remember that this contradiction is apparent only. The principles which constituted the triumph of the preceding stages of the science, may appear to be subverted and ejected by the later discoveries, but in fact they are (so far as they were true) taken up in the subsequent doctrines and included in them. They continue to be an essential part of the science. The earlier truths are not expelled but absorbed, not contradicted but extended; and the history of each science, which may thus appear like a succession of revolutions, is, in reality, a series of developments. In the intellectual, as in the material world,

Omnia mutantur nil interit . . . . . Nec manet ut fuerat nec formas servat easdem, Sed tamen ipsa eadem est.

All changes, naught is lost; the forms are changed, And that which has been is not what it was, Yet that which has been is.

Nothing which was done was useless or unessential, though it ceases to be conspicuous and primary.

Thus the final form of each science contains the substance of each of its preceding modifications; and all that was at any antecedent period discovered and established, ministers to the ultimate development of its proper branch of knowledge. Such previous doctrines may require to be made precise and definite, to have their superfluous and arbitrary portions expunged, to be expressed in new language, to be taken up into the body of science by various processes;--but they do not on such accounts cease to be true doctrines, or to form a portion of the essential constituents of our knowledge.

Terms record Discoveries.[4\1]--The modes in which the earlier truths of science are preserved in its later forms, are indeed various. From being asserted at first as strange discoveries, such truths come at last to be implied as almost self-evident axioms. They are recorded by some familiar maxim, or perhaps by some new word or phrase, which becomes part of the current language of the philosophical world; and thus asserts a principle, while it appears merely to indicate a transient {46} notion;--preserves as well as expresses a truth;--and, like a medal of gold, is a treasure as well as a token. We shall frequently have to notice the manner in which great discoveries thus stamp their impress upon the terms of a science; and, like great political revolutions, are recorded by the change of the current coin which has accompanied them.

Generalization.--The great changes which thus take place in the history of science, the revolutions of the intellectual world, have, as a usual and leading character, this, that they are steps of generalization; transitions from particular truths to others of a wider extent, in which the former are included. This progress of knowledge, from individual facts to universal laws,--from particular propositions to general ones,--and from these to others still more general, with reference to which the former generalizations are particular,--is so far familiar to men's minds, that, without here entering into further explanation, its nature will be understood sufficiently to prepare the reader to recognize the exemplifications of such a process, which he will find at every step of our advance.

Inductive Epochs; Preludes; Sequels.--In our history, it is the progress of knowledge only which we have to attend to. This is the main action of our drama; and all the events which do not bear upon this, though they may relate to the cultivation and the cultivators of philosophy, are not a necessary part of our theme. Our narrative will therefore consist mainly of successive steps of generalization, such as have just been mentioned. But among these, we shall find some of eminent and decisive importance, which have more peculiarly influenced the fortunes of physical philosophy, and to which we may consider the rest as subordinate and auxiliary. These primary movements, when the Inductive process, by which science is formed, has been exercised in a more energetic and powerful manner, may be distinguished as the Inductive Epochs of scientific history; and they deserve our more express and pointed notice. They are, for the most part, marked by the great discoveries and the great philosophical names which all civilized nations have agreed in admiring. But, when we examine more clearly the history of such discoveries, we find that these epochs have not occurred suddenly and without preparation. They have been preceded by a period, which we may call their Prelude during which the ideas and facts on which they turned were called into action;--were gradually evolved into clearness and connection, permanency and certainty; till at last the discovery which marks the epoch, seized and fixed forever the truth which had till then been obscurely and {47} doubtfully discerned. And again, when this step has been made by the principal discoverers, there may generally be observed another period, which we may call the Sequel of the Epoch, during which the discovery has acquired a more perfect certainty and a more complete development among the leaders of the advance; has been diffused to the wider throng of the secondary cultivators of such knowledge, and traced into its distant consequences. This is a work, always of time and labor, often of difficulty and conflict. To distribute the History of science into such Epochs, with their Preludes and Sequels, if successfully attempted, must needs make the series and connections of its occurrences more distinct and intelligible. Such periods form resting-places, where we pause till the dust of the confused march is laid, and the prospect of the path is clear.

Inductive Charts.[5\1]--Since the advance of science consists in collecting by induction true general laws from particular facts, and in combining several such laws into one higher generalization, in which they still retain their truth; we might form a Chart, or Table, of the progress of each science, by setting down the particular facts which have thus been combined, so as to form general truths, and by marking the further union of these general truths into others more comprehensive. The Table of the progress of any science would thus resemble the Map of a River, in which the waters from separate sources unite and make rivulets, which again meet with rivulets from other fountains, and thus go on forming by their junction trunks of a higher and higher order. The representation of the state of a science in this form, would necessarily exhibit all the principal doctrines of the science; for each general truth contains the particular truths from which it was derived, and may be followed backwards till we have these before us in their separate state. And the last and most advanced generalization would have, in such a scheme, its proper place and the evidence of its validity. Hence such an Inductive Table of each science would afford a criterion of the correctness of our distribution of the inductive Epochs, by its coincidence with the views of the best judges, as to the substantial contents of the science in question. By forming, therefore, such Inductive Tables of the principal sciences of which I have here to speak, and by regulating by these tables, my views of the history of the sciences, I conceive that I have secured the distribution of my {48} history from material error; for no merely arbitrary division of the events could satisfy such conditions. But though I have constructed such charts to direct the course of the present history, I shall not insert them in the work, reserving them for the illustration of the philosophy of the subject; for to this they more properly belong, being a part of the Logic of Induction.